Targeting the interaction of pleiotrophin and VEGFA165 with protein tyrosine phosphatase receptor zeta 1 inhibits endothelial cell activation and angiogenesis.

Protein tyrosine phosphatase receptor zeta 1 (PTPRZ1) is a transmembrane tyrosine phosphatase (TP) that serves as a receptor for pleiotrophin (PTN) and vascular endothelial growth factor A 165 (VEGFA 165) to regulate endothelial cell migration. In the present work, we identify a PTN peptide fragment (PTN 97-110) that inhibits the interaction of PTN and VEGFA 165 with PTPRZ1 but not VEGF receptor 2. This peptide abolishes the stimulatory effect of PTN and VEGFA 165 on endothelial cell migration, tube formation on Matrigel, and Akt activation in vitro. It also partially inhibits VEGFA 165 -induced VEGF receptor 2 activation but does not affect ERK1/2 activation and cell proliferation. In vivo , PTN 97-110 inhibits or dysregulates angiogenesis in the chick embryo chorioallantoic membrane and the zebrafish assays, respectively. In glioblastoma cells in vitro, PTN 97-110 abolishes the stimulatory effect of VEGFA 165 on cell migration and inhibits their anchorage-independent growth, suggesting that this peptide might also be exploited in glioblastoma therapy. Finally, in silico and experimental evidence indicates that PTN and VEGFA 165 bind to the extracellular fibronectin type-III (FNIII) domain to stimulate cell migration. Collectively, our data highlight novel aspects of the interaction of PTN and VEGFA 165 with PTPRZ1, strengthen the notion that PTPRZ1 is required for VEGFA 165 -induced signaling, and identify a peptide that targets this interaction and can be exploited for the design of novel anti-angiogenic and anti-glioblastoma therapeutic approaches. • Identification of the PTPRZ1 protein core domain involved in growth factor binding. • Identification of a PTN peptide that inhibits this binding. • Inhibition of PTPRZ1 tyrosine phosphatase activity activates endothelial cells. • Targeting VEGFA/PTN-PTPRZ1 interaction prevents endothelial cell activation and inhibits angiogenesis. • The same approach may also apply to glioblastoma therapy. [ABSTRACT FROM AUTHOR]