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Activation-induced cell death in CAR-T cell therapy. Hum Cell 2022; 35:441-447. [PMID: 35032297 DOI: 10.1007/s13577-022-00670-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 01/05/2022] [Indexed: 01/30/2023]
Abstract
Engineered T cells expressing chimeric antigen receptors (CARs) with tumor specificity have shown remarkable therapeutic effects on hematologic malignancies. However, CAR-T cells are less effective on solid tumors mainly due to the weak persistence of CAR-T cells, which might be caused by T cell death. Significant activation-induced cell death (AICD) of CAR-T cells was triggered by repeated antigen stimulation. AICD of T cell is characterized by the upregulation of death receptors and low persistence of T cells. Understanding the mechanism of AICD is crucial to improve the anti-tumor effect of CAR-T cells against solid tumors. Many approaches have been applied in CAR-T cell modification to enhance their anti-apoptosis ability. In this review, we summarized the molecular mechanisms of AICD in CAR-T cells and the progresses of anti-AICD in CAR-T cells therapy.
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Abstract
Extensive interest in cancer immunotherapy is reported according to the clinical importance of CTLA-4 and (PD-1/PD-L1) [programmed death (PD) and programmed death-ligand (PD-L1)] in immune checkpoint therapies. AXL is a receptor tyrosine kinase expressed in different types of cancer and in relation to resistance against various anticancer therapeutics due to poor clinical prognosis. AXL and its ligand, i.e., growth arrest-specific 6 (GAS6) proteins, are expressed on many cancer cells, and the GAS6/AXL pathway is reported to promote cancer cell proliferation, survival, migration, invasion, angiogenesis, and immune evasion. AXL is an attractive and novel therapeutic target for impairing tumor progression from immune cell contracts in the tumor microenvironment. The GAS6/AXL pathway is also of interest immunologically because it targets fewer antitumor immune responses. In effect, several targeted therapies are selective and nonselective for AXL, which are in preclinical and clinical development in multiple cancer types. Therefore, this review focuses on the role of the GAS6/AXL signaling pathway in triggering the immunosuppressive tumor microenvironment as immune evasion. This includes regulating its composition and activating T-cell exclusion with the immune-suppressive activity of regulatory T cells, which is related to one of the hallmarks of cancer survival. Finally, this article discusses the GAS6/AXL signaling pathway in the context of several immune responses such as NK cell activation, apoptosis, and tumor-specific immunity, especially PD-1/PDL-1 signaling.
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Affiliation(s)
- Hye-Youn Son
- Department of Breast and Endocrine Surgery, Center for Medical Innovation, Seoul National University Hospital, Seoul, South Korea
| | - Hwan-Kyu Jeong
- School of Biosystems and Biomedical Sciences, Korea University, Seoul, South Korea
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Di Stasi R, De Rosa L, D'Andrea LD. Therapeutic aspects of the Axl/Gas6 molecular system. Drug Discov Today 2020; 25:2130-2148. [PMID: 33002607 DOI: 10.1016/j.drudis.2020.09.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/14/2020] [Accepted: 09/21/2020] [Indexed: 12/17/2022]
Abstract
Axl receptor tyrosine kinase (RTK) and its ligand, growth arrest-specific protein 6 (Gas6), are involved in several biological functions and participate in the development and progression of a range of malignancies and autoimmune disorders. In this review, we present this molecular system from a drug discovery perspective, highlighting its therapeutic implications and challenges that need to be addressed. We provide an update on Axl/Gas6 axis biology, exploring its role in fields ranging from angiogenesis, cancer development and metastasis, immune response and inflammation to viral infection. Finally, we summarize the molecules that have been developed to date to target the Axl/Gas6 molecular system for therapeutic and diagnostic applications.
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Affiliation(s)
- Rossella Di Stasi
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy
| | - Lucia De Rosa
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy
| | - Luca D D'Andrea
- Istituto di Biostrutture e Bioimmagini, CNR, Via Nizza 52, 10126 Torino, Italy.
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AXL Receptor Tyrosine Kinase as a Therapeutic Target in Hematological Malignancies: Focus on Multiple Myeloma. Cancers (Basel) 2019; 11:cancers11111727. [PMID: 31694201 PMCID: PMC6896070 DOI: 10.3390/cancers11111727] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/28/2019] [Accepted: 10/31/2019] [Indexed: 01/13/2023] Open
Abstract
AXL belongs to the TAM (TYRO3, AXL, and MERTK) receptor family, a unique subfamily of the receptor tyrosine kinases. Their common ligand is growth arrest-specific protein 6 (GAS6). The GAS6/TAM signaling pathway regulates many important cell processes and plays an essential role in immunity, hemostasis, and erythropoiesis. In cancer, AXL overexpression and activation has been associated with cell proliferation, chemotherapy resistance, tumor angiogenesis, invasion, and metastasis; and has been correlated with a poor prognosis. In hematological malignancies, the expression and function of AXL is highly diverse, not only between the different tumor types but also in the surrounding tumor microenvironment. Most research and clinical evidence has been provided for AXL inhibitors in acute myeloid leukemia. However, recent studies also revealed an important role of AXL in lymphoid leukemia, lymphoma, and multiple myeloma. In this review, we summarize the basic functions of AXL in various cell types and the role of AXL in different hematological cancers, with a focus on AXL in the dormancy of multiple myeloma. In addition, we provide an update on the most promising AXL inhibitors currently in preclinical/clinical evaluation and discuss future perspectives in this emerging field.
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Stabile H, Fionda C, Santoni A, Gismondi A. Impact of bone marrow-derived signals on NK cell development and functional maturation. Cytokine Growth Factor Rev 2018; 42:13-19. [PMID: 29622473 DOI: 10.1016/j.cytogfr.2018.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 12/28/2022]
Abstract
Natural killer (NK) cells are cytotoxic members of type I innate lymphocytes (ILC1) with a prominent role in anti-tumor and anti-viral immune responses. Despite the increasing insight into NK cell biology, the steps and stages leading to mature circulating NK cells require further investigation. Natural killer cell development and functional maturation are complex and multi-stage processes that occur predominantly in the bone marrow (BM) and originate from haematopoietic stem cells CD34+ (HSC). Within the BM, NK cell precursor (NKP) and NK cell development intermediates reside in specialized niches that are characterized by particular cellular components that provide signals required for their maturation. These signals consist of soluble factors or direct cellular-contact interactions mediated by cytokines and growth factors with complementary, as well as overlapping roles in distinct developmental steps. Emerging evidence highlights the plasticity of the early phase of NK cell development, and the capacity of different signal combinations to redirect precursor lineage commitment through other innate cell populations. Here, we summarize the role of signals known to guide NK cell differentiation with a particular focus on the cytokines and the receptor/ligand pairs playing a critical role in these processes. A comprehensive understanding of the mechanisms underlying NK cell development will elucidate their roles in pathological conditions and will improve protocols for NK cell therapeutic application.
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Affiliation(s)
- Helena Stabile
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy.
| | - Cinzia Fionda
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy
| | - Angela Santoni
- Department of Molecular Medicine, Sapienza University of Rome, Laboratory affiliated to Institute Pasteur -Italia, 00161 Rome, Italy; IRCCS, Neuromed, Pozzilli, 86077 IS, Italy
| | - Angela Gismondi
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy; Eleonora Lorillard Spencer Cenci Foundation, Italy
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Gottschalk MG, Cooper JD, Chan MK, Bot M, Penninx BWJH, Bahn S. Discovery of serum biomarkers predicting development of a subsequent depressive episode in social anxiety disorder. Brain Behav Immun 2015; 48:123-31. [PMID: 25929723 DOI: 10.1016/j.bbi.2015.04.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/10/2015] [Accepted: 04/21/2015] [Indexed: 01/04/2023] Open
Abstract
Although social anxiety disorder (SAD) is strongly associated with the subsequent development of a depressive disorder (major depressive disorder or dysthymia), no underlying biological risk factors are known. We aimed to identify biomarkers which predict depressive episodes in SAD patients over a 2-year follow-up period. One hundred sixty-five multiplexed immunoassay analytes were investigated in blood serum of 143 SAD patients without co-morbid depressive disorders, recruited within the Netherlands Study of Depression and Anxiety (NESDA). Predictive performance of identified biomarkers, clinical variables and self-report inventories was assessed using receiver operating characteristics curves (ROC) and represented by the area under the ROC curve (AUC). Stepwise logistic regression resulted in the selection of four serum analytes (AXL receptor tyrosine kinase, vascular cell adhesion molecule 1, vitronectin, collagen IV) and four additional variables (Inventory of Depressive Symptomatology, Beck Anxiety Inventory somatic subscale, depressive disorder lifetime diagnosis, BMI) as optimal set of patient parameters. When combined, an AUC of 0.86 was achieved for the identification of SAD individuals who later developed a depressive disorder. Throughout our analyses, biomarkers yielded superior discriminative performance compared to clinical variables and self-report inventories alone. We report the discovery of a serum marker panel with good predictive performance to identify SAD individuals prone to develop subsequent depressive episodes in a naturalistic cohort design. Furthermore, we emphasise the importance to combine biological markers, clinical variables and self-report inventories for disease course predictions in psychiatry. Following replication in independent cohorts, validated biomarkers could help to identify SAD patients at risk of developing a depressive disorder, thus facilitating early intervention.
