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  • 1.
    Amagasaki, Kenichi
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Kaneto, Hideaki
    Osaka University Graduate School of Medicine, Department of Internal Medicine and Therapeutics (A8), 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    c-Jun N-terminal kinase is necessary for platelet-derived growth factor-mediated chemotaxis in primary fibroblasts2006In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 281, no 31, p. 22173-22179Article in journal (Refereed)
    Abstract [en]

    c-Jun N-terminal kinase (JNK) is a member of the mitogen-activated protein kinase family. It has become clear that JNK does not only have a role in induction of stress responses but also in processes such as cell movement. In this report we demonstrate that JNK activity is necessary for platelet-derived growth factor (PDGF)-BB-induced chemotaxis of primary foreskin fibroblasts and in other cell types. PDGF-BB stimulation was found to lead to activation of JNK with a maximum after 30 min. Inhibition of JNK reduced Ser178 phosphorylation of the focal adhesion component paxillin. Paxillin phosphorylation at this site has been shown to be involved in the dynamics of focal adhesions and consequently cell migration. Moreover, we observed localization of JNK to the actin-dense membrane ruffles induced by PDGF-BB stimulation both using immunofluorescence staining and green fluorescent protein-tagged JNK. This suggests a role for JNK at the leading edge of the cell compatible with a function in cell migration. Furthermore, we show that phosphatidylinositol 3-kinase (PI 3-kinase), which has an established role in PDGF-stimulated cell migration, is necessary for PDGF-induced activation of JNK. In conclusion, JNK is a critical component downstream of PI 3-kinase that may be involved in PDGF-stimulated chemotaxis presumably by modulating the integrity of focal adhesions by phosphorylating its components.

  • 2.
    Arora, Deepika
    et al.
    Institute of Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany.
    Köthe, Susanne
    Institute of Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany.
    van den Eijnden, Monique
    Merck Serono, Geneva 1202, Switzerland.
    van Huijsduijnen, Rob Hooft
    Merck Serono, Geneva 1202, Switzerland.
    Heidel, Florian
    Department of Hematology/Oncology, Otto-von Guericke-University, Magdeburg, Germany.
    Fischer, Thomas
    Department of Hematology/Oncology, Otto-von Guericke-University, Magdeburg, Germany.
    Scholl, Sebastian
    Department of Hematology/Oncology, Clinic for Internal Medicine II, Jena University Hospital, Jena, Germany.
    Tölle, Benjamin
    Institute of Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany.
    Böhmer, Sylvia-Annette
    Institute of Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Isken, Fabienne
    Department of Medicine A, Hematology and Oncology, University of Münster, Münster, Germany.
    Müller-Tidow, Carsten
    Department of Medicine A, Hematology and Oncology, University of Münster, Münster, Germany.
    Böhmer, Frank-D
    Institute of Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany.
    Expression of protein-tyrosine phosphatases in Acute Myeloid Leukemia cells: FLT3 ITD sustains high levels of DUSP6 expression2012In: Cell Communication and Signaling, ISSN 1478-811X, E-ISSN 1478-811X, Vol. 10, no 1, p. 19-Article in journal (Refereed)
    Abstract [en]

    Protein-tyrosine phosphatases (PTPs) are important regulators of cellular signaling and changes in PTP activity can contribute to cell transformation. Little is known about the role of PTPs in Acute Myeloid Leukemia (AML). The aim of this study was therefore to establish a PTP expression profile in AML cells and to explore the possible role of FLT3 ITD (Fms-like tyrosine kinase 3 with internal tandem duplication), an important oncoprotein in AML for PTP gene expression. PTP mRNA expression was analyzed in AML cells from patients and in cell lines using a RT-qPCR platform for detection of transcripts of 92 PTP genes. PTP mRNA expression was also analyzed based on a public microarray data set for AML patients. Highly expressed PTPs in AML belong to all PTP subfamilies. Very abundantly expressed PTP genes include PTPRC, PTPN2, PTPN6, PTPN22, DUSP1, DUSP6, DUSP10, PTP4A1, PTP4A2, PTEN, and ACP1. PTP expression was further correlated with the presence of FLT3 ITD, focusing on a set of highly expressed dual-specificity phosphatases (DUSPs). Elevated expression of DUSP6 in patients harboring FLT3 ITD was detected in this analysis. The mechanism and functional role of FLT3 ITD-mediated upregulation of DUSP6 was then explored using pharmacological inhibitors of FLT3 ITD signal transduction and si/shRNA technology in human and murine cell lines. High DUSP6 expression was causally associated with the presence of FLT3 ITD and dependent on FLT3 ITD kinase activity and ERK signaling. DUSP6 depletion moderately increased ERK1/2 activity but attenuated FLT3 ITD-dependent cell proliferation of 32D cells. In conclusion, DUSP6 may play a contributing role to FLT3 ITD-mediated cell transformation.

  • 3.
    Eger, Glenda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Papadopoulos, Natalia
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    NR4A1 Promotes PDGF-BB-Induced Cell Colony Formation in Soft Agar2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 9, p. e109047-Article in journal (Refereed)
    Abstract [en]

    The fibroblast mitogen platelet-derived growth factor -BB (PDGF-BB) induces a transient expression of the orphan nuclear receptor NR4A1 (also named Nur77, TR3 or NGFIB). The aim of the present study was to investigate the pathways through which NR4A1 is induced by PDGF-BB and its functional role. We demonstrate that in PDGF-BB stimulated NIH3T3 cells, the MEK1/2 inhibitor CI-1040 strongly represses NR4A1 expression, whereas Erk5 downregulation delays the expression, but does not block it. Moreover, we report that treatment with the NF-κB inhibitor BAY11-7082 suppresses NR4A1 mRNA and protein expression. The majority of NR4A1 in NIH3T3 was found to be localized in the cytoplasm and only a fraction was translocated to the nucleus after continued PDGF-BB treatment. Silencing NR4A1 slightly increased the proliferation rate of NIH3T3 cells; however, it did not affect the chemotactic or survival abilities conferred by PDGF-BB. Moreover, overexpression of NR4A1 promoted anchorage-independent growth of NIH3T3 cells and the glioblastoma cell lines U-105MG and U-251MG. Thus, whereas NR4A1, induced by PDGF-BB, suppresses cell growth on a solid surface, it increases anchorage-independent growth.

  • 4.
    Ekerljung, Lina
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Gedda, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    The HER2-binding Affibody Molecule (ZHER2:342)2 Increases Radiosensitivity in SKBR-3 cells2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 11, p. e49579-Article in journal (Refereed)
    Abstract [en]

    We have previously shown that the HER2-specific affibody molecule (ZHER2:342)2 inhibits proliferation of SKBR-3 cells. Here, we continue to investigate its biological effects in vitro by studying receptor dimerization and clonogenic survival following irradiation. We found that (ZHER2:342)2 sensitizes the HER2-overexpressing cell line SKBR-3 to ionizing radiation. The survival after exposure to (ZHER2:342)2 and 8 Gy (S8Gy 0.006) was decreased by a factor of 4 compared to the untreated (S8Gy 0.023). The low HER2-expressing cell line MCF-7 was more radiosensitive than SKBR-3 but did not respond to (ZHER2:342)2. Treatment by (ZHER2:342)2 strongly increased the levels of dimerized and phosphorylated HER2 already after 5 minutes of stimulation. The monomeric ZHER2:342 does not seem to be able to induce receptor phosphorylation and dimerization or sensitize cells to irradiation.

  • 5.
    Ekman, Simon
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Activation of growth factor receptors in esophageal cancer: implications for therapy2007In: The Oncologist, ISSN 1083-7159, E-ISSN 1549-490X, Vol. 12, no 10, p. 1165-1177Article, review/survey (Refereed)
    Abstract [en]

    Esophageal cancer is a highly aggressive disease and is the seventh most common cause of cancer-related death in the western world. Worldwide, it ranks as the sixth most frequent cause of cancer death. Despite advances in surgical techniques and treatment, the prognosis of esophageal cancer remains poor, with very few long-term survivors. The need for novel strategies to detect esophageal cancer earlier and to improve current therapy is urgent. It is well established that growth factors and growth factor receptor-mediated signaling pathways are important components of the transformation process in many forms of cancer, including esophageal cancer. With the recent advances in drug development, there are emerging possibilities to use growth factor signal transduction pathways in targeted therapy. This review provides a summary of the role of growth factors and their receptors in esophageal cancer and discusses their potential roles as biomarkers and as targets in therapy.

  • 6.
    Heldin, Carl-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Structural and functional properties of platelet-derived growth factor and stem cell factor receptors2013In: Cold Spring Harbor Perspectives in Biology, ISSN 1943-0264, E-ISSN 1943-0264, Vol. 5, no 8, p. UNSP a009100-Article in journal (Refereed)
    Abstract [en]

    The receptors for platelet-derived growth factor (PDGF) and stem cell factor (SCF) are members of the type III class of PTK receptors, which are characterized by five Ig-like domains extracellularly and a split kinase domain intracellularly. The receptors are activated by ligand-induced dimerization, leading to autophosphorylation on specific tyrosine residues. Thereby the kinase activities of the receptors are activated and docking sites for downstream SH2 domain signal transduction molecules are created; activation of these pathways promotes cell growth, survival, and migration. These receptors mediate important signals during the embryonal development, and control tissue homeostasis in the adult. Their overactivity is seen in malignancies and other diseases involving excessive cell proliferation, such as atherosclerosis and fibrotic diseases. In cancer, mutations of PDGF and SCF receptors-including gene fusions, point mutations, and amplifications-drive subpopulations of certain malignancies, such as gastrointestinal stromal tumors, chronic myelomonocytic leukemia, hypereosinophilic syndrome, glioblastoma, acute myeloid leukemia, mastocytosis, and melanoma.

