title: A truncated form of CD9-partner 1 (CD9P-1), GS-168AT2, potently inhibits in vivo tumour-induced angiogenesis and tumour growth.
abstract: BACKGROUND
  Tetraspanins are transmembrane proteins known to contribute to angiogenesis. CD9 partner-1 (CD9P-1/EWI-F), a glycosylated type 1 transmembrane immunoglobulin, is a member of the tetraspanin web, but its role in angiogenesis remains to be elucidated.
  
  
  METHODS
  We measured the expression of CD9P-1 under angiogenic and angiostatic conditions, and the influence of its knockdown onto capillary structures formation by human endothelial cells (hECs). A truncated form of CDP-1, GS-168AT2, was produced and challenged vs hEC proliferation, migration and capillaries' formation. Its association with CD9P-1, CD9, CD81 and CD151 and the expressions of these later at hEC surface were analysed. Finally, its effects onto in vivo tumour-induced angiogenesis and tumour growth were investigated.
  
  
  RESULTS
  Vascular endothelial growth factor (VEGF)-induced capillary tube-like formation was inhibited by tumour necrosis factor α and was associated with a rise in CD9P-1 mRNA expression (P<0.05); accordingly, knockdown of CD9P-1 inhibited VEGF-dependent in vitro angiogenesis. GS-168AT2 dose-dependently inhibited in vitro angiogenesis, hEC migration and proliferation (P<0.05). Co-precipitation experiments suggest that GS-168AT2 corresponds to the sequence by which CD9P-1 physiologically associates with CD81. GS-168AT2 induced the depletion of CD151, CD9 and CD9P-1 from hEC surface, correlating with GS-168AT2 degradation. Finally, in vivo injections of GS-168AT2 inhibited tumour-associated angiogenesis by 53.4±9.5% (P=0.03), and reduced tumour growth of Calu 6 tumour xenografts by 73.9±16.4% (P=0.007) without bodyweight loss.
  
  
  CONCLUSIONS
  The truncated form of CD9P-1, GS-168AT2, potently inhibits angiogenesis and cell migration by at least the downregulation of CD151 and CD9, which provides the first evidences for the central role of CD9P-1 in tumour-associated angiogenesis and tumour growth.
authors.affiliation: Gene Signal Research Center, 4 Rue Pierre Fontaine, 91000 Evry, France.
authors.forename: S
authors.initials: S
authors.lastname: Colin
authors.forename: W
authors.initials: W
authors.lastname: Guilmain
authors.forename: E
authors.initials: E
authors.lastname: Creoff
authors.forename: C
authors.initials: C
authors.lastname: Schneider
authors.forename: C
authors.initials: C
authors.lastname: Steverlynck
authors.forename: M
authors.initials: M
authors.lastname: Bongaerts
authors.forename: E
authors.initials: E
authors.lastname: Legrand
authors.forename: J P
authors.initials: JP
authors.lastname: Vannier
authors.forename: M
authors.initials: M
authors.lastname: Muraine
authors.forename: M
authors.initials: M
authors.lastname: Vasse
authors.forename: S
authors.initials: S
authors.lastname: Al-Mahmood
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D017209:Apoptosis; D015153:Blotting, Western; D002417:Cattle; D049109:Cell Proliferation; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D008175:Lung Neoplasms / Q000098:blood supply* / Q000473:pathology / Q000517:prevention & control*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism
chemical_list: D009363:Neoplasm Proteins; C486331:PTGFRN protein, human; D012333:RNA, Messenger; D011994:Recombinant Proteins