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Affiliation(s)
- M G Gottschalk
- Department of Chemical Engineering and Biotechnology, Cambridge Centre for Neuropsychiatric Research, University of Cambridge, Cambridge, UK
| | - J D Cooper
- Department of Chemical Engineering and Biotechnology, Cambridge Centre for Neuropsychiatric Research, University of Cambridge, Cambridge, UK
| | - M K Chan
- Department of Chemical Engineering and Biotechnology, Cambridge Centre for Neuropsychiatric Research, University of Cambridge, Cambridge, UK
| | - M Bot
- Department of Psychiatry, EMGO Institute for Health and Care Research and Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
| | - B W J H Penninx
- Department of Psychiatry, EMGO Institute for Health and Care Research and Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
| | - S Bahn
- Department of Chemical Engineering and Biotechnology, Cambridge Centre for Neuropsychiatric Research, University of Cambridge, Cambridge, UK; Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
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Moon KD, Zhang X, Zhou Q, Geahlen RL. The protein-tyrosine kinase Syk interacts with the C-terminal region of tensin2. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1823:199-205. [PMID: 22019427 DOI: 10.1016/j.bbamcr.2011.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 10/03/2011] [Accepted: 10/05/2011] [Indexed: 12/26/2022]
Abstract
Syk is a 72-kDa protein-tyrosine kinase that regulates signaling through multiple cell surface receptors including those for antigens, immunoglobulins and proteins of the extracellular matrix. As part of its function, Syk binds a variety of downstream effectors through interactions that are often mediated by motifs that recognize phosphotyrosines. In a search for novel Syk-interacting proteins by yeast two-hybrid analysis, we identified tensin2 as a Syk-binding protein. Syk interacts with a fragment of tensin2 located near the C-terminus that contains SH2 and PTB domains. In epithelial cells, tensin2 localizes both to focal adhesions and to large cytoplasmic puncta. It is within these punctuate structures that Syk and tensin2 are co-localized. The clustering of Syk within these structures leads to its phosphorylation on tyrosine.
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Affiliation(s)
- Kyung D Moon
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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8
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Yoo HJ, Yoon SS, Park SY, Lee EY, Lee EB, Kim JH, Song YW. Gene expression profile during chondrogenesis in human bone marrow derived mesenchymal stem cells using a cDNA microarray. J Korean Med Sci 2011; 26:851-8. [PMID: 21738335 PMCID: PMC3124712 DOI: 10.3346/jkms.2011.26.7.851] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 04/27/2011] [Indexed: 01/06/2023] Open
Abstract
Mesenchymal stem cells (MSCs) have the capacity to proliferate and differentiate into multiple connective tissue lineages, which include cartilage, bone, and fat. Cartilage differentiation and chondrocyte maturation are required for normal skeletal development, but the intracellular pathways regulating this process remain largely unclear. This study was designed to identify novel genes that might help clarify the molecular mechanisms of chondrogenesis. Chondrogenesis was induced by culturing human bone marrow (BM) derived MSCs in micromass pellets in the presence of defined medium for 3, 7, 14 or 21 days. Several genes regulated during chondrogenesis were then identified by reverse transcriptase-polymerase chain reaction (RT-PCR). Using an ABI microarray system, we determined the differential gene expression profiles of differentiated chondrocytes and BM-MSCs. Normalization of this data resulted in the identification of 1,486 differentially expressed genes. To verify gene expression profiles determined by microarray analysis, the expression levels of 10 genes with high fold changes were confirmed by RT-PCR. Gene expression patterns of 9 genes (Hrad6B, annexinA2, BMP-7, contactin-1, peroxiredoxin-1, heat shock transcription factor-2, synaptotagmin IV, serotonin receptor-7, Axl) in RT-PCR were similar to the microarray gene expression patterns. These findings provide novel information concerning genes involved in the chondrogenesis of human BM-MSCs.
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Affiliation(s)
- Hyun Jung Yoo
- Department of Internal Medicine, Rheumatism Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Soo Yoon
- Department of Internal Medicine, Rheumatism Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Seon Yang Park
- Department of Internal Medicine, Rheumatism Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Eun Young Lee
- Department of Internal Medicine, Rheumatism Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Eun Bong Lee
- Department of Internal Medicine, Rheumatism Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Ju Han Kim
- Graduate Course of Biomedical Informatics (SNUBI), Seoul National University College of Medicine, Seoul, Korea
| | - Yeong Wook Song
- Department of Internal Medicine, Rheumatism Research Institute, Seoul National University College of Medicine, Seoul, Korea
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Fourcot A, Couchie D, Chobert MN, Zafrani ES, Mavier P, Laperche Y, Brouillet A. Gas6 deficiency prevents liver inflammation, steatohepatitis, and fibrosis in mice. Am J Physiol Gastrointest Liver Physiol 2011; 300:G1043-53. [PMID: 21350191 DOI: 10.1152/ajpgi.00311.2010] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Gas6/Axl pathway has been increasingly implicated in regeneration and tissue repair and, recently, in the control of innate immunity. In liver, we have demonstrated that Gas6 and its receptor Axl are expressed in macrophages, progenitor cells, and myofibroblasts and that Gas6 deficiency reduced inflammation and myofibroblast activation, causing delayed liver repair in response to acute injury. All these data suggest a role of Gas6/Axl signaling in pathogenesis of chronic liver diseases. In the present study, we address the role of Gas6 in steatohepatitis and progression to liver fibrosis using Gas6-deficient mice fed a choline-deficient ethionine-supplemented diet (CDE) or receiving a chronic carbon tetrachloride (CCl(4)) treatment. Gas6 deficiency attenuated hepatic steatosis by limiting CDE-induced downregulation of genes involved in β-oxidation observed in wild-type animals. Moreover, Gas6-deficient mice displayed reduction of hepatic inflammation, revealed by limited F4/80-positive macrophage infiltration, decreased expression of IL-1β, TNF-α, lymphotoxin-β, and monocyte chemotactic protein-1, and attenuated hepatic progenitor cell response to CDE diet. Gas6 deficiency reduced CDE-induced fibrogenesis and hepatic myofibroblast activation and decreased expression of TGF-β and collagen 1 mRNAs. After chronic CCl(4) injury, Gas6-deficient mice also exhibited reduced liver fibrosis as a consequence of defective macrophage recruitment compared with wild-type animals. We conclude that improvement of steatohepatitis and fibrosis in Gas6(-/-) mice is linked to an inhibition of the inflammatory response that controls lipid metabolism and myofibroblast activation. This study highlights the deleterious effect of Gas6 in the progression of steatosis to steatohepatitis and fibrosis.
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Affiliation(s)
- Agnès Fourcot
- INSERM, UMR-S, Groupe Henri Mondor-Albert Chenevier, Département de Pathologie, Créteil, France
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Brindley MA, Hunt CL, Kondratowicz AS, Bowman J, Sinn PL, McCray PB, Quinn K, Weller ML, Chiorini JA, Maury W. Tyrosine kinase receptor Axl enhances entry of Zaire ebolavirus without direct interactions with the viral glycoprotein. Virology 2011; 415:83-94. [PMID: 21529875 DOI: 10.1016/j.virol.2011.04.002] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 01/28/2011] [Accepted: 04/04/2011] [Indexed: 12/27/2022]
Abstract
In a bioinformatics-based screen for cellular genes that enhance Zaire ebolavirus (ZEBOV) transduction, AXL mRNA expression strongly correlated with ZEBOV infection. A series of cell lines and primary cells were identified that require Axl for optimal ZEBOV entry. Using one of these cell lines, we identified ZEBOV entry events that are Axl-dependent. Interactions between ZEBOV-GP and the Axl ectodomain were not detected in immunoprecipitations and reduction of surface-expressed Axl by RNAi did not alter ZEBOV-GP binding, providing evidence that Axl does not serve as a receptor for the virus. However, RNAi knock down of Axl reduced ZEBOV pseudovirion internalization and α-Axl antisera inhibited pseudovirion fusion with cellular membranes. Consistent with the importance of Axl for ZEBOV transduction, Axl transiently co-localized on the surface of cells with ZEBOV virus particles and was internalized during virion transduction. In total, these findings indicate that endosomal uptake of filoviruses is facilitated by Axl.
