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Ma Q, He X, Wang X, Zhao G, Zhang Y, Su C, Wei M, Zhang K, Liu M, Zhu Y, He J. PTPN14 aggravates neointimal hyperplasia via boosting PDGFRβ signaling in smooth muscle cells. Nat Commun 2024; 15:7398. [PMID: 39191789 PMCID: PMC11350182 DOI: 10.1038/s41467-024-51881-x] [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: 11/10/2023] [Accepted: 08/20/2024] [Indexed: 08/29/2024] Open
Abstract
Smooth muscle cell (SMC) phenotypic modulation, primarily driven by PDGFRβ signaling, is implicated in occlusive cardiovascular diseases. However, the promotive and restrictive regulation mechanism of PDGFRβ and the role of protein tyrosine phosphatase non-receptor type 14 (PTPN14) in neointimal hyperplasia remain unclear. Our study observes a marked upregulation of PTPN14 in SMCs during neointimal hyperplasia. PTPN14 overexpression exacerbates neointimal hyperplasia in a phosphatase activity-dependent manner, while SMC-specific deficiency of PTPN14 mitigates this process in mice. RNA-seq indicates that PTPN14 deficiency inhibits PDGFRβ signaling-induced SMC phenotypic modulation. Moreover, PTPN14 interacts with intracellular region of PDGFRβ and mediates its dephosphorylation on Y692 site. Phosphorylation of PDGFRβY692 negatively regulates PDGFRβ signaling activation. The levels of both PTPN14 and phospho-PDGFRβY692 are correlated with the degree of stenosis in human coronary arteries. Our findings suggest that PTPN14 serves as a critical modulator of SMCs, promoting neointimal hyperplasia. PDGFRβY692, dephosphorylated by PTPN14, acts as a self-inhibitory site for controlling PDGFRβ activation.
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MESH Headings
- Animals
- Humans
- Male
- Mice
- Coronary Vessels/pathology
- Coronary Vessels/metabolism
- Hyperplasia/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Neointima/metabolism
- Neointima/pathology
- Phosphorylation
- Protein Tyrosine Phosphatases, Non-Receptor/metabolism
- Protein Tyrosine Phosphatases, Non-Receptor/genetics
- Receptor, Platelet-Derived Growth Factor beta/metabolism
- Receptor, Platelet-Derived Growth Factor beta/genetics
- Signal Transduction
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Affiliation(s)
- Qiannan Ma
- Tianjin Key Laboratory of Metabolic Diseases, Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, 300070, China
- Department of Endocrinology and Metabolism, Tianjin Research Institute of Endocrinology, Tianjin Medical University General Hospital, Tianjin, 300052, China
| | - Xue He
- Tianjin Key Laboratory of Metabolic Diseases, Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, 300070, China
| | - Xue Wang
- Tianjin Key Laboratory of Metabolic Diseases, Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, 300070, China
| | - Guobing Zhao
- Tianjin Key Laboratory of Metabolic Diseases, Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, 300070, China
| | - Yanhong Zhang
- Tianjin Key Laboratory of Metabolic Diseases, Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, 300070, China
| | - Chao Su
- Division of Cardiovascular Surgery, Cardiac and Vascular Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, 518040, China
| | - Minxin Wei
- Division of Cardiovascular Surgery, Cardiac and Vascular Center, The University of Hong Kong-Shenzhen Hospital, Shenzhen, 518040, China
| | - Kai Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Research Institute of Endocrinology, Tianjin Medical University General Hospital, Tianjin, 300052, China.
| | - Yi Zhu
- Tianjin Key Laboratory of Metabolic Diseases, Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, 300070, China.
- Department of Endocrinology and Metabolism, Tianjin Research Institute of Endocrinology, Tianjin Medical University General Hospital, Tianjin, 300052, China.
| | - Jinlong He
- Tianjin Key Laboratory of Metabolic Diseases, Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, 300070, China.
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2
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Rogers MA, Campaña MB, Long R, Fantauzzo KA. PDGFR dimer-specific activation, trafficking and downstream signaling dynamics. J Cell Sci 2022; 135:jcs259686. [PMID: 35946433 PMCID: PMC9482349 DOI: 10.1242/jcs.259686] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 08/03/2022] [Indexed: 11/20/2022] Open
Abstract
Signaling through the platelet-derived growth factor receptors (PDGFRs) plays a critical role in multiple cellular processes during development. The two PDGFRs, PDGFRα and PDGFRβ, dimerize to form homodimers and/or heterodimers. Here, we overcome previous limitations in studying PDGFR dimer-specific dynamics by generating cell lines stably expressing C-terminal fusions of each PDGFR with bimolecular fluorescence complementation (BiFC) fragments corresponding to the N-terminal or C-terminal regions of the Venus fluorescent protein. We find that PDGFRβ receptors homodimerize more quickly than PDGFRα receptors in response to PDGF ligand, with increased levels of autophosphorylation. Furthermore, we demonstrate that PDGFRα homodimers are trafficked and degraded more quickly, whereas PDGFRβ homodimers are more likely to be recycled back to the cell membrane. We show that PDGFRβ homodimer activation results in a greater amplitude of phospho-ERK1/2 and phospho-AKT signaling, as well as increased proliferation and migration. Finally, we demonstrate that inhibition of clathrin-mediated endocytosis leads to changes in cellular trafficking and downstream signaling, particularly for PDGFRα homodimers. Collectively, our findings provide significant insight into how biological specificity is introduced to generate unique responses downstream of PDGFR engagement. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | | | | | - Katherine A. Fantauzzo
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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3
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Neurofibromin Deficiency and Extracellular Matrix Cooperate to Increase Transforming Potential through FAK-Dependent Signaling. Cancers (Basel) 2021; 13:cancers13102329. [PMID: 34066061 PMCID: PMC8150846 DOI: 10.3390/cancers13102329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 11/20/2022] Open
Abstract
Simple Summary Neurofibromatosis type 1 is a genetic disease that predisposes to tumors of the nervous system, primarily the neurofibroma. Plexiform neurofibromas (Pnfs) are of the greatest concern because of location, size, and frequent progression to malignancy. Although research is making great progress, the lack of in-depth understanding of the molecular mechanisms driving neoplastic progression results in the absence of prognostic indicators and therapeutic targets. We document that cell–cell cooperativity and the dynamics of the extracellular matrix play important roles in the growth and transformation of Pnf cells, directly through the cooperation of RAS and focal adhesion kinase (FAK) signaling. In turn, we found that treatment of Pnf cells with both MEK and FAK inhibitors is effective in abolishing the transforming ability of these cells. Abstract Plexiform neurofibromas (Pnfs) are benign peripheral nerve sheath tumors that are major features of the human genetic syndrome, neurofibromatosis type 1 (NF1). Pnfs are derived from Schwann cells (SCs) undergoing loss of heterozygosity (LOH) at the NF1 locus in an NF1+/− milieu and thus are variably lacking in the key Ras-controlling protein, neurofibromin (Nfn). As these SCs are embedded in a dense desmoplastic milieu of stromal cells and abnormal extracellular matrix (ECM), cell–cell cooperativity (CCC) and the molecular microenvironment play essential roles in Pnf progression towards a malignant peripheral nerve sheath tumor (MPNST). The complexity of Pnf biology makes treatment challenging. The only approved drug, the MEK inhibitor Selumetinib, displays a variable and partial therapeutic response. Here, we explored ECM contributions to the growth of cells lacking Nfn. In a 3D in vitro culture, NF1 loss sensitizes cells to signals from a Pnf-mimicking ECM through focal adhesion kinase (FAK) hyperactivation. This hyperactivation correlated with phosphorylation of the downstream effectors, Src, ERK, and AKT, and with colony formation. Expression of the GAP-related domain of Nfn only partially decreased activation of this signaling pathway and only slowed down 3D colony growth of cells lacking Nfn. However, combinatorial treatment with both the FAK inhibitor Defactinib (VS-6063) and Selumetinib (AZD6244) fully suppressed colony growth. These observations pave the way for a new combined therapeutic strategy simultaneously interfering with both intracellular signals and the interplay between the various tumor cells and the ECM.
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4
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The emerging complexity of PDGFRs: activation, internalization and signal attenuation. Biochem Soc Trans 2021; 48:1167-1176. [PMID: 32369556 DOI: 10.1042/bst20200004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/08/2020] [Accepted: 04/14/2020] [Indexed: 12/30/2022]
Abstract
The platelet-derived growth factor receptor (PDGFR) family of receptor tyrosine kinases allows cells to communicate with the environment to regulate diverse cellular activities. Here, we highlight recent data investigating the structural makeup of individual PDGFRs upon activation, revealing the importance of the whole receptor in the propagation of extracellular ligand binding and dimerization. Furthermore, we review ongoing research demonstrating the significance of receptor internalization and signal attenuation in the regulation of PDGFR activity. Interactions with internalization machinery, signaling from endosomes, receptor degradation and receptor recycling are physiological means by which cells fine-tune PDGFR responses to growth factor stimulation. In this review, we discuss the biophysical, structural, in silico and biochemical data that have provided evidence for these mechanisms. We further highlight the commonalities and differences between PDGFRα and PDGFRβ signaling, revealing critical gaps in knowledge. In total, this review provides a conclusive summary on the state of the PDGFR field and underscores the need for novel techniques to fully elucidate the mechanisms of PDGFR activation, internalization and signal attenuation.
