Endothelial Heparan Sulfate 6-O-Sulfation Levels Regulate Angiogenic Responses of Endothelial Cells to Fibroblast Growth Factor 2 and Vascular Endothelial Growth Factor

• Published in: The Journal of biological chemistry Vol. 287; no. 43; pp. 36132 - 36146
• Main Authors: Ferreras, Cristina, Rushton, Graham, Cole, Claire L., Babur, Muhammad, Telfer, Brian A., van Kuppevelt, Toin H., Gardiner, John M., Williams, Kaye J., Jayson, Gordon C., Avizienyte, Egle
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 19.10.2012; American Society for Biochemistry and Molecular Biology
• Subjects: Angiogenesis; Cell Biology; Cells, Cultured; ErbB Receptors - genetics; ErbB Receptors - metabolism; Female; Fibroblast Growth Factor (FGF); Fibroblast Growth Factor 2 - genetics; Fibroblast Growth Factor 2 - metabolism; Fibroblast Growth Factor Receptor (FGFR); Glycosaminoglycan; Heparan Sulfate; Heparitin Sulfate - biosynthesis; Heparitin Sulfate - genetics; Human Umbilical Vein Endothelial Cells - metabolism; Human Umbilical Vein Endothelial Cells - pathology; Humans; Myocytes, Smooth Muscle - metabolism; Myocytes, Smooth Muscle - pathology; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; Neovascularization, Pathologic - genetics; Neovascularization, Pathologic - metabolism; Neovascularization, Pathologic - pathology; Ovarian Neoplasms - blood supply; Ovarian Neoplasms - genetics; Ovarian Neoplasms - metabolism; Ovarian Neoplasms - pathology; Sulfotransferases - genetics; Sulfotransferases - metabolism; Vascular Endothelial Growth Factor (VEGF); Vascular Endothelial Growth Factor A - genetics; Vascular Endothelial Growth Factor A - metabolism; Heparan Sulfate; Angiogenesis; Glycosaminoglycan; Vascular Endothelial Growth Factor (VEGF); Fibroblast Growth Factor (FGF); Fibroblast Growth Factor Receptor (FGFR)
• ISSN: 0021-9258; 1083-351X; 1083-351X
• DOI: 10.1074/jbc.M112.384875

Fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor 165 (VEGF165) 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 VEGF165/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 VEGF165-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 VEGF165-dependent endothelial cell functions in vitro and in vivo and highlight HS6ST-1 and HS6ST-2 as potential targets of novel antiangiogenic agents. Background: Heparan sulfate (HS) is an essential regulator of multiple angiogenic growth factors. Results: Down-regulation of 6-O-sulfation in endothelial cell HS affects FGF2- and VEGF-mediated endothelial cell functions. Conclusion: The level of 6-O-sulfation in specific HS domains regulates endothelial cell responses to angiogenic growth factors. Significance: The relationships between 6-O-sulfation and endothelial phenotypes could help to design HS sequences inhibiting angiogenic growth factors.