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Wu T, Wrennall JA, Dang H, Baines DL, Tarran R. Passaging Primary Human Bronchial Epithelia Reduces CFTR-Mediated Fluid Transport and Alters mRNA Expression. Cells 2023; 12:997. [PMID: 37048070 PMCID: PMC10092965 DOI: 10.3390/cells12070997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Primary human bronchial epithelial cultures (HBECs) are used to study airway physiology, disease, and drug development. HBECs often replicate human airway physiology/pathophysiology. Indeed, in the search for cystic fibrosis (CF) transmembrane conductance regulator (CFTR) therapies, HBECs were seen as the "gold standard" in preclinical studies. However, HBECs are not without their limitations: they are non-immortalized and the requirement for human donors, especially those with rare genetic mutations, can make HBECs expensive and/or difficult to source. For these reasons, researchers may opt to expand HBECs by passaging. This practice is common, but to date, there has not been a robust analysis of the impact of expanding HBECs on their phenotype. Here, we used functional studies of airway surface liquid (ASL) homeostasis, epithelial barrier properties, and RNA-seq and Western blotting to investigate HBEC changes over two passage cycles. We found that passaging impaired CFTR-mediated ASL secretion and led to a reduction in the plasma membrane expression of the epithelial sodium channel (ENaC) and CFTR. Passaging also resulted in an increase in transepithelial resistance and a decrease in epithelial water permeability. We then looked for changes at the mRNA level and found that passaging significantly affected 323 genes, including genes involved in inflammation, cell growth, and extracellular matrix remodeling. Collectively, these data highlight the potential for HBEC expansion to impact research findings.
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Affiliation(s)
- Tongde Wu
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Joe A. Wrennall
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hong Dang
- Marsico Lung Institute, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London SW17 0RE, UK
| | - Robert Tarran
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
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Zhang HJ, Li FS, Wang F, Wang H, He TC, Reid RR, He BC, Xia Q. Transgenic PDGF-BB sericin hydrogel potentiates bone regeneration of BMP9-stimulated mesenchymal stem cells through a crosstalk of the Smad-STAT pathways. Regen Biomater 2022; 10:rbac095. [PMID: 36683747 PMCID: PMC9847547 DOI: 10.1093/rb/rbac095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/08/2022] [Accepted: 11/24/2022] [Indexed: 12/05/2022] Open
Abstract
Silk as a natural biomaterial is considered as a promising bone substitute in tissue regeneration. Sericin and fibroin are the main components of silk and display unique features for their programmable mechanical properties, biocompatibility, biodegradability and morphological plasticity. It has been reported that sericin recombinant growth factors (GFs) can support cell proliferation and induce stem cell differentiation through cross-talk of signaling pathways during tissue regeneration. The transgenic technology allows the productions of bioactive heterologous GFs as fusion proteins with sericin, which are then fabricated into solid matrix or hydrogel format. Herein, using an injectable hydrogel derived from transgenic platelet-derived GF (PDGF)-BB silk sericin, we demonstrated that the PDGF-BB sericin hydrogel effectively augmented osteogenesis induced by bone morphogenetic protein (BMP9)-stimulated mesenchymal stem cells (MSCs) in vivo and in vitro, while inhibiting adipogenic differentiation. Further gene expression and protein-protein interactions studies demonstrated that BMP9 and PDGF-BB synergistically induced osteogenic differentiation through the cross-talk between Smad and Stat3 pathways in MSCs. Thus, our results provide a novel strategy to encapsulate osteogenic factors and osteoblastic progenitors in transgenic sericin-based hydrogel for robust bone tissue engineering.
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Affiliation(s)
- Hui-Jie Zhang
- Key Laboratory of Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing 400016, China
| | - Fu-Shu Li
- Department of Pharmacology, School of Pharmacy, Chongqing Medical University, Chongqing 400016, China
- Department of Pharmacy, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing 400014, China
| | - Feng Wang
- Biological Science Research Center, Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China
| | - Han Wang
- Department of Pharmacology, School of Pharmacy, Chongqing Medical University, Chongqing 400016, China
- Department of Pharmacy, Panzhou People’s Hospital, Guizhou 553599, China
| | - Tong-Chuan He
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Russell R Reid
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Laboratory of Craniofacial Biology and Development, Department of Surgery Section of Plastic Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Bai-Cheng He
- Key Laboratory of Biochemistry and Molecular Pharmacology of Chongqing, Chongqing Medical University, Chongqing 400016, China
- Department of Pharmacology, School of Pharmacy, Chongqing Medical University, Chongqing 400016, China
| | - Qingyou Xia
- Biological Science Research Center, Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China
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Sarri N, Wang K, Tsioumpekou M, Castillejo-López C, Lennartsson J, Heldin CH, Papadopoulos N. Deubiquitinating enzymes USP4 and USP17 finetune the trafficking of PDGFRβ and affect PDGF-BB-induced STAT3 signalling. Cell Mol Life Sci 2022; 79:85. [PMID: 35064336 PMCID: PMC8782881 DOI: 10.1007/s00018-022-04128-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/10/2021] [Accepted: 12/29/2021] [Indexed: 12/24/2022]
Abstract
Interaction of platelet-derived growth factor (PDGF) isoforms with their receptors results in activation and internalization of receptors, with a concomitant activation of downstream signalling pathways. Ubiquitination of PDGFRs serves as a mark to direct the internalization and sorting of the receptors. By overexpressing a panel of deubiquitinating enzymes (DUBs), we found that USP17 and USP4 efficiently deubiquitinate PDGF receptor β (PDGFRβ) and are able to remove both Lys63 and Lys48-linked polyubiquitin chains from the receptor. Deubiquitination of PDGFRβ did not affect its stability, but regulated the timing of its trafficking, whereby USP17 prolonged the presence of the receptor at the cell surface, while USP4 affected the speed of trafficking towards early endosomes. Induction of each of the DUBs in BJhTERT fibroblasts and U2OS osteosarcoma cells led to prolonged and/or shifted activation of STAT3 in response to PDGF-BB stimulation, which in turn led to increased transcriptional activity of STAT3. Induction of USP17 promoted acute upregulation of the mRNA expression of STAT3-inducible genes STAT3, CSF1, junB and c-myc, while causing long-term changes in the expression of myc and CDKN1A. Deletion of USP17 was lethal to fibroblasts, while deletion of USP4 led to a decreased proliferative response to stimulation by PDGF-BB. Thus, USP17- and USP4-mediated changes in ubiquitination of PDFGRβ lead to dysregulated signalling and transcription downstream of STAT3, resulting in defects in the control of cell proliferation.
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Affiliation(s)
- Niki Sarri
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 75123 Uppsala, Sweden
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Kehuan Wang
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 75123 Uppsala, Sweden
| | - Maria Tsioumpekou
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 75123 Uppsala, Sweden
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | | | - Johan Lennartsson
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Carl-Henrik Heldin
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 75123 Uppsala, Sweden
| | - Natalia Papadopoulos
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 75123 Uppsala, Sweden
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Sun J, Wu Z, Wu W, Leng J, Lv X, Zhang T, Wang L, Song L. PDGFRβ Recognizes and Binds Bacteria to Activate Src/Stat Pathway in Oysters. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2021; 207:3060-3069. [PMID: 34799429 DOI: 10.4049/jimmunol.2100486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
The Stat signaling pathway plays important roles in mediating the secretions of a large number of cytokines and growth factors in vertebrates, which is generally triggered by the growth factor receptor, cytokine receptor, G protein coupled receptor, and receptor protein tyrosine kinase. In the current study, a platelet-derived growth factor receptor (defined as CgPDGFRβ) was identified from the Pacific oyster Crassostrea gigas, with a signal peptide, three Ig domains, a transmembrane domain, and an intracellular Ser/Thr/Tyr kinase domain. The two N-terminal Ig domains of CgPDGFRβ showed relatively higher binding activity to Gram-negative bacteria and LPS compared with Gram-positive bacteria and peptidoglycan. Upon binding bacteria, CgPDGFRβ in hemocytes formed a dimer and interacted with protein tyrosine kinase CgSrc to induce the phosphorylation of CgSrc at Tyr416. The activated CgSrc interacted with CgStat to induce the translocation of CgStat into the nucleus of hemocytes, which then promoted the expressions of Big defensin 1 (CgBigdef1), IL17-4 (CgIL17-4), and TNF (CgTNF1). These findings together demonstrated that the Src/Stat signaling was activated after the binding of CgPDGFRβ with bacteria to induce the expressions of CgBigdef1, CgIL17-4, and CgTNF1.
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Affiliation(s)
- Jiejie Sun
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Zhaojun Wu
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Wei Wu
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Jinyuan Leng
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Xiaoqian Lv
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Tong Zhang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Lingling Wang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China;
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
- Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; and
- Dalian Key Laboratory of Aquatic Animal Disease Control, Dalian Ocean University, Dalian, China
| | - Linsheng Song
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China;
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
- Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; and
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5
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Molecular Pathogenesis and Treatment Perspectives for Hypereosinophilia and Hypereosinophilic Syndromes. Int J Mol Sci 2021; 22:ijms22020486. [PMID: 33418988 PMCID: PMC7825323 DOI: 10.3390/ijms22020486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 12/25/2022] Open
Abstract
Hypereosinophilia (HE) is a heterogeneous condition with a persistent elevated eosinophil count of >350/mm3, which is reported in various (inflammatory, allergic, infectious, or neoplastic) diseases with distinct pathophysiological pathways. HE may be associated with tissue or organ damage and, in this case, the disorder is classified as hypereosinophilic syndrome (HES). Different studies have allowed for the discovery of two major pathogenetic variants known as myeloid or lymphocytic HES. With the advent of molecular genetic analyses, such as T-cell receptor gene rearrangement assays and Next Generation Sequencing, it is possible to better characterize these syndromes and establish which patients will benefit from pharmacological targeted therapy. In this review, we highlight the molecular alterations that are involved in the pathogenesis of eosinophil disorders and revise possible therapeutic approaches, either implemented in clinical practice or currently under investigation in clinical trials.
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6
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Pillai VV, Siqueira LG, Das M, Kei TG, Tu LN, Herren AW, Phinney BS, Cheong SH, Hansen PJ, Selvaraj V. Physiological profile of undifferentiated bovine blastocyst-derived trophoblasts. Biol Open 2019; 8:bio037937. [PMID: 30952696 PMCID: PMC6550082 DOI: 10.1242/bio.037937] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 03/29/2019] [Indexed: 12/27/2022] Open
Abstract
Trophectoderm of blastocysts mediate early events in fetal-maternal communication, enabling implantation and establishment of a functional placenta. Inadequate or impaired developmental events linked to trophoblasts directly impact early embryo survival and successful implantation during a crucial period that corresponds with high incidence of pregnancy losses in dairy cows. As yet, the molecular basis of bovine trophectoderm development and signaling towards initiation of implantation remains poorly understood. In this study, we developed methods for culturing undifferentiated bovine blastocyst-derived trophoblasts and used both transcriptomics and proteomics in early colonies to categorize and elucidate their functional characteristics. A total of 9270 transcripts and 1418 proteins were identified and analyzed based on absolute abundance. We profiled an extensive list of growth factors, cytokines and other relevant factors that can effectively influence paracrine communication in the uterine microenvironment. Functional categorization and analysis revealed novel information on structural organization, extracellular matrix composition, cell junction and adhesion components, transcription networks, and metabolic preferences. Our data showcase the fundamental physiology of bovine trophectoderm and indicate hallmarks of the self-renewing undifferentiated state akin to trophoblast stem cells described in other species. Functional features uncovered are essential for understanding early events in bovine pregnancy towards initiation of implantation.