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5
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Maeda TK, Sugiura D, Okazaki IM, Maruhashi T, Okazaki T. Atypical motifs in the cytoplasmic region of the inhibitory immune co-receptor LAG-3 inhibit T cell activation. J Biol Chem 2019; 294:6017-6026. [PMID: 30760527 DOI: 10.1074/jbc.ra119.007455] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/01/2019] [Indexed: 12/17/2022] Open
Abstract
T cell activation is tightly regulated by both stimulatory and inhibitory co-receptors and has been a focus in the development of interventions for managing cancer or autoimmune diseases. Targeting the inhibitory co-receptors programmed cell death 1 (PD-1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4) has successfully eradicated tumors but induced immune-related adverse events in humans and mice. The beneficial and adverse effects of targeting these co-receptors highlight their importance in cancer immunity and also autoimmunity. Although the therapeutic potencies of other inhibitory co-receptors are under extensive investigation, their inhibitory mechanisms and their functional differences are not well understood. Here we analyzed the inhibitory mechanisms of lymphocyte activation gene-3 (LAG-3), another inhibitory co-receptor, by using an in vitro T cell activation system and a high-affinity anti-LAG-3 antibody that strongly interferes with the binding of LAG-3 to its ligand. We found that the expression level of LAG-3 strongly correlates with the inhibitory function of LAG-3, suggesting that LAG-3 functions as a rheostat rather than as a breaker of T cell activation. By evaluating the inhibitory capacities of various LAG-3 variants relative to their expression levels, we found that LAG-3 transduces two independent inhibitory signals through an FXXL motif in the membrane-proximal region and the C-terminal EX repeat. These motifs have not been reported previously for inhibitory co-receptors, suggesting that LAG-3 inhibits T cell activation through a nonredundant inhibitory mechanisms along with the other inhibitory co-receptors. Our findings provide a rationale for combinatorial targeting of LAG-3 and the other inhibitory co-receptors to improve cancer immunotherapy.
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Affiliation(s)
- Takeo K Maeda
- From the Division of Immune Regulation, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Daisuke Sugiura
- From the Division of Immune Regulation, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Il-Mi Okazaki
- From the Division of Immune Regulation, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Takumi Maruhashi
- From the Division of Immune Regulation, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Taku Okazaki
- From the Division of Immune Regulation, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan.
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6
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Das F, Ghosh-Choudhury N, Venkatesan B, Kasinath BS, Ghosh Choudhury G. PDGF receptor-β uses Akt/mTORC1 signaling node to promote high glucose-induced renal proximal tubular cell collagen I (α2) expression. Am J Physiol Renal Physiol 2017; 313:F291-F307. [PMID: 28424212 DOI: 10.1152/ajprenal.00666.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 04/11/2017] [Accepted: 04/12/2017] [Indexed: 01/28/2023] Open
Abstract
Increased expression of PDGF receptor-β (PDGFRβ) has been shown in renal proximal tubules in mice with diabetes. The core molecular network used by high glucose to induce proximal tubular epithelial cell collagen I (α2) expression is poorly understood. We hypothesized that activation of PDGFRβ by high glucose increases collagen I (α2) production via the Akt/mTORC1 signaling pathway in proximal tubular epithelial cells. Using biochemical and molecular biological techniques, we investigated this hypothesis. We show that high glucose increases activating phosphorylation of the PDGFRβ, resulting in phosphorylation of phosphatidylinositol 3-kinase. A specific inhibitor, JNJ-10198409, and small interfering RNAs targeting PDGFRβ blocked this phosphorylation without having any effect on MEK/Erk1/2 activation. We also found that PDGFRβ regulates high glucose-induced Akt activation, its targets tuberin and PRAS40 phosphorylation, and finally, mTORC1 activation. Furthermore, inhibition of PDGFRβ suppressed high glucose-induced expression of collagen I (α2) in proximal tubular cells. Importantly, expression of constitutively active Akt or mTORC1 reversed these processes. As a mechanism, we found that JNJ and PDGFRβ knockdown inhibited high glucose-stimulated Hif1α expression. Furthermore, overexpression of Hif1α restored expression of collagen I (α2) that was inhibited by PDGFRβ knockdown in high glucose-stimulated cells. Finally, we show increased phosphorylation of PDGFRβ and its association with Akt/mTORC1 activation, Hif1α expression, and elevated collagen I (α2) levels in the renal cortex of mice with diabetes. Our results identify PDGFRβ as a driver in activating Akt/mTORC1 nexus for high glucose-mediated expression of collagen I (α2) in proximal tubular epithelial cells, which contributes to tubulointerstitial fibrosis in diabetic nephropathy.
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Affiliation(s)
- Falguni Das
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Nandini Ghosh-Choudhury
- VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, Texas.,Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Balachandar Venkatesan
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Balakuntalam S Kasinath
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas.,VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, Texas
| | - Goutam Ghosh Choudhury
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas; .,VA Biomedical Laboratory Research, South Texas Veterans Health Care System, San Antonio, Texas.,Geriatric Research, Education and Clinical Research, South Texas Veterans Health Care System, San Antonio, Texas; and
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7
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Nelson KN, Peiris MN, Meyer AN, Siari A, Donoghue DJ. Receptor Tyrosine Kinases: Translocation Partners in Hematopoietic Disorders. Trends Mol Med 2016; 23:59-79. [PMID: 27988109 DOI: 10.1016/j.molmed.2016.11.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/11/2016] [Accepted: 11/13/2016] [Indexed: 02/07/2023]
Abstract
Receptor tyrosine kinases (RTKs) activate various signaling pathways and regulate cellular proliferation, survival, migration, and angiogenesis. Malignant neoplasms often circumvent or subjugate these pathways by promoting RTK overactivation through mutation or chromosomal translocation. RTK translocations create a fusion protein containing a dimerizing partner fused to an RTK kinase domain, resulting in constitutive kinase domain activation, altered RTK cellular localization, upregulation of downstream signaling, and novel pathway activation. While RTK translocations in hematological malignancies are relatively rare, clinical evidence suggests that patients with these genetic abnormalities benefit from RTK-targeted inhibitors. Here, we present a timely review of an exciting field by examining RTK chromosomal translocations in hematological cancers, such as Anaplastic Lymphoma Kinase (ALK), Fibroblast Growth Factor Receptor (FGFR), Platelet-Derived Growth Factor Receptor (PDGFR), REarranged during Transfection (RET), Colony Stimulating Factor 1 Receptor (CSF1R), and Neurotrophic Tyrosine Kinase Receptor Type 3 (NTRK3) fusions, and discuss current therapeutic options.
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Affiliation(s)
- Katelyn N Nelson
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - Malalage N Peiris
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - April N Meyer
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - Asma Siari
- Université Joseph Fourier Grenoble, Grenoble, France
| | - Daniel J Donoghue
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA; Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA 92093, USA.
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8
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Liu Y, An S, Ward R, Yang Y, Guo XX, Li W, Xu TR. G protein-coupled receptors as promising cancer targets. Cancer Lett 2016; 376:226-39. [PMID: 27000991 DOI: 10.1016/j.canlet.2016.03.031] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/14/2016] [Accepted: 03/14/2016] [Indexed: 02/07/2023]
Abstract
G protein-coupled receptors (GPCRs) regulate an array of fundamental biological processes, such as growth, metabolism and homeostasis. Specifically, GPCRs are involved in cancer initiation and progression. However, compared with the involvement of the epidermal growth factor receptor in cancer, that of GPCRs have been largely ignored. Recent findings have implicated many GPCRs in tumorigenesis, tumor progression, invasion and metastasis. Moreover, GPCRs contribute to the establishment and maintenance of a microenvironment which is permissive for tumor formation and growth, including effects upon surrounding blood vessels, signaling molecules and the extracellular matrix. Thus, GPCRs are considered to be among the most useful drug targets against many solid cancers. Development of selective ligands targeting GPCRs may provide novel and effective treatment strategies against cancer and some anticancer compounds are now in clinical trials. Here, we focus on tumor related GPCRs, such as G protein-coupled receptor 30, the lysophosphatidic acid receptor, angiotensin receptors 1 and 2, the sphingosine 1-phosphate receptors and gastrin releasing peptide receptor. We also summarize their tissue distributions, activation and roles in tumorigenesis and discuss the potential use of GPCR agonists and antagonists in cancer therapy.
