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Gene Expression Landscape of Chronic Myeloid Leukemia K562 Cells Overexpressing the Tumor Suppressor Gene PTPRG. Int J Mol Sci 2022; 23:ijms23179899. [PMID: 36077295 PMCID: PMC9456469 DOI: 10.3390/ijms23179899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 11/24/2022] Open
Abstract
This study concerns the analysis of the modulation of Chronic Myeloid Leukemia (CML) cell model K562 transcriptome following transfection with the tumor suppressor gene encoding for Protein Tyrosine Phosphatase Receptor Type G (PTPRG) and treatment with the tyrosine kinase inhibitor (TKI) Imatinib. Specifically, we aimed at identifying genes whose level of expression is altered by PTPRG modulation and Imatinib concentration. Statistical tests as differential expression analysis (DEA) supported by gene set enrichment analysis (GSEA) and modern methods of ontological term analysis are presented along with some results of current interest for forthcoming experimental research in the field of the transcriptomic landscape of CML. In particular, we present two methods that differ in the order of the analysis steps. After a gene selection based on fold-change value thresholding, we applied statistical tests to select differentially expressed genes. Therefore, we applied two different methods on the set of differentially expressed genes. With the first method (Method 1), we implemented GSEA, followed by the identification of transcription factors. With the second method (Method 2), we first selected the transcription factors from the set of differentially expressed genes and implemented GSEA on this set. Method 1 is a standard method commonly used in this type of analysis, while Method 2 is unconventional and is motivated by the intention to identify transcription factors more specifically involved in biological processes relevant to the CML condition. Both methods have been equipped in ontological knowledge mining and word cloud analysis, as elements of novelty in our analytical procedure. Data analysis identified RARG and CD36 as a potential PTPRG up-regulated genes, suggesting a possible induction of cell differentiation toward an erithromyeloid phenotype. The prediction was confirmed at the mRNA and protein level, further validating the approach and identifying a new molecular mechanism of tumor suppression governed by PTPRG in a CML context.
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Boni C, Sorio C. The Role of the Tumor Suppressor Gene Protein Tyrosine Phosphatase Gamma in Cancer. Front Cell Dev Biol 2022; 9:768969. [PMID: 35071225 PMCID: PMC8766859 DOI: 10.3389/fcell.2021.768969] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/16/2021] [Indexed: 12/31/2022] Open
Abstract
Members of the Protein Tyrosine Phosphatase (PTPs) family are associated with growth regulation and cancer development. Acting as natural counterpart of tyrosine kinases (TKs), mainly involved in crucial signaling pathways such as regulation of cell cycle, proliferation, invasion and angiogenesis, they represent key parts of complex physiological homeostatic mechanisms. Protein tyrosine phosphatase gamma (PTPRG) is classified as a R5 of the receptor type (RPTPs) subfamily and is broadly expressed in various isoforms in different tissues. PTPRG is considered a tumor-suppressor gene (TSG) mapped on chromosome 3p14-21, a region frequently subject to loss of heterozygosity in various tumors. However, reported mechanisms of PTPRG downregulation include missense mutations, ncRNA gene regulation and epigenetic silencing by hypermethylation of CpG sites on promoter region causing loss of function of the gene product. Inactive forms or total loss of PTPRG protein have been described in sporadic and Lynch syndrome colorectal cancer, nasopharyngeal carcinoma, ovarian, breast, and lung cancers, gastric cancer or diseases affecting the hematopoietic compartment as Lymphoma and Leukemia. Noteworthy, in Central Nervous System (CNS) PTPRZ/PTPRG appears to be crucial in maintaining glioblastoma cell-related neuronal stemness, carving out a pathological functional role also in this tissue. In this review, we will summarize the current knowledge on the role of PTPRG in various human cancers.
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Affiliation(s)
- Christian Boni
- Department of Medicine, General Pathology Division, University of Verona, Verona, Italy
| | - Claudio Sorio
- Department of Medicine, General Pathology Division, University of Verona, Verona, Italy
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Boni C, Laudanna C, Sorio C. A Comprehensive Review of Receptor-Type Tyrosine-Protein Phosphatase Gamma (PTPRG) Role in Health and Non-Neoplastic Disease. Biomolecules 2022; 12:84. [PMID: 35053232 PMCID: PMC8773835 DOI: 10.3390/biom12010084] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 02/07/2023] Open
Abstract
Protein tyrosine phosphatase receptor gamma (PTPRG) is known to interact with and regulate several tyrosine kinases, exerting a tumor suppressor role in several type of cancers. Its wide expression in human tissues compared to the other component of group 5 of receptor phosphatases, PTPRZ expressed as a chondroitin sulfate proteoglycan in the central nervous system, has raised interest in its role as a possible regulatory switch of cell signaling processes. Indeed, a carbonic anhydrase-like domain (CAH) and a fibronectin type III domain are present in the N-terminal portion and were found to be associated with its role as [HCO3-] sensor in vascular and renal tissues and a possible interaction domain for cell adhesion, respectively. Studies on PTPRG ligands revealed the contactins family (CNTN) as possible interactors. Furthermore, the correlation of PTPRG phosphatase with inflammatory processes in different normal tissues, including cancer, and the increasing amount of its soluble form (sPTPRG) in plasma, suggest a possible role as inflammatory marker. PTPRG has important roles in human diseases; for example, neuropsychiatric and behavioral disorders and various types of cancer such as colon, ovary, lung, breast, central nervous system, and inflammatory disorders. In this review, we sum up our knowledge regarding the latest discoveries in order to appreciate PTPRG function in the various tissues and diseases, along with an interactome map of its relationship with a group of validated molecular interactors.