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Affiliation(s)
- Melinda A Brindley
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
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PMA up-regulates the transcription of Axl by AP-1 transcription factor binding to TRE sequences via the MAPK cascade in leukaemia cells. Biol Cell 2011; 103:21-33. [PMID: 20977427 DOI: 10.1042/bc20100094] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Axl is a receptor tyrosine kinase promoting anti-apoptosis, invasion and mitogenesis, and is highly expressed in different solid cancers. Axl basal transcriptional activity is driven by Sp1/Sp3, and overexpression of MZF-1 (myeloid zinc-finger 1) induces Axl transcription and gene expression. Furthermore, Axl expression is epigenetically controlled by CpG hypermethylation; however, little is known about inducible Axl gene expression and Axl regulation in haematopoetic malignancies. RESULTS In the present study, we studied Axl transcriptional regulation under PMA-stimulated conditions in leukaemia cells. Luciferase analysis with sequential 5'-deletion constructs revealed that the -660/-580 region of the Axl promoter is indispensable for induced promoter activity under PMA stimulation. This region includes AP-1 (activator protein 1)/CREB [CRE (cAMP-response-element)-binding protein] motifs, five times partially overlapping TGCGTG repeats and multiple GT repeats. Mutational, supershift and ChIP (chromatin immunoprecipitation) analysis determined that AP-1 family members bind to AP-1 motifs and to the 5 × TGCGTG overlapping repeats, thus transactivating Axl promoter activity. Furthermore, specific inhibitors of PKC (protein kinase C), ERK1/2 (extracellular-signal-regulated kinase 1/2) and p38 reduced Axl expression. Additionally, mithramycin treatment abolished constitutive and PMA-induced Axl expression. CONCLUSIONS Taken together the results of the present study suggest that PMA-induced Axl gene expression in leukaemia cells is mediated by AP-1 motifs and 5 × TGCGTG repeats within the promoter region -660/-580, and through the PKC/ERK1/2/AP-1 or PKC/p-38/AP-1 signalling axis.
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Barone MV, Zanzi D, Maglio M, Nanayakkara M, Santagata S, Lania G, Miele E, Ribecco MTS, Maurano F, Auricchio R, Gianfrani C, Ferrini S, Troncone R, Auricchio S. Gliadin-mediated proliferation and innate immune activation in celiac disease are due to alterations in vesicular trafficking. PLoS One 2011; 6:e17039. [PMID: 21364874 PMCID: PMC3045409 DOI: 10.1371/journal.pone.0017039] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 01/18/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Damage to intestinal mucosa in celiac disease (CD) is mediated both by inflammation due to adaptive and innate immune responses, with IL-15 as a major mediator of the innate immune response, and by proliferation of crypt enterocytes as an early alteration of CD mucosa causing crypts hyperplasia. We have previously shown that gliadin peptide P31-43 induces proliferation of cell lines and celiac enterocytes by delaying degradation of the active epidermal growth factor receptor (EGFR) due to delayed maturation of endocytic vesicles. IL-15 is increased in the intestine of patients affected by CD and has pleiotropic activity that ultimately results in immunoregulatory cross-talk between cells belonging to the innate and adaptive branches of the immune response. Aims of this study were to investigate the role of P31-43 in the induction of cellular proliferation and innate immune activation. METHODS/PRINCIPAL FINDINGS Cell proliferation was evaluated by bromodeoxyuridine (BrdU) incorporation both in CaCo-2 cells and in biopsies from active CD cases and controls. We used real-time PCR to evaluate IL-15 mRNA levels and FACS as well as ELISA and Western Blot (WB) analysis to measure protein levels and distribution in CaCo-2 cells. Gliadin and P31-43 induce a proliferation of both CaCo-2 cells and CD crypt enterocytes that is dependent on both EGFR and IL-15 activity. In CaCo-2 cells, P31-43 increased IL-15 levels on the cell surface by altering intracellular trafficking. The increased IL-15 protein was bound to IL15 receptor (IL-15R) alpha, did not require new protein synthesis and functioned as a growth factor. CONCLUSION In this study, we have shown that P31-43 induces both increase of the trans-presented IL-15/IL5R alpha complex on cell surfaces by altering the trafficking of the vesicular compartments as well as proliferation of crypt enterocytes with consequent remodelling of CD mucosa due to a cooperation of IL-15 and EGFR.
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Affiliation(s)
- M Vittoria Barone
- Department of Pediatrics, European Laboratory for the Investigation of Food-Induced Diseases, University of Naples Federico II, Naples, Italy.
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Budagian V, Bulanova E, Orinska Z, Thon L, Mamat U, Bellosta P, Basilico C, Adam D, Paus R, Bulfone-Paus S. Retraction. A promiscuous liaison between IL-15 receptor and Axl receptor tyrosine kinase in cell death control. EMBO J 2011; 30:627. [PMID: 21285977 DOI: 10.1038/emboj.2011.7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Verbist KC, Cole CJ, Field MB, Klonowski KD. A role for IL-15 in the migration of effector CD8 T cells to the lung airways following influenza infection. THE JOURNAL OF IMMUNOLOGY 2010; 186:174-82. [PMID: 21098221 DOI: 10.4049/jimmunol.1002613] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cytokines generated locally in response to infection play an important role in CD8 T cell trafficking, survival, and effector function, rendering these signals prime candidates for immune intervention. In this paper, we show that localized increases in the homeostatic cytokine IL-15 induced by influenza infection is responsible for the migration of CD8 effector T cells to the site of infection. Moreover, intranasal delivery of IL-15-IL-15Rα soluble complexes (IL-15c) specifically restores the frequency of effector T cells lost in the lung airways of IL-15-deficient animals after influenza infection. Exogenous IL-15c quantitatively augments the respiratory CD8 T cell response, and continued administration of IL-15c throughout the contraction phase of the anti-influenza CD8 T cell response magnifies the resultant CD8 T cell memory generated in situ. This treatment extends the ability of these cells to protect against heterologous infection, immunity that typically depreciates over time. Overall, our studies describe what to our knowledge is a new function for IL-15 in attracting effector CD8 T cells to the lung airways and suggest that adjuvanting IL-15 could be used to prolong anti-influenza CD8 T cell responses at mucosal surfaces to facilitate pathogen elimination.
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Affiliation(s)
- Katherine C Verbist
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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Induction, regulation, and biologic function of Axl receptor tyrosine kinase in Kaposi sarcoma. Blood 2010; 116:297-305. [PMID: 20442363 DOI: 10.1182/blood-2009-12-257154] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Axl is an oncogenic receptor tyrosine kinase that plays multiple roles in tumorigenesis and metastasis of many cancers. This study is the first to demonstrate that Axl is induced in Kaposi sarcoma and Kaposi sarcoma herpesvirus (KSHV) transformed endothelial cells. Conditionally, expression of one KSHV latency protein vFLIP induces Axl expression in endothelial cells. This induction can be blocked by nuclear factor-kappaB inhibitor, consistent with the known vFLIP mechanism of action. KS cell lines lacking KSHV also have elevated Axl expression, which probably resulted from hypomethylation of AXL promoter. Axl activation activates downstream phosphoinositol-3 kinase signaling, and Axl knockdown by siRNA impairs phosphoinositol-3 kinase signaling. Furthermore, Axl knockdown inhibits KS cell growth and invasion. To explore the potential for translation of these findings, we generated monoclonal antibodies to block the biologic functions of Axl. MAb173, which induces receptor degradation, showed activity in vitro to inhibit KS cell invasion. Moreover, in vivo xenograft studies with KS cells with or without KSHV infection showed that MAb173 reduced tumor growth, increased tumor cell apoptosis, and markedly decreased Axl protein level in tumors. Axl thus has a potential role in KS pathogenesis and is a candidate for prognostic and therapeutic investigations.
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Mudduluru G, Vajkoczy P, Allgayer H. Myeloid zinc finger 1 induces migration, invasion, and in vivo metastasis through Axl gene expression in solid cancer. Mol Cancer Res 2010; 8:159-69. [PMID: 20145042 DOI: 10.1158/1541-7786.mcr-09-0326] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Myeloid zinc finger 1 (MZF1) is a member of the SCAN domain family transcription factors that form dimers through their highly conserved SCAN motifs. Silencing of MZF1 inhibits cell proliferation, and abnormal expression of MZF1 results in cancer development. However, a potential role of MZF1 in metastasis remains unclear. Axl is a receptor tyrosine kinase and was first identified as a transforming gene in chronic myeloid leukemia. Axl overexpression induces proliferation, migration, and invasion and is highly expressed in different human cancers. In this study, we show that overexpression of MZF1 induces migration and invasion in colorectal (Rko, SW480) and cervical (HeLa) cancer cells. In addition, we show that MZF1 binds to the Axl promoter, transactivates promoter activity, and enhances Axl-mRNA and protein expression in a dose-dependent manner. In vitro, sh-RNA knockdown of Axl reduced MZF1-induced migration and invasion in HeLa and Rko cells (P = 0.05). Additionally, Rko cells overexpressing MZF1 showed increased tumor formation and liver metastasis in the chicken-embryo-metastasis assay in vivo. Furthermore, the expression of MZF1 and Axl was significantly higher in resected colorectal tumors compared with corresponding normal tissues (P = 0.02; P = 0.05), and MZF1 expression was positively correlated with Axl gene expression in tumor tissues (P < 0.01). Taken together, this is the first study to show that MZF1 induces invasion and in vivo metastasis in colorectal and cervical cancer, at least in part by regulating Axl gene expression.