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Affiliation(s)
- Ying Liu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Su An
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Richard Ward
- Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Yang Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Xiao-Xi Guo
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Wei Li
- Kidney Cancer Research, Diagnosis and Translational Technology Center of Yunnan Province, Department of Urology, The People's Hospital of Yunnan Province, Kunming, Yunnan 650032, China.
| | - Tian-Rui Xu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China.
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9
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Arts FA, Chand D, Pecquet C, Velghe AI, Constantinescu S, Hallberg B, Demoulin JB. PDGFRB mutants found in patients with familial infantile myofibromatosis or overgrowth syndrome are oncogenic and sensitive to imatinib. Oncogene 2015; 35:3239-48. [PMID: 26455322 DOI: 10.1038/onc.2015.383] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 08/27/2015] [Accepted: 09/04/2015] [Indexed: 12/26/2022]
Abstract
Recently, germline and somatic heterozygous mutations in the platelet-derived growth factor receptor β (PDGFRB) have been associated with familial infantile myofibromatosis (IM), which is characterized by soft tissue tumors, and overgrowth syndrome, a disease that predisposes to cancer. These mutations have not been functionally characterized. In the present study, the activity of three PDGFRB mutants associated with familial IM (R561C, P660T and N666K) and one PDGFRB mutant found in patients with overgrowth syndrome (P584R) was tested in various models. The P660T mutant showed no difference with the wild-type receptor, suggesting that it might represent a polymorphic variant unrelated to the disease. By contrast, the three other mutants were constitutively active and able to transform NIH3T3 and Ba/F3 cells to different extents. In particular, the germline mutant identified in overgrowth syndrome, P584R, was a stronger oncogene than the germline R561C mutant associated with myofibromatosis. The distinct phenotypes associated with these two mutations could be related to this difference of potency. Importantly, all activated mutants were sensitive to tyrosine kinase inhibitors such as imatinib, nilotinib and ponatinib. In conclusion, the PDGFRB mutations previously identified in familial IM and overgrowth syndrome activate the receptor in the absence of ligand, supporting the hypothesis that these mutations cause the diseases. Moreover, imatinib seems to be a promising treatment for patients carrying these mutations. To our knowledge, these are the first confirmed gain-of-function point mutations of PDGFRB in human cancer.
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Affiliation(s)
- F A Arts
- De Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - D Chand
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.,Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - C Pecquet
- De Duve Institute, Université Catholique de Louvain, Brussels, Belgium.,Ludwig Institute for Cancer Research, Brussels, Belgium
| | - A I Velghe
- De Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - S Constantinescu
- De Duve Institute, Université Catholique de Louvain, Brussels, Belgium.,Ludwig Institute for Cancer Research, Brussels, Belgium
| | - B Hallberg
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - J-B Demoulin
- De Duve Institute, Université Catholique de Louvain, Brussels, Belgium
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10
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Kuroda Y, Kato-Kogoe N, Tasaki E, Yuasa-Sunagawa M, Yamanegi K, Nakasho K, Nakasyo K, Nakase I, Futaki S, Tohyama Y, Hirose M. Suppressive effect of membrane-permeable peptides derived from autophosphorylation sites of the IGF-1 receptor on breast cancer cells. Eur J Pharmacol 2015; 765:24-33. [PMID: 26276395 DOI: 10.1016/j.ejphar.2015.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/08/2015] [Accepted: 08/04/2015] [Indexed: 12/29/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) receptors play a crucial role in the biology of human cancer, making them an attractive target for anti-cancer agents. We previously designed oligopeptides containing the amino-acid sequences surrounding the autophosphorylation sites of the insulin receptor and found that two of them, namely, Ac-DIYET-NH2 and Ac-DYYRK-NH2, suppressed phosphorylation of purified insulin receptors in a non-ATP-competitive manner, whereas Ac-NIYQT-NH2 and Ac-NYYRK-NH2 suppressed in an ATP-competitive manner. Because the IGF-1 receptor is closely related to the insulin receptor, the aim of this study was to observe the effects of these peptides, which correspond to the amino-acid sequences of the autophosphorylation sites of the IGF-1 receptor, on the activity of the human breast cancer cell lines MCF-7, T47D, MDA-MB-231, and MDA-MB-453. To facilitate peptide delivery into breast cancer cells, the cell-penetrating peptide, human immunodeficiency virus type 1-transactivator of transcription (Tat), was linked to these peptides. When breast cancer cells were treated with each of these synthetic Tat-conjugated peptides, the conjugated peptides penetrated into the cells and suppressed cell proliferation. An inhibitory effect of Tat-conjugated peptides against IGF-1-stimulated phosphorylation of IGF-1 receptors was observed. In addition, we found that combinations of these peptides suppressed phosphorylation of IGF-1 receptors to a greater extent than the peptides did individually. In conclusion, IGF-1 receptor autophosphorylation site-derived membrane-permeable peptides have the potential to suppress IGF-1 receptor function in breast cancer cells and to be developed into novel and useful agents for cancer therapy.
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Affiliation(s)
- Yoshihiro Kuroda
- Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji 670-8524, Japan
| | - Nahoko Kato-Kogoe
- Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji 670-8524, Japan; Department of Pathology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan.
| | - Emi Tasaki
- Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji 670-8524, Japan
| | - Mayumi Yuasa-Sunagawa
- Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji 670-8524, Japan
| | - Koji Yamanegi
- Department of Pathology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | | | - Keiji Nakasyo
- Department of Pathology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Ikuhiko Nakase
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Shiroh Futaki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yumi Tohyama
- Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji 670-8524, Japan
| | - Munetaka Hirose
- Department of Anesthesiology, Hyogo College of Medicine, Nishinomiya 663-8501, Japan
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Abstract
Renal fibrosis is the hallmark of chronic kidney disease progression and is characterized by an exaggerated wound-healing process with the production of renal scar tissue. It comprises both the glomerular and the tubulointerstitial compartments. Among the factors that contribute to kidney fibrosis, the members of the platelet-derived growth factor (PDGF) family are among the best characterized ones. They appear to be the key factors in driving renal fibrosis, independent of the underlying kidney disease. The PDGF family consists of four isoforms (PDGF-A, -B, -C, and -D) and two receptor chains (PDGFR-α and -β), which are constitutively or inducibly expressed in most renal cells. These components have an irreplaceable role in kidney development by recruitment of mesenchymal cells to the glomerular and tubulointerstitial compartments. They further regulate multiple pathophysiologic processes including cell proliferation, cell migration, expression and accumulation of extracellular matrix, production and secretion of pro- and anti-inflammatory mediators, vascular permeability, and hemodynamics. This review provides a brief update on the role of different PDGF isoforms in the development of glomerulosclerosis and tubulointerstitial fibrosis, newly identified endogeneous PDGF antagonists, and resulting potential therapies.
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12
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Arts FA, Velghe AI, Stevens M, Renauld JC, Essaghir A, Demoulin JB. Idiopathic basal ganglia calcification-associated PDGFRB mutations impair the receptor signalling. J Cell Mol Med 2014; 19:239-48. [PMID: 25292412 PMCID: PMC4288366 DOI: 10.1111/jcmm.12443] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 08/21/2014] [Indexed: 12/17/2022] Open
Abstract
Platelet-derived growth factors (PDGF) bind to two related receptor tyrosine kinases, which are encoded by the PDGFRA and PDGFRB genes. Recently, heterozygous PDGFRB mutations have been described in patients diagnosed with idiopathic basal ganglia calcification (IBGC or Fahr disease), a rare inherited neurological disorder. The goal of the present study was to determine whether these mutations had a positive or negative impact on the PDGFRB activity. We first showed that the E1071V mutant behaved like wild-type PDGFRB and may represent a polymorphism unrelated to IBGC. In contrast, the L658P mutant had no kinase activity and failed to activate any of the pathways normally stimulated by PDGF. The R987W mutant activated Akt and MAP kinases but did not induce the phosphorylation of signal transducer and activator of transcription 3 (STAT3) after PDGF stimulation. Phosphorylation of phospholipase Cγ was also decreased. Finally, we showed that the R987W mutant was more rapidly degraded upon PDGF binding compared to wild-type PDGFRB. In conclusion, PDGFRB mutations associated with IBGC impair the receptor signalling. PDGFRB loss of function in IBGC is consistent with recently described inactivating mutations in the PDGF-B ligand. These results raise concerns about the long-term safety of PDGF receptor inhibition by drugs such as imatinib.
