2024-03-29T08:00:19Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/629162022-11-17T02:08:08Zhdl_2115_20055hdl_2115_8527Receptor protein tyrosine phosphatase beta/zeta is a functional binding partner for vascular endothelial growth factorKoutsioumpa, MarinaPoimenidi, EvangeliaPantazaka, EvangeliaTheodoropoulou, ChristinaSkoura, AngelikiMegalooikonomou, VasileiosKieffer, NellyCourty, JoseMizumoto, Shuji1000060154449Sugahara, KazuyukiPapadimitriou, Evangeliaopen accessCreative Commons Attribution 4.0 InternationalChondroitin sulphateEndothelial cellsMigrationPleiotrophinTyrosine phosphatasesVascular endothelial growth factor460Background: Receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ) is a chondroitin sulphate (CS) transmembrane protein tyrosine phosphatase and is a receptor for pleiotrophin (PTN). RPTPβ/ζ interacts with ανβ3 on the cell surface and upon binding of PTN leads to c-Src dephosphorylation at Tyr530, β3 Tyr773 phosphorylation, cell surface nucleolin (NCL) localization and stimulation of cell migration. c-Src-mediated β3 Tyr773 phosphorylation is also observed after vascular endothelial growth factor 165 (VEGF165) stimulation of endothelial cells and is essential for VEGF receptor type 2 (VEGFR2) - ανβ3 integrin association and subsequent signaling. In the present work, we studied whether RPTPβ/ζ mediates angiogenic actions of VEGF. Methods: Human umbilical vein endothelial, human glioma U87MG and stably transfected Chinese hamster ovary cells expressing different β3 subunits were used. Protein-protein interactions were studied by a combination of immunoprecipitation/Western blot, immunofluorescence and proximity ligation assays, properly quantified as needed. RPTPβ/ζ expression was down-regulated using small interference RNA technology. Migration assays were performed in 24-well microchemotaxis chambers, using uncoated polycarbonate membranes with 8 μm pores. Results: RPTPβ/ζ mediates VEGF165-induced c-Src-dependent β3 Tyr773 phosphorylation, which is required for VEGFR2-ανβ3 interaction and the downstream activation of phosphatidylinositol 3-kinase (PI3K) and cell surface NCL localization. RPTPβ/ζ directly interacts with VEGF165, and this interaction is not affected by bevacizumab, while it is interrupted by both CS-E and PTN. Down-regulation of RPTPβ/ζ by siRNA or administration of exogenous CS-E abolishes VEGF165-induced endothelial cell migration, while PTN inhibits the migratory effect of VEGF165 to the levels of its own effect. Conclusions: These data identify RPTPβ/ζ as a cell membrane binding partner for VEGF that regulates angiogenic functions of endothelial cells and suggest that it warrants further validation as a potential target for development of additive or alternative anti-VEGF therapies.Biomed Central Ltd2015-02-03engjournal articleVoRhttp://hdl.handle.net/2115/62916https://doi.org/10.1186/s12943-015-0287-3256444011476-4598Molecular Cancer1419https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/62916/1/MC14-19.pdfapplication/pdf3.59 MB2015-02-03