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Affiliation(s)
- Viju Vijayan Pillai
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Luiz G Siqueira
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA
- Brazilian Agricultural Research Corporation - Embrapa Gado de Leite, Juiz de Fora, Minas Gerais 36038-330, Brazil
| | - Moubani Das
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Tiffany G Kei
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Lan N Tu
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Anthony W Herren
- Genome Center, Proteomics Core Facility, University of California, Davis, CA 95616, USA
| | - Brett S Phinney
- Genome Center, Proteomics Core Facility, University of California, Davis, CA 95616, USA
| | - Soon Hon Cheong
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Peter J Hansen
- Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Vimal Selvaraj
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
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7
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Ung PMU, Sonoshita M, Scopton AP, Dar AC, Cagan RL, Schlessinger A. Integrated computational and Drosophila cancer model platform captures previously unappreciated chemicals perturbing a kinase network. PLoS Comput Biol 2019; 15:e1006878. [PMID: 31026276 PMCID: PMC6506148 DOI: 10.1371/journal.pcbi.1006878] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 05/08/2019] [Accepted: 02/18/2019] [Indexed: 12/13/2022] Open
Abstract
Drosophila provides an inexpensive and quantitative platform for measuring whole animal drug response. A complementary approach is virtual screening, where chemical libraries can be efficiently screened against protein target(s). Here, we present a unique discovery platform integrating structure-based modeling with Drosophila biology and organic synthesis. We demonstrate this platform by developing chemicals targeting a Drosophila model of Medullary Thyroid Cancer (MTC) characterized by a transformation network activated by oncogenic dRetM955T. Structural models for kinases relevant to MTC were generated for virtual screening to identify unique preliminary hits that suppressed dRetM955T-induced transformation. We then combined features from our hits with those of known inhibitors to create a ‘hybrid’ molecule with improved suppression of dRetM955T transformation. Our platform provides a framework to efficiently explore novel kinase inhibitors outside of explored inhibitor chemical space that are effective in inhibiting cancer networks while minimizing whole body toxicity. Effective and safe treatment of multigenic diseases often involves drugs that address multiple points along disease networks, i.e., polypharmacology. Polypharmacology is increasingly appreciated as a potentially desirable property of kinase drugs. However, most known drugs that interact with multiple targets have been identified as such by chance and most polypharmacological compounds are not chemically unique, resembling structures of known kinase inhibitors. The fruit fly Drosophila provides an inexpensive, rapid, quantitative, whole animal screening platform that has the potential to complement computational approaches. We present a chemical genetics approach that efficiently combines Drosophila with structural prediction and virtual screening, creating a unique discovery platform. We demonstrate the utility of our approach by developing useful small molecules targeting a kinase network in a Drosophila model of Medullary Thyroid Cancer (MTC) driven by oncogenic dRetM955T.
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Affiliation(s)
- Peter M U Ung
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Masahiro Sonoshita
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Alex P Scopton
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Arvin C Dar
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Ross L Cagan
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
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8
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Bousoik E, Montazeri Aliabadi H. "Do We Know Jack" About JAK? A Closer Look at JAK/STAT Signaling Pathway. Front Oncol 2018; 8:287. [PMID: 30109213 PMCID: PMC6079274 DOI: 10.3389/fonc.2018.00287] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 07/09/2018] [Indexed: 12/14/2022] Open
Abstract
Janus tyrosine kinase (JAK) family of proteins have been identified as crucial proteins in signal transduction initiated by a wide range of membrane receptors. Among the proteins in this family JAK2 has been associated with important downstream proteins, including signal transducers and activators of transcription (STATs), which in turn regulate the expression of a variety of proteins involved in induction or prevention of apoptosis. Therefore, the JAK/STAT signaling axis plays a major role in the proliferation and survival of different cancer cells, and may even be involved in resistance mechanisms against molecularly targeted drugs. Despite extensive research focused on the protein structure and mechanisms of activation of JAKs, and signal transduction through these proteins, their importance in cancer initiation and progression seem to be underestimated. This manuscript is an attempt to highlight the role of JAK proteins in cancer biology, the most recent developments in targeting JAKs, and the central role they play in intracellular cross-talks with other signaling cascades.
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Affiliation(s)
- Emira Bousoik
- Department of Biomedical and Pharmaceutical Sciences, Center for Targeted Drug Delivery, School of Pharmacy, Chapman University, Irvine, CA, United States.,School of Pharmacy, Omar Al-Mukhtar University, Dèrna, Libya
| | - Hamidreza Montazeri Aliabadi
- Department of Biomedical and Pharmaceutical Sciences, Center for Targeted Drug Delivery, School of Pharmacy, Chapman University, Irvine, CA, United States
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9
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Wang D, Uhrin P, Mocan A, Waltenberger B, Breuss JM, Tewari D, Mihaly-Bison J, Huminiecki Ł, Starzyński RR, Tzvetkov NT, Horbańczuk J, Atanasov AG. Vascular smooth muscle cell proliferation as a therapeutic target. Part 1: molecular targets and pathways. Biotechnol Adv 2018; 36:1586-1607. [PMID: 29684502 DOI: 10.1016/j.biotechadv.2018.04.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/15/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022]
Abstract
Cardiovascular diseases are a major cause of human death worldwide. Excessive proliferation of vascular smooth muscle cells contributes to the etiology of such diseases, including atherosclerosis, restenosis, and pulmonary hypertension. The control of vascular cell proliferation is complex and encompasses interactions of many regulatory molecules and signaling pathways. Herein, we recapitulated the importance of signaling cascades relevant for the regulation of vascular cell proliferation. Detailed understanding of the mechanism underlying this process is essential for the identification of new lead compounds (e.g., natural products) for vascular therapies.
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Affiliation(s)
- Dongdong Wang
- Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, ul. Postepu 36A, Jastrzębiec, 05-552 Magdalenka, Poland; Department of Pharmacognosy, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Institute of Clinical Chemistry, University Hospital Zurich, Wagistrasse 14, 8952 Schlieren, Switzerland
| | - Pavel Uhrin
- Center for Physiology and Pharmacology, Institute of Vascular Biology and Thrombosis Research, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria.
| | - Andrei Mocan
- Department of Pharmaceutical Botany, "Iuliu Hațieganu" University of Medicine and Pharmacy, Strada Gheorghe Marinescu 23, 400337 Cluj-Napoca, Romania; Institute for Life Sciences, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Calea Mănăştur 3-5, 400372 Cluj-Napoca, Romania
| | - Birgit Waltenberger
- Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Johannes M Breuss
- Center for Physiology and Pharmacology, Institute of Vascular Biology and Thrombosis Research, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria
| | - Devesh Tewari
- Department of Pharmaceutical Sciences, Faculty of Technology, Kumaun University, Bhimtal, 263136 Nainital, Uttarakhand, India
| | - Judit Mihaly-Bison
- Center for Physiology and Pharmacology, Institute of Vascular Biology and Thrombosis Research, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria
| | - Łukasz Huminiecki
- Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, ul. Postepu 36A, Jastrzębiec, 05-552 Magdalenka, Poland
| | - Rafał R Starzyński
- Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, ul. Postepu 36A, Jastrzębiec, 05-552 Magdalenka, Poland
| | - Nikolay T Tzvetkov
- Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany; NTZ Lab Ltd., Krasno Selo 198, 1618 Sofia, Bulgaria
| | - Jarosław Horbańczuk
- Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, ul. Postepu 36A, Jastrzębiec, 05-552 Magdalenka, Poland
| | - Atanas G Atanasov
- Department of Molecular Biology, Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, ul. Postepu 36A, Jastrzębiec, 05-552 Magdalenka, Poland; Department of Pharmacognosy, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
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10
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Topical Sunitinib ointment alleviates Psoriasis-like inflammation by inhibiting the proliferation and apoptosis of keratinocytes. Eur J Pharmacol 2018; 824:57-63. [PMID: 29382533 DOI: 10.1016/j.ejphar.2018.01.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/26/2018] [Accepted: 01/26/2018] [Indexed: 12/11/2022]
Abstract
Psoriasis is a chronic auto-immune inflammation disease with skin lesions and abnormal keratinocyte proliferation. Sunitinib, a multi-targeted tyrosine kinase inhibitor, is known to selectively inhibit several growth factor receptors, including vascular endothelial growth factor receptor, platelet-derived growth factor receptor and stem cell factor. It was reported that a patient with renal cell carcinoma (RCC) whose psoriatic lesion was resolved dramatically during treatment with Sunitinib, however, the mechanism is still unclear. We applied Sunitinib ointment to treat imiquimod-induced mouse model of psoriasis and found that Sunitinib ointment could alleviate imiquimod-induced psoriasis-like inflammation and reduce the Ki67 expression, while Sunitinib ointment couldn't reduce imiquimod-induced splenomegaly of the mouse model, then we concentrated on studying the effect of Sunitinib on the proliferation and apoptosis of keratinocytes, we cultivated HaCaT cells with epidermal growth factor (HaCaT/E cells) to represent as a state of highly proliferative psoriatic keratinocytes. We found that Sunitinib could inhibit the proliferation of Hacat/E cell in a time and concentration dependent manner by influencing the expression level of cell cycle protein D1, cycle protein E1, in addition, Sunitinib could induce the apoptosis of Hacat/E cell and up-regulate the expression of poly ADP-ribose polymerase (PARP). Sunitinib down-regulated the expression of phosphorylated signal transduction and activator of transcription 3 (p-Stat3) of Hacat/E cells significantly. We conclude that Sunitinib alleviates imiquimod-induced psoriasis-like inflammation by regulating the proliferation and apoptosis of HaCaT cells through inhibiting the expression of p-Stat3.
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11
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Zulkifli AA, Tan FH, Putoczki TL, Stylli SS, Luwor RB. STAT3 signaling mediates tumour resistance to EGFR targeted therapeutics. Mol Cell Endocrinol 2017; 451:15-23. [PMID: 28088467 DOI: 10.1016/j.mce.2017.01.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 01/09/2017] [Indexed: 01/20/2023]
Abstract
Several EGFR inhibitors are currently undergoing clinical assessment or are approved for the clinical management of patients with varying tumour types. However, treatment often results in a lack of response in many patients. The majority of patients that initially respond eventually present with tumours that display acquired resistance to the original therapy. A large number of receptor tyrosine and intracellular kinases have been implicated in driving signaling that mediates this tumour resistance to anti-EGFR targeted therapy, and in a few cases these discoveries have led to overall changes in prospective tumour screening and clinical practice (K-RAS in mCRC and EGFR T790M in NSCLC). In this mini-review, we specifically focus on the role of the STAT3 signaling axis in providing both intrinsic and acquired resistance to inhibitors of the EGFR. We also focus on STAT3 pathway targeting in an attempt to overcome resistance to anti-EGFR therapeutics.
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Affiliation(s)
- Ahmad A Zulkifli
- Department of Surgery, The University of Melbourne, The Royal Melbourne Hospital, Parkville, Victoria 3050, Australia
| | - Fiona H Tan
- Department of Surgery, The University of Melbourne, The Royal Melbourne Hospital, Parkville, Victoria 3050, Australia
| | - Tracy L Putoczki
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3050, Australia
| | - Stanley S Stylli
- Department of Surgery, The University of Melbourne, The Royal Melbourne Hospital, Parkville, Victoria 3050, Australia; Department of Neurosurgery, The Royal Melbourne Hospital, Parkville, Victoria 3050, Australia
| | - Rodney B Luwor
- Department of Surgery, The University of Melbourne, The Royal Melbourne Hospital, Parkville, Victoria 3050, Australia.