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Affiliation(s)
- Florence A Arts
- De Duve Institute, Université catholique de Louvain, Brussels, Belgium
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13
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Demoulin JB, Essaghir A. PDGF receptor signaling networks in normal and cancer cells. Cytokine Growth Factor Rev 2014; 25:273-83. [DOI: 10.1016/j.cytogfr.2014.03.003] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/10/2014] [Indexed: 01/05/2023]
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14
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Bera A, Das F, Ghosh-Choudhury N, Li X, Pal S, Gorin Y, Kasinath BS, Abboud HE, Ghosh Choudhury G. A positive feedback loop involving Erk5 and Akt turns on mesangial cell proliferation in response to PDGF. Am J Physiol Cell Physiol 2014; 306:C1089-100. [PMID: 24740537 DOI: 10.1152/ajpcell.00387.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Platelet-derived growth factor BB and its receptor (PDGFRβ) play a pivotal role in the development of renal glomerular mesangial cells. Their roles in increased mesangial cell proliferation during mesangioproliferative glomerulonephritis have long been noted, but the operating logic of signaling mechanisms regulating these changes remains poorly understood. We examined the role of a recently identified MAPK, Erk5, in this process. PDGF increased the activating phosphorylation of Erk5 and tyrosine phosphorylation of proteins in a time-dependent manner. A pharmacologic inhibitor of Erk5, XMD8-92, abrogated PDGF-induced DNA synthesis and mesangial cell proliferation. Similarly, expression of dominant negative Erk5 or siRNAs against Erk5 blocked PDGF-stimulated DNA synthesis and proliferation. Inhibition of Erk5 attenuated expression of cyclin D1 mRNA and protein, resulting in suppression of CDK4-mediated phosphorylation of the tumor suppressor protein pRb. Expression of cyclin D1 or CDK4 prevented the dominant negative Erk5- or siErk5-mediated inhibition of DNA synthesis and mesangial cell proliferation induced by PDGF. We have previously shown that phosphatidylinositol 3-kinase (PI3-kinase) contributes to PDGF-induced proliferation of mesangial cells. Inhibition of PI3-kinase blocked PDGF-induced phosphorylation of Erk5. Since PI3-kinase acts through Akt, we determined the role of Erk5 on Akt phosphorylation. XMD8-92, dominant negative Erk5, and siErk5 inhibited phosphorylation of Akt by PDGF. Interestingly, we found inhibition of PDGF-induced Erk5 phosphorylation by a pharmacological inhibitor of Akt kinase and kinase dead Akt in mesangial cells. Thus our data unfold the presence of a positive feedback microcircuit between Erk5 and Akt downstream of PI3-kinase nodal point for PDGF-induced mesangial cell proliferation.
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Affiliation(s)
- Amit Bera
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; and
| | - Falguni Das
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; and
| | - Nandini Ghosh-Choudhury
- Veterans Administration Research Service, South Texas Veterans Health Care System, San Antonio, Texas; Department of Pathology, University of Texas Health Science Center, San Antonio, Texas;
| | - Xiaonan Li
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; and
| | - Sanjay Pal
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; and
| | - Yves Gorin
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; and
| | - Balakuntalam S Kasinath
- Veterans Administration Research Service, South Texas Veterans Health Care System, San Antonio, Texas; Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; and
| | - Hanna E Abboud
- Veterans Administration Research Service, South Texas Veterans Health Care System, San Antonio, Texas; Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; and
| | - Goutam Ghosh Choudhury
- Veterans Administration Research Service, South Texas Veterans Health Care System, San Antonio, Texas; Department of Medicine, University of Texas Health Science Center, San Antonio, Texas; and Geriatric Research, Education, and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas
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15
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Heldin CH. Targeting the PDGF signaling pathway in tumor treatment. Cell Commun Signal 2013; 11:97. [PMID: 24359404 PMCID: PMC3878225 DOI: 10.1186/1478-811x-11-97] [Citation(s) in RCA: 349] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 12/11/2013] [Indexed: 01/15/2023] Open
Abstract
Platelet-derived growth factor (PDGF) isoforms and PDGF receptors have important functions in the regulation of growth and survival of certain cell types during embryonal development and e.g. tissue repair in the adult. Overactivity of PDGF receptor signaling, by overexpression or mutational events, may drive tumor cell growth. In addition, pericytes of the vasculature and fibroblasts and myofibroblasts of the stroma of solid tumors express PDGF receptors, and PDGF stimulation of such cells promotes tumorigenesis. Inhibition of PDGF receptor signaling has proven to useful for the treatment of patients with certain rare tumors. Whether treatment with PDGF/PDGF receptor antagonists will be beneficial for more common malignancies is the subject for ongoing studies.
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Affiliation(s)
- Carl-Henrik Heldin
- Ludwig Institute for Cancer Research, Science for life laboratory, Uppsala University, Box 595SE-751 24 Uppsala, Sweden.
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16
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Platelet-derived growth factor. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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17
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Heldin CH, Lennartsson J. Structural and functional properties of platelet-derived growth factor and stem cell factor receptors. Cold Spring Harb Perspect Biol 2013; 5:a009100. [PMID: 23906712 DOI: 10.1101/cshperspect.a009100] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The receptors for platelet-derived growth factor (PDGF) and stem cell factor (SCF) are members of the type III class of PTK receptors, which are characterized by five Ig-like domains extracellularly and a split kinase domain intracellularly. The receptors are activated by ligand-induced dimerization, leading to autophosphorylation on specific tyrosine residues. Thereby the kinase activities of the receptors are activated and docking sites for downstream SH2 domain signal transduction molecules are created; activation of these pathways promotes cell growth, survival, and migration. These receptors mediate important signals during the embryonal development, and control tissue homeostasis in the adult. Their overactivity is seen in malignancies and other diseases involving excessive cell proliferation, such as atherosclerosis and fibrotic diseases. In cancer, mutations of PDGF and SCF receptors-including gene fusions, point mutations, and amplifications-drive subpopulations of certain malignancies, such as gastrointestinal stromal tumors, chronic myelomonocytic leukemia, hypereosinophilic syndrome, glioblastoma, acute myeloid leukemia, mastocytosis, and melanoma.
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Affiliation(s)
- Carl-Henrik Heldin
- Ludwig Institute for Cancer Research, Uppsala University, SE-751 24 Uppsala, Sweden.
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18
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PDGFRA alterations in cancer: characterization of a gain-of-function V536E transmembrane mutant as well as loss-of-function and passenger mutations. Oncogene 2013; 33:2568-76. [PMID: 23752188 DOI: 10.1038/onc.2013.218] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 03/21/2013] [Accepted: 04/04/2013] [Indexed: 12/23/2022]
Abstract
Activating mutations in the platelet-derived growth factor (PDGF) receptor alpha (PDGFRA) have been described in patients with gastrointestinal stromal tumors or myeloid malignancies associated with hypereosinophilia. These patients respond well to imatinib mesylate, raising the question as to whether patients with a PDGF receptor mutation in other tumor types should receive a tyrosine kinase inhibitor treatment. We characterized 10 novel somatic point mutations in PDGFRA that have been reported in isolated cases of glioblastoma, melanoma, acute myeloid leukemia, peripheral nerve sheath tumors and neuroendocrine carcinoma. The PDGFRA transmembrane domain mutation V536E stimulated Ba/F3 cell growth and signaling via ERK and STAT5 in the absence of ligand. This mutant, identified in glioblastoma, was strongly inhibited by imatinib. Modeling suggested that the mutation modulates the packing of the transmembrane domain helices in the receptor dimer. By contrast, two mutations in highly conserved residues affected the receptor traffic to the cell surface or kinase activity, thereby preventing the response to PDGF. The other mutations had no significant impact on the receptor activity. This functional analysis matched the predictions of SIFT and PolyPhen for only five mutations and these algorithms do not discriminate gain from loss of function. Finally, an E996K variant that had been identified in a melanoma cell line was not expressed in these cells. Altogether, several newly identified PDGFRA mutations do not activate the receptor and may therefore represent passenger mutations. Our results also underline the importance of characterizing novel kinase alterations in cancer patients.
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19
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Medves S, Demoulin JB. Tyrosine kinase gene fusions in cancer: translating mechanisms into targeted therapies. J Cell Mol Med 2012; 16:237-48. [PMID: 21854543 PMCID: PMC3823288 DOI: 10.1111/j.1582-4934.2011.01415.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tyrosine kinase fusion genes represent an important class of oncogenes associated with leukaemia and solid tumours. They are produced by translocations and other chromosomal rearrangements of a subset of tyrosine kinase genes, including ABL, PDGFRA, PDGFRB, FGFR1, SYK, RET, JAK2 and ALK. Based on recent findings, this review discusses the common mechanisms of activation of these fusion genes. Enforced oligomerization and inactivation of inhibitory domains are the two key processes that switch on the kinase domain. Activated tyrosine kinase fusions then signal via an array of transduction cascades, which are largely shared. In addition, the fusion partner provides a scaffold for the recruitment of proteins that contribute to signalling, protein stability, cellular localization and oligomerization. The expression level of the fusion protein is another critical parameter. Its transcription is controlled by the partner gene promoter, while translation may be regulated by miRNA. Several mechanisms also prevent the degradation of the oncoprotein by proteasomes and lysosomes, leading to its accumulation in cells. The selective inhibition of the tyrosine kinase activity by adenosine-5'-triphosphate competitors, such as imatinib, is a major therapeutic success. Imatinib induces remission in leukaemia patients that are positive for BCR-ABL or PDGFR fusions. Recently, crizotinib produced promising results in a subtype of lung cancers with ALK fusion. However, resistance was reported in both cases, partially due to mutations. To tackle this problem, additional levels of therapeutic interventions are suggested by the complex mechanisms of fusion tyrosine kinase activation. New approaches include allosteric inhibition and interfering with oligomerization or chaperones.