  • 7.
    Heldin, Carl-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Hellberg, Carina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Feedback Control: The role of negative feedback in signal transduction control2008In: European Journal of Human Genetics, ISSN 1018-4813, E-ISSN 1476-5438, Vol. 16, no 7, p. 769-770Article in journal (Other academic)
    Abstract [en]

    -

  • 8.
    Heldin, Carl-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Westermark, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology.
    Involvement of platelet-derived growth factor ligands and receptors in tumorigenesis2018In: Journal of Internal Medicine, ISSN 0954-6820, E-ISSN 1365-2796, Vol. 283, no 1, p. 16-44Article, review/survey (Refereed)
    Abstract [en]

    Platelet-derived growth factor (PDGF) isoforms and their receptors have important roles during embryogenesis, particularly in the development of various mesenchymal cell types in different organs. In the adult, PDGF stimulates wound healing and regulates tissue homeostasis. However, overactivity of PDGF signalling is associated with malignancies and other diseases characterized by excessive cell proliferation, such as fibrotic conditions and atherosclerosis. In certain tumours, genetic or epigenetic alterations of the genes for PDGF ligands and receptors drive tumour cell proliferation and survival. Examples include the rare skin tumour dermatofibrosarcoma protuberance, which is driven by autocrine PDGF stimulation due to translocation of a PDGF gene, and certain gastrointestinal stromal tumours and leukaemias, which are driven by constitute activation of PDGF receptors due to point mutations and formation of fusion proteins ofthe receptors, respectively. Moreover, PDGF stimulates cells in tumour stroma and promotes angiogenesis as well as the development of cancer-associated fibroblasts, both of which promote tumour progression. Inhibitors of PDGF signalling may thus be of clinical usefulness in the treatment of certain tumours.

  • 9.
    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.

  • 10.
    Hägg, Maria
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Liljegren, Åsa
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Carlsson, Jörgen
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Rönnstrand, Lars
    Ludwiginstitutet för Cancerforskning.
    Lennartsson, Johan
    Ludwiginstitutet för Cancerforskning.
    EGF and dextran-conjugated EGF induces differential phosphorylation of the EGF receptor2002In: International Journal of Molecular Medicine, ISSN 1107-3756, E-ISSN 1791-244X, Vol. 10, no 5, p. 655-659Article in journal (Refereed)
    Abstract [en]

    Dextran-conjugated EGF (EGF-dextran) has a potential use for targeted radionuclide therapy of tumors that overexpress the epidermal growth factor receptor (EGFR). There are plans to treat both bladder carcinomas and malignant gliomas with local injections of radiolabeled EGF-dextran since these tumors often express high levels of EGFR. In this report we show that EGF and EGF-dextran differentially activate the EGFR. In the human glioma cell line U-343, activation of the serine/threonine kinases Erk and Akt is identical upon stimulation with EGF or EGF-dextran. However, the effect on phospholipase Cgamma1 (PLCgamma1) phosphorylation differs. In cells stimulated with EGF-dextran, the PLCgamma1 phosphorylation is lower than in cells stimulated with EGF. This observation could be explained by the fact that the PLCgamma1 association sites in the EGFR, tyrosine residues 992 and 1173, were phosphorylated to a lower degree when the receptor was stimulated with EGF-dextran as compared to with EGF.

  • 11.
    Häggblad Sahlberg, Sara
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Spiegelberg, Diana
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Nygren, Peter
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Glimelius, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Stenerlöw, Bo
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Biomedical Radiation Sciences.
    The effect of a dimeric Affibody molecule (ZEGFR:1907)2 targeting EGFR in combination with radiation in colon cancer cell lines2012In: International Journal of Oncology, ISSN 1019-6439, Vol. 40, no 1, p. 176-184Article in journal (Refereed)
    Abstract [en]

    The epidermal growth factor receptor (EGFR) is frequently overexpressed in colorectal cancer and is therefore an attractive target for treatment. (ZEGFR:1907)2 is a newly developed dimeric affibody molecule with high affinity to the extracellular part of EGFR. In this study, we evaluated the cytotoxic effects of (ZEGFR:1907)2 in combination with external radiation and the possible inhibitory effects in the EGFR signalling pathways in the colon cancer cell lines HT-29 and HCT116. The effects were compared with an EGFR antibody (cetuximab) and the tyrosine kinase inhibitors (erlotinib and sunitinib). These cell lines are genotypically different with respect to e.g. KRAS and BRAF mutational status, recently shown to be of clinical significance for therapeutic effects. Both cell lines express approximately 100,000-150,000 EGFRs per cell but differ in the radiation response (HCT116, SF2=0.28 and HT-29, SF2=0.70). Exposure to (ZEGFR:1907)2 produced a small, but significant, reduction in survival in HCT116 but did not affect HT-29 cells. Similar results were obtained after exposure to EGF and the EGFR antibody cetuximab. The EGFR tyrosine kinase targeting inhibitor erlotinib and the multi-tyrosine kinase inhibitor sunitinib reduced survival in both cell lines. However, none of the drugs had any significant radiosensitizing effects in combination with radiation. Akt and Erk are central proteins in the EGFR downstream signalling and in the cellular response to ionizing radiation. The activation of Akt (Ser 473) and Erk (Thr202/Tyr204) by radiation was both dose- and time-dependent. However the activation of EGFR was not clearly affected by radiation. Neither (ZEGFR:1907)2 nor any of the other drugs were able to completely inactivate Akt or Erk. On the contrary, erlotinib stimulated Akt phosphorylation in both cell lines and in HCT116 cells Erk was activated. Overall the results illustrate the complexity in response to radiation and drugs in cells with differential phenotypic status.

  • 12.
    Lennartsson, Johan
    et al.
    Ludwiginstitutet för Cancerforskning.
    Carlsson, Jörgen
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Stenerlöw, Bo
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Targeting the epidermal growth factor receptor family in radionuclide therapy of tumors-signal transduction and DNA repair2006In: Letters in Drug Design & Discovery, ISSN 1570-1808, E-ISSN 1875-628X, Vol. 3, no 6, p. 357-368Article, review/survey (Other academic)
    Abstract [en]

    To therapeutically target disseminated tumor cells, while sparing the surrounding tissues, it is necessary to develop agents that interact with structures exposed selectively on the tumor cell surface. Members of the epidermal growth factor receptor family are commonly overexpressed in several tumor types and may serve as targeting structures. In this review we discuss the effects of EGFR and HER2 targeting agents that can deliver radioactive nuclides, i.e. antibodies and affibody molecules, on intracellular signaling. If the targeting agent, in addition to deliver radioactivity to the tumor, can sensitize the tumor for its effects by influencing signal pathways that regulate cell survival and proliferation this will probably be advantageous. We discuss the changes in intracellular signaling that occurs after treatment of cancer cells with the clinically approved monoclonal antibodies cetuximab (anti-EGFR), trastuzumab (anti-HER2) as well as HER2 targeted affibody molecules which are under preclinical development. An important defence mechanism for cells against radiation is to activate DNA repair systems and we also address how DNA repair proteins are regulated in response to radiation or EGFR activation.

  • 13.
    Lennartsson, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Ma, Haisha
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Wardega, Piotr
    Pelka, Karin
    Institute of Innate Immunity, University Hospitals Bonn, Bonn, Germany.
    Engström, Ulla
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Hellberg, Carina
    School of Biosciences, University of Birmingham, Birmingham, UK.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    The Fer Tyrosine Kinase Is Important for Platelet-derived Growth Factor-BB-induced Signal Transducer and Activator of Transcription 3 (STAT3) Protein Phosphorylation, Colony Formation in Soft Agar, and Tumor Growth in Vivo.2013In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 288, no 22, p. 15736-15744Article in journal (Refereed)
    Abstract [en]

    Fer is a cytoplasmic tyrosine kinase that is activated in response to platelet-derived growth factor (PDGF) stimulation. In the present report, we show that Fer associates with the activated PDGF β-receptor (PDGFRβ) through multiple autophosphorylation sites, i.e. Tyr-579, Tyr-581, Tyr-740, and Tyr-1021. Using low molecular weight inhibitors, we found that PDGF-BB-induced Fer activation is dependent on PDGFRβ kinase activity, but not on the enzymatic activity of Src or Jak kinases. In cells in which Fer was down-regulated using siRNA, PDGF-BB was unable to induce phosphorylation of STAT3, whereas phosphorylations of STAT5, ERK1/2, and Akt were unaffected. PDGF-BB-induced activation of STAT3 occurred also in cells expressing kinase-dead Fer, suggesting a kinase-independent adaptor role of Fer. Expression of Fer was dispensable for PDGF-BB-induced proliferation and migration but essential for colony formation in soft agar. Tumor growth in vivo was delayed in cells depleted of Fer expression. Our data suggest a critical role of Fer in PDGF-BB-induced STAT3 activation and cell transformation.

  • 14.
    Lennartsson, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Rönnstrand, Lars
    Experimental Clinical Chemistry, Wallenberg Laboratory, Department of Laboratory Medicine, Lund University, Skåne University Hospital, Malmö, Sweden.
    Stem Cell Factor Receptor/c-Kit: From Basic Science to Clinical Implications.2012In: Physiological Reviews, ISSN 0031-9333, E-ISSN 1522-1210, Vol. 92, no 4, p. 1619-1649Article, review/survey (Refereed)
    Abstract [en]

    Stem cell factor (SCF) is a dimeric molecule that exerts its biological functions by binding to and activating the receptor tyrosine kinase c-Kit. Activation of c-Kit leads to its autophosphorylation and initiation of signal transduction. Signaling proteins are recruited to activated c-Kit by certain interaction domains (e.g., SH2 and PTB) that specifically bind to phosphorylated tyrosine residues in the intracellular region of c-Kit. Activation of c-Kit signaling has been found to mediate cell survival, migration, and proliferation depending on the cell type. Signaling from c-Kit is crucial for normal hematopoiesis, pigmentation, fertility, gut movement, and some aspects of the nervous system. Deregulated c-Kit kinase activity has been found in a number of pathological conditions, including cancer and allergy. The observation that gain-of-function mutations in c-Kit can promote tumor formation and progression has stimulated the development of therapeutics agents targeting this receptor, e.g., the clinically used inhibitor imatinib mesylate. Also other clinically used multiselective kinase inhibitors, for instance, sorafenib and sunitinib, have c-Kit included in their range of targets. Furthermore, loss-of-function mutations in c-Kit have been observed and shown to give rise to a condition called piebaldism. This review provides a summary of our current knowledge regarding structural and functional aspects of c-Kit signaling both under normal and pathological conditions, as well as advances in the development of low-molecular-weight molecules inhibiting c-Kit function.