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Affiliation(s)
| | | | - Claudio Sorio
- Department of Medicine, General Pathology Division, University of Verona, 37134 Verona, Italy; (C.B.); (C.L.)
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Elhassan RM, Hou X, Fang H. Recent advances in the development of allosteric protein tyrosine phosphatase inhibitors for drug discovery. Med Res Rev 2021; 42:1064-1110. [PMID: 34791703 DOI: 10.1002/med.21871] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 09/26/2021] [Accepted: 10/24/2021] [Indexed: 01/07/2023]
Abstract
Protein tyrosine phosphatases (PTPs) superfamily catalyzes tyrosine de-phosphorylation which affects a myriad of cellular processes. Imbalance in signal pathways mediated by PTPs has been associated with development of many human diseases including cancer, metabolic, and immunological diseases. Several compelling evidence suggest that many members of PTP family are novel therapeutic targets. However, the clinical development of conventional PTP-based active-site inhibitors originally was hampered by the poor selectivity and pharmacokinetic properties. In this regard, PTPs has been widely dismissed as "undruggable." Nonetheless, allosteric modulation has become increasingly an influential and alternative approach that can be exploited for drug development against PTPs. Unlike active-site inhibitors, allosteric inhibitors exhibit a remarkable target-selectivity, drug-likeness, potency, and in vivo activity. Intriguingly, there has been a high interest in novel allosteric PTPs inhibitors within the last years. In this review, we focus on the recent advances of allosteric inhibitors that have been explored in drug discovery and have shown an excellent result in the development of PTPs-based therapeutics. A special emphasis is placed on the structure-activity relationship and molecular mechanistic studies illustrating applications in chemical biology and medicinal chemistry.
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Affiliation(s)
- Reham M Elhassan
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmacy, Shandong University, Jinan, Shandong, China
| | - Xuben Hou
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmacy, Shandong University, Jinan, Shandong, China
| | - Hao Fang
- Department of Medicinal Chemistry and Key Laboratory of Chemical Biology of Natural Products (MOE), School of Pharmacy, Shandong University, Jinan, Shandong, China
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Ion Channels, Transporters, and Sensors Interact with the Acidic Tumor Microenvironment to Modify Cancer Progression. Rev Physiol Biochem Pharmacol 2021; 182:39-84. [PMID: 34291319 DOI: 10.1007/112_2021_63] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Solid tumors, including breast carcinomas, are heterogeneous but typically characterized by elevated cellular turnover and metabolism, diffusion limitations based on the complex tumor architecture, and abnormal intra- and extracellular ion compositions particularly as regards acid-base equivalents. Carcinogenesis-related alterations in expression and function of ion channels and transporters, cellular energy levels, and organellar H+ sequestration further modify the acid-base composition within tumors and influence cancer cell functions, including cell proliferation, migration, and survival. Cancer cells defend their cytosolic pH and HCO3- concentrations better than normal cells when challenged with the marked deviations in extracellular H+, HCO3-, and lactate concentrations typical of the tumor microenvironment. Ionic gradients determine the driving forces for ion transporters and channels and influence the membrane potential. Cancer and stromal cells also sense abnormal ion concentrations via intra- and extracellular receptors that modify cancer progression and prognosis. With emphasis on breast cancer, the current review first addresses the altered ion composition and the changes in expression and functional activity of ion channels and transporters in solid cancer tissue. It then discusses how ion channels, transporters, and cellular sensors under influence of the acidic tumor microenvironment shape cancer development and progression and affect the potential of cancer therapies.