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Affiliation(s)
- Giridhar Mudduluru
- Department of Experimental Surgery/Molecular Oncology of Solid Tumors, DKFZ and University of Heidelberg, Heidelberg, Germany
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Affiliation(s)
- Udo Rudloff
- National Cancer Institute, Surgery Branch, Bethesda, MD
| | - Yardena Samuels
- National Human Genome Research Institute, Cancer Genetics Branch, Bethesda, MD
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Gas6 and the receptor tyrosine kinase Axl in clear cell renal cell carcinoma. PLoS One 2009; 4:e7575. [PMID: 19888345 PMCID: PMC2766033 DOI: 10.1371/journal.pone.0007575] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 10/05/2009] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The molecular biology of renal cell carcinoma (RCC) is complex and not fully understood. We have recently found that the expression of the receptor tyrosine kinase Axl in the RCC tumors independently correlates with survival of the patients. PRINCIPAL FINDINGS Here, we have investigated the role of Axl and its ligand Gas6, the vitamin-K dependent protein product of the growth arrest-specific gene 6, in clear cell RCC (ccRCC) derived cells. The Axl protein was highly expressed in ccRCC cells deficient in functional von Hippel-Lindau (VHL) protein, a tumor suppressor gene often inactivated in ccRCC. VHL reconstituted cells expressed decreased levels of Axl protein, but not Axl mRNA, suggesting VHL to regulate Axl expression. Gas6-mediated activation of Axl in ccRCC cells resulted in Axl phosphorylation, receptor down-regulation, decreased cell-viability and migratory capacity. No effects of the Gas6/Axl system could be detected on invasion. Moreover, in ccRCC tumor tissues, Axl was phosphorylated and Gas6 gamma-carboxylated, suggesting these molecules to be active in vivo. SIGNIFICANCE These results provide novel information regarding the complex function of the Gas6/Axl system in ccRCC.
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Stonier SW, Schluns KS. Trans-presentation: a novel mechanism regulating IL-15 delivery and responses. Immunol Lett 2009; 127:85-92. [PMID: 19818367 DOI: 10.1016/j.imlet.2009.09.009] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 09/25/2009] [Accepted: 09/25/2009] [Indexed: 11/18/2022]
Abstract
Interleukin (IL)-15 is a cytokine that acts on a wide range of cell types but is most crucial for the development, homeostasis, and function of a specific group of immune cells that includes CD8 T cells, NK cells, NKT cells, and CD8 alpha alpha intraepithelial lymphocytes. IL-15 signals are transmitted through the IL-2/15R beta and common gamma (gamma C) chains; however, it is the delivery of IL-15 to these signaling components that is quite unique. As opposed to other cytokines that are secreted, IL-15 primarily exists bound to the high affinity IL-15R alpha. When IL-15/IL-15R alpha complexes are shuttled to the cell surface, they can stimulate opposing cells through the beta/gamma C receptor complex. This novel mechanism of IL-15 delivery has been called trans-presentation. This review discusses how the theory of trans-presentation came to be, evidence that it is the major mechanism of action, the current understanding of the cell types thought to mediate trans-presentation, and possible alternatives for IL-15 delivery.
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Affiliation(s)
- Spencer W Stonier
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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22
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Uehara S, Handa H, Gotoh K, Tomita H, Sennshuu M. Plasma concentrations of growth arrest-specific protein 6 and protein S in patients with acute pancreatitis. J Gastroenterol Hepatol 2009; 24:1567-73. [PMID: 19744001 DOI: 10.1111/j.1440-1746.2009.05875.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND The aim of the present study was to clarify the changes in plasma concentrations of growth arrest-specific protein 6 (Gas6) and protein S (PS) in patients with mild or severe acute pancreatitis (AP). METHODS The study group comprised 29 consecutive patients with AP (24 males, five females; mean age, 54.8 +/- 15.0 years) and 20 healthy controls (10 males, 10 females; mean age, 53.0 +/- 15.3 years). Plasma concentrations of Gas6 and PS were measured by enzyme-linked immunosorbent assay. RESULTS The concentration of Gas6 was significantly higher in both severe and mild AP than in healthy controls, and was significantly correlated with two of the multiple organ failure assessment scores. Furthermore, when compared with survivors, the concentrations of Gas6 in non-survivors of severe AP were significantly increased. The concentrations of free PS and total PS were significantly decreased compared with normal controls, but there was no difference between cases and controls in the concentrations of C4 binding protein-PS. CONCLUSION Plasma concentrations of Gas6 and PS correlate with disease severity. High concentrations of Gas6 reflect microcirculatory abnormalities, and phagocytosis of dying cells in sepsis associated with severe AP.
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Affiliation(s)
- Soichiro Uehara
- Department of Internal Medicine and Gastroenterology, Ohtakionsen Hospital, Hokkaido, Japan.
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23
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Scutera S, Fraone T, Musso T, Cappello P, Rossi S, Pierobon D, Orinska Z, Paus R, Bulfone-Paus S, Giovarelli M. Survival and migration of human dendritic cells are regulated by an IFN-alpha-inducible Axl/Gas6 pathway. THE JOURNAL OF IMMUNOLOGY 2009; 183:3004-13. [PMID: 19657094 DOI: 10.4049/jimmunol.0804384] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Axl, a prototypic member of the transmembrane tyrosine kinase receptor family, is known to regulate innate immunity. In this study, we show that Axl expression is induced by IFN-alpha during human dendritic cell (DC) differentiation from monocytes (IFN/DC) and that constitutively Axl-negative, IL-4-differentiated DC (IL-4/DC) can be induced to up-regulate Axl by IFN-alpha. This effect is inhibited by TLR-dependent maturation stimuli such as LPS, poly(I:C), TLR7/8 ligand, and CD40L. LPS-induced Axl down-regulation on the surface of human IFN-alpha-treated DC correlates with an increased proteolytic cleavage of Axl and with elevated levels of its soluble form. GM6001 and TAPI-1, general inhibitors of MMP and ADAM family proteases, restored Axl expression on the DC surface and diminished Axl shedding. Furthermore, stimulation of Axl by its ligand, Gas6, induced chemotaxis of human DC and rescued them from growth factor deprivation-induced apoptosis. Our study provides the first evidence that Gas6/Axl-mediated signaling regulates human DC activities, and identifies Gas6/Axl as a new DC chemotaxis pathway. This encourages one to explore whether dysregulation of this novel pathway in human DC biology is involved in autoimmunity characterized by high levels of IFN-alpha.
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Affiliation(s)
- Sara Scutera
- Department of Public Health and Microbiology, University of Torino, Torino, Italy
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24
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Axl as a potential therapeutic target in cancer: role of Axl in tumor growth, metastasis and angiogenesis. Oncogene 2009; 28:3442-55. [PMID: 19633687 DOI: 10.1038/onc.2009.212] [Citation(s) in RCA: 221] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Dysregulation of Axl and its ligand growth arrest-specific 6 is implicated in the pathogenesis of several human cancers. In this study, we have used RNAi and monoclonal antibodies to assess further the oncogenic potential of Axl. Here we show that Axl knockdown reduces growth of lung and breast cancer xenograft tumors. Inhibition of Axl expression attenuates breast cancer cell migration and inhibits metastasis to the lung in an orthotopic model, providing the first in vivo evidence that links Axl directly to cancer metastasis. Axl knockdown in endothelial cells impaired tube formation and this effect was additive with anti-vascular endothelial growth factor (VEGF). Further analysis demonstrated that Axl regulates endothelial cell functions by modulation of signaling through angiopoietin/Tie2 and Dickkopf (DKK3) pathways. We have developed and characterized Axl monoclonal antibodies that attenuate non-small cell lung carcinoma xenograft growth by downregulation of receptor expression, reducing tumor cell proliferation and inducing apoptosis. Our data demonstrate that Axl plays multiple roles in tumorigenesis and that therapeutic antibodies against Axl may block Axl functions not only in malignant tumor cells but also in the tumor stroma. The additive effect of Axl inhibition with anti-VEGF suggests that blocking Axl function could be an effective approach for enhancing antiangiogenic therapy.