  • 15.
    Lennartsson, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Rönnstrand, Lars
    Experimental Clinical Chemistry, Dept. of Laboratory Medicine, Lund University, Malmö University Hospital, SE-205 02 Malmö, Sweden.
    The stem cell factor receptor/c-Kit as a drug target in cancer2006In: Current Cancer Drug Targets, ISSN 1568-0096, E-ISSN 1873-5576, Vol. 6, no 1, p. 65-75Article in journal (Refereed)
    Abstract [en]

    Tyrosine phosphorylation has a key role in intracellular signaling. Inappropriate proliferation and survival cues in tumor cells often occur as a consequence of unregulated tyrosine kinase activity. Much of the current development of anti-cancer therapies tries to target causative proteins in a specific manner to minimize side-effects. One attractive group of target proteins is the kinases. c-Kit is a receptor tyrosine kinase that normally controls the function of primitive hematopoietic cells, melanocytes and germ cells. It has become clear that uncontrolled activity of c-Kit contributes to formation of an array of human tumors. The unregulated activity of c-Kit may be due to overexpression, autocrine loops or mutational activation. This makes c-Kit an excellent target for cancer therapies in these tumors. In this review we will highlight the current knowledge on the signal transduction molecules and pathways activated by c-Kit under normal conditions and in cancer cells, and the role of aberrant c-Kit signaling in cancer progression. Recent advances in the development of specific inhibitors interfering with these signal transduction pathways will be discussed.

  • 16.
    Lennartsson, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Voytyuk, Olexandr
    Heiss, Elke
    Sundberg, Christina
    Sun, Jianmin
    Rönnstrand, Lars
    C-Kit signal transduction and involvement in cancer2005In: Cancer Therapy, Vol. 3, no A, p. 5-28Article in journal (Refereed)
  • 17.
    Lennartsson, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Wardega, Piotr
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Engström, Ulla
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Hellman, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Alix Facilitates the Interaction between c-Cbl and Platelet-derived Growth Factor beta-Receptor and Thereby Modulates Receptor Down-regulation2006In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 281, no 51, p. 39152-39158Article in journal (Refereed)
    Abstract [en]

    Alix (ALG-2-interacting protein X) is an adaptor protein involved in down-regulation and sorting of cell surface receptors through the endosomal compartments toward the lysosome. In this study, we show that Alix interacts with the C-terminal region of the platelet-derived growth factor (PDGF) β-receptor (PDGFRβ) and becomes transiently tyrosine-phosphorylated in response to PDGF-BB stimulation. Increased expression levels of Alix resulted in a reduced rate of PDGFRβ removal from the cell surface following receptor activation, and this was associated with decreased receptor degradation. Furthermore, Alix was found to co-immunoprecipitate with the ubiquitin ligase c-Cbl, and elevated Alix levels increased the interaction between c-Cbl and PDGFRβ. Interestingly, Alix interacted constitutively with both c-Cbl and PDGFRβ. Moreover, c-Cbl was found to be hyperphosphorylated in cells engineered to overexpress Alix compared with control cells. The increased c-Cbl phosphorylation correlated with enhanced proteasomal degradation of c-Cbl, which in turn correlated with a decreased ubiquitination of PDGFRβ. Our data suggest that Alix inhibits down-regulation of PDGFRβ by modulating the interaction between c-Cbl and the receptor, thereby affecting the ubiquitination of the receptor.

  • 18.
    Lennartsson, Johan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Wernstedt, Christer
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Engström, Ulla
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Hellman, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Rönnstrand, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Identification of Tyr900 in the kinase domain of c-Kit as a Src-dependent phosphorylation site mediating interaction with c-Crk2003In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 288, no 1, p. 110-118Article in journal (Refereed)
    Abstract [en]

    We have previously demonstrated that ligand-stimulation of c-Kit induces phosphorylation of Tyr568 and Tyr570 in the juxtamembrane region of the receptor, leading to recruitment, phosphorylation and activation of members of the Src family of tyrosine kinases. In this paper, we demonstrate that members of the Src family of tyrosine kinases are able to phosphorylate c-Kit selectively on one particular tyrosine residue, Tyr900, located in the second part of the tyrosine kinase domain. In order to identify potential docking partners of Tyr900, a synthetic phosphopeptide corresponding to the amino acid sequence surrounding Tyr900 was used as an affinity matrix. By use of MALDI-TOF mass spectrometry, CrkII was identified as a protein that specifically bound to Tyr900 in a phosphorylation dependent manner, possibly via the p85 subunit of PI3-kinase. Expression of a mutant receptor where Tyr900 had been replaced with a phenylalanine residue (Y900F) resulted in a receptor with reduced ability to phosphorylate CrkII. Together these data support a model where c-Src phosphorylates the receptor, thereby creating docking sites for SH2 domain containing proteins, leading to recruitment of Crk to the receptor.

  • 19. Li, Xuri
    et al.
    Tjwa, Marc
    Moons, Lieve
    Fons, Pierre
    Noel, Agnes
    Ny, Annelii
    Zhou, Jian Min
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Li, Hong
    Luttun, Aernout
    Pontén, Annica
    Devy, Laetitia
    Bouché, Ann
    Oh, Hideyasu
    Manderveld, Ann
    Blacher, Silvia
    Communi, David
    Savi, Pierre
    Bono, Françoise
    Dewerchin, Mieke
    Foidart, Jean-Michel
    Autiero, Monica
    Herbert, Jean-Marc
    Collen, D
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Eriksson, Ulf
    Carmeliet, Peter
    Revascularization of ischemic tissues by PDGF-CC via effects on endothelial cells and their progenitors2005In: Journal of Clinical Investigation, ISSN 0021-9738, E-ISSN 1558-8238, Vol. 115, no 1, p. 118-127Article in journal (Refereed)
    Abstract [en]

    The angiogenic mechanism and therapeutic potential of PDGF-CC, a recently discovered member of the VEGF/PDGF superfamily, remain incompletely characterized. Here we report that PDGF-CC mobilized endothelial progenitor cells in ischemic conditions; induced differentiation of bone marrow cells into ECs; and stimulated migration of ECs. Furthermore, PDGF-CC induced the differentiation of bone marrow cells into smooth muscle cells and stimulated their growth during vessel sprouting. Moreover, delivery of PDGF-CC enhanced postischemic revascularization of the heart and limb. Modulating the activity of PDGF-CC may provide novel opportunities for treating ischemic diseases.

  • 20.
    Li, Yang
    et al.
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    Zhang, Fan
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    Nagai, Nobuo
    Department of Physiology, Kinki University School of Medicine, Osakasayama, Osaka, Japan.
    Tang, Zhongshu
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    Zhang, Shuihua
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    Scotney, Pierre
    CSL Limited, Parkville, Victoria, Australia.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Zhu, Chaoyong
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    Qu, Yi
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    Fang, Changge
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    Hua, Jianyuan
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    Matsuo, Osamu
    Department of Physiology, Kinki University School of Medicine, Osakasayama, Osaka, Japan.
    Fong, Guo-Hua
    Center for Vascular Biology, University of Connecticut Health Center, Farmington, Connecticut, USA.
    Ding, Hao
    Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada.
    Cao, Yihai
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden..
    Becker, Kevin G
    TRIAD Technology Center, National Institute on Aging, NIH, Baltimore, Maryland, USA.
    Nash, Andrew
    CSL Limited, Parkville, Victoria, Australia.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Li, Xuri
    National Eye Institute, NIH, Porter Neuroscience Research Center, Bethesda, Maryland, USA.
    VEGF-B inhibits apoptosis via VEGFR-1-mediated suppression of the expression of BH3-only protein genes in mice and rats.2008In: Journal of Clinical Investigation, ISSN 0021-9738, E-ISSN 1558-8238, Vol. 118, no 3, p. 913-923Article in journal (Refereed)
    Abstract [en]

    Despite its early discovery and high sequence homology to the other VEGF family members, the biological functions of VEGF-B remain poorly understood. We revealed here a novel function for VEGF-B as a potent inhibitor of apoptosis. Using gene expression profiling of mouse primary aortic smooth muscle cells, and confirming the results by real-time PCR using mouse and rat cell lines, we showed that VEGF-B inhibited the expression of genes encoding the proapoptotic BH3-only proteins and other apoptosis- and cell death-related proteins, including p53 and members of the caspase family, via activation of VEGFR-1. Consistent with this, VEGF-B treatment rescued neurons from apoptosis in the retina and brain in mouse models of ocular neurodegenerative disorders and stroke, respectively. Interestingly, VEGF-B treatment at the dose effective for neuronal survival did not cause retinal neovascularization, suggesting that VEGF-B is the first member of the VEGF family that has a potent antiapoptotic effect while lacking a general angiogenic activity. These findings indicate that VEGF-B may potentially offer a new therapeutic option for the treatment of neurodegenerative diseases.