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12
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Haan S, Bahlawane C, Wang J, Nazarov PV, Muller A, Eulenfeld R, Haan C, Rolvering C, Vallar L, Satagopam VP, Sauter T, Wiesinger MY. The oncogenic FIP1L1-PDGFRα fusion protein displays skewed signaling properties compared to its wild-type PDGFRα counterpart. JAKSTAT 2015; 4:e1062596. [PMID: 26413425 PMCID: PMC4583054 DOI: 10.1080/21623996.2015.1062596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/05/2015] [Accepted: 06/09/2015] [Indexed: 01/05/2023] Open
Abstract
Aberrant activation of oncogenic kinases is frequently observed in human cancers, but the underlying mechanism and resulting effects on global signaling are incompletely understood. Here, we demonstrate that the oncogenic FIP1L1-PDGFRα kinase exhibits a significantly different signaling pattern compared to its PDGFRα wild type counterpart. Interestingly, the activation of primarily membrane-based signal transduction processes (such as PI3-kinase- and MAP-kinase- pathways) is remarkably shifted toward a prominent activation of STAT factors. This diverging signaling pattern compared to classical PDGF-receptor signaling is partially coupled to the aberrant cytoplasmic localization of the oncogene, since membrane targeting of FIP1L1-PDGFRα restores activation of MAPK- and PI3K-pathways. In stark contrast to the classical cytokine-induced STAT activation process, STAT activation by FIP1L1-PDGFRα does neither require Janus kinase activity nor Src kinase activity. Furthermore, we investigated the mechanism of STAT5 activation via FIP1L1-PDGFRα in more detail and found that STAT5 activation does not involve an SH2-domain-mediated binding mechanism. We thus demonstrate that STAT5 activation occurs via a non-canonical activation mechanism in which STAT5 may be subject to a direct phosphorylation by FIP1L1-PDGFRα.
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Affiliation(s)
- Serge Haan
- Molecular Disease Mechanisms Group; Life Sciences Research Unit; University of Luxembourg; Luxembourg , Luxembourg
| | - Christelle Bahlawane
- Molecular Disease Mechanisms Group; Life Sciences Research Unit; University of Luxembourg; Luxembourg , Luxembourg
| | - Jiali Wang
- Molecular Disease Mechanisms Group; Life Sciences Research Unit; University of Luxembourg; Luxembourg , Luxembourg
| | - Petr V Nazarov
- Genomics Research Unit; Luxembourg Institute of Health; Luxembourg , Luxembourg
| | - Arnaud Muller
- Genomics Research Unit; Luxembourg Institute of Health; Luxembourg , Luxembourg
| | - René Eulenfeld
- Signal Transduction Group; Life Sciences Research Unit; University of Luxembourg; Luxembourg , Luxembourg
| | - Claude Haan
- Signal Transduction Group; Life Sciences Research Unit; University of Luxembourg; Luxembourg , Luxembourg
| | - Catherine Rolvering
- Signal Transduction Group; Life Sciences Research Unit; University of Luxembourg; Luxembourg , Luxembourg
| | - Laurent Vallar
- Genomics Research Unit; Luxembourg Institute of Health; Luxembourg , Luxembourg
| | - Venkata P Satagopam
- Luxembourg Center for Systems Biomedicine; University of Luxembourg ; Esch-sur-Alzette, Luxembourg
| | - Thomas Sauter
- Systems Biology Group; Life Sciences Research Unit; University of Luxembourg; Luxembourg , Luxembourg
| | - Monique Yvonne Wiesinger
- Systems Biology Group; Life Sciences Research Unit; University of Luxembourg; Luxembourg , Luxembourg
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13
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Constitutive activation of oncogenic PDGFRα-mutant proteins occurring in GIST patients induces receptor mislocalisation and alters PDGFRα signalling characteristics. Cell Commun Signal 2015; 13:21. [PMID: 25880691 PMCID: PMC4396151 DOI: 10.1186/s12964-015-0096-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/05/2015] [Indexed: 12/11/2022] Open
Abstract
Background Gastrointestinal stromal tumours (GIST) are mainly characterised by the presence of activating mutations in either of the two receptor tyrosine kinases c-KIT or platelet-derived growth factor receptor-α (PDGFRα). Most mechanistic studies dealing with GIST mutations have focused on c-KIT and far less is known about the signalling characteristics of the mutated PDGFRα proteins. Here, we study the signalling capacities and corresponding transcriptional responses of the different PDGFRα proteins under comparable genomic conditions. Results We demonstrate that the constitutive signalling via the oncogenic PDGFRα mutants favours a mislocalisation of the receptors and that this modifies the signalling characteristics of the mutated receptors. We show that signalling via the oncogenic PDGFRα mutants is not solely characterised by a constitutive activation of the conventional PDGFRα signalling pathways. In contrast to wild-type PDGFRα signal transduction, the activation of STAT factors (STAT1, STAT3 and STAT5) is an integral part of signalling mediated via mutated PDGF-receptors. Furthermore, this unconventional STAT activation by mutated PDGFRα is already initiated in the endoplasmic reticulum whereas the conventional signalling pathways rather require cell surface expression of the receptor. Finally, we demonstrate that the activation of STAT factors also translates into a biologic response as highlighted by the induction of STAT target genes. Conclusion We show that the overall oncogenic response is the result of different signatures emanating from different cellular compartments. Furthermore, STAT mediated responses are an integral part of mutated PDGFRα signalling. Electronic supplementary material The online version of this article (doi:10.1186/s12964-015-0096-8) contains supplementary material, which is available to authorized users.
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14
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Xu B, Luo Y, Liu Y, Li BY, Wang Y. Platelet-derived growth factor-BB enhances MSC-mediated cardioprotection via suppression of miR-320 expression. Am J Physiol Heart Circ Physiol 2015; 308:H980-9. [PMID: 25724494 DOI: 10.1152/ajpheart.00737.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 02/21/2015] [Indexed: 01/10/2023]
Abstract
Delivery of bone marrow-derived mesenchymal stem cells (MSCs) to myocardium protects ischemic tissue through the paracrine release of beneficial angiogenic and cytoprotective factors. Platelet-derived growth factor (PDGF)-BB, a potent mitogen of MSCs, is involved in the pathophysiology of ischemic heart disease. However, the role(s) of PDGF in MSC-mediated cardioprotection remains unknown. Here, we found that PDGF treatment of MSCs resulted in rapid activation of both Akt and ERK (central intracellular signal mediators), upregulated VEGF, and induced phosphorylation of the activator protein-1 (AP-1) transcription factor c-Jun. Examination of several microRNA genes having predicted promoter c-Jun-binding sites showed that PDGF treatment resulted in upregulation of miR-16-2 and downregulation of miRs-23b, -27b, and -320b. To examine possible PDGF augmentation of therapeutic potential, we evaluated the effects of PDGF using an ex vivo isolated mouse heart ischemia-reperfusion model. Human MSCs, with or without PDGF preconditioning, were infused into the coronary circulation of isolated mouse hearts. The hearts that received PDGF-treated MSCs exhibited a greater functional recovery compared with naïve MSC-infused hearts, following ischemia-reperfusion injury. This enhanced functional recovery was abolished by overexpression of miR-320, a microRNA we found downregulated by PDGF-activated c-Jun. Overexpression of miR-320 also resulted in upregulation of insulin-like growth factor binding protein (IGFBP) family members, suggesting PDGF "cross talk" with the mitogenic IGF signaling pathway. Collectively, we conclude that PDGF enhances MSC-mediated cardioprotection via a c-Jun/miR-320 signaling mechanism and PDGF MSC preconditioning may be an effective therapeutic strategy for cardiac ischemia.
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Affiliation(s)
- Bing Xu
- Department of Pharmacology, Harbin Medical University, Harbin, China; Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Yong Luo
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Yunlong Liu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana; and
| | - Bai-Yan Li
- Department of Pharmacology, Harbin Medical University, Harbin, China; Department of Biomedical Engineering, Indiana University Purdue University, Indianapolis, Indiana
| | - Yue Wang
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana;
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15
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Lee MS, Jones T, Song DY, Jang JH, Jung JU, Gao SJ. Exploitation of the complement system by oncogenic Kaposi's sarcoma-associated herpesvirus for cell survival and persistent infection. PLoS Pathog 2014; 10:e1004412. [PMID: 25254972 PMCID: PMC4177982 DOI: 10.1371/journal.ppat.1004412] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 08/19/2014] [Indexed: 11/26/2022] Open
Abstract
During evolution, herpesviruses have developed numerous, and often very ingenious, strategies to counteract efficient host immunity. Specifically, Kaposi's sarcoma-associated herpesvirus (KSHV) eludes host immunity by undergoing a dormant stage, called latency wherein it expresses a minimal number of viral proteins to evade host immune activation. Here, we show that during latency, KSHV hijacks the complement pathway to promote cell survival. We detected strong deposition of complement membrane attack complex C5b-9 and the complement component C3 activated product C3b on Kaposi's sarcoma spindle tumor cells, and on human endothelial cells latently infected by KSHV, TIME-KSHV and TIVE-LTC, but not on their respective uninfected control cells, TIME and TIVE. We further showed that complement activation in latently KSHV-infected cells was mediated by the alternative complement pathway through down-regulation of cell surface complement regulatory proteins CD55 and CD59. Interestingly, complement activation caused minimal cell death but promoted the survival of latently KSHV-infected cells grown in medium depleted of growth factors. We found that complement activation increased STAT3 tyrosine phosphorylation (Y705) of KSHV-infected cells, which was required for the enhanced cell survival. Furthermore, overexpression of either CD55 or CD59 in latently KSHV-infected cells was sufficient to inhibit complement activation, prevent STAT3 Y705 phosphorylation and abolish the enhanced survival of cells cultured in growth factor-depleted condition. Together, these results demonstrate a novel mechanism by which an oncogenic virus subverts and exploits the host innate immune system to promote viral persistent infection. The complement system is an important part of the innate immune system. Pathogens have evolved diverse strategies to evade host immune responses including attack of the complement system. Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with Kaposi's sarcoma (KS), primary effusion lymphoma and a subset of multicentric Castleman's disease. KSHV encodes a number of viral proteins to counter host immune responses during productive lytic replication. On the other hand, KSHV utilizes latency as a default replication program during which it expresses a minimal number of proteins to evade host immune detection. Thus, the complement system is expected to be silent during KSHV latency. In this study, we have found that the complement system is unexpectedly activated in latently KSHV-infected endothelial cells and in KS tumor cells wherein KSHV downregulates the expression of CD55 and CD59 complement regulatory proteins. More interestingly, most of latently KSHV-infected cells not only are resistant to complement-mediated cell killing, but also acquire survival advantage by inducing STAT3 tyrosine phosphorylation. These results demonstrate a novel mechanism by which an oncogenic virus exploits the host innate immune system to promote viral persistent infection.
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MESH Headings
- Apoptosis/immunology
- Blotting, Western
- Cell Proliferation
- Cells, Cultured
- Complement C3b/genetics
- Complement C3b/metabolism
- Complement C5b/genetics
- Complement C5b/metabolism
- Endothelium, Vascular/immunology
- Endothelium, Vascular/pathology
- Endothelium, Vascular/virology
- Flow Cytometry
- Fluorescent Antibody Technique
- Herpesvirus 8, Human/physiology
- Human Umbilical Vein Endothelial Cells/immunology
- Human Umbilical Vein Endothelial Cells/pathology
- Human Umbilical Vein Endothelial Cells/virology
- Humans
- Inflammation/immunology
- Inflammation/pathology
- Inflammation/virology
- Neovascularization, Pathologic
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- STAT3 Transcription Factor/genetics
- STAT3 Transcription Factor/metabolism
- Sarcoma, Kaposi/immunology
- Sarcoma, Kaposi/pathology
- Sarcoma, Kaposi/virology
- Viral Proteins/genetics
- Viral Proteins/immunology
- Viral Proteins/metabolism
- Virus Latency
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Affiliation(s)
- Myung-Shin Lee
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Department of Microbiology and Immunology, Eulji University School of Medicine, Daejeon, Republic of Korea
| | - Tiffany Jones
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Dae-Yong Song
- Department of Anatomy and Neuroscience, Eulji University School of Medicine, Daejeon, Republic of Korea
| | - Jae-Hyuk Jang
- Department of Microbiology and Immunology, Eulji University School of Medicine, Daejeon, Republic of Korea
| | - Jae U. Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Shou-Jiang Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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16
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Blazevic T, Schwaiberger AV, Schreiner CE, Schachner D, Schaible AM, Grojer CS, Atanasov AG, Werz O, Dirsch VM, Heiss EH. 12/15-lipoxygenase contributes to platelet-derived growth factor-induced activation of signal transducer and activator of transcription 3. J Biol Chem 2013; 288:35592-603. [PMID: 24165129 PMCID: PMC3853304 DOI: 10.1074/jbc.m113.489013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We showed previously that the small molecule indirubin-3′-monoxime (I3MO) prevents vascular smooth muscle cell (VSMC) proliferation by selectively inhibiting signal transducer and activator of transcription 3 (STAT3). Looking for the underlying upstream molecular mechanism, we here reveal the important role of reactive oxygen species (ROS) for PDGF-induced STAT3 activation in VSMC. We show that neither NADPH-dependent oxidases (Noxes) nor mitochondria, but rather 12/15-lipoxygenase (12/15-LO) are pivotal ROS sources involved in the redox-regulated signal transduction from PDGFR to STAT3. Accordingly, pharmacological and genetic interference with 12/15-LO activity selectively inhibited PDGF-induced Src activation and STAT3 phosphorylation. I3MO is able to blunt PDGF-induced ROS and 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) production, indicating an inhibitory action of I3MO on 12/15-LO and consequently on STAT3. We identify 12/15-LO as a hitherto unrecognized signaling hub in PDGF-triggered STAT3 activation and show for the first time a negative impact of I3MO on 12/15-LO.