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Affiliation(s)
- Sandrine Medves
- De Duve Institute, Université catholique de Louvain, Brussels, Belgium
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20
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Effects of somatic mutations in the C-terminus of insulin-like growth factor 1 receptor on activity and signaling. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:804801. [PMID: 22778948 PMCID: PMC3384887 DOI: 10.1155/2012/804801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 04/28/2012] [Indexed: 02/03/2023]
Abstract
The insulin-like growth factor I receptor (IGF1R) is overexpressed in several forms of human cancer, and it has emerged as an important target for anticancer drug design. Cancer genome sequencing efforts have recently identified three somatic mutations in IGF1R: A1374V, a deletion of S1278 in the C-terminal tail region of the receptor, and M1255I in the C-terminal lobe of the kinase catalytic domain. The possible effects of these mutations on IGF1R activity and biological function have not previously been tested. Here, we tested the effects of the mutations on the in vitro biochemical activity of IGF1R and on major IGF1R signaling pathways in mammalian cells. While the mutations do not affect the intrinsic tyrosine kinase activity of the receptor, we demonstrate that the basal (unstimulated) levels of MAP kinase and Akt activation are increased in the mutants (relative to wild-type IGF1R). We hypothesize that the enhanced signaling potential of these mutants is due to changes in protein-protein interactions between the IGF1R C-terminus and cellular substrates or modulators.
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21
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van Roeyen CRC, Ostendorf T, Floege J. The platelet-derived growth factor system in renal disease: an emerging role of endogenous inhibitors. Eur J Cell Biol 2011; 91:542-51. [PMID: 21872965 DOI: 10.1016/j.ejcb.2011.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 07/05/2011] [Accepted: 07/05/2011] [Indexed: 01/28/2023] Open
Abstract
The platelet-derived growth factor (PDGF) family consists of four isoforms which are secreted as homodimers (PDGF-AA, PDGF-BB, PDGF-CC and PDGF-DD) or heterodimers (PDGF-AB), and two receptor chains (PDGFR-α and -β). All members of the PDGF system are constitutively or inducibly expressed in renal cells and are involved in the regulation of cell proliferation and migration, the accumulation of extracellular matrix proteins and the secretion of pro- and anti-inflammatory mediators. Particular roles have been identified in mediating mesangioproliferative changes, renal interstitial fibrosis and glomerular angiogenesis. Different endogenous inhibitors of PDGF-induced biological responses exist which affect the activation/deactivation of PDGF isoforms, the activity of the PDGFRs, or which block downstream signaling pathways of the autophosphorylated PDGFRs. The novel endogenous inhibitor nephroblastoma overexpressed gene (NOV, CCN3) reduces PDGF-induced cell proliferation and is downregulated by PDGF isoforms itself. Among all identified inhibitors only few "true" PDGF antagonists have been identified. A better understanding of these inhibitors may aid in the design of novel therapeutic approaches to PDGF-mediated diseases.
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Affiliation(s)
- Claudia R C van Roeyen
- Department of Nephrology and Clinical Immunology, RWTH University Hospital Aachen, Pauwelsstr. 30, D-52057 Aachen, Germany.
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22
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Linking differential domain functions of the GS3 protein to natural variation of grain size in rice. Proc Natl Acad Sci U S A 2010; 107:19579-84. [PMID: 20974950 DOI: 10.1073/pnas.1014419107] [Citation(s) in RCA: 420] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Grain yield in many cereal crops is largely determined by grain size. Here we report the genetic and molecular characterization of GS3, a major quantitative trait locus for grain size. It functions as a negative regulator of grain size and organ size. The wild-type isoform is composed of four putative domains: a plant-specific organ size regulation (OSR) domain in the N terminus, a transmembrane domain, a tumor necrosis factor receptor/nerve growth factor receptor (TNFR/NGFR) family cysteine-rich domain, and a von Willebrand factor type C (VWFC) in the C terminus. These domains function differentially in grain size regulation. The OSR domain is both necessary and sufficient for functioning as a negative regulator. The wild-type allele corresponds to medium grain. Loss of function of OSR results in long grain. The C-terminal TNFR/NGFR and VWFC domains show an inhibitory effect on the OSR function; loss-of-function mutations of these domains produced very short grain. This study linked the functional domains of the GS3 protein to natural variation of grain size in rice.
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23
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EGFRvIV: a previously uncharacterized oncogenic mutant reveals a kinase autoinhibitory mechanism. Oncogene 2010; 29:5850-60. [PMID: 20676128 DOI: 10.1038/onc.2010.313] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Tumor cells often subvert normal regulatory mechanisms of signal transduction. This study shows this principle by studying yet uncharacterized mutants of the epidermal growth factor receptor (EGFR) previously identified in glioblastoma multiforme, which is the most aggressive brain tumor in adults. Unlike the well-characterized EGFRvIII mutant form, which lacks a portion of the ligand-binding cleft within the extracellular domain, EGFRvIVa and EGFRvIVb lack internal segments distal to the intracellular tyrosine kinase domain. By constructing the mutants and by ectopic expression in naive cells, we show that both mutants confer an oncogenic potential in vitro, as well as tumorigenic growth in animals. The underlying mechanisms entail constitutive receptor dimerization and basal activation of the kinase domain, likely through a mechanism that relieves a restraining molecular fold, along with stabilization due to association with HSP90. Phosphoproteomic analyses delineated the signaling pathways preferentially engaged by EGFRvIVb-identified unique substrates. This information, along with remarkable sensitivities to tyrosine kinase blockers and to a chaperone inhibitor, proposes strategies for pharmacological interception in brain tumors harboring EGFRvIV mutations.
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24
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Chi SS, Vetiska SM, Gill RS, Hsiung MS, Liu F, Van Tol HH. Transactivation of PDGFRbeta by dopamine D4 receptor does not require PDGFRbeta dimerization. Mol Brain 2010; 3:22. [PMID: 20659339 PMCID: PMC2919524 DOI: 10.1186/1756-6606-3-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Accepted: 07/26/2010] [Indexed: 11/25/2022] Open
Abstract
Growth factor-induced receptor dimerization and cross-phosphorylation are hallmarks of signal transduction via receptor tyrosine kinases (RTKs). G protein-coupled receptors (GPCRs) can activate RTKs through a process known as transactivation. The prototypical model of RTK transactivation involves ligand-mediated RTK dimerization and cross-phosphorylation. Here, we show that the platelet-derived growth factor receptor β (PDGFRβ) transactivation by the dopamine receptor D4 (DRD4) is not dependent on ligands for PDGFRβ. Furthermore, when PDGFRβ dimerization is inhibited and receptor phosphorylation is suppressed to near basal levels, the receptor maintains its ability to be transactivated and is still effective in signaling to ERK1/2. Hence, the DRD4-PDGFRβ-ERK1/2 pathway can occur independently of a PDGF-like ligand, PDGFRβ cross-phosphorylation and dimerization, which is distinct from other known forms of transactivation of RTKs by GPCRs.
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Affiliation(s)
- Sum Shing Chi
- Department of Neuroscience, Centre for Addiction and Mental Health, University of Toronto, Toronto M5T 1R8, Canada
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25
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New insights into the mechanisms of hematopoietic cell transformation by activated receptor tyrosine kinases. Blood 2010; 116:2429-37. [PMID: 20581310 DOI: 10.1182/blood-2010-04-279752] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A large number of alterations in genes encoding receptor tyrosine kinase (RTK), namely FLT3, c-KIT, platelet-derived growth factor (PDGF) receptors, fibroblast growth factor (FGF) receptors, and the anaplastic large cell lymphoma kinase (ALK), have been found in hematopoietic malignancies. They have drawn much attention after the development of tyrosine kinase inhibitors. RTK gene alterations include point mutations and gene fusions that result from chromosomal rearrangements. In both cases, they activate the kinase domain in the absence of ligand, producing a permanent signal for cell proliferation. Recently, this simple model has been refined. First, by contrast to wild-type RTK, many mutated RTK do not seem to signal from the plasma membrane, but from various locations inside the cell. Second, their signal transduction properties are altered: the pathways that are crucial for cell transformation, such as signal transducer and activator of transcription (STAT) factors, do not necessarily contribute to the physiologic functions of these receptors. Finally, different mechanisms prevent the termination of the signal, which normally occurs through receptor ubiquitination and degradation. Several mutations inactivating CBL, a key RTK E3 ubiquitin ligase, have been recently described. In this review, we discuss the possible links among RTK trafficking, signaling, and degradation in leukemic cells.