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Regulative Loop between β-catenin and Protein Tyrosine Receptor Type γ in Chronic Myeloid Leukemia. Int J Mol Sci 2020; 21:ijms21072298. [PMID: 32225105 PMCID: PMC7177637 DOI: 10.3390/ijms21072298] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 11/17/2022] Open
Abstract
Protein tyrosine phosphatase receptor type γ (PTPRG) is a tumor suppressor gene, down-regulated in Chronic Myeloid Leukemia (CML) cells by the hypermethylation of its promoter region. β-catenin (CTNNB1) is a critical regulator of Leukemic Stem Cells (LSC) maintenance and CML proliferation. This study aims to demonstrate the antagonistic regulation between β-catenin and PTPRG in CML cells. The specific inhibition of PTPRG increases the activation state of BCR-ABL1 and modulates the expression of the BCR-ABL1- downstream gene β-Catenin. PTPRG was found to be capable of dephosphorylating β-catenin, eventually causing its cytosolic destabilization and degradation in cells expressing PTPRG. Furthermore, we demonstrated that the increased expression of β-catenin in PTPRG-negative CML cell lines correlates with DNA (cytosine-5)-methyl transferase 1 (DNMT1) over-expression, which is responsible for PTPRG promoter hypermethylation, while its inhibition or down-regulation correlates with PTPRG re-expression. We finally confirmed the role of PTPRG in regulating BCR-ABL1 and β-catenin phosphorylation in primary human CML samples. We describe here, for the first time, the existence of a regulative loop occurring between PTPRG and β-catenin, whose reciprocal imbalance affects the proliferation kinetics of CML cells.
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Behzad MM, Shahrabi S, Jaseb K, Bertacchini J, Ketabchi N, Saki N. Aberrant DNA Methylation in Chronic Myeloid Leukemia: Cell Fate Control, Prognosis, and Therapeutic Response. Biochem Genet 2018; 56:149-175. [DOI: 10.1007/s10528-018-9841-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/18/2018] [Indexed: 01/24/2023]
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Mafficini A, Vezzalini M, Zamai L, Galeotti L, Bergamini G, Peruta MD, Melotti P, Sorio C. Protein Tyrosine Phosphatase Gamma (PTPγ) is a Novel Leukocyte Marker Highly Expressed by CD34+ Precursors. Biomark Insights 2017. [DOI: 10.1177/117727190700200036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Protein Tyrosine Phosphatase gamma (PTPγ) is a receptor-like transmembrane protein belonging to the family of classical protein tyrosine phosphatases. PTPγ is known to regulate haematopoietic differentiation in a murine embryonic stem cells model. We have recently demonstrated that PTPγ mRNA is expressed in monocytes, tissue-localized myeloid dendritic cells and in both myeloid and plasmacytoid dendritic cells in peripheral blood. We now developed a PTPγ specific antibody that recognizes the protein by flow cytometry. PTPγ expression was detected in monocytes and both myeloid and plasmacytoid dendritic cells, while PMN showed a low but consistent staining in contrast with previous mRNA data. B cells were found to express the phosphatase while T cells were negative. In keeping with RNA data, PTPγ was detected in monocyte-derived dendritic cells and its expression rose upon LPS stimulation. Finally, we discovered that CD34+ haematopoietic precursors express high PTPγ level that drops during in vitro expansion induced by IL-3 and SCF growth factors. We therefore propose PTPγ as a new functionally regulated leukocyte marker whose role in normal and pathological context deserve further investigation.
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Affiliation(s)
| | | | - Loris Zamai
- Institute of Histology and Laboratory Analysis, University of Urbino “Carlo Bo”, Italy
- Flow Cytometry and Cytomorphology Center, University of Urbino “Carlo Bo”, Italy
- INFN-Gran Sasso National Laboratory, SS17bis km 18+910, 67010 Assergi, L'Aquila, Italy
| | - Laura Galeotti
- Institute of Histology and Laboratory Analysis, University of Urbino “Carlo Bo”, Italy
- Flow Cytometry and Cytomorphology Center, University of Urbino “Carlo Bo”, Italy
| | | | | | - Paola Melotti
- Cystic Fibrosis Center, Azienda Ospedaliera of Verona, Verona, Italy
| | - Claudio Sorio
- Department of Pathology, University of Verona, Italy
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Meeusen B, Janssens V. Tumor suppressive protein phosphatases in human cancer: Emerging targets for therapeutic intervention and tumor stratification. Int J Biochem Cell Biol 2017; 96:98-134. [PMID: 29031806 DOI: 10.1016/j.biocel.2017.10.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/04/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023]
Abstract
Aberrant protein phosphorylation is one of the hallmarks of cancer cells, and in many cases a prerequisite to sustain tumor development and progression. Like protein kinases, protein phosphatases are key regulators of cell signaling. However, their contribution to aberrant signaling in cancer cells is overall less well appreciated, and therefore, their clinical potential remains largely unexploited. In this review, we provide an overview of tumor suppressive protein phosphatases in human cancer. Along their mechanisms of inactivation in defined cancer contexts, we give an overview of their functional roles in diverse signaling pathways that contribute to their tumor suppressive abilities. Finally, we discuss their emerging roles as predictive or prognostic markers, their potential as synthetic lethality targets, and the current feasibility of their reactivation with pharmacologic compounds as promising new cancer therapies. We conclude that their inclusion in clinical practice has obvious potential to significantly improve therapeutic outcome in various ways, and should now definitely be pushed forward.