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Lafdil F, Chobert MN, Deveaux V, Zafrani ES, Mavier P, Nakano T, Laperche Y, Brouillet A. Growth arrest-specific protein 6 deficiency impairs liver tissue repair after acute toxic hepatitis in mice. J Hepatol 2009; 51:55-66. [PMID: 19443073 DOI: 10.1016/j.jhep.2009.02.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 02/02/2009] [Accepted: 02/04/2009] [Indexed: 01/07/2023]
Abstract
BACKGROUND/AIMS Resident macrophages and myofibroblasts derived from hepatic stellate cells play a key role in liver wound healing. We previously reported that these sinusoidal cells secrete the growth arrest-specific protein 6 (Gas6) and express Axl, one of its receptors. Here we address the role of Gas6 in the healing process during acute liver injury. METHODS Toxic hepatitis was induced by a single carbon tetrachloride injection in Gas6 deficient (Gas6(-/-)) mice and liver recovery was compared with wild-type animals. RESULTS Gas6 deficiency did not cause any change in CCl(4)-induced liver damage. At 72 h, an efficient tissue repair was observed in wild-type animals whereas in Gas6(-/-) mice, we noticed a defective wound healing accounted by reduced Kupffer cell activation revealed by a decrease in the induction of CD14, TNF-alpha, IL6 and MCP-1. Gas6-deficiency, by limiting cytokine/chemokine release, prevents hepatocyte proliferation, recruitment of circulating monocytes and accumulation of myofibroblasts in healing areas. We also report a direct chemotactic effect of Gas6 on circulating monocytes which might explain defective macrophage infiltration in liver necrotic areas of Gas6(-/-) mice. Interestingly in Gas6(-/-) mice, we observed a high and constitutive expression of Axl and an induction of the suppressor of cytokine signaling SOCS1 after CCl(4) treatment. CONCLUSIONS The lower level of cytokines/chemokines in Gas6(-/-) mice after CCl(4) injury, is the consequence of an inhibitory signal arising from Axl receptor overexpression, leading to delayed liver repair in deficient mice.
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Affiliation(s)
- Fouad Lafdil
- INSERM, U955, Institut Mondor de Recherche Biomédicale, 94010 Créteil, France
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26
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Weinger JG, Omari KM, Marsden K, Raine CS, Shafit-Zagardo B. Up-regulation of soluble Axl and Mer receptor tyrosine kinases negatively correlates with Gas6 in established multiple sclerosis lesions. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:283-93. [PMID: 19541935 DOI: 10.2353/ajpath.2009.080807] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Multiple sclerosis is a disease that is characterized by inflammation, demyelination, and axonal damage; it ultimately forms gliotic scars and lesions that severely compromise the function of the central nervous system. Evidence has shown previously that altered growth factor receptor signaling contributes to lesion formation, impedes recovery, and plays a role in disease progression. Growth arrest-specific protein 6 (Gas6), the ligand for the TAM receptor tyrosine kinase family, consisting of Tyro3, Axl, and Mer, is important for cell growth, survival, and clearance of debris. In this study, we show that levels of membrane-bound Mer (205 kd), soluble Mer ( approximately 150 kd), and soluble Axl (80 kd) were all significantly elevated in homogenates from established multiple sclerosis lesions comprised of both chronic active and chronic silent lesions. Whereas in normal tissue Gas6 positively correlated with soluble Axl and Mer, there was a negative correlation between Gas6 and soluble Axl and Mer in established multiple sclerosis lesions. In addition, increased levels of soluble Axl and Mer were associated with increased levels of mature ADAM17, mature ADAM10, and Furin, proteins that are associated with Axl and Mer solubilization. Soluble Axl and Mer are both known to act as decoy receptors and block Gas6 binding to membrane-bound receptors. These data suggest that in multiple sclerosis lesions, dysregulation of protective Gas6 receptor signaling may prolong lesion activity.
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Affiliation(s)
- Jason G Weinger
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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Abstract
Cytokines are soluble mediators of cell communication that are critical in immune regulation. They induce specific gene-expression programs in responsive cells. Recent findings, however, indicate that cytokine receptors can regulate immune cell functions by transcription-independent mechanisms. Here we review the current understanding of how cytokine signaling regulates the functions of other signaling pathways by first discussing the 'traditional' transcription-mediated consequences of cytokine signaling and then providing a detailed description of transcription-independent lateral communications between cytokine receptors and other cellular receptors.
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Curtis JL, Todt JC, Hu B, Osterholzer JJ, Freeman CM. Tyro3 receptor tyrosine kinases in the heterogeneity of apoptotic cell uptake. Front Biosci (Landmark Ed) 2009; 14:2631-46. [PMID: 19273223 DOI: 10.2741/3401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mononuclear phagocytes comprise a mobile, broadly dispersed and highly adaptable system that lies at the very epicenter of host defense against pathogens and the interplay of the innate and adaptive arms of immunity. Understanding the molecular mechanisms that control the response of mononuclear phagocytes to apoptotic cells and the anti-inflammatory consequences of that response is an important goal with implications for multiple areas of biomedical sciences. This review details current understanding of the heterogeneity of apoptotic cell uptake by different members of the mononuclear phagocyte family in humans and mice. It also recounts the unique role of the Tyro3 family of receptor tyrosine kinases, best characterized for Mertk, in the signal transduction leading both to apoptotic cell ingestion and the anti-inflammatory effects that result.
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Affiliation(s)
- Jeffrey L Curtis
- Pulmonary and Critical Care Medicine, Department of Veterans Affairs Healthsystem and University of Michigan Health System, Ann Arbor, MI 48105, USA.
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The Axl/Gas6 pathway is required for optimal cytokine signaling during human natural killer cell development. Blood 2008; 113:2470-7. [PMID: 18840707 DOI: 10.1182/blood-2008-05-157073] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Interleukin-15 (IL-15) is essential for natural killer (NK) cell differentiation. In this study, we assessed whether the receptor tyrosine kinase Axl and its ligand, Gas6, are involved in IL-15-mediated human NK differentiation from CD34(+) hematopoietic progenitor cells (HPCs). Blocking the Axl-Gas6 interaction with a soluble Axl fusion protein (Axl-Fc) or the vitamin K inhibitor warfarin significantly diminished the absolute number and percentage of CD3(-)CD56(+) NK cells derived from human CD34(+) HPCs cultured in the presence of IL-15, probably resulting in part from reduced phosphorylation of STAT5. In addition, CD3(-)CD56(+) NK cells derived from culture of CD34(+) HPCs with IL-15 and Axl-Fc had a significantly diminished capacity to express interferon-gamma or its master regulator, T-BET. Culture of CD34(+) HPCs in the presence of c-Kit ligand and Axl-Fc resulted in a significant decrease in the frequency of NK precursor cells responding to IL-15, probably the result of reduced c-Kit phosphorylation. Collectively, our data suggest that the Axl/Gas6 pathway contributes to normal human NK-cell development, at least in part via its regulatory effects on both the IL-15 and c-Kit signaling pathways in CD34(+) HPCs, and to functional NK-cell maturation via an effect on the master regulatory transcription factor T-BET.
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Ullrich E, Bonmort M, Mignot G, Jacobs B, Bosisio D, Sozzani S, Jalil A, Louache F, Bulanova E, Geissman F, Ryffel B, Chaput N, Bulfone-Paus S, Zitvogel L. Trans-presentation of IL-15 dictates IFN-producing killer dendritic cells effector functions. THE JOURNAL OF IMMUNOLOGY 2008; 180:7887-97. [PMID: 18523252 DOI: 10.4049/jimmunol.180.12.7887] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
IFN-producing killer dendritic cells (IKDC) were initially described as B220(+)CD11c(+)CD3(-)NK1.1(+) tumor-infiltrating cells that mediated part of the antitumor effects of the combination therapy with imatinib mesylate and IL-2. In this study, we show their functional dependency on IL-15 during homeostasis and inflammatory processes. Trans-presentation of IL-15 by IL-15Ralpha allows dramatic expansion of IKDC in vitro and in vivo, licenses IKDC for TRAIL-dependent killing and endows IKDC with immunizing potential, all three biological attributes not shared by B220(-)NK cells. However, IL-15 down-regulates the capacity of IKDC to induce MHC class I- or II-restricted T cell activation in vitro. Trans-presentation of IL-15 by IL-15Ralpha allows IKDC to respond to TLR3 and TLR4 ligands for the production of CCL2, a chemokine that is critical for IKDC trafficking into tumor beds (as described recently). We conclude that IKDC represent a unique subset of innate effectors functionally distinguishable from conventional NK cells in their ability to promptly respond to IL-15-driven inflammatory processes.
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Affiliation(s)
- Evelyn Ullrich
- Institut National de la Santé et de la Recherche Médicale U805, Center of Clinical Investigations CBT507, Institut Gustave Roussy, Villejuif, France
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31
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Linger RMA, Keating AK, Earp HS, Graham DK. TAM receptor tyrosine kinases: biologic functions, signaling, and potential therapeutic targeting in human cancer. Adv Cancer Res 2008; 100:35-83. [PMID: 18620092 DOI: 10.1016/s0065-230x(08)00002-x] [Citation(s) in RCA: 533] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Tyro-3, Axl, and Mer constitute the TAM family of receptor tyrosine kinases (RTKs) characterized by a conserved sequence within the kinase domain and adhesion molecule-like extracellular domains. This small family of RTKs regulates an intriguing mix of processes, including cell proliferation/survival, cell adhesion and migration, blood clot stabilization, and regulation of inflammatory cytokine release. Genetic or experimental alteration of TAM receptor function can contribute to a number of disease states, including coagulopathy, autoimmune disease, retinitis pigmentosa, and cancer. In this chapter, we first provide a comprehensive review of the structure, regulation, biologic functions, and downstream signaling pathways of these receptors. In addition, we discuss recent evidence which suggests a role for TAM receptors in oncogenic mechanisms as family members are overexpressed in a spectrum of human cancers and have prognostic significance in some. Possible strategies for targeted inhibition of the TAM family in the treatment of human cancer are described. Further research will be necessary to evaluate the full clinical implications of TAM family expression and activation in cancer.