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Affiliation(s)
- Tina Blazevic
- From the Department for Pharmacognosy, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria and
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17
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Subramaniam A, Shanmugam MK, Perumal E, Li F, Nachiyappan A, Dai X, Swamy SN, Ahn KS, Kumar AP, Tan BKH, Hui KM, Sethi G. Potential role of signal transducer and activator of transcription (STAT)3 signaling pathway in inflammation, survival, proliferation and invasion of hepatocellular carcinoma. Biochim Biophys Acta Rev Cancer 2012; 1835:46-60. [PMID: 23103770 DOI: 10.1016/j.bbcan.2012.10.002] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 10/18/2012] [Accepted: 10/21/2012] [Indexed: 12/14/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the most lethal malignancies, and is also the fourth most common cancer worldwide with around 700,000 new cases each year. Currently, first line chemotherapeutic drugs used for HCC include fluorouracil, cisplatin, doxorubicin, paclitaxel and mitomycin, but most of these are non-selective cytotoxic molecules with significant side effects. Sorafenib is the only approved targeted therapy by the U.S. Food and Drug Administration for HCC treatment, but patients suffer from various kinds of adverse effects, including hypertension. The signal-transducer-and-activator-of-transcription 3 (STAT3) protein, one of the members of STATs transcription factor family, has been implicated in signal transduction by different cytokines, growth factors and oncogenes. In normal cells, STAT3 activation is tightly controlled to prevent dysregulated gene transcription, whereas constitutively activated STAT3 plays an important role in tumorigenesis through the upregulation of genes involved in anti-apoptosis, proliferation and angiogenesis. Thus, pharmacologically safe and effective agents that can block STAT3 activation have the potential both for the prevention and treatment of HCC. In the present review, we discuss the possible role of STAT3 signaling cascade and its interacting partners in the initiation of HCC and also analyze the role of various STAT3 regulated genes in HCC progression, inflammation, survival, invasion and angiogenesis.
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Affiliation(s)
- Aruljothi Subramaniam
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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18
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Doucette TA, Kong LY, Yang Y, Ferguson SD, Yang J, Wei J, Qiao W, Fuller GN, Bhat KP, Aldape K, Priebe W, Bögler O, Heimberger AB, Rao G. Signal transducer and activator of transcription 3 promotes angiogenesis and drives malignant progression in glioma. Neuro Oncol 2012; 14:1136-45. [PMID: 22753228 DOI: 10.1093/neuonc/nos139] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Signal transducer and activator of transcription (STAT) 3 has been described as a "master regulator" of signaling pathways involved in the transition from low-grade glioma (LGG) to high-grade glioma (HGG). Although STAT3 is overexpressed in HGGs, it remains unclear whether its overexpression is sufficient to induce or promote the malignant progression of glioma. To characterize the effect of STAT3 expression on tumor progression in vivo, we expressed the STAT3 gene in glioneuronal progenitor cells in mice. STAT3 was expressed alone or concurrently with platelet-derived growth factor B (PDGFB), a well-described initiator of LGG. STAT3 alone was insufficient to induce tumor formation; however, coexpression of STAT3 with PDGFB in mice resulted in a significantly higher incidence of HGGs than PDGFB alone. The median symptomatic tumor latency in mice coexpressing STAT3 and PDGFB was significantly shorter, and mice that developed symptomatic tumors demonstrated significantly higher expression of phosphorylated STAT3 intratumorally. In HGGs, expression of STAT3 was associated with suppression of apoptosis and an increase in tumor cell proliferation. HGGs induced by STAT3 and PDGFB also displayed frequent foci of necrosis and microvascular proliferation. The expression of CD31 (a marker of endothelial proliferation) was significantly higher in tumors induced by coexpression of STAT3 and PDGFB. When mice injected with PDGFB and STAT3 were treated with a STAT3 inhibitor, median survival increased and the incidence of HGG and CD31 expression decreased significantly. These results demonstrate that STAT3 promotes the malignant progression of glioma. Inhibiting STAT3 expression mitigates tumor progression and improves survival, validating it as a therapeutic target.
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19
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Thingnes J, Lavelle TJ, Gjuvsland AB, Omholt SW, Hovig E. Towards a quantitative understanding of the MITF-PIAS3-STAT3 connection. BMC SYSTEMS BIOLOGY 2012; 6:11. [PMID: 22316093 PMCID: PMC3341200 DOI: 10.1186/1752-0509-6-11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2011] [Accepted: 02/08/2012] [Indexed: 01/27/2023]
Abstract
Background Expression of the two transcription factors microphthalmia-associated transcription factor (MITF) and signal transducer and activator of transcription 3 (STAT3) are tightly connected to cell proliferation and survival, and are important for melanocyte development. The co-regulation of MITF and STAT3 via their binding to a common inhibitor Protein Inhibitor of Activated STAT3 (PIAS3) is intriguing. A better quantitative understanding of this regulation is likely to be important for elucidation of the melanocyte biology. Results We present a mathematical model describing the MITF-PIAS3-STAT3 signalling network. A default parameter set was developed, partly informed by the literature and partly by constraining the model to mimic reported behavioural features of the system. In addition, a set of experiment-specific parameters was derived for each of 28 experiments reported in the literature. The model seems capable of accounting for most of these experiments in terms of observed temporal development of protein amounts and phosphorylation states. Further, the results also suggest that this system possesses some regulatory features yet to be elucidated. Conclusions We find that the experimentally observed crosstalk between MITF and STAT3 via PIAS3 in melanocytes is faithfully reproduced in our model, offering mechanistic explanations for this behaviour, as well as providing a scaffold for further studies of MITF signalling in melanoma.
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Affiliation(s)
- Josef Thingnes
- Centre for Integrative Genetics, Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, 1430 Ås, Norway.
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20
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Chen PY, Simons M, Friesel R. FRS2 via fibroblast growth factor receptor 1 is required for platelet-derived growth factor receptor beta-mediated regulation of vascular smooth muscle marker gene expression. J Biol Chem 2009; 284:15980-92. [PMID: 19339244 DOI: 10.1074/jbc.m809399200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vascular smooth muscle cells (VSMC) exhibit phenotypic plasticity and change from a quiescent contractile phenotype to a proliferative synthetic phenotype during physiological arteriogenesis and pathological conditions such as atherosclerosis and restenosis. Platelet-derived growth factor (PDGF)-BB is a potent inducer of the VSMC synthetic phenotype; however, much less is known about the role of fibroblast growth factor-2 (FGF2) in this process. Here, we show using signal transduction mutants of FGF receptor 1 (FGFR1) expressed in rat VSMC that the adaptor protein FRS2 is essential for FGFR1-mediated phenotypic modulation and down-regulation of VSMC smooth muscle alpha-actin (SMA) gene expression. In addition, we show that PDGF-BB and FGF2 act synergistically to induce cell proliferation and down-regulate SMA and SM22alpha in VSMC. Furthermore, we show that PDGF-BB induces tyrosine phosphorylation of FGFR1 and that this phosphorylation is mediated by PDGF receptor-beta (PDGFRbeta), but not c-Src. We demonstrate that FRS2 co-immunoprecipitates with PDGFRbeta in a complex that requires FGFR1 and that both the extracellular and the intracellular domains of FGFR1 are required for association with PDGFRbeta, whereas the cytoplasmic domain of FGFR1 is required for FRS2 association with the FGFR1-PDGFRbeta complex. Knockdown of FRS2 in VSMC by RNA interference inhibited PDGF-BB-mediated down-regulation of SMA and SM22alpha without affecting PDGF-BB mediated cell proliferation or ERK activation. Together, these data support the notion that PDGFRbeta down-regulates SMA and SM22alpha through formation of a complex that requires FGFR1 and FRS2 and prove novel insight into VSMC phenotypic plasticity.
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Affiliation(s)
- Pei-Yu Chen
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074, USA.
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21
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Regis G, Pensa S, Boselli D, Novelli F, Poli V. Ups and downs: the STAT1:STAT3 seesaw of Interferon and gp130 receptor signalling. Semin Cell Dev Biol 2008; 19:351-9. [PMID: 18620071 DOI: 10.1016/j.semcdb.2008.06.004] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 06/04/2008] [Accepted: 06/17/2008] [Indexed: 02/04/2023]
Abstract
Downstream of cytokine or growth factor receptors, STAT3 counteracts inflammation and promotes cell survival/proliferation and immune tolerance while STAT1 inhibits proliferation and favours innate and adaptive immune responses. STAT1 and STAT3 activation are reciprocally regulated and perturbation in their balanced expression or phosphorylation levels may re-direct cytokine/growth factor signals from proliferative to apoptotic, or from inflammatory to anti-inflammatory. Here we review the functional canonical and non-canonical effects of STAT1/3 activation and discuss the hypothesis that perturbation of their expression and/or activation levels may provide novel therapeutic strategies in different clinical settings and particularly in cancer.
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Affiliation(s)
- Gabriella Regis
- Molecular Biotechnology Center, University of Turin, via Nizza 52, 10126 Turin, Italy.
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22
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Herrmann A, Vogt M, Mönnigmann M, Clahsen T, Sommer U, Haan S, Poli V, Heinrich PC, Müller-Newen G. Nucleocytoplasmic shuttling of persistently activated STAT3. J Cell Sci 2007; 120:3249-61. [PMID: 17726064 DOI: 10.1242/jcs.03482] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Persistent activation of the transcription factor STAT3 has been detected in many types of cancer and plays an important role in tumor progression, immune evasion and metastasis. To analyze persistent STAT3 activation we coexpressed STAT3 with v-Src. We found that tyrosine phosphorylation of STAT3 by v-Src is independent of Janus kinases (Jaks), the canonical activators of STATs. The STAT3-induced feedback inhibitor, suppressor of cytokine signaling 3 (SOCS3), did not interfere with STAT3 activation by v-Src. However, the protein inhibitor of activated STAT3 (PIAS3) suppressed gene induction by persistently activated STAT3. We measured nucleocytoplasmic shuttling of STAT3 in single cells by bleaching the YFP moiety of double-labelled STAT3-CFP-YFP in the cytoplasm. Analysis of the subcellular distribution of CFP and YFP fluorescence over time by mathematical modeling and computational parameter estimation revealed that activated STAT3 shuttles more rapidly than non-activated STAT3. Inhibition of exportin-1-mediated nuclear export slowed down nucleocytoplasmic shuttling of v-Src-activated STAT3 resulting in reduced tyrosine phosphorylation, decreased induction of STAT3 target genes and increased apoptosis. We propose passage of persistently activated STAT3 through the nuclear pore complex as a new target for intervention in cancer.