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Affiliation(s)
- Bob Meeusen
- Laboratory of Protein Phosphorylation & Proteomics, Dept. of Cellular & Molecular Medicine, Faculty of Medicine, KU Leuven & Leuven Cancer Institute (LKI), KU Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Dept. of Cellular & Molecular Medicine, Faculty of Medicine, KU Leuven & Leuven Cancer Institute (LKI), KU Leuven, Belgium.
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Elson A. Stepping out of the shadows: Oncogenic and tumor-promoting protein tyrosine phosphatases. Int J Biochem Cell Biol 2017; 96:135-147. [PMID: 28941747 DOI: 10.1016/j.biocel.2017.09.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 09/15/2017] [Accepted: 09/16/2017] [Indexed: 12/18/2022]
Abstract
Protein tyrosine phosphorylation is critical for proper function of cells and organisms. Phosphorylation is regulated by the concerted but generically opposing activities of tyrosine kinases (PTKs) and tyrosine phosphatases (PTPs), which ensure its proper regulation, reversibility, and ability to respond to changing physiological situations. Historically, PTKs have been associated mainly with oncogenic and pro-tumorigenic activities, leading to the generalization that protein dephosphorylation is anti-oncogenic and hence that PTPs are tumor-suppressors. In many cases PTPs do suppress tumorigenesis. However, a growing body of evidence indicates that PTPs act as dominant oncogenes and drive cell transformation in a number of contexts, while in others PTPs support transformation that is driven by other oncogenes. This review summarizes the known transforming and tumor-promoting activities of the classical, tyrosine specific PTPs and highlights their potential as drug targets for cancer therapy.
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Affiliation(s)
- Ari Elson
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, 76100, Israel.
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Targeting PTPRZ inhibits stem cell-like properties and tumorigenicity in glioblastoma cells. Sci Rep 2017; 7:5609. [PMID: 28717188 PMCID: PMC5514153 DOI: 10.1038/s41598-017-05931-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 06/06/2017] [Indexed: 01/08/2023] Open
Abstract
The R5 subfamily of receptor-type protein tyrosine phosphatases (RPTPs) comprises PTPRZ and PTPRG. A recent study on primary human glioblastomas suggested a close association between PTPRZ1 (human PTPRZ) expression and cancer stemness. However, the functional roles of PTPRZ activity in glioma stem cells have remained unclear. In the present study, we found that sphere-forming cells from the rat C6 and human U251 glioblastoma cell lines showed high expression levels of PTPRZ-B, the short receptor isoform of PTPRZ. Stable PTPRZ knockdown altered the expression levels of stem cell transcription factors such as SOX2, OLIG2, and POU3F2 and decreased the sphere-forming abilities of these cells. Suppressive effects on the cancer stem-like properties of the cells were also observed following the knockdown of PTPRG. Here, we identified NAZ2329, a cell-permeable small molecule that allosterically inhibits both PTPRZ and PTPRG. NAZ2329 reduced the expression of SOX2 in C6 and U251 cells and abrogated the sphere-forming abilities of these cells. Tumor growth in the C6 xenograft mouse model was significantly slower with the co-treatment of NAZ2329 with temozolomide, an alkylating agent, than with the individual treatments. These results indicate that pharmacological inhibition of R5 RPTPs is a promising strategy for the treatment of malignant gliomas.
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Vezzalini M, Mafficini A, Tomasello L, Lorenzetto E, Moratti E, Fiorini Z, Holyoake TL, Pellicano F, Krampera M, Tecchio C, Yassin M, Al-Dewik N, Ismail MA, Al Sayab A, Monne M, Sorio C. A new monoclonal antibody detects downregulation of protein tyrosine phosphatase receptor type γ in chronic myeloid leukemia patients. J Hematol Oncol 2017. [PMID: 28637510 PMCID: PMC5479035 DOI: 10.1186/s13045-017-0494-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Protein tyrosine phosphatase receptor gamma (PTPRG) is a ubiquitously expressed member of the protein tyrosine phosphatase family known to act as a tumor suppressor gene in many different neoplasms with mechanisms of inactivation including mutations and methylation of CpG islands in the promoter region. Although a critical role in human hematopoiesis and an oncosuppressor role in chronic myeloid leukemia (CML) have been reported, only one polyclonal antibody (named chPTPRG) has been described as capable of recognizing the native antigen of this phosphatase by flow cytometry. Protein biomarkers of CML have not yet found applications in the clinic, and in this study, we have analyzed a group of newly diagnosed CML patients before and after treatment. The aim of this work was to characterize and exploit a newly developed murine monoclonal antibody specific for the PTPRG extracellular domain (named TPγ B9-2) to better define PTPRG protein downregulation in CML patients. METHODS TPγ B9-2 specifically recognizes PTPRG (both human and murine) by flow cytometry, western blotting, immunoprecipitation, and immunohistochemistry. RESULTS Co-localization experiments performed with both anti-PTPRG antibodies identified the presence of isoforms and confirmed protein downregulation at diagnosis in the Philadelphia-positive myeloid lineage (including CD34+/CD38bright/dim cells). After effective tyrosine kinase inhibitor (TKI) treatment, its expression recovered in tandem with the return of Philadelphia-negative hematopoiesis. Of note, PTPRG mRNA levels remain unchanged in tyrosine kinase inhibitors (TKI) non-responder patients, confirming that downregulation selectively occurs in primary CML cells. CONCLUSIONS The availability of this unique antibody permits its evaluation for clinical application including the support for diagnosis and follow-up of these disorders. Evaluation of PTPRG as a potential therapeutic target is also facilitated by the availability of a specific reagent capable to specifically detect its target in various experimental conditions.