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Affiliation(s)
- Rachel M A Linger
- Department of Pediatrics, University of Colorado at Denver and Health Sciences Center, Aurora, CO, USA
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Abstract
Recent studies have revealed that the TAM receptor protein tyrosine kinases--TYRO3, AXL and MER--have pivotal roles in innate immunity. They inhibit inflammation in dendritic cells and macrophages, promote the phagocytosis of apoptotic cells and membranous organelles, and stimulate the maturation of natural killer cells. Each of these phenomena may depend on a cooperative interaction between TAM receptor and cytokine receptor signalling systems. Although its importance was previously unrecognized, TAM signalling promises to have an increasingly prominent role in studies of innate immune regulation.
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Affiliation(s)
- Greg Lemke
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 N. Torrey Pines Road, La Jolla, California 92037, USA.
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The human receptor tyrosine kinase Axl gene--promoter characterization and regulation of constitutive expression by Sp1, Sp3 and CpG methylation. Biosci Rep 2008; 28:161-76. [PMID: 18522535 DOI: 10.1042/bsr20080046] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Axl is a receptor tyrosine kinase which promotes anti-apoptosis, mitogenesis, invasion, angiogenesis and metastasis, and is highly expressed in cancers. However, the transcriptional regulation of this important gene has never been characterized. The present study was initiated to characterize the promoter, cis-acting elements and promoter methylation driving expression of Axl. The 2.4 kb sequence upstream of the translational start site, and sequential 5'-deletions were cloned and revealed a minimal GC-rich region (-556 to +7) to be sufficient for basal Axl promoter activity in Rko, HCT116 and HeLa cells. Within this minimal region, five Sp (specificity protein)-binding sites were identified. Two sites (Sp a and Sp b) proximal to the translation start site were indispensable for Axl promoter activity, whereas mutation of three additional upstream motifs (Sp c, Sp d and Sp e) was of additional relevance. Gel-shift assays and chromatin immunoprecipitation identified that Sp1 and Sp3 bound to all five motifs, and mutation of all motifs abolished binding. Mithramycin, which inhibits binding of Sp factors to GC-rich sites, dramatically reduced Axl promoter activity and Axl, Sp1 and Sp3 expression. In Drosophila Schneider SL2-cells, exogenous expression of Sp1/Sp3 increased Axl promoter activity. Use of Sp1/Sp3 siRNAs (small interfering RNAs) significantly reduced Axl promoter activity and protein levels in Rko and HeLa cells. Methylation-bisulfite sequencing detected methylated CpG sites within three Sp motifs (Sp a, Sp b and Sp c) and GC-rich flanking sequences, and demethylation by 5-aza-2'-deoxycytidine up-regulated Axl and Sp3 expression in low-Axl-expressing Colo206f/WiDr cells, but not in high-Axl-expressing Rko cells. The results of the present study suggest that Axl gene expression in cancer cells is (1) constitutively driven by Sp1/Sp3 bound to five core promoter motifs, and (2) restricted by methylation within/around Sp-binding sites. This might enhance the understanding and treatment of essential mechanisms associated with cancer and other diseases.
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How a cytokine is chaperoned through the secretory pathway by complexing with its own receptor: lessons from interleukin-15 (IL-15)/IL-15 receptor alpha. Mol Cell Biol 2008; 28:4851-61. [PMID: 18505820 DOI: 10.1128/mcb.02178-07] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
While it is well appreciated that receptors for secreted cytokines transmit ligand-induced signals, little is known about additional roles for cytokine receptor components in the control of ligand transport and secretion. Here, we show that interleukin-15 (IL-15) translocation into the endoplasmic reticulum occurs independently of the presence of IL-15 receptor alpha (IL-15R alpha). Subsequently, however, IL-15 is transported through the Golgi apparatus only in association with IL-15R alpha and then is secreted. This intracellular IL-15/IL-15R alpha complex already is formed in the endoplasmic reticulum and, thus, enables the further trafficking of complexed IL-15 through the secretory pathway. Just transfecting IL-15R alpha in cells, which transcribe but normally do not secrete IL-15, suffices to induce IL-15 secretion. Thus, we provide the first evidence of how a cytokine is chaperoned through the secretory pathway by complexing with its own high-affinity receptor and show that IL-15/IL-15R alpha offers an excellent model system for the further exploration of this novel mechanism for the control of cytokine secretion.
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Bellido-Martín L, de Frutos PG. Vitamin K-dependent actions of Gas6. VITAMINS AND HORMONES 2008; 78:185-209. [PMID: 18374195 DOI: 10.1016/s0083-6729(07)00009-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gas6 (growth arrest-specific gene 6) is the last addition to the family of plasma vitamin K-dependent proteins. Gas6 was cloned and characterized in 1993 and found to be similar to the plasma anticoagulant protein S. Soon after it was recognized as a growth factor-like molecule, as it interacted with receptor tyrosine kinases (RTKs) of the TAM family; Tyro3, Axl, and MerTK. Since then, the role of Gas6, protein S, and the TAM receptors has been found to be important in inflammation, hemostasis, and cancer, making this system an interesting target in biomedicine. Gas6 employs a unique mechanism of action, interacting through its vitamin K-dependent Gla module with phosphatidylserine-containing membranes and through its carboxy-terminal LG domains with the TAM membrane receptors. The fact that these proteins are affected by anti-vitamin K therapy is discussed in detail.
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Affiliation(s)
- Lola Bellido-Martín
- Department of Cell Death and Proliferation, Institute for Biomedical Research of Barcelona, IIBB-CSIC-IDIBAPS, Barcelona 08036, Spain
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Abstract
The expression of cytokines and cytokine receptors was investigated in enriched populations of human fetal Schwann cells by reverse transcribed-PCR and enzyme-linked immunosorbent assay. Human fetal Schwann cells constitutively expressed mRNA of IL-1beta, IL-6, IL-8, IL-11, IL-12, IL-15 and TGF-beta, and also cytokine receptors for IL-1, IL-4, IL-6, IL-8, IL-13, tissue necrosis factor and gp130. The expression of IL-1beta, IL-6 and IL-15 was upregulated following treatment with IL-1beta or TGF-beta. The protein levels of IL-6 were increased with IL-1beta treatment, but were decreased with IFN-gamma treatment. Human Schwann cells may respond to cytokine signals in the nerve injury sites and modify the pathological conditions by secreting cytokines. The secreted cytokines may play a role in leukocyte recruitment and exacerbation of axonal injury process.
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Zhang YX, Knyazev PG, Cheburkin YV, Sharma K, Knyazev YP, Orfi L, Szabadkai I, Daub H, Kéri G, Ullrich A. AXL is a potential target for therapeutic intervention in breast cancer progression. Cancer Res 2008; 68:1905-15. [PMID: 18339872 DOI: 10.1158/0008-5472.can-07-2661] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Protein kinases play important roles in tumor development and progression. A variety of members of this family of signal transduction enzymes serve as targets for therapeutic intervention in cancer. We have identified the receptor tyrosine kinase (RTK) AXL as a potential mediator of motility and invasivity of breast cancer cells. AXL is expressed in most highly invasive breast cancer cells, but not in breast cancer cells of low invasivity. Ectopic expression of AXL was sufficient to confer a highly invasive phenotype to weakly invasive MCF7 breast cancer cells. Experimental inhibition of AXL signaling by a dominant-negative AXL mutant, an antibody against the extracellular domain of AXL, or short hairpin RNA knockdown of AXL decreased motility and invasivity of highly invasive breast cancer cells. To selectively interfere with cancer cell properties defining the rate of disease progression, we identified 3-quinolinecarbonitrile compounds, which displayed potent inhibitory activity against AXL and showed strong interference with motility and invasivity of breast cancer cells. Our findings validated the RTK AXL as a critical element in the signaling network that governs motility and invasivity of breast cancer cells, and allowed the identification of experimental anti-AXL small molecular inhibitors that represent lead substances for the development of antimetastatic breast cancer therapy.
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Affiliation(s)
- Yi-Xiang Zhang
- Max Planck Institute of Biochemistry, Martinsried, Germany
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Genes and structure of selected cytokines involved in pathogenesis of psoriasis. Folia Histochem Cytobiol 2008; 46:11-21. [PMID: 18296259 DOI: 10.2478/v10042-008-0002-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Psoriasis is a common skin disease involving 1-4% of human population worldwide, of strong genetic background. The following cytokines are directly involved in psoriasis: TNF, IL-1, IL-2, IL-6, IL-7, IL-8, IL-15, IL-18, IL-19, IL-20, IL-23 whereas IL-4, IL-10, IL-12 as well as IL-11, IL-17 and IFN-gamma are rather indirectly engaged. This work is a review of some genetic factors and structure of selected cytokines and receptors and their genes location.