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Affiliation(s)
- Andreas Herrmann
- Institut für Biochemie, Universitätsklinikum RWTH Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany
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23
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Cain JA, Xiang Z, O'Neal J, Kreisel F, Colson A, Luo H, Hennighausen L, Tomasson MH. Myeloproliferative disease induced by TEL-PDGFRB displays dynamic range sensitivity to Stat5 gene dosage. Blood 2007; 109:3906-14. [PMID: 17218386 PMCID: PMC1874559 DOI: 10.1182/blood-2006-07-036335] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Accepted: 12/26/2006] [Indexed: 12/28/2022] Open
Abstract
Expression of the constitutively activated TEL/PDGFbetaR fusion protein is associated with the t(5;12)(q33;p13) chromosomal translocation found in a subset of patients with chronic myelomonocytic leukemia. TEL/PDGFbetaR activates multiple signal transduction pathways in cell-culture systems, and expression of the TEL-PDGFRB fusion gene induces myeloproliferative disease (MPD) in mice. We used gene-targeted mice to characterize the contribution of signal transducer and activator of transcription (Stat) and Src family genes to TEL-PDGFRB-mediated transformation in methylcellulose colony and murine bone marrow transduction/transplantation assays. Fetal liver hematopoietic stem and progenitor cells harboring targeted deletion of both Stat5a and Stat5b (Stat5ab(null/null)) genes were refractory to transformation by TEL-PDGFRB in methylcellulose colony assays. Notably, these cell populations were maintained in Stat5ab(null/null) fetal livers and succumbed to transformation by c-Myc. Surprisingly, targeted disruption of either Stat5a or Stat5b alone also impaired TEL-PDGFRB-mediated transformation. Survival of TPiGFP-->Stat5a(-/-) and TPiGFP-->Stat5a(+/-) mice was significantly prolonged, demonstrating significant sensitivity of TEL-PDGFRB-induced MPD to the dosage of Stat5a. TEL-PDGFRB-mediated MPD was incompletely penetrant in TPiGFP-->Stat5b(-/-) mice. In contrast, Src family kinases Lyn, Hck, and Fgr and the Stat family member Stat1 were dispensable for TEL-PDGFRB disease. Together, these data demonstrate that Stat5a and Stat5b are dose-limiting mediators of TEL-PDGFRB-induced myeloproliferation.
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MESH Headings
- Animals
- Bone Marrow/metabolism
- Bone Marrow/pathology
- Gene Dosage
- Gene Expression Regulation, Leukemic/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Mice
- Mice, Knockout
- Oncogene Proteins, Fusion/biosynthesis
- Oncogene Proteins, Fusion/genetics
- Proto-Oncogene Proteins c-ets/biosynthesis
- Proto-Oncogene Proteins c-ets/genetics
- Receptor, Platelet-Derived Growth Factor beta/biosynthesis
- Receptor, Platelet-Derived Growth Factor beta/genetics
- Repressor Proteins/biosynthesis
- Repressor Proteins/genetics
- STAT5 Transcription Factor/biosynthesis
- STAT5 Transcription Factor/deficiency
- Signal Transduction/genetics
- Translocation, Genetic/genetics
- Tumor Stem Cell Assay
- src-Family Kinases/metabolism
- ETS Translocation Variant 6 Protein
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Affiliation(s)
- Jennifer A Cain
- Department of Internal Medicine, Division of Oncology, Washington University Siteman Cancer Center, 550 S. Euclid Avenue, St. Louis, MO 63110, USA
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24
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Kiessling A, Sperl B, Hollis A, Eick D, Berg T. Selective inhibition of c-Myc/Max dimerization and DNA binding by small molecules. ACTA ACUST UNITED AC 2006; 13:745-51. [PMID: 16873022 DOI: 10.1016/j.chembiol.2006.05.011] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 05/03/2006] [Accepted: 05/08/2006] [Indexed: 12/11/2022]
Abstract
bZip and bHLHZip protein family members comprise a large fraction of eukaryotic transcription factors and need to bind DNA in order to exert most of their fundamental biological roles. Their binding to DNA requires homo- or heterodimerization via alpha-helical domains, which generally do not contain obvious binding sites for small molecules. We have identified two small molecules, dubbed Mycro1 and Mycro2, which inhibit the protein-protein interactions between the bHLHZip proteins c-Myc and Max. Mycros are the first inhibitors of c-Myc/Max dimerization, which have been demonstrated to inhibit DNA binding of c-Myc with preference over other dimeric transcription factors in vitro. Mycros inhibit c-Myc-dependent proliferation, gene transcription, and oncogenic transformation in the low micromolar concentration range. Our data support the idea that dimeric transcription factors can be druggable even in the absence of obvious small-molecule binding pockets.
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Affiliation(s)
- Anke Kiessling
- Department of Molecular Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
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25
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Gotlib J, Cross NCP, Gilliland DG. Eosinophilic disorders: molecular pathogenesis, new classification, and modern therapy. Best Pract Res Clin Haematol 2006; 19:535-69. [PMID: 16781488 DOI: 10.1016/j.beha.2005.07.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Before the 1990s, lack of evidence for a reactive cause of hypereosinophilia or chronic eosinophilic leukemia (e.g. presence of a clonal cytogenetic abnormality or increased blood or bone marrow blasts) resulted in diagnosticians characterizing such nebulous cases as 'idiopathic hypereosinophilic syndrome (HES)'. However, over the last decade, significant advances in our understanding of the molecular pathophysiology of eosinophilic disorders have shifted an increasing proportion of cases from this idiopathic HES 'pool' to genetically defined eosinophilic diseases with recurrent molecular abnormalities. The majority of these genetic lesions result in constitutively activated fusion tyrosine kinases, the phenotypic consequence of which is an eosinophilia-associated myeloid disorder. Most notable among these is the recent discovery of the cryptic FIP1L1-PDGFRA gene fusion in karyotypically normal patients with systemic mast cell disease with eosinophilia or idiopathic HES, redefining these diseases as clonal eosinophilias. Rearrangements involving PDGFRA and PDGFRB in eosinophilic chronic myeloproliferative disorders, and of fibroblast growth factor receptor 1 (FGFR1) in the 8p11 stem cell myeloproliferative syndrome constitute additional examples of specific genetic alterations linked to clonal eosinophilia. The identification of populations of aberrant T-lymphocytes secreting eosinophilopoietic cytokines such as interleukin-5 establish a pathophysiologic basis for cases of lymphocyte-mediated hypereosinophilia. This recent revival in understanding the biologic basis of eosinophilic disorders has permitted more genetic specificity in the classification of these diseases, and has translated into successful therapeutic approaches with targeted agents such as imatinib mesylate and recombinant anti-IL-5 antibody.
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Affiliation(s)
- Jason Gotlib
- Stanford Cancer Center, 875 Blake Wilbur Drive, Room 2327B, Stanford, CA 94305-5821, USA.
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26
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Lo RKH, Wong YH. Transcriptional activation of c-Fos by constitutively active Galpha(16)QL through a STAT1-dependent pathway. Cell Signal 2006; 18:2143-53. [PMID: 16781847 DOI: 10.1016/j.cellsig.2006.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 04/25/2006] [Indexed: 02/06/2023]
Abstract
Hematopoietic restrictive Galpha(16) has long been known to stimulate phospholipase Cbeta (PLCbeta) and induce mitogen-activated protein kinase (MAPK) phosphorylation. Recently, we have demonstrated that Galpha(16) is capable of inducing the phosphorylation and transcriptional activation of transcription factors, such as signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappaB (NFkappaB). However, the downstream signaling regulation by Galpha(16) has not yet been documented. In the present study, we have determined the signaling mechanism by which constitutively active Galpha(16) mediates c-Fos transcriptional activation in human embryonic kidney (HEK) 293 cells. Overexpression of constitutively active Galpha(16), Galpha(16)QL, resulted in the stimulation of c-Fos transcriptional activation in HEK 293 cells. The participation of PLCbeta, c-Src/Janus kinase 2 (JAK2) and extracellular signal-regulated kinase (ERK) signaling pathways in Galpha(16)QL-induced c-Fos transcriptional activation was demonstrated by the use of their specific inhibitors. However, c-Jun N terminal kinase (JNK), p38 MAPK and phosphatidylinositol-3 kinase (PI3K) were not required. Interestingly, the dominant negative mutant of STAT1, but not STAT3, suppressed c-Fos transcriptional activation induced by Galpha(16)QL, implying that STAT1 was involved in this signaling mechanism. To further examine the role of STAT1 in the signaling pathway of Galpha(16), we demonstrated that Galpha(16)QL was able to induce STAT1 activation. Also, stimulation of adenosine A1 receptor-coupled Galpha(16) was shown to induce ERK and STAT1 phosphorylations in a concentration-dependent manner. Using selective inhibitors, PLCbeta, c-Src/JAK and ERK, but not JNK, p38 MAPK and PI3K, were shown to be involved in Galpha(16)QL-induced STAT1 activation. Collectively, our results demonstrate for the first time that stimulation of Galpha(16) can lead to STAT1-dependent c-Fos transcriptional activation via PLCbeta, c-Src/JAK and ERK pathways.
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Affiliation(s)
- Rico K H Lo
- Department of Biochemistry, Molecular Neuroscience Center, and Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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27
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Banerji L, Sattler M. Targeting mutated tyrosine kinases in the therapy of myeloid leukaemias. Expert Opin Ther Targets 2006; 8:221-39. [PMID: 15161429 DOI: 10.1517/14728222.8.3.221] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Myeloid leukaemias are frequently associated with translocations and mutations of tyrosine kinase genes. The products of these oncogenes, including BCR-ABL, TEL-PDGFR, Flt3 and c-Kit, have elevated tyrosine kinase activity and transform haematopoietic cells, mainly by augmentation of proliferation and enhanced viability. Activated ABL kinases are associated with chronic myeloid leukaemia. Mutations in platelet-derived growth factor receptor beta are associated with chronic myelomonocytic leukaemia. Flt3 or c-Kit cooperate with other types of oncogenes to create fully transformed acute leukaemias. Elevated activity of these tyrosine kinases is crucial for transformation, thus making the kinase domain an ideal target for therapeutic intervention. Tyrosine kinase inhibitors for various kinases are currently being evaluated in clinical trials and are potentially useful therapeutic agents in myeloid leukaemias. Here, the authors review the signalling activities, mechanism of transformation and therapeutic targeting of several tyrosine kinase oncogenes important in myeloid leukaemias.
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Affiliation(s)
- Lolita Banerji
- Dana-Farber Cancer Institute, Department of Medical Oncology, Boston, MA 02115, USA
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28
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Masamune A, Satoh M, Kikuta K, Suzuki N, Shimosegawa T. Activation of JAK-STAT pathway is required for platelet-derived growth factor-induced proliferation of pancreatic stellate cells. World J Gastroenterol 2005; 11:3385-91. [PMID: 15948243 PMCID: PMC4315992 DOI: 10.3748/wjg.v11.i22.3385] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To clarify the role of Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway in platelet-derived growth factor (PDGF) induced proliferation in activated pancreatic stellate cells (PSCs).
METHODS: PSCs were isolated from rat pancreas tissue, and used in their culture-activated, myofibroblast-like phenotype. STAT-specific binding activity was assessed by electrophoretic mobility shift assay. Activation of Src, JAK2, STAT1, STAT3, and ERK was determined by Western blotting using anti-phosphospecific antibodies. Cell proliferation was assessed by measuring the incorporation of 5-bromo-2’-deoxyuridine.
RESULTS: PDGF-BB induced STAT-specific binding activity, and activation of Src, JAK2, STAT1, STAT3, and ERK. Ethanol and acetaldehyde at clinically relevant concentrations decreased basal activation of JAK2 and STAT3. PDGF-induced activation of STAT1 and STAT3 was inhibited by a Src inhibitor PP1 and a JAK2 inhibitor AG490, whereas PDGF-induced activation of ERK was inhibited by PP1, and not by AG490. PDGF-induced proliferation was inhibited by PP1 and AG490 as well as by STAT3 antisense oligonucleotide.
