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Bilotta A, Dattilo V, D'Agostino S, Belviso S, Scalise S, Bilotta M, Gaudio E, Paduano F, Perrotti N, Florio T, Fusco A, Iuliano R, Trapasso F. A novel splice variant of the protein tyrosine phosphatase PTPRJ that encodes for a soluble protein involved in angiogenesis. Oncotarget 2018; 8:10091-10102. [PMID: 28052032 PMCID: PMC5354644 DOI: 10.18632/oncotarget.14350] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/13/2016] [Indexed: 02/01/2023] Open
Abstract
PTPRJ is a receptor protein tyrosine phosphatase with tumor suppressor activity. Very little is known about the role of PTPRJ ectodomain, although recently both physiological and synthetic PTPRJ ligands have been identified. A putative shorter spliced variant, coding for a 539 aa protein corresponding to the extracellular N-terminus of PTPRJ, is reported in several databases but, currently, no further information is available. Here, we confirmed that the PTPRJ short isoform (named sPTPRJ) is a soluble protein secreted into the supernatant of both endothelial and tumor cells. Like PTPRJ, also sPTPRJ undergoes post-translational modifications such as glycosylation, as assessed by sPTPRJ immunoprecipitation. To characterize its functional activity, we performed an endothelial cell tube formation assay and a wound healing assay on HUVEC cells overexpressing sPTPRJ and we found that sPTPRJ has a proangiogenic activity. We also showed that sPTPRJ expression down-regulates endothelial adhesion molecules, that is a hallmark of proangiogenic activity. Moreover, sPTPRJ mRNA levels in human high-grade glioma, one of the most angiogenic tumors, are higher in tumor samples compared to controls. Further studies will be helpful not only to clarify the way sPTPRJ works but also to supply clues to circumvent its activity in cancer therapy.
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Affiliation(s)
- Anna Bilotta
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Vincenzo Dattilo
- Department of Scienze della Salute, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Sabrina D'Agostino
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Stefania Belviso
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Stefania Scalise
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Mariaconcetta Bilotta
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Eugenio Gaudio
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy.,Lymphoma and Genomics Research Program, Institute of Oncology Research (IOR), Bellinzona, Switzerland
| | - Francesco Paduano
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy.,Tecnologica Research Institute, Biomedical Section, Crotone, Italy
| | - Nicola Perrotti
- Department of Scienze della Salute, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Tullio Florio
- Laboratory of Pharmacology, Dept. of Internal Medicine, and Center of Excellence for Biomedical Research (CEBR), University of Genova, Genova, Italy
| | - Alfredo Fusco
- Istituto di Endocrinologia e Oncologia Sperimentale - CNR c/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, University Federico II of Napoli, Napoli, Italy
| | - Rodolfo Iuliano
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Francesco Trapasso
- Department of Medicina Sperimentale e Clinica, University Magna Graecia of Catanzaro, Catanzaro, Italy
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