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Tai KY, Shieh YS, Lee CS, Shiah SG, Wu CW. Axl promotes cell invasion by inducing MMP-9 activity through activation of NF-kappaB and Brg-1. Oncogene 2008; 27:4044-55. [PMID: 18345028 DOI: 10.1038/onc.2008.57] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Activity of the Axl receptor tyrosine kinase is positively correlated with tumor metastasis; however, its detailed role in the mechanism of tumor invasion is still not completely understood. Here, we show that Axl enhances the expression of matrix metalloproteinase 9 (MMP-9), required for Axl-mediated invasion both in vitro and in vivo. We found that the highly selective MEK1/2 inhibitors U0126 and PD98059, and the expressed dominant-negative form of extracellular signal-regulated kinase (ERK), completely block Axl-mediated MMP-9 activation. In contrast, the phosphatidylinositol 3-kinase inhibitor LY294002 and wortmannin had little effect on activation. Interestingly, however, the Axl ligand Gas6 is not involved in Axl-mediated MMP-9 activation. Mutation of Glu59(Axl) and Thr77(Axl) dramatically reduced Gas6-Axl binding but continued to induce MMP-9 activation. In addition, overexpression of Axl-activated ERK and enhanced nuclear factor-kappaB (NF-kappaB) transactivation and brahma-related gene-1 (Brg-1) translocation. Exposure to the NF-kappaB inhibitor silibinin, which inhibits IkappaBalpha kinase activity, or overexpression of the dominant-negative mutant IkappaB and Brg-1 strikingly inhibited Axl-mediated MMP-9 activation. These data indicate that coordination of ERK signaling and NF-kappaB and Brg-1 activation are indispensable to regulation of Axl-dependent MMP-9 gene transcription. Together with previous data, our results provide a plausible mechanism for Axl-mediated tumor invasion and establish a functional link between the Axl and MMP-9 signaling pathways.
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Affiliation(s)
- K-Y Tai
- Institute of Cancer Research, National Health Research Institutes, Miaoli County, Taiwan
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Rothlin CV, Ghosh S, Zuniga EI, Oldstone MBA, Lemke G. TAM receptors are pleiotropic inhibitors of the innate immune response. Cell 2008; 131:1124-36. [PMID: 18083102 DOI: 10.1016/j.cell.2007.10.034] [Citation(s) in RCA: 754] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 08/15/2007] [Accepted: 10/09/2007] [Indexed: 11/17/2022]
Abstract
The activation of Toll-like receptors (TLRs) in dendritic cells (DCs) triggers a rapid inflammatory response to pathogens. However, this response must be tightly regulated because unrestrained TLR signaling generates a chronic inflammatory milieu that often leads to autoimmunity. We have found that the TAM receptor tyrosine kinases-Tyro3, Axl, and Mer-broadly inhibit both TLR and TLR-induced cytokine-receptor cascades. Remarkably, TAM inhibition of inflammation is transduced through an essential stimulator of inflammation-the type I interferon receptor (IFNAR)-and its associated transcription factor STAT1. TLR induction of IFNAR-STAT1 signaling upregulates the TAM system, which in turn usurps the IFNAR-STAT1 cassette to induce the cytokine and TLR suppressors SOCS1 and SOCS3. These results illuminate a self-regulating cycle of inflammation, in which the obligatory, cytokine-dependent activation of TAM signaling hijacks a proinflammatory pathway to provide an intrinsic feedback inhibitor of both TLR- and cytokine-driven immune responses.
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Affiliation(s)
- Carla V Rothlin
- Molecular Neurobiology Laboratory, The Salk Institute, La Jolla, CA 92037, USA
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A biophysical approach to IL-2 and IL-15 receptor function: localization, conformation and interactions. Immunol Lett 2008; 116:117-25. [PMID: 18280585 DOI: 10.1016/j.imlet.2007.12.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2007] [Accepted: 12/30/2007] [Indexed: 12/25/2022]
Abstract
Interleukin-2 and interleukin-15 (IL-2, IL-15) are key participants in T and NK cell activation and function. Sharing the beta and gamma receptor subunits results in several common functions: e.g. the promotion of T cell proliferation. On the other hand, due to their distinct alpha receptor subunits, they also play opposing roles in immune processes such as activation induced cell death and immunological memory. Divergence of signaling pathways must ensue already at the plasma membrane where the cytokines interact with their receptors. Therefore understanding molecular details of receptor organization and mapping interactions with other membrane proteins that might influence receptor conformation and function, are of key importance. Biophysical/advanced microscopic methods (fluorescence resonance energy transfer (FRET), fluorescence crosscorrelation spectroscopy (FCCS), near-field scanning optical microscopy (NSOM), X-ray crystallography, surface plasmon resonance, NMR spectroscopy) have been instrumental in clarifying the details of receptor structure and organization from the atomic level to the assembly and dynamics of supramolecular clusters. In this short review some important contributions shaping our current view of IL-2 and IL-15 receptors are presented.
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Ball SG, Shuttleworth CA, Kielty CM. Mesenchymal stem cells and neovascularization: role of platelet-derived growth factor receptors. J Cell Mol Med 2008; 11:1012-30. [PMID: 17979880 PMCID: PMC4401270 DOI: 10.1111/j.1582-4934.2007.00120.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
There is now accumulating evidence that bone marrow-derived mesenchymal stem cells (MSCs) make an important contribution to postnatal vasculogenesis, especially during tissue ischaemia and tumour vascularization. Identifying mechanisms which regulate the role of MSCs in vasculogenesis is a key therapeutic objective, since while increased neovascularization can be advantageous during tissue ischaemia, it is deleterious during tumourigenesis. The potent angiogenic stimulant vascular endothelial growth factor (VEGF) is known to regulate MSC mobilization and recruitment to sites of neovascularization, as well as directing the differentiation of MSCs to a vascular cell fate. Despite the fact that MSCs did not express VEGF receptors, we have recently identified that VEGF-A can stimulate platelet-derived growth factor (PDGF) receptors, which regulates MSC migration and proliferation. This review focuses on the role of PDGF receptors in regulating the vascular cell fate of MSCs, with emphasis on the function of the novel VEGF-A/PDGF receptor signalling mechanism.
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Affiliation(s)
- Stephen G Ball
- UK Centre for Tissue Engineering, Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
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Wittnebel S, Da Rocha S, Giron-Michel J, Jalil A, Opolon P, Escudier B, Validire P, Khawam K, Chouaib S, Azzarone B, Caignard A. Membrane-bound interleukin (IL)-15 on renal tumor cells rescues natural killer cells from IL-2 starvation-induced apoptosis. Cancer Res 2007; 67:5594-9. [PMID: 17575122 DOI: 10.1158/0008-5472.can-06-4406] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Renal cell carcinoma primary tumors and lung metastases are infiltrated by activated natural killer (NK) cells. Interleukin (IL)-15, a major cytokine involved in cross-talk between accessory cells (dendritic cells and macrophages) and NK cells, is produced by epithelial renal cells. We show that renal cell carcinoma cells and normal renal cells express IL-15 mRNA and membrane-bound IL-15 (MbIL-15). These cells also express IL-15 receptor alpha (IL-15Ralpha). Silencing of IL-15Ralpha by specific small interfering RNA in renal cell carcinoma had no effect on MbIL-15 production, indicating that the cytokine is not cross-presented by IL-15Ralpha in renal cell carcinoma cells but anchored to the membrane. Furthermore, we show that MbIL-15 from renal cell carcinoma cells is functional and involved in rapid nuclear translocation of phosphorylated signal transducers and activators of transcription 3 in IL-2-starved NK cells. MbIL-15 on the target did not interfere with resting NK cell activation and target cell cytolysis but rescued NK cells from IL-2 starvation-induced apoptosis through contact-dependent interaction. Masking of MbIL-15 with soluble IL-15Ralpha molecules restored NK cell apoptosis. These findings suggest that IL-15 produced by renal tumor cells is involved in the maintenance of active NK cells at the tumor site.
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Roth C, Rothlin C, Riou S, Raulet DH, Lemke G. Stromal-cell regulation of natural killer cell differentiation. J Mol Med (Berl) 2007; 85:1047-56. [PMID: 17426948 DOI: 10.1007/s00109-007-0195-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 03/12/2007] [Accepted: 03/14/2007] [Indexed: 10/23/2022]
Abstract
Natural killer (NK) cells are bone-marrow-derived lymphocytes that play a crucial role in host defense against some viral and bacterial infections, as well as against tumors. Their phenotypic and functional maturation requires intimate interactions between the bone marrow stroma and committed precursors. In parallel to the identification of several phenotypic and functional stages of NK cell development, recent studies have shed new light on the role of stromal cells in driving functional maturation of NK cells. In this review, we provide an overview of the role of bone marrow microenvironment in NK cell differentiation.
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Affiliation(s)
- Claude Roth
- Laboratoire Immunité Cellulaire Antivirale, Département d'Immunologie, Institut Pasteur, 75724, Paris Cedex 15, France.