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26
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Toffalini F, Hellberg C, Demoulin JB. Critical role of the platelet-derived growth factor receptor (PDGFR) beta transmembrane domain in the TEL-PDGFRbeta cytosolic oncoprotein. J Biol Chem 2010; 285:12268-78. [PMID: 20164181 PMCID: PMC2852966 DOI: 10.1074/jbc.m109.076638] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 02/09/2010] [Indexed: 01/31/2023] Open
Abstract
The fusion of TEL with platelet-derived growth factor receptor (PDGFR) beta (TPbeta) is found in a subset of patients with atypical myeloid neoplasms associated with eosinophilia and is the archetype of a larger group of hybrid receptors that are produced by rearrangements of PDGFR genes. TPbeta is activated by oligomerization mediated by the pointed domain of TEL/ETV6, leading to constitutive activation of the PDGFRbeta kinase domain. The receptor transmembrane (TM) domain is retained in TPbeta and in most of the described PDGFRbeta hybrids. Deletion of the TM domain (DeltaTM-TPbeta) strongly impaired the ability of TPbeta to sustain growth factor-independent cell proliferation. We confirmed that TPbeta resides in the cytosol, indicating that the PDGFRbeta TM domain does not act as a transmembrane domain in the context of the hybrid receptor but has a completely different function. The DeltaTM-TPbeta protein was expressed at a lower level because of increased degradation. It could form oligomers, was phosphorylated at a slightly higher level, co-immunoprecipitated with the p85 adaptor protein, but showed a much reduced capacity to activate STAT5 and ERK1/2 in Ba/F3 cells, compared with TPbeta. In an in vitro kinase assay, DeltaTM-TPbeta was more active than TPbeta and less sensitive to imatinib, a PDGFR inhibitor. In conclusion, we show that the TM domain is required for TPbeta-mediated signaling and proliferation, suggesting that the activation of the PDGFRbeta kinase domain is not enough for cell transformation.
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Affiliation(s)
- Federica Toffalini
- From the Université Catholique de Louvain, de Duve Institute, BE-1200 Brussels, Belgium and
| | - Carina Hellberg
- the Ludwig Institute for Cancer Research, S-751 24 Uppsala, Sweden
| | - Jean-Baptiste Demoulin
- From the Université Catholique de Louvain, de Duve Institute, BE-1200 Brussels, Belgium and
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27
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Sturk C, Kim H, Jones N, Dumont D. A negative regulatory role for Y1111 on the Tie-2 RTK. Cell Signal 2010; 22:676-83. [DOI: 10.1016/j.cellsig.2009.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 11/18/2009] [Accepted: 12/08/2009] [Indexed: 11/28/2022]
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28
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Essaghir A, Toffalini F, Knoops L, Kallin A, van Helden J, Demoulin JB. Transcription factor regulation can be accurately predicted from the presence of target gene signatures in microarray gene expression data. Nucleic Acids Res 2010; 38:e120. [PMID: 20215436 PMCID: PMC2887972 DOI: 10.1093/nar/gkq149] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Deciphering transcription factor networks from microarray data remains difficult. This study presents a simple method to infer the regulation of transcription factors from microarray data based on well-characterized target genes. We generated a catalog containing transcription factors associated with 2720 target genes and 6401 experimentally validated regulations. When it was available, a distinction between transcriptional activation and inhibition was included for each regulation. Next, we built a tool (www.tfacts.org) that compares submitted gene lists with target genes in the catalog to detect regulated transcription factors. TFactS was validated with published lists of regulated genes in various models and compared to tools based on in silico promoter analysis. We next analyzed the NCI60 cancer microarray data set and showed the regulation of SOX10, MITF and JUN in melanomas. We then performed microarray experiments comparing gene expression response of human fibroblasts stimulated by different growth factors. TFactS predicted the specific activation of Signal transducer and activator of transcription factors by PDGF-BB, which was confirmed experimentally. Our results show that the expression levels of transcription factor target genes constitute a robust signature for transcription factor regulation, and can be efficiently used for microarray data mining.
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Affiliation(s)
- Ahmed Essaghir
- de Duve Institute, Université Catholique de Louvain, MEXP74.30, avenue Hippocrates 74-75, B-1200 Brussels, Belgium
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29
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Kato M, Abe M, Kuroda Y, Hirose M, Nakano M, Handa T. Synthetic pentapeptides inhibiting autophosphorylation of insulin receptor in a non-ATP-competitive mechanism. J Pept Sci 2009; 15:327-36. [PMID: 19206072 DOI: 10.1002/psc.1114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In an attempt to develop non-ATP-competitive inhibitors of the autophosphorylation of IR, the effects of the synthetic peptides, Ac-DIY(1158)ET-NH(2) and Ac-DY(1162)Y(1163)RK-NH(2), on the phosphorylation of IR were studied in vitro. The peptides were derived from the amino-acid sequence in the activation loop of IR. They inhibited the autophosphorylation of IR to 20.5 and 40.7%, respectively, at 4000 microM. The Asp/Asn- and Glu/Gln-substituted peptides, Ac-NIYQT-NH(2) and Ac-NYYRK-NH(2), more potently inhibited the autophosphorylation than did the corresponding parent peptides. The inhibitory potencies of the substituted peptides were decreased with increasing concentrations of ATP, indicating that these peptides employ an ATP-competitive mechanism in inhibiting the autophosphorylation of IR. In contrast, those of the parent peptides were not affected. Mass spectrometry showed that the parent peptides were phosphorylated by IR, suggesting that they interact with the catalytic loop. Moreover, docking simulations predicted that the substituted peptides would interact with the ATP-binding region of IR, whereas their parent peptides would interact with the catalytic loop of IR. Thus, Ac-DIYET-NH(2) and Ac-DYYRK-NH(2) are expected to be non-ATP-competitive inhibitors. These peptides could contribute to the development of a drug employing a novel mechanism.
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Affiliation(s)
- Masaki Kato
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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30
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The ErbB kinase domain: structural perspectives into kinase activation and inhibition. Exp Cell Res 2008; 315:649-58. [PMID: 18761339 DOI: 10.1016/j.yexcr.2008.07.031] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 07/31/2008] [Accepted: 07/31/2008] [Indexed: 01/21/2023]
Abstract
Epidermal growth factor receptor (EGFR) and its family members, ErbB2, ErbB3 and ErbB4, are receptor tyrosine kinases which send signals into the cell to regulate many critical processes including development, tissue homeostasis, and tumorigenesis. Central to the signaling of these receptors is their intracellular kinase domain, which is activated by ligand-induced dimerization of the receptor and phosphorylates several tyrosine residues in the C-terminal tail. The phosphorylated tail then recruits other signaling molecules and relays the signal to downstream pathways. A model of the autoinhibition, activation and feedback inhibition mechanisms for the ErbB kinase domain has emerged from a number of recent structural studies. Meanwhile, recent clinical studies have revealed the relationship between specific ErbB kinase mutations and the responsiveness to kinase inhibitor drugs. We will review these regulation mechanisms of the ErbB kinase domain, and discuss the binding specificity of kinase inhibitors and the effects of kinase domain mutations found in cancer patients from a structural perspective.
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Venkatesan B, Ghosh-Choudhury N, Das F, Mahimainathan L, Kamat A, Kasinath BS, Abboud HE, Choudhury GG. Resveratrol inhibits PDGF receptor mitogenic signaling in mesangial cells: role of PTP1B. FASEB J 2008; 22:3469-82. [PMID: 18567737 DOI: 10.1096/fj.08-109488] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Mesangioproliferative glomerulonephritis is associated with overactive PDGF receptor signal transduction. We show that the phytoalexin resveratrol dose dependently inhibits PDGF-induced DNA synthesis in mesangial cells with an IC(50) of 10 microM without inducing apoptosis. Remarkably, the increased SIRT1 deacetylase activity induced by resveratrol was not necessary for this inhibitory effect. Resveratrol significantly blocked PDGF-stimulated c-Src and Akt kinase activation, resulting in reduced cyclin D1 expression and attenuated pRb phosphorylation and cyclin-dependent kinase-2 (CDK2) activity. Furthermore, resveratrol inhibited PDGFR phosphorylation at the PI 3 kinase and Grb-2 binding sites tyrosine-751 and tyrosine-716, respectively. This deficiency in PDGFR phosphorylation resulted in significant inhibition of PI 3 kinase and Erk1/2 MAPK activity. Interestingly, resveratrol increased the activity of protein tyrosine phosphatase PTP1B, which dephosphorylates PDGF-stimulated phosphorylation at tyrosine-751 and tyrosine-716 on PDGFR with concomitant reduction in Akt and Erk1/2 kinase activity. PTP1B significantly inhibited PDGF-induced DNA synthesis without inducing apoptosis. These results for the first time provide evidence that the stilbene resveratrol targets PTP1B to inhibit PDGFR mitogenic signaling.