  • 21.
    Ma, Haisha
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Wardega, Piotr
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mazaud, David
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Klosowska-Wardega, Agnieszka
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Jurek, Aleksandra
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Engström, Ulla
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Histidine-domain-containing protein tyrosine phosphatase regulates platelet-derived growth factor receptor intracellular sorting and degradation2015In: Cellular Signalling, ISSN 0898-6568, E-ISSN 1873-3913, Vol. 27, no 11, p. 2209-2219Article in journal (Refereed)
    Abstract [en]

    Histidine domain-containing protein tyrosine phosphatase (HD-PTP) is a putative phosphatase that has been shown to affect the signaling and downregulation of certain receptor tyrosine kinases. To investigate if HD-PTP affects platelet-derived growth factor receptor beta (PDGFR beta) signaling, we employed the overexpression of HA-tagged HD-PTP, as well as siRNA-mediated and lentivirus shRNA-mediated silencing of HD-PTP in NIH3T3 cells. We found that HD-PTP was recruited to the PDGFR beta in a ligand-dependent manner. Depletion of HD-PTP resulted in an inability of PDGF-BB to promote tyrosine phosphorylation of the ubiquitin ligases c-Cbl and Cbl-b, with a concomitant missorting and reduction of the degradation of activated PDGFRS. In contrast, ligand-induced internalization of PDGFR beta was unaffected by HD-FTP silencing. Furthermore, the levels of STAM and Hrs of the ESCRT0 machinery were decreased, and immunofluorescence staining showed that in HD-PTP-depleted cells, PDGFR beta accumulated in large aberrant intracellular structures. After the reduction of HD-PTP expression, an NIH3T3-derived cell line that has autocrine PDGF-BB signaling (sis-3 T3) showed increased ability of anchorage-independent growth. However, exogenously added PDGF-BB promoted efficient additional colony formation in control cells, but was not able to do so in HD-PTP-depleted cells. Furthermore, cells depleted of HD-PTP migrated faster than control cells. In summary, HD-PTP affects the intracellular sorting of activated PDGFRS and the migration, proliferation and tumorigenicity of cells stimulated by PDGF.

  • 22.
    Möller, Christine
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Alfredsson, Jessica
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Engström, Maria
    Wootz, Hanna
    Ludwiginstitutet för Cancerforskning.
    Xiang, Zou
    Lennartsson, Johan
    Ludwiginstitutet för Cancerforskning.
    Jönsson, Jan-Ingvar
    Nilsson, Gunnar
    Stem cell factor promotes mast cell survival via inactivation of FOXO3a-mediated transcriptional induction and MEK-regulated phosphorylation of the proapoptotic protein Bim.2005In: Blood, ISSN 0006-4971, Vol. 106, no 4, p. 1330-6Article in journal (Refereed)
    Abstract [en]

    Mast cells are found in tissues throughout the body where they play important roles in the regulation of inflammatory responses. One characteristic feature of mast cells is their longevity. Although it is well established that mast cell survival is dependent on stem cell factor (SCF), it has not been described how this process is regulated. Herein, we report that SCF promotes mast cell survival through inactivation of the Forkhead transcription factor FOXO3a (forkhead box, class O3A) and down-regulation and phosphorylation of its target Bim (Bcl-2 [B-cell lymphoma-2] interacting modulator of cell death), a Bcl-2 homology 3 (BH3)-only proapoptotic protein. SCF induced a rapid and transient phosphorylation of Akt (protein kinase B) and FOXO3a. SCF treatment prevented up-regulation of Bim protein expression and led to increased Bim phosphorylation. Bim phosphorylation was inhibited by PD98059 and LY294002 treatment, suggesting the involvement of mitogen-activated protein kinase kinase/mitogen-activated protein kinase (MEK/MAPK) and phosphatidylinositol 3 (PI3)-kinase pathways in this process. Overexpression of phosphorylation-deficient FOXO3a caused an up-regulation of Bim and induced mast cell apoptosis even in the presence of SCF. Mast cell apoptosis induced by the phosphorylation-deficient FOXO3a was attenuated in bim-/- mast cells. Because apoptosis is abnormally reduced in bim-/- mast cells, these data provide evidence that Akt-mediated inhibition of FOXO3a and its transcription target Bim provides an important mechanism by which SCF acts to prevent apoptosis in mast cells.

  • 23.
    Nehru, Vishal
    et al.
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Box 280, Nobels v¨ag 16, SE-171 77, Stockholm, Sweden.
    Voytyuk, Oleksandr
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Aspenström, Pontus
    1Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Box 280, Nobels v¨ag 16, SE-171 77, Stockholm, Sweden.
    RhoD Binds the Rab5 Effector Rabankyrin-5 and has a Role in Trafficking of the Platelet-derived Growth Factor Receptor2013In: Traffic: the International Journal of Intracellular Transport, ISSN 1398-9219, E-ISSN 1600-0854, Vol. 14, no 12, p. 1242-1254Article in journal (Refereed)
    Abstract [en]

    RhoD is a member of the classical Rho GTPases and it has essential roles in the regulation of actin dynamics. RhoD localizes to early endosomes and recycling endosomes, which indicates its important role in the regulation of endosome trafficking. Here, we show that RhoD binds to the Rab5 effector Rabankyrin-5, and RhoD and Rabankyrin-5 colocalize to Rab5-positive endosomes, which suggests a role for Rabankyrin-5 in the coordination of RhoD and Rab5 in endosomal trafficking. Interestingly, depletion of RhoD using siRNA techniques interfered with the internalization of the PDGF receptor and the subsequent activation of the downstream signaling cascades. Our data suggest that RhoD and Rabankyrin-5 have important roles in coordinating RhoD and Rab activities during internalization and trafficking of activated tyrosine kinase receptors.

  • 24. Nore, Beston F
    et al.
    Mattsson, Pekka T
    Antonsson, Per
    Bäckesjö, Carl-Magnus
    Westlund, Anna
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Hansson, Henrik
    Löw, Peter
    Rönnstrand, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Smith, C I Edvard
    Identification of phosphorylation sites within the SH3 domains of Tec family tyrosine kinases2003In: Biochimica et Biophysica Acta, ISSN 0006-3002, E-ISSN 1878-2434, Vol. 1645, no 2, p. 123-132Article in journal (Refereed)
    Abstract [en]

    Tec family protein tyrosine kinases (TFKs) play a central role in hematopoietic cellular signaling. Initial activation takes place through specific tyrosine phosphorylation situated in the activation loop. Further activation occurs within the SH3 domain via a transphosphorylation mechanism, which for Bruton's tyrosine kinase (Btk) affects tyrosine 223. We found that TFKs phosphorylate preferentially their own SH3 domains, but differentially phosphorylate other member family SH3 domains, whereas non-related SH3 domains are not phosphorylated. We demonstrate that SH3 domains are good and reliable substrates. We observe that transphosphorylation is selective not only for SH3 domains, but also for dual SH3SH2 domains. However, the dual domain is phosphorylated more effectively. The major phosphorylation sites were identified as conserved tyrosines, for Itk Y180 and for Bmx Y215, both sites being homologous to the Y223 site in Btk. There is, however, one exception because the Tec-SH3 domain is phosphorylated at a non-homologous site, nevertheless a conserved tyrosine, Y206. Consistent with these findings, the 3D structures for SH3 domains point out that these phosphorylated tyrosines are located on the ligand-binding surface. Because a number of Tec family kinases are coexpressed in cells, it is possible that they could regulate the activity of each other through transphosphorylation.

  • 25.
    Papadopoulos, Natalia
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Lennartsson, Johan
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    The PDGF/PDGFR pathway as a drug target2018In: Molecular Aspects of Medicine, ISSN 0098-2997, E-ISSN 1872-9452, Vol. 62, p. 75-88Article, review/survey (Refereed)
    Abstract [en]

    Platelet-derived growth factors (PDGF) promotes cell proliferation, survival and migration, primarily of cells of mesenchymal origin. Dysfunction of PDGF signaling has been observed in a wide array of pathological conditions, such as cancer, fibrosis, neurological conditions and atherosclerosis. Reported abnormalities of the PDGF pathway include overexpression or amplification of PDGF receptors (PDGFRs), gain of function point mutations or activating chromosomal translocations. Current development of therapeutic drugs often aims at producing compounds that specifically target interaction between PDGFs and their receptors by specific DNA aptamers and ligand traps, or downregulate PDGFRs with blocking antibodies, or inhibit tyrosine kinase activity of PDGFRs with small molecules. In this review, we discuss some of the approaches taken to interfere with PDGF signaling, review a panel of existing therapeutic drugs, and consider clinically successful cases and remaining challenges.

  • 26.
    Papadopoulos, Natalia
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab. Ludwig Inst Canc Res, Uppsala, Sweden.
    Lennartsson, Johan
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences. Ludwig Inst Canc Res, Uppsala, Sweden.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab. Ludwig Inst Canc Res, Uppsala, Sweden.
    PDGFR beta translocates to the nucleus and regulates chromatin remodeling via TATA element-modifying factor 12018In: Journal of Cell Biology, ISSN 0021-9525, E-ISSN 1540-8140, Vol. 217, no 5, p. 1701-1717Article in journal (Refereed)
    Abstract [en]

    Translocation of full-length or fragments of receptors to the nucleus has been reported for several tyrosine kinase receptors. In this paper, we show that a fraction of full-length cell surface platelet-derived growth factor (PDGF) receptor beta (PDG FR beta) accumulates in the nucleus at the chromatin and the nuclear matrix after ligand stimulation. Nuclear translocation of PDG FR beta was dependent on PDGF-BB-induced receptor dimerization, clathrin-mediated endocytosis, beta-importin, and intact Golgi, occurring in both normal and cancer cells. In the nucleus, PDG FR beta formed ligand-inducible complexes with the tyrosine kinase Fer and its substrate, TATA element-modifying factor 1 (TMF-1). PDGF-BB stimulation decreased TMF-1 binding to the transcriptional regulator Brahma-related gene 1 (Brg-1) and released Brg-1 from the SWI-SNF chromatin remodeling complex. Moreover, knockdown of TMF-1 by small interfering RNA decreased nuclear translocation of PDG FR beta and caused significant up-regulation of the Brg-1/p53-regulated cell cycle inhibitor CDKN1A (encoding p21) without affecting PDG FR beta-inducible immediate-early genes. In conclusion, nuclear interactions of PDG FR beta control proliferation by chromatin remodeling and regulation of p21 levels.