CONCLUSION: PDGF-BB activated JAK2-STAT pathway via Src-dependent mechanism. Activation of JAK2-STAT3 pathway, in addition to ERK, may play a role in PDGF-induced proliferation of PSCs.
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Affiliation(s)
- Atsushi Masamune
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-cyo, Aoba-ku, Sendai 980-8574, Japan.
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29
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Gotlib J. Molecular classification and pathogenesis of eosinophilic disorders: 2005 update. Acta Haematol 2005; 114:7-25. [PMID: 15995322 DOI: 10.1159/000085559] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Use of the term "idiopathic hypereosinophilic syndrome (HES)" has highlighted our basic lack of understanding of the molecular pathophysiology of eosinophilic disorders. However, over the last 10 years, the study of hypereosinophilia has enjoyed a revival. This interest has been rekindled by two factors: (1) the development of increasingly sophisticated molecular biology techniques that have unmasked recurrent genetic abnormalities linked to eosinophilia, and (2) the successful application of targeted therapy with agents such as imatinib to treat eosinophilic diseases. To date, most of these recurrent molecular abnormalities have resulted in constitutively activated fusion tyrosine kinases whose phenotypic consequence is an eosinophilia-associated myeloid disorder. Most notable among these are rearrangements of platelet-derived growth factor receptors alpha and beta (PDGFRalpha, PDGFRbeta), which define a small subset of patients with eosinophilic chronic myeloproliferative disorders (MPDs) and/or overlap myelodysplastic syndrome/MPD syndromes, including chronic myelomonocytic leukemia. Discovery of the cryptic FIP1L1-PDGFRA gene fusion in cytogenetically normal patients with systemic mast cell disease with eosinophilia or idiopathic HES has redefined these diseases as clonal eosinophilias. A growing list of fibroblast growth factor receptor 1 fusion partners has similarly emerged in the 8p11 myeloproliferative syndromes, which are often characterized by elevated eosinophil counts. Herein the focus is on the molecular gains made in these MPD-type eosinophilias, and the classification and clinicopathological issues related to hypereosinophilic syndromes, including the lymphocyte variant. Success in establishing the molecular basis of a group of once seemingly heterogeneous diseases has now the laid the foundation for establishing a semi-molecular classification scheme of eosinophilic disorders.
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MESH Headings
- Humans
- Hypereosinophilic Syndrome/classification
- Hypereosinophilic Syndrome/genetics
- Hypereosinophilic Syndrome/pathology
- Leukemia, Myelomonocytic, Chronic/classification
- Leukemia, Myelomonocytic, Chronic/genetics
- Leukemia, Myelomonocytic, Chronic/pathology
- Mastocytosis, Systemic/classification
- Mastocytosis, Systemic/genetics
- Mastocytosis, Systemic/pathology
- Myeloproliferative Disorders/classification
- Myeloproliferative Disorders/genetics
- Myeloproliferative Disorders/pathology
- Oncogene Proteins, Fusion/genetics
- Proto-Oncogene Proteins/genetics
- Receptor, Platelet-Derived Growth Factor alpha/genetics
- Receptor, Platelet-Derived Growth Factor beta/genetics
- Translocation, Genetic/genetics
- mRNA Cleavage and Polyadenylation Factors/genetics
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Affiliation(s)
- Jason Gotlib
- Stanford Cancer Center, 875 Blake Wilbur Drive, Rm. 2327B, Stanford, CA 94305-5821, USA.
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30
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Neeli I, Liu Z, Dronadula N, Ma ZA, Rao GN. An essential role of the Jak-2/STAT-3/cytosolic phospholipase A(2) axis in platelet-derived growth factor BB-induced vascular smooth muscle cell motility. J Biol Chem 2004; 279:46122-8. [PMID: 15322111 DOI: 10.1074/jbc.m406922200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Platelet-derived growth factor-BB (PDGF-BB) is a potent motogen for vascular smooth muscle cells (VSMCs). To understand its motogenic signaling events, we have studied the role of the Janus-activated kinase/signal transducers and activators of transcription (Jak/STAT) pathway and cytosolic phospholipase A(2) (cPLA(2)). PDGF-BB stimulated tyrosine phosphorylation of Jak-2 and STAT-3 in a time-dependent manner in VSMCs. In addition, AG490 and Jak-2KEpRK5, a selective pharmacological inhibitor and a dominant negative mutant, respectively, of Jak-2, attenuated PDGF-BB-induced STAT-3 tyrosine phosphorylation and its DNA binding and reporter gene activities. PDGF-BB induced VSMC motility in a dose-dependent manner with a maximum effect at 10 ng/ml. Dominant negative mutant-dependent suppression of Jak-2 and STAT-3 blocked PDGF-BB-induced VSMC motility. PDGF-BB induced the expression of cPLA(2) in a Jak-2/STAT-3-dependent manner, and pharmacological inhibitors of cPLA(2) prevented PDGFBB-induced VSMC motility. Furthermore, either exogenous addition of arachidonic acid or forced expression of cPLA(2) rescued PDGF-BB-induced VSMC motility from inhibition by blockade of Jak-2 and STAT-3 activation. Together, these results for the first time show that PDGF-BB-induced VSMC motility requires activation of the Jak-2/STAT-3/cPLA(2) signaling axis.
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Affiliation(s)
- Indira Neeli
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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31
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Guren TK, Ødegård J, Abrahamsen H, Thoresen GH, Susa M, Andersson Y, Østby E, Christoffersen T. EGF receptor-mediated, c-Src-dependent, activation of Stat5b is downregulated in mitogenically responsive hepatocytes. J Cell Physiol 2003; 196:113-23. [PMID: 12767047 DOI: 10.1002/jcp.10282] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Signal transducer and activator of transcription (STAT) proteins may be activated by epidermal growth factor (EGF), but their role in EGF receptor-mediated mitogenic signaling is not clear. We previously showed that Stat5b was activated by EGF in rat hepatocytes in primary monolayer culture. In the present study, we found that EGF induced tyrosine phosphorylation of Stat5b both on Tyr-699, which correlated with specific DNA binding activity, and also on other tyrosine residues. The Src tyrosine kinase inhibitor CGP77675 blocked the EGF-induced activation of Stat5b, but did not affect the Stat5b activation by growth hormone (GH) or prolactin (PRL). The Stat5b response to EGF was most pronounced soon (3 h) after plating (early G(1)) and at high cell density (50,000 hepatocytes per cm(2)). However, at this cell density EGF did not stimulate DNA synthesis. In hepatocytes at 24 h of culturing (mid/late G(1)) with 20,000 cells per cm(2), EGF induced strong phosphorylation of the EGF receptor, as well as Shc and ERK, and stimulated DNA synthesis, but did not activate Stat5b, although the Stat5b response to GH or PRL was retained. A strong GH-induced Stat5b activation neither influenced the DNA synthesis alone nor enhanced the mitogenic effect of EGF. The results show that EGF induces tyrosine phosphorylation and DNA-binding activity of Stat5b in a manner different from GH and PRL, apparently by a Src-dependent mechanism. The data also provide further evidence that Stat5b is not required for mitogenic signaling from the EGF receptor.
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Affiliation(s)
- Tormod K Guren
- Department of Pharmacology, Faculty of Medicine, University of Oslo, Oslo, Norway.
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32
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Yellaturu CR, Rao GN. Cytosolic phospholipase A2 is an effector of Jak/STAT signaling and is involved in platelet-derived growth factor BB-induced growth in vascular smooth muscle cells. J Biol Chem 2003; 278:9986-92. [PMID: 12529382 DOI: 10.1074/jbc.m211276200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Platelet-derived growth factor-BB (PDGF-BB) is a potent mitogen and chemoattractant for vascular smooth muscle cells (VSMC). To understand its mitogenic and chemotactic signaling events, we studied the role of cytosolic phospholipase A(2) (cPLA(2)) and the Jak/STAT pathway. PDGF-BB induced the expression and activity of cPLA(2) in a time-dependent manner in VSMC. Arachidonyl trifluoromethyl ketone, a potent and specific inhibitor of cPLA(2), significantly reduced PDGF-BB-induced arachidonic acid release and DNA synthesis. PDGF-BB stimulated tyrosine phosphorylation of Jak-2 in a time-dependent manner. In addition, PDGF-BB activated STAT-3 as determined by its tyrosine phosphorylation, DNA-binding activity, and reporter gene expression, and these responses were suppressed by AG490, a selective inhibitor of Jak-2. AG490 and a dominant-negative mutant of STAT-3 also attenuated PDGF-BB-induced expression of cPLA(2,) arachidonic acid release, and DNA synthesis in VSMC. Together, these results suggest that induction of expression of cPLA(2) and arachidonic acid release are involved in VSMC growth in response to PDGF-BB and that these events are mediated by Jak-2-dependent STAT-3 activation.
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Affiliation(s)
- Chandrahasa R Yellaturu
- Department of Physiology and the Center for Vascular Biology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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33
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Le MN, Kohanski RA, Wang LH, Sadowski HB. Dual mechanism of signal transducer and activator of transcription 5 activation by the insulin receptor. Mol Endocrinol 2002; 16:2764-79. [PMID: 12456798 DOI: 10.1210/me.2002-0017] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Insulin stimulates signal transducer and activator of transcription 5 (Stat5) activation in insulin receptor (IR)-overexpressing cell lines and in insulin target tissues of mice. Stat5b and insulin receptor substrate 1 (IRS-1) interact with the same autophosphorylation site in the IR [phosphotyrosine (pY) 972] in yeast two-hybrid assays, and the IR phosphorylates Stat5b in vitro. These data suggest that Stat5 proteins might be recruited to, and phosphorylated by, the activated IR in vivo. Nevertheless, insulin activates Janus kinases (JAKs) in IR-overexpressing cell lines and in insulin target tissues. To determine whether Stat5 proteins must be recruited to the pY972LSA motif in the IR for insulin-stimulated activation in mammalian cells, we generated and tested a series of IR mutants. The L973R/A975D mutation abolishes the ability of the IR to induce Stat5 activation, whereas IRS-1 phosphorylation is unaffected. In contrast, the N969A/P970A mutation in the IR has no effect on Stat5 activation but significantly reduces IRS-1 phosphorylation. In coimmunoprecipitation assays, insulin-stimulated Stat5 activation correlates with Stat5 recruitment to the IR. We also find that insulin stimulates tyrosine phosphorylation of JAKs that are constitutively associated with the IR. Expression of dominant-negative (DN) JAKs, the JAK inhibitor suppressor of cytokine signaling 1, or pretreatment with the JAK inhibitor, AG490, reduces, but does not eliminate, insulin-induced Stat5 activation. Expression of the appropriate pair of DN JAKs in each of the singly JAK-deficient cell lines further establishes a component of insulin-stimulated Stat5 activation that is JAK independent. This likely represents phosphorylation of Stat5 proteins by the IR, as we find that IR kinase domain phosphorylates Stat5b in vitro on Y699 as efficiently as JAK2. Increasing the concentration of Stat5 proteins in cells favors the direct phosphorylation of Stat5 by the IR kinase where the DN-JAK inhibition of insulin-stimulated Stat5 activation becomes insignificant. At physiological levels of Stat5 however, we propose that JAKs and the IR both contribute to the insulin-induced phosphorylation of Stat5.