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Affiliation(s)
- Balachandar Venkatesan
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA
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32
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FIP1L1-PDGFRα alone or with other genetic abnormalities reveals disease progression in chronic eosinophilic leukemia but good response to imatinib. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200805020-00001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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33
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Craddock BP, Cotter C, Miller WT. Autoinhibition of the insulin-like growth factor I receptor by the juxtamembrane region. FEBS Lett 2007; 581:3235-40. [PMID: 17586502 PMCID: PMC1986766 DOI: 10.1016/j.febslet.2007.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 05/23/2007] [Accepted: 06/07/2007] [Indexed: 11/20/2022]
Abstract
The juxtamembrane (JM) regions of several receptor tyrosine kinases are involved in autoinhibitory interactions that maintain the low basal activity of the receptors; mutations can give rise to constitutive kinase activity and signaling. In this report, we show that the JM region of the human insulin-like growth factor I receptor (IGF1R) plays a role in kinase regulation. We mutated JM residues that were conserved in this subfamily of receptor tyrosine kinases, and expressed and purified the cytoplasmic domains using the Sf9/baculovirus system. We show that a kinase-proximal mutation (Y957F) and (to a lesser extent) a mutation in the central part of the JM region (N947A) increase the autophosphorylation activity of the kinase. Steady-state kinetic measurements show the mutations cause an increase in V(max) for phosphorylation of peptide substrates. When the holoreceptors were expressed in fibroblasts derived from IGF1R-deficient mice, the Y957F mutation led to a large increase in basal and in IGF1-stimulated receptor autophosphorylation. Together, these data demonstrate that the JM region of IGF1R plays an important role in limiting the basal activity of the receptor.
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34
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Li YH, Zhong S, Rong ZL, Ren YM, Li ZY, Zhang SP, Chang Z, Liu L. The carboxyl terminal tyrosine 417 residue of NOK has an autoinhibitory effect on NOK-mediated signaling transductions. Biochem Biophys Res Commun 2007; 356:444-9. [PMID: 17367757 DOI: 10.1016/j.bbrc.2007.02.154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Accepted: 02/27/2007] [Indexed: 11/21/2022]
Abstract
Receptor protein tyrosine kinases (RPTKs) are essential mediators of cell growth, differentiation, migration, and metabolism. Recently, a novel RPTK named NOK has been cloned and characterized. In current study, we investigated the role of the carboxyl terminal tyrosine 417 residue of NOK in the activations of different signaling pathways. A single tyrosine to phenylalanine point mutation at Y417 site (Y417F) not only dramatically enhanced the NOK-induced activation of extracellular signal-regulated kinase (ERK), but also markedly promoted the NOK-mediated activation of both signal transducer and activator of transcription 1 and 3 (STAT1 and 3). Moreover, the proliferation potential of NIH3T3-NOK (Y417F) stable cells were significantly elevated as compared with that of NIH3T3-NOK. Overall, our results demonstrate that the tyrosine Y417 residue at the carboxyl tail of NOK exhibits an autoinhibitory role in NOK-mediated signaling transductions.
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Affiliation(s)
- Ying-Hua Li
- Tsinghua Institute of Genome Research, Institute of Biomedicine & School of Medicine, Tsinghua University, Beijing 100084, China
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35
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Li J, Jin H. Regulation of brassinosteroid signaling. TRENDS IN PLANT SCIENCE 2007; 12:37-41. [PMID: 17142084 DOI: 10.1016/j.tplants.2006.11.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 10/26/2006] [Accepted: 11/24/2006] [Indexed: 05/12/2023]
Abstract
Both animal and plant steroids mainly rely on transcriptional factors to bring about specific physiological responses; however, the signaling mechanisms that regulate these transcriptional factors are different. Steroid binding inside an animal cell directly alters the transcriptional activity of intracellular steroid receptors, whereas brassinosteroid (BR) binding to a cell surface receptor activates a phosphorylation-mediated signaling cascade that changes the amount, subcellular localization, and/or DNA-binding activity of a family of novel transcription factors. Genetic and molecular studies conducted over the past several years have uncovered several crucial BR signaling components that have dramatically increased our understanding of the signaling process of plant steroid hormones. In this review, we discuss the biochemical mechanisms of these signaling proteins for regulating the activity of the membrane BR receptor and the transduction of the BR signal from the cell surface to the nucleus.
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Affiliation(s)
- Jianming Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 N. University, Ann Arbor, MI 48109-1048, USA.
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36
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Foveau B, Leroy C, Ancot F, Deheuninck J, Ji Z, Fafeur V, Tulasne D. Amplification of apoptosis through sequential caspase cleavage of the MET tyrosine kinase receptor. Cell Death Differ 2006; 14:752-64. [PMID: 17186028 DOI: 10.1038/sj.cdd.4402080] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Activation of the MET tyrosine kinase receptor by hepatocyte growth factor/scatter factor is classically associated with cell survival. Nonetheless, stress stimuli can lead to a caspase-dependent cleavage of MET within its juxtamembrane region, which generate a proapoptotic 40 kDa fragment (p40 MET). We report here that p40 MET is in fact generated through an additional caspase cleavage of MET within its extreme C-terminal region, which removes only few amino acids. We evidenced a hierarchical organization of these cleavages, with the C-terminal cleavage favoring the juxtamembrane one. As a functional consequence, the removal of the last amino acids of p40 MET increases its apoptotic capacity. Finally, cells expressing a MET receptor mutated at the C-terminal caspase site are unable to generate p40 MET and are resistant to apoptosis, indicating that generation of p40 MET amplifies apoptosis. These results revealed a two-step caspase cleavage of MET resulting in the reshaping of this survival receptor to a proapoptotic factor.
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Affiliation(s)
- B Foveau
- 1CNRS UMR 8161, Institut de Biologie de Lille, CNRS-Institut Pasteur de Lille-Université de Lille 1-Université de Lille 2, Lille cedex, France
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37
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Correll PH, Paulson RF, Wei X. Molecular regulation of receptor tyrosine kinases in hematopoietic malignancies. Gene 2006; 374:26-38. [PMID: 16524673 DOI: 10.1016/j.gene.2006.01.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 01/02/2006] [Accepted: 01/08/2006] [Indexed: 10/24/2022]
Abstract
Dysregulation of receptor tyrosine kinase (RTK) activity has been implicated in the progression of a variety of human leukemias. Most notably, mutations and chromosomal translocations affecting regulation of tyrosine kinase activity in the Kit receptor, the Flt3 receptor, and the PDGFbeta/FGF1 receptors have been demonstrated in mast cell leukemia, acute myeloid leukemia (AML), and chronic myelogenous leukemias (CML), respectively. In addition, critical but non-overlapping roles for the Ron and Kit receptor tyrosine kinases in the progression of animal models of erythroleukemia have been demonstrated [Persons, D., Paulson, R., Loyd, M., Herley, M., Bodner, S., Bernstein, A., Correll, P. and Ney, P., 1999. Fv2 encodes a truncated form of the Stk receptor tyrosine kinase. Nat. Gen. 23, 159-165.; Subramanian, A., Teal, H.E., Correll, P.H. and Paulson, R.F., 2005. Resistance to friend virus-induced erythroleukemia in W/Wv mice is caused by a spleen-specific defect which results in a severe reduction in target cells and a lack of Sf-Stk expression. J. Virol. 79 (23), 14586-14594.]. The various classes of RTKs implicated in the progression of leukemia have been recently reviewed [Reilly, J., 2003. Receptor tyrosine kinases in normal and malignant haematopoiesis. Blood Rev. 17 (4), 241-248.]. Here, we will discuss the mechanism by which alterations in these receptors result in transformation of hematopoietic cells, in the context of what is known about the molecular regulation of RTK activity, with a focus on our recent studies of the Ron receptor tyrosine kinase.
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Affiliation(s)
- Pamela H Correll
- Department of Veterinary and Biomedical Sciences, Center for Molecular Immunology and Infectious Disease, The Pennsylvania State University, 115 Henning Building, University Park, PA 16802-3500, United States.
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38
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Johnson KL, Ingram GC. Sending the right signals: regulating receptor kinase activity. CURRENT OPINION IN PLANT BIOLOGY 2005; 8:648-56. [PMID: 16183327 DOI: 10.1016/j.pbi.2005.09.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Accepted: 09/13/2005] [Indexed: 05/04/2023]
Abstract
Knowledge of the functions of plant receptor-like-kinases (RLKs) is increasing rapidly, but how their cytoplasmic signalling activity is regulated and how signals are transduced to cytoplasmic or nuclear proteins remain important questions. Recent studies, particularly of the BRASSINOSTEROID INSENSITIVE1 RLK, have begun to shed light on the mechanistic details of RLK activation, including the possible role of ligand binding. Studies of this and other RLKs have also highlighted the potential importance of hetero-oligomerisation and receptor internalisation in RLK signalling. Finally, a range of potential regulatory proteins and putative downstream signalling substrates have been identified for various RLKs. Despite some similarities with animal receptor kinase signalling systems, mechanisms that affect the intracellular behaviour, regulation and interactions of RLKs appear to be very diverse, potentially explaining how signalling specificity is maintained at the cytoplasmic level.