  • 27.
    Pielberg, Gerli Rosengren
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Golovko, Anna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Sundström, Elisabeth
    Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, SE-751 24 Uppsala, Sweden.
    Curik, Ino
    Animal Science Department, Faculty of Agriculture, University of Zagreb, HR-10000 Zagreb, Croatia.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Seltenhammer, Monika H.
    Department of Clinical Surgery and Ophthalmology, University of Veterinary Medicine, A-1200 Vienna, Austria.
    Druml, Thomas
    Department of Sustainable Agricultural Systems, University of Natural Resources and Applied Life Sciences, Vienna, A-1180 Vienna, Austria.
    Binns, Matthew
    Royal Veterinary College, Royal College Street, London, NW1 0TU, UK.
    Fitzsimmons, Carolyn
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Lindgren, Gabriella
    Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, SE-751 24 Uppsala, Sweden.
    Sandberg, Kaj
    Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, SE-751 24 Uppsala, Sweden.
    Baumung, Roswitha
    Department of Sustainable Agricultural Systems, University of Natural Resources and Applied Life Sciences, Vienna, A-1180 Vienna, Austria.
    Vetterlein, Monika
    Centre for Anatomy and Cell Biology, Department of Cell Biology and Ultrastructure Research, Medical University of Vienna, A-1080 Vienna, Austria.
    Strömberg, Sara
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Grabherr, Manfred
    Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142, USA.
    Wade, Claire
    Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142, USA; Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
    Lindblad-Toh, Kerstin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Pontén, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology, Molecular and Morphological Pathology.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Sölkner, Johann
    Department of Sustainable Agricultural Systems, University of Natural Resources and Applied Life Sciences, Vienna, A-1180 Vienna, Austria.
    Andersson, Leif
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    A cis-acting regulatory mutation causes premature hair graying and susceptibility to melanoma in the horse2008In: Nature Genetics, ISSN 1061-4036, E-ISSN 1546-1718, Vol. 40, no 8, p. 1004-1009Article in journal (Refereed)
    Abstract [en]

    In horses, graying with age is an autosomal dominant trait associated with a high incidence of melanoma and vitiligo-like depigmentation. Here we show that the Gray phenotype is caused by a 4.6-kb duplication in intron 6 of STX17 (syntaxin-17) that constitutes a cis-acting regulatory mutation. Both STX17 and the neighboring NR4A3 gene are overexpressed in melanomas from Gray horses. Gray horses carrying a loss-of-function mutation in ASIP (agouti signaling protein) had a higher incidence of melanoma, implying that increased melanocortin-1 receptor signaling promotes melanoma development in Gray horses. The Gray horse provides a notable example of how humans have cherry-picked mutations with favorable phenotypic effects in domestic animals.

  • 28.
    Razmara, Masoud
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Eger, Glenda
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Rorsman, Charlotte
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    MKP3 negatively modulates PDGF-induced Akt and Erk5 phosphorylation as well as chemotaxis2012In: Cellular Signalling, ISSN 0898-6568, E-ISSN 1873-3913, Vol. 24, no 3, p. 635-640Article in journal (Refereed)
    Abstract [en]

    MAP kinase phosphatase-3 (MKP3), also known as DUSP6 or Pyst1, is a dual specificity phosphatase considered to selectively dephosphorylate extracellular-signal-regulated kinase 1/2 (Erk1/2). Here, we report that in NIH3T3 cells, MKP3 is induced in response to platelet-derived growth factor (PDGF)-BB treatment in an Erk1/2- and phosphatidylinositol 3-kinase (PI3K)-dependent manner, but independently of Erk5 expression. Silencing of MKP3 expression did not affect PDGF-BB-induced Erk1/2 or p38 phosphorylation; however, their basal level of phosphorylation was elevated. Furthermore, we found that PDGF-BB-mediated activation of Erk5 and Akt was enhanced when the MKP3 expression was reduced. Interfering with Mek1/2 or PI3K using the inhibitors CI-1040 and LY-294002, respectively, inhibited PDGF-BB-induced MKP3 expression. Functionally, we found that MKP3 silencing did not affect cell proliferation, but enhanced the chemotactic response toward PDGF-BB. Although both Akt and Erk5 have been linked to increased cell survival, downregulation of MKP3 did not alter the ability of PDGF-BB to protect NIH3T3 cells from starvation-induced apoptosis. However, we observed an increased apoptosis in untreated cells with reduced MKP3 expression. In summary, our data indicate that there is negative cross-talk between Erk1/2 and Erk5 that involves regulation of MKP3 expression, and that PI3K in addition to promoting Akt phosphorylation also negatively modulates Akt, through MKP3 expression.

  • 29.
    Razmara, Masoud
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Platelet-derived growth factor-induced Akt phosphorylation requires mTOR/Rictor and phospholipase C-gamma1, whereas S6 phosphorylation depends on mTOR/Raptor and phospholipase D2013In: Cell Communication and Signaling, ISSN 1478-811X, E-ISSN 1478-811X, Vol. 11, no 3Article in journal (Refereed)
    Abstract [en]

     

    Mammalian target of rapamycin (mTOR) can be found in two multi-protein complexes, i.e. mTORC1 (containing Raptor) and mTORC2 (containing Rictor). Here, we investigated the mechanisms by which mTORC1 and mTORC2 are activated and their downstream targets in response to platelet-derived growth factor (PDGF)-BB treatment. Inhibition of phosphatidylinositol 3-kinase (PI3K) inhibited PDGF-BB activation of both mTORC1 and mTORC2. We found that in Rictor-null mouse embryonic fibroblasts, or after prolonged rapamycin treatment of NIH3T3 cells, PDGF-BB was not able to promote phosphorylation of Ser473 in the serine/threonine kinase Akt, whereas Thr308 phosphorylation was less affected, suggesting that Ser473 in Akt is phosphorylated in an mTORC2-dependent manner. This reduction in Akt phosphorylation did not influence the phosphorylation of the S6 protein, a well established protein downstream of mTORC1. Consistently, triciribine, an inhibitor of the Akt pathway, suppressed PDGF-BB-induced Akt phosphorylation without having any effect on S6 phosphorylation. Thus, mTORC2 does not appear to be upstream of mTORC1. We could also demonstrate that in Rictor-null cells the phosphorylation of phospholipase Cgamma1 (PLCgamma1) and protein kinase C (PKC) was impaired, and the PKCalpha protein levels strongly reduced. Furthermore, interfering with the PLCgamma/Ca2+/PKC pathway inhibited PDGF-BB-induced Akt phosphorylation. In addition, PDGF-BB-induced activation of mTORC1, as measured by phosphorylation of the downstream S6 protein, was dependent on phospholipase D (PLD). It has been shown that Erk1/2 MAP-kinase directly phosphorylates and activates mTORC1; in partial agreement with this finding, we found that a Mek1/2 inhibitor delayed S6 phosphorylation in response to PDGF-BB, but it did not block it. Thus, whereas both mTORC1 and mTORC2 are activated in a PI3K-dependent manner, different additional signaling pathways are needed. mTORC1 is activated in a PLD-dependent manner and promotes phosphorylation of the S6 protein, whereas mTORC2, in concert with PLCgamma signaling, promotes Akt phosphorylation.

  • 30.
    Reyhani, Vahid
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Tsioumpekou, Maria
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    van Wieringen, Tijs
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Rask, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Rubin, Kristofer
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    PDGF-BB enhances collagen gel contraction through a PI3K-PLCγ-PKC-cofilin pathway2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, no 1, article id 8924Article in journal (Refereed)
    Abstract [en]

    Cell-mediated contraction of collagenous matrices is modulated by various growth factors and cytokines, such as platelet-derived growth factor-BB (PDGF-BB). Here we used a genetic cell model to delineate defined signaling pathways that enhance collagen gel contraction downstream of ligand-stimulated platelet-derived growth factor receptor-β (PDGF-Rβ). Our data show that PDGF BB-enhanced activations of phosphatidylinositol 3'-kinase (PI3K) and phospholipase Cγ (PLCγ) were necessary for PDGF-enhanced collagen gel contraction. Importantly, other defined signaling pathways down-stream of PDGF-Rβ were, however, dispensable. The decisive roles for PI3K and PLCγ were corroborated by experiments using selective inhibitors. Furthermore, we show that de-phosphorylation and thereby activation of cofilin that is important for the turnover of actin filaments, is depended on PI3K and PLCγ down-stream of PDGF-Rβ. Moreover, inhibition of protein kinase C (PKC) by GÖ6976 and bisindolylmaleimide-II abolished cofilin de-phosphorylation, as well as PDGF-enhanced contraction. In contrast, activation of the PKC protein family by 4β-phorbol 12-myristate 13-acetate (PMA) did not accelerate collagen gel contraction although it induced long-term cofilin de-phosphorylation, showing the need of a dynamic control of cofilin de-phosphorylation for PDGF-enhanced collagen gel contraction. Taken together, our data point to the involvement of a PI3K/PLCγ-PKC-cofilin pathway in both PDGF-enhanced cofilin de-phosphorylation and PDGF-enhanced collagen gel contraction.

  • 31.
    Rorsman, Charlotte
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Tsioumpekou, Maria
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    The Ubiquitin Ligases c-Cbl and Cbl-b Negatively Regulate Platelet-derived Growth Factor (PDGF) BB-induced Chemotaxis by Affecting PDGF Receptor beta (PDGFR beta) Internalization and Signaling2016In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 291, no 22, p. 11608-11618Article in journal (Refereed)
    Abstract [en]

    Protein ubiquitination controls protein stability and subcellular localization of tyrosine kinase receptors, hence affecting signaling both quantitatively and qualitatively. In this report, we demonstrate that, after ligand stimulation, the PDGF beta receptor (PDGFR beta) becomes ubiquitinated in a manner requiring both the c-Cbl and Cbl-b ubiquitin ligases. Simultaneous depletion of c-Cbl and Cbl-b resulted in reduced ligand-induced PDGFR beta clearance from the cell surface because of reduced endocytosis of the receptor. Cbl-b formed a complex with c-Cbl, as well as with the PDGFR beta, in response to PDGF-BB stimulation. We were unable to find a direct interaction between the receptor and c-Cbl, raising the possibility that Cbl-b is necessary for c-Cbl to interact with PDGFR beta. Phosphorylated Tyr-1021 in PDGFR beta was the primary interaction site for Cbl-b, with some contribution from Tyr-1009. Depletion of c-Cbl and Cbl-b led to an increased ligand-induced tyrosine phosphorylation of the receptor. Several tyrosine residues with elevated phosphorylation (i.e. Tyr-579, Tyr-581, Tyr-1009, and Tyr-1021) have previously been shown to interact with Src kinases and PLC gamma. Indeed, in cells depleted of c-Cbl and Cbl-b, both Src and PLC gamma phosphorylation were enhanced, whereas activation of other pathways, such as Erk1/2 MAP kinase and Akt, were not affected. In addition, Stat3 phosphorylation, which has been connected to Src activity, was also elevated in cells lacking c-Cbl and Cbl-b. Functionally, we found that cells depleted of c-Cbl and Cbl-b were more prone to migrate toward PDGF-BB, whereas no reproducible effect on cell proliferation could be observed. In conclusion, internalization as well as signaling via PDGFR beta are controlled by ubiquitination.