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Affiliation(s)
- Marzia Vezzalini
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy
| | - Andrea Mafficini
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy.,ARC-Net Research Centre, University and Hospital Trust of Verona, 37134, Verona, Italy
| | - Luisa Tomasello
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy.,Present address: The Ohio State University, Wexner Medical Center Biomedical Research Tower, 460W 12th Avenue, room 1070, Columbus, OH, 43210, USA
| | - Erika Lorenzetto
- Section of Physiology, Department of Neurological, Neuropsychological, Morphological and Motor Sciences, University of Verona, Verona, Italy
| | - Elisabetta Moratti
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy
| | - Zeno Fiorini
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy
| | - Tessa L Holyoake
- Paul O'Gorman Leukaemia Research Centre, College of Medical, Veterinary & Life Sciences, Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Francesca Pellicano
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, Scotland, UK
| | - Mauro Krampera
- Section of Hematology, Department of Medicine, University of Verona, Verona, Italy
| | - Cristina Tecchio
- Section of Hematology, Department of Medicine, University of Verona, Verona, Italy
| | - Mohamed Yassin
- National Center for Cancer Care and Research (NCCCR), Hamad Medical Corporation (HMC), Doha, Qatar
| | - Nader Al-Dewik
- Qatar Medical Genetics Center, Hamad Medical Corporation (HMC), Doha, Qatar
| | - Mohamed A Ismail
- Interim Translational Research Institute (iTRI), Hamad Medical Corporation, Doha, Qatar
| | - Ali Al Sayab
- National Center for Cancer Care and Research (NCCCR), Hamad Medical Corporation (HMC), Doha, Qatar
| | - Maria Monne
- Centro di Diagnostica Biomolecolare e Citogenetica Emato-Oncologica, "San Francesco" Hospital, ASL3, Nuoro, 08100, Italy
| | - Claudio Sorio
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy.
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Kiflemariam S, Ljungström V, Pontén F, Sjöblom T. Tumor vessel up-regulation of INSR revealed by single-cell expression analysis of the tyrosine kinome and phosphatome in human cancers. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:1600-9. [PMID: 25864925 DOI: 10.1016/j.ajpath.2015.02.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/08/2015] [Accepted: 02/18/2015] [Indexed: 01/16/2023]
Abstract
The tyrosine kinome and phosphatome harbor oncogenes and tumor suppressor genes and important regulators of angiogenesis and tumor stroma formation. To provide a better understanding of their potential roles in cancer, we analyzed the expression of 85 tyrosine kinases and 42 tyrosine phosphatases by in situ hybridization 48 human normal and 24 tumor tissue specimens. Nine-tenths of the assessed transcripts had tumor cell expression concordant with expression array databases. Further, pan-cancer expression of AATK, PTPRK, and PTPRU and expression of PTPRS in a subset of tumors were observed. To demonstrate tumor subcompartment resolution, we validated the predicted tumor stroma-specific markers HTRA1, HTRA3, MXRA5, MXRA8, and SERPING1 in situ. In addition to known vascular and stromal markers such as PDGFRB, we observed stromal expression of PTK6 and TNS1 and vascular expression of INSR, PTPRF, PTPRG, PTPRU, and TNS1, of which INSR emerged as a tumor-specific vessel marker. This study demonstrates the feasibility of large-scale analyses to chart the transcriptome in situ in human cancers and their ability to identify novel cancer biomarkers.
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Affiliation(s)
- Sara Kiflemariam
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Viktor Ljungström
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Fredrik Pontén
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Tobias Sjöblom
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
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Identification of protein tyrosine phosphatase receptor gamma extracellular domain (sPTPRG) as a natural soluble protein in plasma. PLoS One 2015; 10:e0119110. [PMID: 25775014 PMCID: PMC4361625 DOI: 10.1371/journal.pone.0119110] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 01/28/2015] [Indexed: 02/06/2023] Open
Abstract
Background PTPRG is a widely expressed protein tyrosine phosphatase present in various isoforms. Peptides from its extracellular domain have been detected in plasma by proteomic techniques. We aim at characterizing the plasmatic PTPRG (sPTPRG) form and to identify its source. Methodology/Principal Findings The expression of sPTPRG was evaluated in human plasma and murine plasma and tissues by immunoprecipitation and Western blotting. The polypeptides identified have an apparent Mr of about 120 kDa (major band) and 90 kDa (minor band) respectively. Full length PTPRG was identified in the 100.000×g pelleted plasma fraction, suggesting that it was present associated to cell-derived vesicles (exosomes). The release of sPTPRG by HepG2 human hepatocellular carcinoma cell line was induced by ethanol and sensitive to metalloproteinase and not to Furin inhibitors. Finally, increased levels of the plasmatic ∼120 kDa isoform were associated with the occurrence of liver damage. Conclusions These results demonstrate that sPTPRG represent a novel candidate protein biomarker in plasma whose increased expression is associated to hepatocyte damage. This observation could open a new avenue of investigation in this challenging field.