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Affiliation(s)
- Kim L Johnson
- Institute of Molecular Plant Sciences, Rutherford Building, University of Edinburgh, Kings Buildings, Edinburgh EH9 3JR, UK
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39
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Wang X, Li X, Meisenhelder J, Hunter T, Yoshida S, Asami T, Chory J. Autoregulation and homodimerization are involved in the activation of the plant steroid receptor BRI1. Dev Cell 2005; 8:855-65. [PMID: 15935775 DOI: 10.1016/j.devcel.2005.05.001] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Revised: 02/09/2005] [Accepted: 05/02/2005] [Indexed: 11/20/2022]
Abstract
The leucine-rich-repeat receptor serine/threonine kinase, BRI1, is a cell-surface receptor for brassinosteroids (BRs), the steroid hormones of plants, yet its activation mechanism is unknown. Here, we report a unique autoregulatory mechanism of BRI1 activation. Removal of BRI1's C terminus leads to a hypersensitive receptor, indicated by suppression of dwarfism of BR-deficient and BR-perception mutants and by enhanced BR signaling as a result of elevated phosphorylation of BRI1. Several sites in the C-terminal region can be phosphorylated in vitro, and transgenic Arabidopsis expressing BRI1 mutated at these sites demonstrates an essential role of phosphorylation in BRI1 activation. BRI1 is a ligand-independent homo-oligomer, as evidenced by the transphosphorylation of BRI1 kinase in vitro, the dominant-negative effect of a kinase-inactive BRI1 in transgenic Arabidopsis, and coimmunoprecipitation experiments. Our results support a BRI1-activation model that involves inhibition of kinase activity by its C-terminal domain, which is relieved upon ligand binding to the extracellular domain.
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MESH Headings
- Amino Acid Sequence
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis Proteins/chemistry
- Arabidopsis Proteins/metabolism
- Blotting, Western/methods
- Cell Membrane/metabolism
- Dose-Response Relationship, Drug
- Enzyme Inhibitors/pharmacology
- Gene Expression Regulation, Plant/drug effects
- Gene Expression Regulation, Plant/physiology
- Green Fluorescent Proteins/metabolism
- Homeostasis/physiology
- Immunoprecipitation/methods
- In Vitro Techniques
- Models, Biological
- Mutagenesis/physiology
- Mutation
- Oligopeptides
- Peptide Mapping/methods
- Peptides/metabolism
- Phenotype
- Phosphorylation
- Plant Growth Regulators/physiology
- Plants, Genetically Modified
- Protein Kinases/chemistry
- Protein Kinases/metabolism
- Protein Structure, Tertiary
- Sequence Homology, Amino Acid
- Steroids, Heterocyclic/chemistry
- Steroids, Heterocyclic/metabolism
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Affiliation(s)
- Xuelu Wang
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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40
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Landau M, Fleishman SJ, Ben-Tal N. A putative mechanism for downregulation of the catalytic activity of the EGF receptor via direct contact between its kinase and C-terminal domains. Structure 2005; 12:2265-75. [PMID: 15576039 DOI: 10.1016/j.str.2004.10.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2004] [Revised: 09/22/2004] [Accepted: 10/08/2004] [Indexed: 01/01/2023]
Abstract
Tyrosine kinase receptors of the EGFR family play a significant role in vital cellular processes and in various cancers. EGFR members are unique among kinases, as the regulatory elements of their kinase domains are constitutively ready for catalysis. Nevertheless, the receptors are not constantly active. This apparent paradox has prompted us to seek mechanisms of regulation in EGFR's cytoplasmic domain that do not involve conformational changes of the kinase domain. Our computational analyses, based on the three-dimensional structure of EGFR's kinase domain suggest that direct contact between the kinase and a segment from the C-terminal regulatory domains inhibits enzymatic activity. EGFR activation would then involve temporal dissociation of this stable complex, for example, via ligand-induced contact formation between the extracellular domains, leading to the reorientation of the transmembrane and intracellular domains. The model provides an explanation at the molecular level for the effects of several cancer-causing EGFR mutations.
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Affiliation(s)
- Meytal Landau
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv 69978, Israel
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41
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Abstract
Current drug discovery efforts generally focus on a limited number of protein classes, typically including proteins with well-defined catalytic active sites (e.g., kinases) or ligand binding sites (e.g., G protein-coupled receptors). Nevertheless, many clinically important pathways are mediated by proteins with no such obvious targets for small molecule inhibitors. Allosteric inhibitors offer an alternative approach to inhibition of protein activities, particularly for proteins that undergo conformational changes as part of their activity cycle. Proteins regulated by autoinhibitory domains represent one broad class of proteins that meets this criterion. In this article, we discuss the potential of autoinhibited proteins as targets for allosteric inhibitors and describe two examples of small molecules that act by stabilizing native autoinhibited conformations of their targets. We propose that proteins regulated by autoinhibition may be generally amenable to allosteric inhibition by small molecules that stabilize the native, autoinhibited fold.
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Affiliation(s)
- Jeffrey R Peterson
- Division of Basic Sciences, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA
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42
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Yokoyama N, Ischenko I, Hayman MJ, Miller WT. The C terminus of RON tyrosine kinase plays an autoinhibitory role. J Biol Chem 2005; 280:8893-900. [PMID: 15632155 DOI: 10.1074/jbc.m412623200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RON is a receptor tyrosine kinase in the MET family. We have expressed and purified active RON using the Sf9/baculovirus system. The constructs used in this study comprise the kinase domain alone and the kinase domain plus the C-terminal region. The construct containing the kinase domain alone has a higher specific activity than the construct containing the kinase and C-terminal domains. Purified RON undergoes autophosphorylation, and the exogenous RON C terminus serves as a substrate. Peptides containing a dityrosine motif derived from the C-terminal tail inhibit RON in vitro or when delivered into intact cells, consistent with an autoinhibitory mechanism. Phenylalanine substitutions within these peptides increase the inhibitory potency. Moreover, introduction of these Phe residues into the dityrosine motif of the RON kinase leads to a decrease in kinase activity. Taken together, our data suggest a model in which the C-terminal tail of RON regulates kinase activity via an interaction with the kinase catalytic domain.
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Affiliation(s)
- Noriko Yokoyama
- Department of Physiology and Biophysics, School of Medicine, State University of New York at Stony Brook, Stony Brook, New York 11794, USA
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43
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Chiara F, Goumans MJ, Forsberg H, Ahgrén A, Rasola A, Aspenström P, Wernstedt C, Hellberg C, Heldin CH, Heuchel R. A Gain of Function Mutation in the Activation Loop of Plateletderived Growth Factor β-Receptor Deregulates Its Kinase Activity. J Biol Chem 2004; 279:42516-27. [PMID: 15284236 DOI: 10.1074/jbc.m406051200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The platelet-derived growth factor receptors (PDGFRs) are receptor tyrosine kinases implicated in multiple aspects of cell growth, differentiation, and survival. Recently, a gain of function mutation in the activation loop of the human PDGFRalpha has been found in patients with gastrointestinal stromal tumors. Here we show that a mutation in the corresponding codon in the activation loop of the murine PDGFRbeta, namely an exchange of asparagine for aspartic acid at amino acid position 849 (D849N), confers transforming characteristics to embryonic fibroblasts from mutant mice, generated by a knock-in strategy. By comparing the enzymatic properties of the wild-type versus the mutant receptor protein, we demonstrate that the D849N mutation lowers the threshold for kinase activation, causes a dramatic alteration in the pattern of tyrosine phosphorylation kinetics following ligand stimulation, and induces a ligand-independent phosphorylation of several tyrosine residues. These changes result in deregulated recruitment of specific signal transducers. The GTPase-activating protein for Ras (RasGAP), a negative regulator of the Ras mitogenic pathway, displayed a delayed binding to the mutant receptor. Moreover, we have observed enhanced ligand-independent ERK1/2 activation and an increased proliferation of mutant cells. The p85 regulatory subunit of the phosphatidylinositol 3 '-kinase was constitutively associated with the mutant receptor, and this ligand-independent activation of the phosphatidylinositol 3'-kinase pathway may explain the observed strong protection against apoptosis and increased motility in cellular wounding assays. Our findings support a model whereby an activating point mutation results in a deregulated PDGFRbeta with oncogenic predisposition.
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Affiliation(s)
- Federica Chiara
- Ludwig Institute for Cancer Research, Box 595, Uppsala S-751 24, Sweden
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