  • 32.
    Sooman, Linda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Ekman, S.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Bergstrom, S.
    Johansson, M.
    Wu, Xuping
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Blomquist, Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    SHP1 expression is epigenetically regulated and influences the sensitivity to chemotherapeutic agents in glioblastoma cells2012In: Neuro-Oncology, ISSN 1522-8517, E-ISSN 1523-5866, Vol. 14, no suppl 3, p. iii18-iii18Article in journal (Other academic)
    Abstract [en]

    INTRODUCTION: Glioblastoma is characterized by chemoresistance. One factor than can contribute to chemoresistance is aberrant DNA methylation of specific genes relevant for drug response, e.g. tumor suppressor genes. AIM: The aim of this study was to investigate whether the tumor suppressor gene SHP1 is epigenetically regulated and if its overexpression affects the sensitivity to chemotherapeutic drugs with different mechanisms of action in glioblastoma cell lines.

    METHODS: Differences in methylation levels in the SHP1 promoter and SHP1 protein expressions between untreated cells and cells treated with the demethylating agent decitabine were analyzed with bisulfite Pyrosequencing and Western blotting. Differences in drug sensitivity to a panel of chemotherapeutic drugs with different mechanisms of action between SHP1 overexpressing clones and control clones were analyzed with the fluorometric microculture cytotoxicity assay.

    RESULTS: We demonstrated that SHP1 promoter methylation was correlated to SHP1 expression and that the expression was increased upon demethylation. Overexpression of SHP1 resulted in lower (p < 0.05) sensitivity to the proteasome inhibitor bortezomib and the alkylating agents cisplatin and melphalan.

    CONCLUSION: SHP1 expression may be epigenetically regulated and its overexpression influences the sensitivity to chemotherapeutic drugs in glioblastoma derived cells.

  • 33.
    Sooman, Linda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Ekman, Simon
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Andersson, Claes
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Johansson, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Göransson-Kultima, Hanna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Isaksson, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Blomquist, Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Synergistic Effects of PI3K or P38 MAPK Inhibition in Combination With Vandetanib Treatment in Glioblastoma Cells2012In: European Journal of Cancer, ISSN 0959-8049, E-ISSN 1879-0852, Vol. 48, no S5, p. S244-S244Article in journal (Refereed)
  • 34.
    Sooman, Linda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Ekman, Simon
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Andersson, Claes
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Kultima, Hanna Göransson
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Isaksson, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Johansson, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Blomquist, Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Synergistic interactions between camptothecin and EGFR or RAC1 inhibitors and between imatinib and Notch signaling or RAC1 inhibitors in glioblastoma cell lines2013In: Cancer Chemotherapy and Pharmacology, ISSN 0344-5704, E-ISSN 1432-0843, Vol. 72, no 2, p. 329-340Article in journal (Refereed)
    Abstract [en]

    The current treatment strategies for glioblastoma have limited health and survival benefits for the patients. A common obstacle in the treatment is chemoresistance. A possible strategy to evade this problem may be to combine chemotherapeutic drugs with agents inhibiting resistance mechanisms. The aim with this study was to identify molecular pathways influencing drug resistance in glioblastoma-derived cells and to evaluate the potential of pharmacological interference with these pathways to identify synergistic drug combinations. Global gene expressions and drug sensitivities to three chemotherapeutic drugs (imatinib, camptothecin and temozolomide) were measured in six human glioblastoma-derived cell lines. Gene expressions that correlated to drug sensitivity or resistance were identified and mapped to specific pathways. Selective inhibitors of these pathways were identified. The effects of six combinations of inhibitors and chemotherapeutic drugs were evaluated in glioblastoma-derived cell lines. Drug combinations with synergistic effects were also evaluated in non-cancerous epithelial cells. Four drug combinations had synergistic effects in at least one of the tested glioblastoma-derived cell lines; camptothecin combined with gefitinib (epidermal growth factor receptor inhibitor) or NSC 23766 (ras-related C3 botulinum toxin substrate 1 inhibitor) and imatinib combined with DAPT (Notch signaling inhibitor) or NSC 23766. Of these, imatinib combined with DAPT or NSC 23766 did not have synergistic effects in non-cancerous epithelial cells. Two drug combinations had at least additive effects in one of the tested glioblastoma-derived cell lines; temozolomide combined with gefitinib or PF-573228 (focal adhesion kinase inhibitor). Four synergistic and two at least additive drug combinations were identified in glioblastoma-derived cells. Pathways targeted by these drug combinations may serve as targets for future drug development with the potential to increase efficacy of currently used/evaluated chemotherapy.

  • 35.
    Sooman, Linda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Ekman, Simon
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Tsakonas, Georgios
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Jaiswal, Archita
    Navani, Sanjay
    Edqvist, Per-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Pontén, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bergström, Stefan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Johansson, Mikael
    Wu, Xuping
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Blomquist, Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    PTPN6 expression is epigenetically regulated and influences survival and response to chemotherapy in high-grade gliomas2014In: Tumor Biology, ISSN 1010-4283, E-ISSN 1423-0380, Vol. 35, no 5, p. 4479-4488Article in journal (Refereed)
    Abstract [en]

    Background: The prognosis of high-grade glioma patients is poor and the tumors are characterized by resistance to therapy. The aims of this study were to analyze the prognostic value of the expression of the protein tyrosine phosphatase, non-receptor type 6 (PTPN6, also referred to as SHP1) in high-grade glioma patients and the epigenetic regulation of the expression of PTPN6 and the role of its expression in chemotherapy resistance in glioma-derived cells.

    Material and methods: PTPN6 expression was analyzed with immunohistochemistry in 89 high-grade glioma patients. Correlation between PTPN6 expression and overall survival was analyzed with Kaplan-Meier univariate analysis and Cox regression multivariate analysis. Differences in drug sensitivity to a panel of 16 chemotherapeutic drugs between PTPN6 overexpressing clones and control clones were analyzed in vitro with the fluorometric microculture cytotoxicity assay. Cell cycle analysis was done with Krishan staining and flow cytometry. Apoptosis was analyzed with a cell death detection ELISA kit as well as cleaved caspase-3 and caspase-9 Western blotting. Autophagy was analyzed with LC3B Western blotting. Methylation of the PTPN6 promoter was analyzed with bisulfite-Pyrosequencing and demethylation of PTPN6 was done with decitabine treatment.

    Results: PTPN6 expression correlated in univariate analysis to poor survival for anaplastic glioma patients (p=0.026). In glioma-derived cell lines, overexpression of PTPN6 caused increased resistance (p<0.05) to the chemotherapeutic drugs bortezomib, cisplatin and melphalan. PTPN6 expression did not affect bortezomib-induced cell cycle arrest, apoptosis or autophagy. Low PTPN6 promoter methylation correlated to protein expression and the protein expression was increased upon demethylation in glioma-derived cells.

    Conclusion: PTPN6 expression may be a factor contributing to poor survival for anaplastic glioma patients and in glioma-derived cells its expression is epigenetically regulated and influences the response to chemotherapy.

  • 36.
    Sooman, Linda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Freyhult, Eva
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Jaiswal, Archita
    Navani, Sanjay
    Edqvist, Per-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Pontén, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Tchougounova, Elena
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Cancer and Vascular Biology.
    Smits, Anja
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology.
    Elsir, Tamador
    Cancer Center Karolinska, Karolinska University Hospital Solna, Stockholm, Sweden.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Ekman, Simon
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    FGF2 as a potential prognostic biomarker for proneural glioma patients2015In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 54, no 3, p. 385-394Article in journal (Refereed)
    Abstract [en]

    Background. The survival of high-grade glioma patients is poor and the treatment of these patients can cause severe side effects. This fosters the necessity to identify prognostic biomarkers, in order to optimize treatment and diminish unnecessary suffering of patients. The aim of this study was to identify prognostic biomarkers for high-grade glioma patients.

    Methods. Eleven proteins were selected for analysis due to their suggested importance for survival of patients with other types of cancers and due to a high variation in protein levels between glioma patients (according to the Human Protein Atlas, www.proteinatlas.org). Protein expression patterns of these 11 proteins were analyzed by immunohistochemistry in tumor samples from 97 high-grade glioma patients. The prognostic values of the proteins were analyzed with univariate and multivariate Cox regression analyses for the high-grade glioma patients, including subgroup analyses of histological subtypes and immunohistochemically defined molecular subtypes.

    Results. The proteins with the most significant (univariate and multivariate p < 0.05) correlations were analyzed further with cross-validated Kaplan-Meier analyses for the possibility of predicting survival based on the protein expression pattern of the corresponding candidate. Random Forest classification with variable subset selection was used to analyze if a protein signature consisting of any combination of the 11 proteins could predict survival for the high-grade glioma patients and the subgroup with glioblastoma patients. The proteins which correlated most significantly (univariate and multivariate p < 0.05) to survival in the Cox regression analyses were Myc for all high-grade gliomas and FGF2, CA9 and CD44 for the subgroup of proneural gliomas, with FGF2 having a strong negative predictive value for survival. No prognostic signature of the proteins could be found.

    Conclusion. FGF2 is a potential prognostic biomarker for proneural glioma patients, and warrants further investigation.