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Galvan A, Colombo F, Frullanti E, Dassano A, Noci S, Wang Y, Eisen T, Matakidou A, Tomasello L, Vezzalini M, Sorio C, Dugo M, Ambrogi F, Iacobucci I, Martinelli G, Incarbone M, Alloisio M, Nosotti M, Tosi D, Santambrogio L, Pelosi G, Pastorino U, Houlston RS, Dragani TA. Germline polymorphisms and survival of lung adenocarcinoma patients: a genome-wide study in two European patient series. Int J Cancer 2015; 136:E262-71. [PMID: 25196286 DOI: 10.1002/ijc.29195] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 08/04/2014] [Accepted: 08/05/2014] [Indexed: 11/09/2022]
Abstract
In lung cancer, the survival of patients with the same clinical stage varies widely for unknown reasons. In this two-phase study, we examined the hypothesis that germline variations influence the survival of patients with lung adenocarcinoma. First, we analyzed existing genotype and clinical data from 289 UK-resident patients with lung adenocarcinoma, identifying 86 single nucleotide polymorphisms (SNPs) that associated with survival (p < 0.01). We then genotyped these candidate SNPs in a validation series of 748 patients from Italy that resulted genetically compatible with the UK series based on principal component analysis. In a Cox proportional hazard model adjusted for age, sex and clinical stage, four SNPs were confirmed on the basis of their having a hazard ratio (HR) indicating the same direction of effect in the two series and p < 0.05. The strongest association was provided by rs2107561, an intronic SNP of PTPRG, protein tyrosine phosphatase, receptor type, G; the C allele was associated with poorer survival in both patient series (pooled analysis loge HR = 0.31; 95% CI: 0.15-0.46, p = 8.5 × 10(-5) ). PTPRG mRNA levels in 43 samples of lung adenocarcinoma were 40% of those observed in noninvolved lung tissue from the same patients. PTPRG overexpression significantly inhibited the clonogenicity of A549 lung carcinoma cells and the anchorage-independent growth of the NCI-H460 large cell lung cancer line. These four germline variants represent promising candidates that, with further study, may help predict clinical outcome. In addition, the PTPRG locus may have a role in tumor progression.
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Mirenda M, Toffali L, Montresor A, Scardoni G, Sorio C, Laudanna C. Protein tyrosine phosphatase receptor type γ is a JAK phosphatase and negatively regulates leukocyte integrin activation. THE JOURNAL OF IMMUNOLOGY 2015; 194:2168-79. [PMID: 25624455 DOI: 10.4049/jimmunol.1401841] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Regulation of signal transduction networks depends on protein kinase and phosphatase activities. Protein tyrosine kinases of the JAK family have been shown to regulate integrin affinity modulation by chemokines and mediated homing to secondary lymphoid organs of human T lymphocytes. However, the role of protein tyrosine phosphatases in leukocyte recruitment is still elusive. In this study, we address this issue by focusing on protein tyrosine phosphatase receptor type γ (PTPRG), a tyrosine phosphatase highly expressed in human primary monocytes. We developed a novel methodology to study the signaling role of receptor type tyrosine phosphatases and found that activated PTPRG blocks chemoattractant-induced β2 integrin activation. Specifically, triggering of LFA-1 to high-affinity state is prevented by PTPRG activation. High-throughput phosphoproteomics and computational analyses show that PTPRG activation affects the phosphorylation state of at least 31 signaling proteins. Deeper examination shows that JAKs are critically involved in integrin-mediated monocyte adhesion and that PTPRG activation leads to JAK2 dephosphorylation on the critical 1007-1008 phosphotyrosine residues, implying JAK2 inhibition and thus explaining the antiadhesive role of PTPRG. Overall, the data validate a new approach to study receptor tyrosine phosphatases and show that, by targeting JAKs, PTPRG downmodulates the rapid activation of integrin affinity in human monocytes, thus emerging as a potential novel critical regulator of leukocyte trafficking.
