Specific inhibition of FGF-2 signaling with 2-O-sulfated octasaccharides of heparan sulfate.
In fibroblast growth factor (FGF)-2 signaling, the formation of a ternary complex of FGF-2, tyrosine-kinase fibroblast growth factor receptor (FGFR)-1, and cell surface heparan sulfate (HS) proteoglycan is known to be critical for the activation of FGFR-1 and downstream signal transduction. Exogenous heparin polymer and some octasaccharides inhibited FGF-2-induced phosphorylation both of FGFR-1 and of extracellular signal-regulated kinase (ERK1/2) in Chinese hamster ovary (CHO)-K1 cells transfected with FGFR-1, which present HS on their cell surface. The inhibitory effect of octasaccharide was dependent on the number of 2-O-sulfate groups within a molecule but independent of the number of 6-O-sulfate groups. Sulfation at the 2-O-position was a prerequisite not only for the binding of HS to FGF-2 but also for regulation of FGF-2 signaling and competitive inhibition with endogenous HS. Interestingly, FGF-4-induced phosphorylation was impeded only by specific octasaccharides containing both 2-O- and 6-O-sulfated groups, which were necessary for binding FGF-4. In CHO-677 cells deficient in HS biosynthesis, heparin enhanced FGF-2-induced phosphorylation of ERK1/2. On the other hand, an FGF-2-binding octasaccharide inhibited the phosphorylation. Our data suggest that the activity of particular heparin-binding factors can be inhibited by distinctive oligosaccharides that can bind the factors but cannot form functional signaling complexes irrespective of whether cells have a normal complement of HS or lack HS.
Ashikari-Hada
Satoko
S
Institute for Molecular Science of Medicine, Aichi Medical University, Yazako, Nagakute, Aichi, Japan.
Habuchi
Hiroko
H
Sugaya
Noriko
N
Kobayashi
Takashi
T
Kimata
Koji
K
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D006497:Heparan Sulfate / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D009844:Oligosaccharides / Q000737:chemistry / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
D016222:Fibroblast Growth Factor 2; D006497:Heparan Sulfate; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D009844:Oligosaccharides; D051496:Receptor, Fibroblast Growth Factor, Type 1