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A peptide corresponding to the C‐terminal region of pleiotrophin inhibits angiogenesis in vivo and in vitro
Author(s) -
Mikelis Constantinos,
Lamprou Margarita,
Koutsioumpa Marina,
Koutsioubas Alexandros G.,
Spyranti Zinovia,
Zompra Aikaterini A.,
Spiliopoulos Nikolaos,
Vradis Alexandros A.,
Katsoris Panagiotis,
Spyroulias Georgios A.,
Cordopatis Paul,
Courty Jose,
Papadimitriou Evangelia
Publication year - 2011
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.23066
Subject(s) - pleiotrophin , angiogenesis , chemistry , phosphorylation , peptide , microbiology and biotechnology , fibronectin , integrin , tyrosine phosphorylation , in vitro , in vivo , biochemistry , extracellular matrix , growth factor , receptor , biology , cancer research
Pleiotrophin (PTN) is a heparin‐binding growth factor that plays a significant role in tumor growth and angiogenesis. We have previously shown that in order for PTN to induce migration of endothelial cells, binding to both α ν β 3 integrin and its receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ) is required. In the present study we show that a synthetic peptide corresponding to the last 25 amino acids of the C‐terminal region of PTN (PTN 112–136 ) inhibited angiogenesis in the in vivo chicken embryo chorioallantoic membrane (CAM) assay and PTN‐induced migration and tube formation of human endothelial cells in vitro. PTN 112–136 inhibited binding of PTN to α ν β 3 integrin, and as shown by surface plasmon resonance (SPR) measurements, specifically interacted with the specificity loop of the extracellular domain of β 3 . Moreover, it abolished PTN‐induced FAK Y397 phosphorylation, similarly to the effect of a neutralizing α ν β 3 ‐selective antibody. PTN 112–136 did not affect binding of PTN to RPTPβ/ζ in endothelial cells and induced β 3 Y773 phosphorylation and ERK1/2 activation to a similar extent with PTN. This effect was inhibited by down‐regulation of RPTPβ/ζ by siRNA or by c‐src inhibition, suggesting that PTN 112–136 may interact with RPTPβ/ζ. NMR spectroscopy studies showed that PTN 112–136 was characterized by conformational flexibility and absence of any element of secondary structure at room temperature, although the biologically active peptide segment 123–132 may adopt a defined structure at lower temperature. Collectively, our data suggest that although PTN 112–136 induces some of the signaling pathways triggered by PTN, it inhibits PTN‐induced angiogenic activities through inhibition of PTN binding to α ν β 3 integrin. J. Cell. Biochem. 112: 1532–1543, 2011. © 2011 Wiley‐Liss, Inc.