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Affiliation(s)
- Michela Mirenda
- Division of General Pathology, Department of Pathology and Diagnostics, School of Medicine, University of Verona, Verona 37134, Italy; and
| | - Lara Toffali
- Division of General Pathology, Department of Pathology and Diagnostics, School of Medicine, University of Verona, Verona 37134, Italy; and Center for Biomedical Computing, University of Verona, Verona 37134, Italy
| | - Alessio Montresor
- Division of General Pathology, Department of Pathology and Diagnostics, School of Medicine, University of Verona, Verona 37134, Italy; and Center for Biomedical Computing, University of Verona, Verona 37134, Italy
| | - Giovanni Scardoni
- Center for Biomedical Computing, University of Verona, Verona 37134, Italy
| | - Claudio Sorio
- Division of General Pathology, Department of Pathology and Diagnostics, School of Medicine, University of Verona, Verona 37134, Italy; and
| | - Carlo Laudanna
- Division of General Pathology, Department of Pathology and Diagnostics, School of Medicine, University of Verona, Verona 37134, Italy; and Center for Biomedical Computing, University of Verona, Verona 37134, Italy
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Lorenzetto E, Moratti E, Vezzalini M, Harroch S, Sorio C, Buffelli M. Distribution of different isoforms of receptor protein tyrosine phosphatase γ (Ptprg-RPTP γ) in adult mouse brain: upregulation during neuroinflammation. Brain Struct Funct 2013; 219:875-90. [DOI: 10.1007/s00429-013-0541-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 03/12/2013] [Indexed: 01/06/2023]
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18
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Nikolaienko RM, Agyekum B, Bouyain S. Receptor protein tyrosine phosphatases and cancer: new insights from structural biology. Cell Adh Migr 2012; 6:356-64. [PMID: 22796942 DOI: 10.4161/cam.21242] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
There is general agreement that many cancers are associated with aberrant phosphotyrosine signaling, which can be caused by the inappropriate activities of tyrosine kinases or tyrosine phosphatases. Furthermore, incorrect activation of signaling pathways has been often linked to changes in adhesion events mediated by cell surface receptors. Among these receptors, receptor protein tyrosine phosphatases (RPTPs) both antagonize tyrosine kinases as well as engage extracellular ligands. A recent wealth of data on this intriguing family indicates that its members can fulfill either tumor suppressing or oncogenic roles. The interpretation of these results at a molecular level has been greatly facilitated by the recent availability of structural information on the extra- and intracellular regions of RPTPs. These structures provide a molecular framework to understand how alterations in extracellular interactions can inactivate RPTPs in cancers or why the overexpression of certain RPTPs may also participate in tumor progression.
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Affiliation(s)
- Roman M Nikolaienko
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
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19
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Lin G, Aranda V, Muthuswamy SK, Tonks NK. Identification of PTPN23 as a novel regulator of cell invasion in mammary epithelial cells from a loss-of-function screen of the 'PTP-ome'. Genes Dev 2011; 25:1412-25. [PMID: 21724833 DOI: 10.1101/gad.2018911] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We used an RNAi-mediated loss-of-function screen to study systematically the role of the protein tyrosine phosphatase (PTP) superfamily of enzymes in mammary epithelial cell motility in the absence or presence of the oncoprotein tyrosine kinase ERBB2. We report that although shRNAs directed against most of the PTP family were without effect, suppression of three PTPs-PRPN23, PTPRG, and PTPRR-enhanced cell motility. Furthermore, we found that suppression of PTPN23, but not PTPRG or PTPRR, induced cell invasion. Suppression of PTPN23 increased E-cadherin internalization, impaired early endosome trafficking of E-cadherin, induced the expression of mesenchymal proteins, and caused cell scattering. The activity of SRC and β-catenin was elevated when PTPN23 was suppressed. Moreover, we identified SRC, E-cadherin, and β-catenin as direct substrates of PTPN23. Inhibition of SRC with the small molecular inhibitor SU6656 blocked the effects of PTPN23 depletion. These findings suggest that loss of PTPN23 may increase the activity of SRC and the phosphorylation status of the E-cadherin/β-catenin signaling complex to promote tumor growth and invasive behavior in breast cancer. In addition, our studies highlight functional specificity among PTPs and reveal new roles for PTPs in mammary epithelial cell biology.
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Affiliation(s)
- Guang Lin
- Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, New York 11794, USA
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20
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Abstract
Members of the protein tyrosine phosphatase (Ptp) family dephosphorylate target proteins and counter the activities of protein tyrosine kinases that are involved in cellular phosphorylation and signalling. As such, certain PTPs might be tumour suppressors. Indeed, PTPs play an important part in the inhibition or control of growth, but accumulating evidence indicates that some PTPs may exert oncogenic functions. Recent large-scale genetic analyses of various human tumours have highlighted the relevance of PTPs either as putative tumour suppressors or as candidate oncoproteins. Progress in understanding the regulation and function of PTPs has provided insights into which PTPs might be potential therapeutic targets in human cancer.