  • 37.
    Sooman, Linda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Pharmacology.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Tsakonas, Georgios
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Johansson, Fredrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Edqvist, Per-Henrik
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology.
    Pontén, Fredrik
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology.
    Jaiswal, Archita
    The Human Protein Atlas Project, Mumbai Site, Lab Surgpath, 204 Bombay Market, 731/1 Tardeo Main Road, Mumbai 400034, India.
    Navani, Sanjay
    The Human Protein Atlas Project, Mumbai Site, Lab Surgpath, 204 Bombay Market, 731/1 Tardeo Main Road, Mumbai 400034, India.
    Alafuzoff, Irina
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology.
    Popova, Svetlana
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology.
    Blomquist, Erik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Ekman, Simon
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Vandetanib combined with a p38 MAPK inhibitor synergistically reduces glioblastoma cell survival2013In: Medical Oncology, ISSN 1357-0560, E-ISSN 1559-131X, Vol. 30, no 3, p. 638-Article in journal (Refereed)
    Abstract [en]

    The survival for patients with high-grade glioma is poor, and only a limited number of patients respond to the therapy. The aim of this study was to analyze the significance of using p38 MAPK phosphorylation as a prognostic marker in high-grade glioma patients and as a therapeutic target in combination chemotherapy with vandetanib. p38 MAPK phosphorylation was analyzed with immunohistochemistry in 90 high-grade glioma patients. Correlation between p38 MAPK phosphorylation and overall survival was analyzed with Mann-Whitney U test analysis. The effects on survival of glioblastoma cells of combining vandetanib with the p38 MAPK inhibitor SB 203580 were analyzed in vitro with the median-effect method with the fluorometric microculture cytotoxicity assay. Two patients had phosphorylated p38 MAPK in both the cytoplasm and nucleus, and these two presented with worse survival than patients with no detectable p38 MAPK phosphorylation or phosphorylated p38 MAPK only in the nucleus. This was true for both high-grade glioma patients (WHO grade III and IV, n = 90, difference in median survival: 6.1 months, 95 % CI [0.20, 23], p = 0.039) and for the subgroup with glioblastoma patients (WHO grade IV, n = 70, difference in median survival: 6.1 months, 95 % CI [0.066, 23], p = 0.043). The combination of vandetanib and the p38 MAPK inhibitor SB 203580 had synergistic effects on cell survival for glioblastoma-derived cells in vitro. In conclusion, p38 MAPK phosphorylation may be a prognostic marker for high-grade glioma patients, and vandetanib combined with a p38 MAPK inhibitor may be useful combination chemotherapy for glioma patients.

  • 38.
    Strömberg, Thomas
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Ekman, Simon
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Girnita, Leonard
    Dimberg, Lina Y
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology. Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Larsson, Olle
    Axelson, Magnus
    Lennartsson, Johan
    Ludwiginstitutet för Cancerforskning.
    Hellman, Ulf
    Ludwiginstitutet för Cancerforskning.
    Carlson, Kristina
    Department of Medical Sciences.
    Österborg, Anders
    Vanderkerken, Karin
    Nilsson, Kenneth
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Jernberg-Wiklund, Helena
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology. Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    IGF-1 receptor tyrosine kinase inhibition by the cyclolignan PPP induces G2/M-phase accumulation and apoptosis in multiple myeloma cells.2006In: Blood, ISSN 0006-4971, Vol. 107, no 2, p. 669-78Article in journal (Refereed)
    Abstract [en]

    Emerging evidence suggests the insulin-like growth factor-1 receptor (IGF-1R) to be an important mediator of tumor-cell survival and resistance to cytotoxic therapy in multiple myeloma (MM). Recently, members of the cyclolignan family have been shown to selectively inhibit the receptor tyrosine kinase (RTK) activity of the IGF-1R beta-chain. The effects of the cyclolignan picropodophyllin (PPP) were studied in vitro using a panel of 13 MM cell lines and freshly purified tumor cells from 10 patients with MM. PPP clearly inhibited growth in all MM cell lines and primary MM samples cultured in the presence or absence of bone marrow stromal cells. PPP induced a profound accumulation of cells in the G(2)/M-phase and an increased apoptosis. Importantly, IGF-1, IGF-2, insulin, or IL-6 did not reduce the inhibitory effects of PPP. As demonstrated by in vitro kinase assays, PPP down-regulated the IGF-1 RTK activity without inhibiting the insulin RTK activity. This conferred decreased phosphorylation of Erk1/2 and reduced cyclin dependent kinase (CDK1) activity. In addition, the expression of mcl-1 and survivin was reduced. Taken together, we suggest that interfering with the IGF-1 RTK by using the cyclolignan PPP offers a novel and selective therapeutic strategy for MM.

  • 39.
    Strömberg, Thomas
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology.
    Feng, Xiaoying
    Delforoush, Maryam
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Experimental and Clinical Oncology.
    Berglund, Mattias
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Experimental and Clinical Oncology.
    Lin, Yingbo
    Axelson, Magnus
    Larsson, Olle
    Georgii-Hemming, Patrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Enblad, Gunilla
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Experimental and Clinical Oncology.
    Picropodophyllin inhibits proliferation and survival of diffuse large B-cell lymphoma cells2015In: Medical Oncology, ISSN 1357-0560, E-ISSN 1559-131X, Vol. 32, no 7, article id 188Article in journal (Refereed)
    Abstract [en]

    Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma in adults. Although chemotherapy in combination with anti-CD20 antibodies results in a cure rate of 60-70 %, novel treatment approaches are warranted for the remaining patients. The insulin-like growth factor-1 receptor (IGF-1R) and its principal ligands IGF-1 and IGF-2 have been suggested to play pivotal roles in different cancers. However, in DLBCL the importance of this system is less well understood. To assess whether interference with IGF-1R-mediated signaling may represent a therapeutic option for this malignancy, we used a panel of eight DLBCL cell lines together with primary tumor cells derived from lymph nodes in four DLBCL patients. The cells were treated with the cyclolignan picropodophyllin (PPP), a small molecule compound initially described to selectively inhibit the IGF-1R. PPP dose-dependently inhibited proliferation/survival in all cell lines and primary cell preparations. In parallel experiments, the IGF-1R inhibitor NVP-AEW541 and the microtubule-destabilizing compounds podophyllotoxin (PPT) and colchicine were demonstrated to also inhibit growth of the cell lines. Linear regression analysis showed that the responses of the cell lines to PPP correlated with their responses to the microtubule inhibitors PPT and colchicine, but not with the response to NVP-AEW541 or the expression level of surface IGF-1R. Analysis of cell cycle phase distribution revealed that treatment with PPP for only 1 h induced a clear accumulation of cells in the G2/M-phase with a corresponding depletion of the G0/G1-phase. Interestingly, these cell cycle effects could be closely mimicked by using PPT or colchicine. Treatment with PPP led to increased apoptotic cell death in the SU-DHL-6 and U-2932 cell lines, whereas the DB and U-2940 did not undergo apoptosis. However, the DB cells were still killed by PPP, suggesting another mode of cell death for this cell line. The U-2940 cells responded to PPP mainly by inhibition of proliferation. Pretreatment of U-2932 or U-2940 cell lines with PPP at biologically active concentrations did not prevent ligand-induced phosphorylation of IGF-1R at Tyr1131/1136 or its downstream targets AKT and ERK1/2. In contrast, the IGF-1R inhibitor NVP-AEW541 clearly inhibited phosphorylation of IGF-1R and AKT, while ERK1/2 phosphorylation was less affected. Taken together, the inhibitory effects of PPP in DLBCL cells together with its low toxicity in vivo makes it a promising drug candidate in the treatment of this disease. However, we suggest that the primary target of PPP in these cells is not related to inhibition of IGF-1R phosphorylation.

  • 40.
    Tsioumpekou, Maria
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Papadopoulos, Natalia
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Burovic, Fatima
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Mechanism of platelet-derived growth factor (PDGF) Erk5 MAP-kinase activation is cell type-dependent and can be independent of PDGF receptor kinase activity2015In: International Journal of Molecular Medicine, ISSN 1107-3756, E-ISSN 1791-244X, Vol. 36, no Supplement: 1, p. S20-S20Article in journal (Other academic)
  • 41.
    Vanlandewijck, Michael
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology. Karolinska Inst, Novum, ICMC, SE-14157 Stockholm, Sweden..
    Lebouvier, Thibaud
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    Mae, Maarja Andaloussi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    Nahar, Khayrun
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    Hornemann, Simone
    Univ Zurich, Univ Zurich Hosp, Inst Neuropathol, CH-8091 Zurich, Switzerland..
    Kenkel, David
    Univ Zurich, Univ Zurich Hosp, Inst Diagnost & Intervent Radiol, CH-8091 Zurich, Switzerland..
    Cunha, Sara I.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Boss, Andreas
    Univ Zurich, Univ Zurich Hosp, Inst Diagnost & Intervent Radiol, CH-8091 Zurich, Switzerland..
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Keller, Annika
    Univ Zurich, Univ Zurich Hosp, Div Neurosurg, CH-8091 Zurich, Switzerland..
    Betsholtz, Christer
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    Functional Characterization of Germline Mutations in PDGFB and PDGFRB in Primary Familial Brain Calcification2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 11, article id e0143407Article in journal (Refereed)
    Abstract [en]

    Primary Familial Brain Calcification (PFBC), a neurodegenerative disease characterized by progressive pericapillary calcifications, has recently been linked to heterozygous mutations in PDGFB and PDGFRB genes. Here, we functionally analyzed several of these mutations in vitro. All six analyzed PDGFB mutations led to complete loss of PDGF-B function either through abolished protein synthesis or through defective binding and/or stimulation of PDGF-R beta. The three analyzed PDGFRB mutations had more diverse consequences. Whereas PDGF-R beta autophosphorylation was almost totally abolished in the PDGFRB L658P mutation, the two sporadic PDGFRB mutations R987W and E1071V caused reductions in protein levels and specific changes in the intensity and kinetics of PLC. activation, respectively. Since at least some of the PDGFB mutations were predicted to act through haploinsufficiency, we explored the consequences of reduced Pdgfb or Pdgfrb transcript and protein levels in mice. Heterozygous Pdgfb or Pdgfrb knockouts, as well as double Pdgfb(+/-); Pdgfrb(+/-) mice did not develop brain calcification, nor did Pdgfrb(redeye/redeye) mice, which show a 90% reduction of PDGFR beta protein levels. In contrast, Pdgfb(ret/ret) mice, which have altered tissue distribution of PDGF-B protein due to loss of a proteoglycan binding motif, developed brain calcifications. We also determined pericyte coverage in calcification-prone and non-calcification-prone brain regions in Pdgfb(ret/ret) mice. Surprisingly and contrary to our hypothesis, we found that the calcification-prone brain regions in Pdgfb(ret/ret) mice model had a higher pericyte coverage and a more intact blood-brain barrier (BBB) compared to non-calcification-prone brain regions. While our findings provide clear evidence that loss-of-function mutations in PDGFB or PDGFRB cause PFBC, they also demonstrate species differences in the threshold levels of PDGF-B/PDGF-R beta signaling that protect against small-vessel calcification in the brain. They further implicate region-specific susceptibility factor(s) in PFBC pathogenesis that are distinct from pericyte and BBB deficiency.

