title: Endothelial heparan sulfate 6-O-sulfation levels regulate angiogenic responses of endothelial cells to fibroblast growth factor 2 and vascular endothelial growth factor.
abstract: Fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor 165 (VEGF(165)) are potent pro-angiogenic growth factors that play a pivotal role in tumor angiogenesis. The activity of these growth factors is regulated by heparan sulfate (HS), which is essential for the formation of FGF2/FGF receptor (FGFR) and VEGF(165)/VEGF receptor signaling complexes. However, the structural characteristics of HS that determine activation or inhibition of such complexes are only partially defined. Here we show that ovarian tumor endothelium displays high levels of HS sequences that harbor glucosamine 6-O-sulfates when compared with normal ovarian vasculature where these sequences are also detected in perivascular area. Reduced HS 6-O-sulfotransferase 1 (HS6ST-1) or 6-O-sulfotransferase 2 (HS6ST-2) expression in endothelial cells impacts upon the prevalence of HS 6-O-sulfate moieties in HS sequences, which consist of repeating short, highly sulfated S domains interspersed by transitional N-acetylated/N-sulfated domains. 1-40% reduction in 6-O-sulfates significantly compromises FGF2- and VEGF(165)-induced endothelial cell sprouting and tube formation in vitro and FGF2-dependent angiogenesis in vivo. Moreover, HS on wild-type neighboring endothelial or smooth muscle cells fails to restore endothelial cell sprouting and tube formation. The affinity of FGF2 for HS with reduced 6-O-sulfation is preserved, although FGFR1 activation is inhibited correlating with reduced receptor internalization. These data show that 6-O-sulfate moieties in endothelial HS are of major importance in regulating FGF2- and VEGF(165)-dependent endothelial cell functions in vitro and in vivo and highlight HS6ST-1 and HS6ST-2 as potential targets of novel antiangiogenic agents.
authors.affiliation: Translational Angiogenesis Group, School of Cancer and Enabling Sciences, The University of Manchester, Manchester M20 4BX, United Kingdom.
authors.forename: Cristina
authors.initials: C
authors.lastname: Ferreras
authors.forename: Graham
authors.initials: G
authors.lastname: Rushton
authors.forename: Claire L
authors.initials: CL
authors.lastname: Cole
authors.forename: Muhammad
authors.initials: M
authors.lastname: Babur
authors.forename: Brian A
authors.initials: BA
authors.lastname: Telfer
authors.forename: Toin H
authors.initials: TH
authors.lastname: van Kuppevelt
authors.forename: John M
authors.initials: JM
authors.lastname: Gardiner
authors.forename: Kaye J
authors.initials: KJ
authors.lastname: Williams
authors.forename: Gordon C
authors.initials: GC
authors.lastname: Jayson
authors.forename: Egle
authors.initials: E
authors.lastname: Avizienyte
mesh_terms: D002478:Cells, Cultured; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism*; D006497:Heparan Sulfate / Q000096:biosynthesis* / Q000235:genetics; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D032389:Myocytes, Smooth Muscle / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D010051:Ovarian Neoplasms / Q000098:blood supply* / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: D066246:ErbB Receptors; D016222:Fibroblast Growth Factor 2; D006497:Heparan Sulfate; D009363:Neoplasm Proteins; D015238:Sulfotransferases; D042461:Vascular Endothelial Growth Factor A; C467484:VEGFA protein, human; C512478:EGFR protein, human; C485757:HS6ST2 protein, human