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Affiliation(s)
- Maithao N Le
- Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA
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34
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Abstract
Stats (signal transducer and activator of transcription) are latent transcription factors that translocate from the cytoplasm to the nucleus. Constitutive activation of Stat3 alpha by upstream oncoproteins and receptor tyrosine kinases has been found in many human tumors and tumor-derived cell lines. Constitutively activated Stat3 alpha is often correlated with the activation of ErbB-2, a member of the EGFR family. To explore the involvement of ErbB-2 in the activation of Stat3 and the mechanism underlying this event, an ErbB-2 point mutant was used as a model of constitutively activated receptor. Phenylalanine mutations (Y-->F) were made in the autophosphorylation sites of the receptor, and their ability to activate Stat3 alpha was evaluated. Our results suggest that Stat3 alpha and JAK2 associates with ErbB-2 prior to phosphorylation of the receptor and that full activation of Stat3 alpha by ErbB-2 requires the participation of other non-receptor tyrosine kinases. Both Src and Jak2 kinases contribute to the activation of Stat3 alpha but Src binds to ErbB-2 only when the receptor is phosphorylated. Our results also suggest that tyrosine 1139 may be important for Src homology 2 domain association because a mutant lacking this tyrosine reduces the ability of the Src homology 2 domain to bind to ErbB-2 and significantly decreases its ability to activate Stat3 alpha.
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Affiliation(s)
- Zhiyong Ren
- Department of Neurosurgery, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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35
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Irusta PM, Luo Y, Bakht O, Lai CC, Smith SO, DiMaio D. Definition of an inhibitory juxtamembrane WW-like domain in the platelet-derived growth factor beta receptor. J Biol Chem 2002; 277:38627-34. [PMID: 12181311 DOI: 10.1074/jbc.m204890200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A variety of tumors contain activating mutations in the cytoplasmic juxtamembrane domain of the type III family of receptor-tyrosine kinases, and some constructed mutations in this domain induce ligand-independent receptor activation. To explore the role of this domain in regulation of receptor activity, we subjected the juxtamembrane domain of the murine platelet-derived growth factor (PDGF) beta receptor to alanine-scanning mutagenesis. The mutant receptors were expressed in Ba/F3 cells and tested for constitutive tyrosine phosphorylation, association with phosphatidylinositol 3'-kinase, and their ability to induce cell survival and proliferation in the absence of interleukin-3. The mutant receptors accumulated to similar levels and appeared to undergo a normal PDGF-induced increase in tyrosine phosphorylation. Alanine substitutions at numerous positions located throughout the juxtamembrane domain caused constitutive receptor activation, as did an alanine insertion in the membrane-proximal segment of the juxtamembrane domain and a six-amino acid deletion in the center of the domain. It is possible to model the PDGF receptor juxtamembrane domain as a short alpha-helix followed by a three-stranded beta-sheet very similar to the known structures of WW domains. Strikingly, the activating mutations clustered in the central portions of the first and second beta strands and along one face of the beta-sheet, whereas the loops connecting the strands were largely devoid of mutationally sensitive positions. These findings provide strong support for the model that the activating mutations in the juxtamembrane region stimulate receptor activity by disrupting an inhibitory WW-like domain.
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Affiliation(s)
- Pablo M Irusta
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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36
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Cross NCP, Reiter A. Tyrosine kinase fusion genes in chronic myeloproliferative diseases. Leukemia 2002; 16:1207-12. [PMID: 12094244 DOI: 10.1038/sj.leu.2402556] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2002] [Accepted: 02/14/2002] [Indexed: 11/08/2022]
Abstract
With the exception of chronic myeloid leukemia (CML), chronic myeloproliferative disorders (CMPDs) are a heterogeneous spectrum of conditions for which the molecular pathogenesis is not well understood. Most cases have a normal or aneuploid karyotype, but a minority present with a reciprocal translocation that disrupts specific tyrosine kinase genes, most commonly PDGFRB or FGFR1. These translocations result in the production of constitutively active tyrosine kinase fusion proteins that deregulate hemopoiesis in a manner analogous to BCR-ABL. With the advent of targeted signal transduction therapy, an accurate clinical and molecular diagnosis of CMPDs has become increasingly important. Currently, patients with PDGFRB or ABL fusion genes are candidates for treatment with Imatinib (STI571), but it is likely that alternative strategies will be necessary for the treatment of most other patients.
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Affiliation(s)
- N C P Cross
- Wessex Regional Genetics Laboratory, Salisbury, UK
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37
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Frame MC. Src in cancer: deregulation and consequences for cell behaviour. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1602:114-30. [PMID: 12020799 DOI: 10.1016/s0304-419x(02)00040-9] [Citation(s) in RCA: 272] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Considerable evidence now implicates elevated expression and/or activity of Src in cancer development. In cells, endogenous Src is switched from an inactive to an active state by a variety of mechanisms that simultaneously relieve constraints on the kinase and protein-interacting Src homology (SH) domains. As a result, Src is translocated to the cell periphery, often to sites of cell adhesion, where myristylation mediates attachment to the inner surface of the plasma membrane. From these peripheral sites, Src's catalytic activity initiates intracellular signal transduction pathways that influence cell growth and adhesion strength, the latter contributing to control of cell migration. De-regulation in cancer cells may therefore enhance tumour growth and/or stimulate migratory or invasive potential in cells that would normally be relatively non-motile. Evidence now exists to suggest that Src may also influence the life or death decisions that cells make during many biological processes. Thus, Src modulation in cancer cells can alter cell responses that are often perturbed in cancer. Consequently, there is optimism that drugs which inhibit Src's kinase activity, or the activity of its downstream effectors, might have profound effects on cancer cell behaviour and be useful therapeutic agents.
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Affiliation(s)
- Margaret C Frame
- The Beatson Institute for Cancer Research and Institute of Biomedical and Life Sciences, CRC Beatson Laboratories (University of Glasgow), Glasgow, UK.
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38
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Scheijen B, Griffin JD. Tyrosine kinase oncogenes in normal hematopoiesis and hematological disease. Oncogene 2002; 21:3314-33. [PMID: 12032772 DOI: 10.1038/sj.onc.1205317] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tyrosine kinase oncogenes are formed as a result of mutations that induce constitutive kinase activity. Many of these tyrosine kinase oncogenes that are derived from genes, such as c-Abl, c-Fes, Flt3, c-Fms, c-Kit and PDGFRbeta, that are normally involved in the regulation of hematopoiesis or hematopoietic cell function. Despite differences in structure, normal function, and subcellular location, many of the tyrosine kinase oncogenes signal through the same pathways, and typically enhance proliferation and prolong viability. They represent excellent potential drug targets, and it is likely that additional mutations will be identified in other kinases, their immediate downstream targets, or in proteins regulating their function.
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Affiliation(s)
- Blanca Scheijen
- Department of Adult Oncology, Dana-Farber Cancer Institute, 44 Binney Street, Boston, Massachusetts, MA 02115, USA
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Deb A, Zamanian-Daryoush M, Xu Z, Kadereit S, Williams BR. Protein kinase PKR is required for platelet-derived growth factor signaling of c-fos gene expression via Erks and Stat3. EMBO J 2001; 20:2487-96. [PMID: 11350938 PMCID: PMC125453 DOI: 10.1093/emboj/20.10.2487] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The double-stranded RNA (dsRNA)-activated protein kinase PKR is an interferon (IFN)-induced enzyme that controls protein synthesis through phosphorylation of eukaryotic initiation factor 2alpha (eIF-2alpha). PKR also regulates signals initiated by diverse stimuli, including dsRNA, IFN-gamma, tumor necrosis factor-alpha, interleukin-1 and lipopolysaccharide, to different transcription factors, resulting in pro-inflammatory gene expression. Stat3 plays an essential role in promoting cell survival and proliferation by different growth factors, including platelet-derived growth factor (PDGF). Here we show that PKR physically interacts with Stat3 and is required for PDGF-induced phosphorylation of Stat3 at Tyr705 and Ser727, resulting in DNA binding and transcriptional activation. PKR-mediated phosphorylation of Stat3 on Ser727 is indirect and channeled through ERKS: Although PKR is pre-associated with the PDGF beta-receptor, treatment with PDGF only modestly activates PKR. However, the induction of c-fos by PDGF is defective in PKR-null cells. Taken together, these results establish PKR as an upstream regulator of activation of Stat3 and as a common mediator of both growth-promoting and growth-inhibitory signals.
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Affiliation(s)
| | | | | | | | - Bryan R.G. Williams
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
Corresponding author e-mail:
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Bowman T, Broome MA, Sinibaldi D, Wharton W, Pledger WJ, Sedivy JM, Irby R, Yeatman T, Courtneidge SA, Jove R. Stat3-mediated Myc expression is required for Src transformation and PDGF-induced mitogenesis. Proc Natl Acad Sci U S A 2001; 98:7319-24. [PMID: 11404481 PMCID: PMC34666 DOI: 10.1073/pnas.131568898] [Citation(s) in RCA: 374] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2000] [Indexed: 12/30/2022] Open
Abstract
Signal transducer and activator of transcription (STAT) proteins perform key roles in mediating signaling by cytokines and growth factors, including platelet-derived growth factor (PDGF). In addition, Src family kinases activate STAT signaling and are required for PDGF-induced mitogenesis in normal cells. One STAT family member, Stat3, has been shown to have an essential role in cell transformation by the Src oncoprotein. However, the mechanisms by which STAT-signaling pathways contribute to mitogenesis and transformation are not fully defined. We show here that disruption of Stat3 signaling by using dominant-negative Stat3beta protein in NIH 3T3 fibroblasts suppresses c-Myc expression concomitant with inhibition of v-Src-induced transformation. Ectopic expression of c-Myc is able to partially reverse this inhibition, suggesting that c-Myc is a downstream effector of Stat3 signaling in v-Src transformation. Furthermore, c-myc gene knockout fibroblasts are refractory to transformation by v-Src, consistent with a requirement for c-Myc protein in v-Src transformation. In normal NIH 3T3 cells, disruption of Stat3 signaling with dominant-negative Stat3beta protein inhibits PDGF-induced mitogenesis in a manner that is reversed by ectopic c-Myc expression. Moreover, inhibition of Src family kinases with the pharmacologic agent, SU6656, blocks Stat3 activation by PDGF. These findings, combined together, delineate the signaling pathway, PDGF --> Src --> Stat3 --> Myc, that is important in normal PDGF-induced mitogenesis and subverted in Src transformation.
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Affiliation(s)
- T Bowman
- Molecular Oncology Program, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida College of Medicine, 12902 Magnolia Drive, Tampa, FL 33612, USA
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Pieper M, Rupprecht HD, Bruch KM, De Heer E, Schöcklmann HO. Requirement of heat shock protein 90 in mesangial cell mitogenesis. Kidney Int 2000; 58:2377-89. [PMID: 11115071 DOI: 10.1046/j.1523-1755.2000.00421.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Hyperplasia of mesangial cells (MCs) is a frequent finding in glomerulonephritis. Heat shock protein 90 (HSP90) is a major cellular chaperone that assists protein folding under physiological and stress conditions. METHODS To identify genes that are potentially involved in the pathogenesis of glomerulonephritis, we analyzed glomerular gene expression in mesangioproliferative rat anti-Thy1.1 nephritis by representational difference analysis (RDA). Expression of HSP90beta in anti-Thy1.1 nephritis was studied by Northern and Western blot analyses and immunohistochemistry. In cultured rat MCs, the requirement of HSP90 for mitogenic signaling steps and MC replication was studied by incubation with the specific HSP90 inhibitor geldanamycin. RESULTS By RDA, a cDNA fragment homologous to HSP90beta was identified. Glomerular mRNA and protein expression of HSP90beta was markedly and transiently up-regulated during the course of anti-Thy1.1 nephritis, with a maximum at day 6, coinciding with the peak of MC proliferation. By immunohistochemistry, HSP90beta expression in normal glomeruli was detected in podocytes. However, in anti-Thy1.1 nephritis, glomerular HSP90beta protein expression was strongly and transiently increased in mesangial localization. In vitro, mitogenic stimulation of rat MCs led to the induction of HSP90beta mRNA and protein. Incubation of MCs with geldanamycin dose-dependently inhibited DNA synthesis and replication. Moreover, geldanamycin interfered with mitogen-induced phosphorylation of extracellular signal-regulated kinase and transcription of c-fos and Egr-1, but not with transactivation of STAT1 transcription factor. Cell cycle analysis of serum-stimulated MCs revealed that geldanamycin inhibited kinase activity of cyclin D1/CDK4 complexes and blocked progression in the G0/G1 phase and at the S/G2 phase transition. CONCLUSIONS The up-regulation of HSP90beta in anti-Thy1.1 nephritis may reflect its functional involvement in phenotypical alterations of MCs in mesangioproliferative glomerulonephritis. Our in vitro studies indicate that HSP90 governs the capacity of MCs to respond to proliferative stimuli by regulating critical mitogenic signaling steps necessary for G1 entry and S-phase progression.