  • 42.
    Voytyuk, Olexandr
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Mogi, Akira
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Caruana, Georgina
    Courtneidge, Sara
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Ashman, Leonie K
    Rönnstrand, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Src family kinases are involved in the differential signaling from two splice forms of c-Kit2003In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 278, no 11, p. 9159-9166Article in journal (Refereed)
    Abstract [en]

    In both mice and humans alternate splicing results in isoforms of c-Kit characterized by the presence or the absence of a tetrapeptide sequence, GNNK, in the juxtamembrane region of the extracellular domain. Dramatic differences in the kinetics and magnitude of activation of the intrinsic tyrosine kinase activity of c-Kit between the GNNK- and GNNK+ isoforms has previously been shown. Here we report the analysis of downstream targets of receptor signaling, which revealed that the signaling was differentially regulated in the two splice forms. The kinetics of phosphorylation of Shc, previously demonstrated to be phosphorylated by Src downstream of c-Kit, was stronger and more rapid in the GNNK- form, whereas it showed slower kinetics in the GNNK+ form. Inhibition of Src family kinases with the specific Src family kinase inhibitor SU6656 altered the kinetics of activation of the GNNK- form of c-Kit so that it resembled that of the GNNK+ form. In cells expressing the GNNK- form, SCF was rapidly degraded, whereas in cells expressing the GNNK+ form only showed a very slow rate of degradation of SCF. In the GNNK+ form the Src inhibitor SU6656 only had a weak effect on degradation, whereas in the GNNK- form it dramatically inhibited degradation. In summary, the two splice forms show, despite only a four-amino acid sequence difference, remarkable differences in their signaling capabilities.

  • 43.
    Wollberg, Patrik
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Gottfridsson, Eva
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Yoshimura, Akihiko
    Rönnstrand, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    The adapter protein APS associates with the multifunctional docking sites Tyr-568 and Tyr-936 in c-Kit2003In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 370, no Pt 3, p. 1033-1038Article in journal (Refereed)
    Abstract [en]

    The adapter protein APS has previously been shown to be involved in recruiting the ubiquitin E3 ligase c-Cbl to the insulin receptor, the platelet-derived growth factor beta-receptor and the erythropoietin receptor, leading to increased degradation of the receptors and inhibition of mitogenesis. Here we demonstrate, by use of immobilized synthetic phosphopeptides corresponding to various autophosphorylated tyrosine residues in the receptor for stem-cell factor (c-Kit), that APS preferentially associates with phosphorylated Tyr-568 and Tyr-936. Tyr-568 has previously been identified as the binding site of the Src family of tyrosine kinases, the Csk-homologous kinase CHK, and the protein tyrosine phosphatase SHP-2. We have recently demonstrated that Tyr-936 is an autophosphorylation site involved in binding the adapter proteins Grb2 and Grb7. We could further demonstrate that the critical determinant for binding of APS is the presence of either a leucine or an isoleucine residue in the position +3 to the phosphorylated tyrosine. This allowed us to design mutants that selectively failed to associate with APS, while still associating with Src family members, SHP-2 and Grb2, respectively.

  • 44.
    Wu, Xuping
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Hedman, Håkan
    Department of Radiation Sciences and Oncology, Umeå University.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Bergström, Stefan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Henriksson, Roger
    Department of Radiation Sciences and Oncology, Umeå University.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Pharmacology.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Hesselius, Patrik
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Economics.
    Ekman, Simon
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Expression of EGFR and LRIG proteins in oesophageal carcinoma with emphasis on patient survival and cellular chemosensitivity2012In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 51, no 1, p. 69-76Article in journal (Refereed)
    Abstract [en]

    Background. Leucine-rich and immunoglobulin-like domains 1-3 (LRIG1-3) proteins have been implicated in the regulation of EGFR signalling. In the present study, we investigated the clinical implications of the expression of EGFR and LRIG1-3 in oesophageal carcinoma, as well as the correlation between their expression levels and the chemosensitivity of oesophageal carcinoma cell lines.

    Patients and methods. Tumours from 80 patients with oesophageal carcinoma were investigated for the expression of EGFR and LRIG proteins by immunohistochemistry. Oesophageal carcinoma cell lines were investigated for their expression of EGFR and LRIG1, 2, and 3 by quantitative real time RT-PCR and for their sensitivity to commonly used chemotherapeutics by a cytotoxicity assay.

    Results and discussion: Based on a total score of intensity and expression rates, a trend towards survival difference was found for EGFR (p = 0.09) and LRIG2 (p = 0.18) whereas for LRIG1 and -3 there was no trend towards any association with survival. Correlation analysis revealed a correlation with the clinical expression of EGFR and LRIG3 (p = 0.0007). Significant correlations were found between LRIG1 expression levels and sensitivity to cisplatin (r = -0.74), docetaxel (r = -0.69), and vinorelbine (r = -0.82) in oesophageal carcinoma cell lines. EGFR and the LRIG proteins may be functionally involved in oesophageal carcinoma, but larger materials are needed to fully elucidate the clinical implication.

  • 45.
    Wu, Xuping
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Sooman, Linda
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Bergström, Stefan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Bergqvist, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cancer Pharmacology and Computational Medicine.
    Ekman, Simon
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Oncology.
    Microtubule inhibition causes epidermal growth factor receptor inactivation in oesophageal cancer cells2013In: International Journal of Oncology, ISSN 1019-6439, Vol. 42, no 1, p. 297-304Article in journal (Refereed)
    Abstract [en]

    Drugs that interfere with microtubule function can prevent cells from mitosis and may cause cell cycle arrest or apoptosis. Various microtubule targeting agents, both stabilizers and inhibitors, are used in a clinical setting to treat cancer. In the current study, we investigated the sensitivity of oesophageal cancer cells to different microtubule targeting agents. The current study demonstrated that different microtubule targeting agents disrupted the microtubule network and inhibited survival of oesophageal cancer cells in a dose-dependent manner. Interestingly, an additional cellular effect with inhibition of tyrosine phosphorylation of the EGFR and subsequent downregulation of EGFR-induced signalling was also observed, suggesting an additional mechanism of action for microtubule destabilising agents. A tyrosine phosphatase inhibitor, sodium orthovanadate, could reverse the EGFR dephosphorylation effects induced by microtubule targeting agents. The EGFR dephosphorylation could be reversed by a tyrosine phosphatase inhibitor, indicating that disruption of the microtubule network may lead to activation of a protein tyrosine phosphatasc (PTP) that can regulate EGFR phosphorylation and activation, an effect of potential clinical relevance for combination therapies in patients.

  • 46.
    Wu, Xuping
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Oncology. The Second Hospital of Nanjing, Medical School of Southeast University, Nanjing, China .
    Sooman, Linda
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Oncology.
    Wickström, Malin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Pharmacology.
    Fryknäs, Mårten
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Pharmacology.
    Dyrager, Christine
    Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg.
    Lennartsson, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Gullbo, Joachim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Pharmacology.
    Alternative Cytotoxic Effects of the Postulated IGF-IR Inhibitor Picropodophyllin In Vitro2013In: Molecular Cancer Therapeutics, ISSN 1535-7163, E-ISSN 1538-8514, Vol. 12, no 8, p. 1526-1536Article in journal (Refereed)
    Abstract [en]

    The insulin-like growth factor-1 (IGF-I) and its receptors play an important role in transformation and progression of several malignancies. Inhibitors of this pathway have been developed and evaluated but generally performed poorly in clinical trials, and several drug candidates have been abandoned. The cyclolignan picropodophyllin (PPP) has been described as a potent and selective IGF-IR inhibitor and is currently undergoing clinical trials. We investigated PPP's activity in panels of human cancer cell lines (e.g., esophageal squamous carcinoma cell lines) but found no effects on the phosphorylation or expression of IGF-IR. Nor was the cytotoxic activity of PPP related to the presence or spontaneous phosphorylation of IGF-IR. However, its activity correlated with that of known tubulin inhibitors, and it destabilized microtubule assembly at cytotoxic concentrations also achievable in patients. PPP is a stereoisomer of podophyllotoxin (PPT), a potent tubulin inhibitor, and an equilibrium between the two has previously been described. PPP could thus potentially act as a reservoir for the continuous generation of low doses of PPT. Interestingly, PPP also inhibited downstream signaling from tyrosine kinase receptors, including the serine/threonine kinase Akt. This effect is associated with microtubule-related downregulation of the EGF receptor, rather than the IGF-IR. These results suggest that the cytotoxicity and pAkt inhibition observed following treatment with the cyclolignan PPP in vitro result from microtubule inhibition (directly or indirectly by spontaneous PPT formation), rather than any effect on IGF-IR. It is also suggested that PPT should be used as a reference compound in all future studies on PPP.

1 - 46 of 46
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