Differential regulation of FGF-1 and -2 mitogenic activity is related to their kinetics of binding to heparan sulfate in MDA-MB-231 human breast cancer cells.
The growth of the malignant human mammary MDA-MB-231 cells is stimulated by fibroblast growth factor-1 (FGF-1) but not by FGF-2. When these cells are cultured in the presence of chlorate, an inhibitor of heparan sulfate (HS) sulfation, their proliferation is stimulated by both FGF-1 and FGF-2. We analyzed the interactions of FGF-1 and FGF-2 with HS purified from the cell layer and the culture medium of control and chlorate-treated MDA-MB-231 cells. The HS from the cell layer bound FGF-1 with faster association kinetics than the HS from the culture medium, and so had a higher affinity for FGF-1. Chlorate treatment had no significant effect on the FGF-1 binding kinetics of the HS. In contrast to FGF-1, chlorate treatment of the cells significantly altered the FGF-2 binding kinetics. The HS from untreated cells possessed two binding sites for FGF-2, one with fast association kinetics (k(ass) 470,000 to 610,000 M(-1) s(-1)) and a high affinity (K(d) 46 to 70 nM) and one with slower association kinetics (k(ass) 74,000 to 100,000 M(-1) s(-1)) and a lower affinity (K(d) 290 to 400 nM). HS from chlorate-treated cells possessed just a single binding site for FGF-2 with fast association kinetics (k(ass) 270,000 to 290,000 M(-1) s(-1)) and a high affinity (K(d) 41 to 57 nM). These results show that there is a relationship between the binding kinetics of FGFs and their ability to stimulate cell growth.
Fernig
D G
DG
School of Biological Sciences, Life Sciences Building, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom.
Chen
H L
HL
Rahmoune
H
H
Descamps
S
S
Boilly
B
B
Hondermarck
H
H
D016477:Artifacts; D001943:Breast Neoplasms; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002704:Chlorates / Q000494:pharmacology; D005260:Female; D016220:Fibroblast Growth Factor 1; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism / Q000494:pharmacology*; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D002704:Chlorates; D016220:Fibroblast Growth Factor 1; D016222:Fibroblast Growth Factor 2; D006497:Heparan Sulfate; D011994:Recombinant Proteins