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Affiliation(s)
- M Pieper
- Medizinische Klinik IV, Universität Erlangen-Nürnberg, Erlangen, Germany, and Department of Pathology, University of Leiden, Leiden, The Netherlands
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Weinstein-Oppenheimer CR, Blalock WL, Steelman LS, Chang F, McCubrey JA. The Raf signal transduction cascade as a target for chemotherapeutic intervention in growth factor-responsive tumors. Pharmacol Ther 2000; 88:229-79. [PMID: 11337027 DOI: 10.1016/s0163-7258(00)00085-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This review focuses on the Ras-Raf-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) signal transduction pathway and the consequences of its unregulation in the development of cancer. The roles of some of the cell membrane receptors involved in the activation of this pathway, the G-protein Ras, the Raf, MEK and ERK kinases, the phosphatases that regulate these kinases, as well as the downstream transcription factors that become activated, are discussed. The roles of the Ras-Raf-MEK-ERK pathway in the regulation of apoptosis and cell cycle progression are also analyzed. In addition, potential targets for pharmacological intervention in growth factor-responsive cells are evaluated.
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Affiliation(s)
- C R Weinstein-Oppenheimer
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Brody Building of Medical Sciences 5N98C, Greenville, NC 27858, USA
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Tse KF, Mukherjee G, Small D. Constitutive activation of FLT3 stimulates multiple intracellular signal transducers and results in transformation. Leukemia 2000; 14:1766-76. [PMID: 11021752 DOI: 10.1038/sj.leu.2401905] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Aberrant expression of FLT3 has been found in most cases of B-lineage ALL and AML, and subsets of T cell ALL, CML in blast crisis and CLL. In 20% of patients with AML the receptor has small internal tandem duplications of the juxtamembrane region which appear to contitutively activate the receptor. To investigate whether FLT3 activation could play a role in leukemia, we generated a constitutively activated FLT3 by fusing its cytoplasmic domain to the helix-loop-helix domain of TEL in analogy to the fusion that occurs with TEL-PDGFR in CMML. In vitro translation assays demonstrated oligomerization and intrinsic tyrosine kinase activity of the TEL-FLT3 chimeric receptor. Constitutively activated TEL-FLT3 conferred IL-3 independence and long-term proliferation to transfected Ba/F3 cells. Immunoblot analyses showed that JAK 2, STAT 3, STAT 5a, STAT 5b and CBL were tyrosine-phosphorylated in TEL-FLT3 expressing Ba/F3 cells in the absence of IL-3. These data suggest a possible role for the JAK/STAT pathway in FLT3 signaling. Transplantation of TEL-FLT3 expressing Ba/F3 cells into syngeneic mice caused mortality in all mice by 3 weeks after injection. Histopathologic analysis demonstrated a massive infiltration of mononuclear cells in the liver, spleen and bone marrow. The mimicking of naturally occurring TEL fusions provides an approach to assess aspects of the biology of activated FLT3, or other receptor-type tyrosine kinases (RTKs) in leukemic transformation.
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Affiliation(s)
- K F Tse
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Zong CS, Chan J, Levy DE, Horvath C, Sadowski HB, Wang LH. Mechanism of STAT3 activation by insulin-like growth factor I receptor. J Biol Chem 2000; 275:15099-105. [PMID: 10747872 DOI: 10.1074/jbc.m000089200] [Citation(s) in RCA: 184] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent evidence indicates that STAT proteins can be activated by a variety of receptor and non-receptor protein-tyrosine kinases. Unlike cytokine-induced activation of STATs, where JAKs are known to play a pivotal role in phosphorylating STATs, the mechanism for receptor protein-tyrosine kinase-mediated activation of STATs remains elusive. In this study, we investigated the activation of STAT proteins by the insulin-like growth factor I receptor (IGF-IR) in vitro and in vivo and assessed the role of JAKs in the process of activation. We found that STAT3, but not STAT5, was activated in response to IGF-I in 293T cells cotransfected with IGF-IR and STAT expression vectors. Moreover, tyrosine phosphorylation of STAT3, JAK1, and JAK2 was increased upon IGF-I stimulation of endogenous IGF-IR in 293T cells transfected with the respective STAT or JAK expression vector. Supporting the observation in 293T cells, endogenous STAT3 was tyrosine-phosphorylated upon IGF-I stimulation in the muscle cell line C2C12 as well as in various embryonic and adult mouse organs during different stages of development. Dominant-negative JAK1 or JAK2 was able to block the IGF-IR-mediated tyrosine phosphorylation of STAT3 in 293T cells. A newly identified family of proteins called SOCS (suppressor of cytokine signaling), including SOCS1, SOCS2, SOCS3 and CIS, was able to inhibit the IGF-I-induced STAT3 activation as well with varying degrees of potency, in which SOCS1 and SOCS3 appeared to have the higher inhibitory ability. Inhibition of STAT3 activation by SOCS could be overcome by overexpression of native JAK1 and JAK2. We conclude that IGF-I/IGF-IR is able to mediate activation of STAT3 in vitro and in vivo and that JAKs are essential for the process of activation.
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Affiliation(s)
- C S Zong
- Department of Microbiology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Ramana CV, Chatterjee-Kishore M, Nguyen H, Stark GR. Complex roles of Stat1 in regulating gene expression. Oncogene 2000; 19:2619-27. [PMID: 10851061 DOI: 10.1038/sj.onc.1203525] [Citation(s) in RCA: 245] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Stat1 is a fascinating and complex protein with multiple, yet contrasting transcriptional functions. Upon activation, it drives the expression of many genes but also suppresses the transcription of others. These opposing characteristics also apply to its role in facilitating crosstalk between signal transduction pathways, as it participates in both synergistic activation and inhibition of gene expression. Stat1 is a functional transcription factor even in the absence of inducer-mediated activation, participating in the constitutive expression of some genes. This review summarizes the well studied involvement of Stat1 in IFN-dependent and growth factor-dependent signaling and then describes the roles of Stat1 in positive, negative and constitutive regulation of gene expression as well as its participation in crosstalk between signal transduction pathways. Oncogene (2000).
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Affiliation(s)
- C V Ramana
- Department of Molecular Biology, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio, OH 44195 USA
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Wang YZ, Wharton W, Garcia R, Kraker A, Jove R, Pledger WJ. Activation of Stat3 preassembled with platelet-derived growth factor beta receptors requires Src kinase activity. Oncogene 2000; 19:2075-85. [PMID: 10815799 DOI: 10.1038/sj.onc.1203548] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Members of the STAT family of transcriptional regulators modulate the expression of a variety of gene products that promote cell proliferation, survival and transformation. Although initially identified as mediators of cytokine signaling, the STAT proteins are also activated by, and thus may contribute to the actions of, polypeptide growth factors. To define the mechanism by which these factors activate STATs, we examined the process of Stat3 activation in Balb/c-3T3 fibroblasts treated with platelet-derived growth factor (PDGF). As STATs are activated by tyrosine phosphorylation, and as PDGF receptors are ligand-activated tyrosine kinases, we considered the possibility that Stat3 interacts with and is phosphorylated by PDGF receptors. We find that Stat3 associates with PDGF beta receptors in both the presence and, surprisingly, the absence of PDGF. Moreover, Stat3 was phosphorylated on tyrosine in PDGF beta receptor immunoprecipitates of PDGF-treated but not untreated cells. Although required, receptor activation was insufficient for Stat3 activation. When added to cells in combination with a pharmacologic agent (PD180970) that specifically inhibits the activity of Src family tyrosine kinases, PDGF did not activate Stat3 as monitored by electrophoretic mobility shift assay. PD180970 did not affect MAPK activation by PDGF or the JAK-dependent activation of Stat3 by interleukin-6. The necessity of Src activity for Stat3 activation by PDGF was further evidenced by data showing the presence of Src in complexes containing both Stat3 and PDGF beta receptors in PDGF-treated cells. These results suggest a novel mechanism of STAT activation in which inactive Stat3 pre-assembles with inactive PDGF receptors, and in response to ligand binding and in a manner dependent on Src kinase activity, is rapidly phosphorylated and activated. Additional data demonstrate that Src kinase activity is also required for PDGF stimulation of DNA synthesis in density-arrested cells.
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Affiliation(s)
- Y Z Wang
- Molecular Oncology, Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida 33612, USA
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Tomasson MH, Sternberg DW, Williams IR, Carroll M, Cain D, Aster JC, Ilaria RL, Van Etten RA, Gilliland DG. Fatal myeloproliferation, induced in mice by TEL/PDGFbetaR expression, depends on PDGFbetaR tyrosines 579/581. J Clin Invest 2000; 105:423-32. [PMID: 10683371 PMCID: PMC289168 DOI: 10.1172/jci8902] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/1999] [Accepted: 12/30/1999] [Indexed: 01/14/2023] Open
Abstract
The t(5;12)(q33;p13) translocation associated with chronic myelomonocytic leukemia (CMML) generates a TEL/PDGFbetaR fusion gene. Here, we used a murine bone marrow transplant (BMT) assay to test the transforming properties of TEL/PDGFbetaR in vivo. TEL/PDGFbetaR, introduced into whole bone marrow by retroviral transduction, caused a rapidly fatal myeloproliferative disease that closely recapitulated human CMML. TEL/PDGFbetaR transplanted mice developed leukocytosis with Gr-1(+) granulocytes, splenomegaly, evidence of extramedullary hematopoiesis, and bone marrow fibrosis, but no lymphoproliferative disease. We assayed mutant forms of the TEL/PDGFbetaR fusion protein - including 8 tyrosine to phenylalanine substitutions at phosphorylated PDGFbetaR sites to which various SH2 domain-containing signaling intermediates bind - for ability to transform hematopoietic cells. All of the phenylalanine (F-) mutants tested conferred IL-3-independence to a cultured murine hematopoietic cell line, but, in the BMT assay, different F-mutants displayed distinct transforming properties. In transplanted animals, tyrosines 579/581 proved critical for the development of myeloproliferative phenotype. F-mutants with these residues mutated showed no sign of myeloproliferation but instead developed T-cell lymphomas. In summary, TEL/PDGFbetaR is necessary and sufficient to induce a myeloproliferative disease in a murine BMT model, and PDGFbetaR residues Y579/581 are required for this phenotype.
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Affiliation(s)
- M H Tomasson
- Department of Medicine, Brigham and Women's Hospital, Harvard Institutes of Medicine, Boston, Massachusetts 02115, USA
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Affiliation(s)
- C L Abram
- SUGEN, 230 East Grand Avenue, South San Francisco, California, 94080, USA
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Abstract
The observation that platelet-derived growth factor (PDGF) increases the catalytic activity of Src family members (Src) suggests that they contribute to PDGF-dependent responses. The role of Src in PDGF-dependent cell cycle progression, phosphorylation of proteins, and chemotaxis has been tested by investigators using a variety of cell types and approaches, and it appears that the contribution of Src is highly variable. This idea is perhaps best illustrated by the finding that Src plays radically different roles downstream of the PDGF alpha- and beta-receptor subunits. Hence, Src is a versatile signal relay enzyme, whose contribution to a signaling cascade depends on variables such as the nature of the receptor via which the cell is activated, as well as the cell type itself.
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Affiliation(s)
- K A DeMali
- Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, Massachusetts, 02114, USA
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