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Collett GDM, Sage AP, Kirton JP, Alexander MY, Gilmore AP, Canfield AE. Axl/Phosphatidylinositol 3-Kinase Signaling Inhibits Mineral Deposition by Vascular Smooth Muscle Cells. Circ Res 2007; 100:502-9. [PMID: 17255529 DOI: 10.1161/01.res.0000258854.03388.02] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The calcification of blood vessels correlates with increased morbidity and mortality in patients with atherosclerosis, diabetes, and end-stage kidney disease. The receptor tyrosine kinase Axl is emerging as an important regulator of adult mammalian physiology and pathology. This study tests the hypothesis that Axl prevents the deposition of a calcified matrix by vascular smooth muscle cells (VSMCs) and that this occurs via the phosphatidylinositol 3-kinase (PI3K) signaling pathway. First, we demonstrate that Axl is expressed and phosphorylated in confluent VSMCs and that its expression is markedly downregulated as these cells calcify their matrix. Second, we demonstrate that overexpression of wild-type Axl, using recombinant adenoviruses, enhances Axl phosphorylation and downstream signaling via PI3K and Akt. Furthermore, overexpression of Axl significantly inhibits mineral deposition by VSMCs, as assessed by alizarin red staining and
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Ca accumulation. Third, the addition of a PI3K inhibitor, wortmannin, negates the inhibition of mineralization by overexpression of wild-type Axl, suggesting that activation of downstream signaling via PI3K is crucial for its inhibitory activity. In contrast, Axl-mediated signaling is not enhanced by overexpression of kinase-dead Axl and mineralization is accelerated, although β-glycerophosphate is still required for this effect. Finally, the caspase inhibitor zVAD.fmk attenuates the increased mineralization induced by kinase-dead Axl, suggesting that kinase-dead Axl stimulates mineralization by inhibiting the antiapoptotic effect of endogenous Axl. Together, these results demonstrate that signaling through Axl inhibits vascular calcification in vitro and suggest that therapeutics targeting this receptor may open up new avenues for the prevention of vascular calcification in vivo.
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Affiliation(s)
- Georgina D M Collett
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
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Bulanova E, Budagian V, Duitman E, Orinska Z, Krause H, Rückert R, Reiling N, Bulfone-Paus S. Soluble Interleukin IL-15Ralpha is generated by alternative splicing or proteolytic cleavage and forms functional complexes with IL-15. J Biol Chem 2007; 282:13167-79. [PMID: 17327231 DOI: 10.1074/jbc.m610036200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interleukin 15 (IL-15) is a pleiotropic cytokine that is hardly detectable in biological fluids. Here, we show that IL-15 forms functional heterocomplexes with soluble high affinity IL-15 receptor alpha (IL-15Ralpha) chain in mouse serum and cell-conditioned medium, which prevents IL-15 detection by ELISA. We also demonstrate that two soluble IL-15Ralpha (sIL-15Ralpha) sushi domain isoforms are generated through a novel alternative splicing mechanism within the IL-15Ralpha gene. These isoforms potentiate IL-15 action by promoting the IL-15-mediated proliferation of the CTLL cell line and interferon gamma production by murine NK cells, which suggests a role in IL-15 transpresentation. Conversely, a full-length sIL-15Ralpha ectodomain released by tumor necrosis factor-alpha-converting enzyme (TACE)-dependent proteolysis inhibits IL-15 activity. Thus, a dual mechanism of sIL-15Ralpha generation exists in mice, giving rise to polypeptides with distinct properties, which regulate IL-15 function.
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Affiliation(s)
- Elena Bulanova
- Department of Immunology and Cell Biology and Immunochemistry and Biochemical Microbiology, Research Center Borstel, Borstel D-23845, Germany.
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Chiossone L, Vitale C, Cottalasso F, Moretti S, Azzarone B, Moretta L, Mingari MC. Molecular analysis of the methylprednisolone-mediated inhibition of NK-cell function: evidence for different susceptibility of IL-2– versus IL-15–activated NK cells. Blood 2007; 109:3767-75. [PMID: 17234744 DOI: 10.1182/blood-2006-07-037846] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Abstract
Steroids have been shown to inhibit the function of fresh or IL-2–activated natural killer (NK) cells. Since IL-15 plays a key role in NK-cell development and function, we comparatively analyzed the effects of methylprednisolone on IL-2– or IL-15–cultured NK cells. Methylprednisolone inhibited the surface expression of the major activating receptors NKp30 and NKp44 in both conditions, whereas NK-cell proliferation and survival were sharply impaired only in IL-2–cultured NK cells. Accordingly, methylprednisolone inhibited Tyr phosphorylation of STAT1, STAT3, and STAT5 in IL-2–cultured NK cells but only marginally in IL-15–cultured NK cells, whereas JAK3 was inhibited under both conditions. Also, the NK cytotoxicity was similarly impaired in IL-2– or IL-15–cultured NK cells. This effect strictly correlated with the inhibition of ERK1/2 Tyr phosphorylation, perforin release, and cytotoxicity in a redirected killing assay against the FcRγ+ P815 target cells upon cross-linking of NKp46, NKG2D, or 2B4 receptors. In contrast, in the case of CD16, inhibition of ERK1/2 Tyr phosphorylation, perforin release, and cytotoxicity were not impaired. Our study suggests a different ability of IL-15–cultured NK cells to survive to steroid treatment, thus offering interesting clues for a correct NK-cell cytokine conditioning in adoptive immunotherapy.
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Hafizi S, Dahlbäck B. Gas6 and protein S. Vitamin K-dependent ligands for the Axl receptor tyrosine kinase subfamily. FEBS J 2006; 273:5231-44. [PMID: 17064312 DOI: 10.1111/j.1742-4658.2006.05529.x] [Citation(s) in RCA: 257] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gas6 and protein S are two homologous secreted proteins that depend on vitamin K for their execution of a range of biological functions. A discrete subset of these functions is mediated through their binding to and activation of the receptor tyrosine kinases Axl, Sky and Mer. Furthermore, a hallmark of the Gas6-Axl system is the unique ability of Gas6 and protein S to tether their non receptor-binding regions to the negatively charged membranes of apoptotic cells. Numerous studies have shown the Gas6-Axl system to regulate cell survival, proliferation, migration, adhesion and phagocytosis. Consequently, altered activity/expression of its components has been detected in a variety of pathologies such as cancer and vascular, autoimmune and kidney disorders. Moreover, Axl overactivation can equally occur without ligand binding, which has implications for tumorigenesis. Further knowledge of this exquisite ligand-receptor system and the circumstances of its activation should provide the basis for development of novel therapies for the above diseases.
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Affiliation(s)
- Sassan Hafizi
- Lund University, Department of Laboratory Medicine, Section for Clinical Chemistry, Wallenberg Laboratory, University Hospital Malmö, Sweden.
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Abstract
Although interleukin 2 (IL-2) and IL-15 signal through the common gamma chain (γc) and through IL-2 receptor β–chain (CD122) subunits, they direct distinct physiologic and immunotherapeutic responses in T cells. The present study provides some insight into why IL-2 and IL-15 differentially regulate T-cell function by revealing that these cytokines are strikingly distinct in their ability to control protein synthesis and T-cell mass. IL-2 and IL-15 are shown to be equivalent mitogens for antigen-stimulated CD8+ T cells but not for equivalent growth factors. Antigen-primed T cells cannot autonomously maintain amino acid incorporation or de novo protein synthesis without exogenous cytokine stimulation. Both IL-2 and IL-15 induce amino acid uptake and protein synthesis in antigen-activated T cells; however, the IL-2 response is strikingly more potent than the IL-15 response. The differential action of IL-2 and IL-15 on amino acid uptake and protein synthesis is explained by temporal differences in signaling induced by these 2 cytokines. Hence, the present results show that cytokines that are equivalent mitogens can have different potency in terms of regulating protein synthesis and cell growth.
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Bulfone-Paus S, Bulanova E, Budagian V, Paus R. The interleukin-15/interleukin-15 receptor system as a model for juxtacrine and reverse signaling. Bioessays 2006; 28:362-77. [PMID: 16547946 DOI: 10.1002/bies.20380] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Interleukin-15 (IL-15) is a pleiotropic cytokine of the 4 alpha-helix bundle family, which binds to a receptor complex that displays common elements with the IL-2 receptor and a unique high-affinity alpha chain. This review focuses on juxtacrine and reverse signaling levels in the IL-15/IL-15R system. Specifically, we discuss how agonistic stimulation of membrane-bound IL-15 induces phosphorylation of members of the MAP kinase family and of focal adhesion kinase (FAK), thereby upregulating processes including cytokine secretion, cell adhesion and migration. In addition, we explore IL-15 trans-presentation and intracellular signaling, and define promising molecular targets for future pharmacological intervention in infectious diseases and immunological disorders. These frontiers in IL-15/IL-15Ralpha research serve as highly instructive examples for key concepts, unsolved problems and therapeutic opportunities in juxtacrine and reverse signaling in general.
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Affiliation(s)
- Silvia Bulfone-Paus
- Department of Immunology and Cell Biology, Research Center Borstel, Germany.
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