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Affiliation(s)
- Sofi G Julien
- Goodman Cancer Research Centre, Department of Biochemistry, McGill University, Montreal, Quebec, Canada
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21
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Della Peruta M, Martinelli G, Moratti E, Pintani D, Vezzalini M, Mafficini A, Grafone T, Iacobucci I, Soverini S, Murineddu M, Vinante F, Tecchio C, Piras G, Gabbas A, Monne M, Sorio C. Protein Tyrosine Phosphatase Receptor Type γ Is a Functional Tumor Suppressor Gene Specifically Downregulated in Chronic Myeloid Leukemia. Cancer Res 2010; 70:8896-906. [DOI: 10.1158/0008-5472.can-10-0258] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Révillion F, Puech C, Rabenoelina F, Chalbos D, Peyrat JP, Freiss G. Expression of the putative tumor suppressor gene PTPN13/PTPL1 is an independent prognostic marker for overall survival in breast cancer. Int J Cancer 2008; 124:638-43. [PMID: 19004008 DOI: 10.1002/ijc.23989] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although it is well established that some protein tyrosine kinases have a prognostic value in breast cancer, the involvement of protein tyrosine phosphatases (PTPs) is poorly substantiated for breast tumors. Three of these enzymes (PTP-gamma, LAR, and PTPL1) are already known to be regulated by estrogens or their antagonists in human breast cancer cells. We used a real-time reverse transcriptase polymerase chain reaction method to test the expression levels of PTP-gamma, LAR and its neuronal isoform, and PTPL1 in a training set of RNA from 59 breast tumors. We sought correlations between levels of these molecular markers, current tumor markers, and survival. We then quantified the expression level of the selected phosphatase in 232 additional samples, resulting in a testing set of 291 breast tumor RNAs from patients with a median follow-up of 6.4 years. The Spearman nonparametric test revealed correlations between PTPL1 expression and differentiation markers. Cox univariate analysis of the overall survival studies demonstrated that PTPL1 is a prognostic factor [risk ratio (RR)=0.45], together with the progesterone receptor (PR) (RR=0.52) and node involvement (RR=1.58). In multivariate analyses, PTPL1 and PR retained their prognostic value (RRs of 0.48 and 0.55, respectively). This study demonstrates for the first time that PTPL1 expression level is an independent prognostic indicator of favorable outcome for patients with breast cancer. In conjunction with our mechanistic studies, this finding identifies PTPL1 as an important regulatory element of human breast tumor aggressiveness and sensitivity to treatments such as antiestrogens and antiaromatase.
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Affiliation(s)
- Françoise Révillion
- Contrôle de la progression des cancers hormono-dépendants, Laboratoire d'Oncologie Moléculaire Humaine, Centre Régional de Lutte contre le Cancer Oscar Lambret, Lille, France
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Cheung AKL, Lung HL, Hung SC, Law EWL, Cheng Y, Yau WL, Bangarusamy DK, Miller LD, Liu ETB, Shao JY, Kou CW, Chua D, Zabarovsky ER, Tsao SW, Stanbridge EJ, Lung ML. Functional analysis of a cell cycle-associated, tumor-suppressive gene, protein tyrosine phosphatase receptor type G, in nasopharyngeal carcinoma. Cancer Res 2008; 68:8137-45. [PMID: 18829573 DOI: 10.1158/0008-5472.can-08-0904] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Functional studies to identify the potential role of a chromosome 3p14-21 gene, protein tyrosine phosphatase receptor type G (PTPRG), were performed. PTPRG was identified as a candidate tumor suppressor gene (TSG) in nasopharyngeal carcinoma (NPC) by differential gene profiling of tumorigenic and nontumorigenic NPC chromosome 3 microcell hybrids (MCH). Down-regulation of this gene was found in tumor segregants when compared with their corresponding tumor-suppressive MCHs, as well as in NPC cell lines and tumor biopsies. Promoter hypermethylation and loss of heterozygosity were found to be important mechanisms contributing to PTPRG silencing. PTPRG overexpression in NPC cell lines induces growth suppression and reduced anchorage-independent growth in vitro. This is the first study to use a tetracycline-responsive vector expression system to study PTPRG stable transfectants. Results indicate its ability to induce significant tumor growth suppression in nude mice under conditions activating transgene expression. These studies now provide functional evidence indicating critical interactions of PTPRG in the extracellular matrix milieu induce cell arrest and changes in cell cycle status. This is associated with inhibition of pRB phosphorylation through down-regulation of cyclin D1. These novel findings enhance our current understanding of how PTPRG may contribute to tumorigenesis.
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Affiliation(s)
- Arthur Kwok Leung Cheung
- Department of Biology and Center for Cancer Research, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, People's Republic of China
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24
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Maulik D, Ashraf QM, Mishra OP, Delivoria-Papadopoulos M. Effect of hypoxia on protein tyrosine phosphatase activity and expression of protein tyrosine phosphatases PTP-1B, PTP-SH1 and PTP-SH2 in the cerebral cortex of guinea pig fetus. Neurosci Lett 2008; 432:174-8. [DOI: 10.1016/j.neulet.2007.11.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 11/07/2007] [Accepted: 11/11/2007] [Indexed: 01/03/2023]
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