Interaction of Heparan Sulfate from Mammary Cells with Acidic Fibroblast Growth Factor (FGF) and Basic FGF
REGULATION OF THE ACTIVITY OF BASIC FGF BY HIGH AND LOW AFFINITY BINDING SITES IN HEPARAN SULFATE*
- From the ‡School of Biological Sciences, Life Sciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB and the §Cancer Research Campaign Department of Medical Oncology, Christie Hospital, Wilmslow Road, Manchester M20 9BX, United Kingdom
Abstract
We have determined the relationship between the binding sites for acidic fibroblast growth factor (aFGF) and basic FGF (bFGF) in heparan sulfate (HS) prepared from a panel of mammary cell lines and the ability of the HS to activate aFGF and bFGF in DNA synthesis assays. The k a of the HS for aFGF fell into three groups, whereas the k d (0.0015–0.016 s−1) and the K d (0.4–8.6 μm) formed a continuum. bFGF possessed a high affinity binding site (K d 22–30 nm) with a fastk a (320,000–550,000 m −1s−1), termed “fast/high,” and a lower affinity site (K d 47–320 nm) with a slowerk a (35,000–150,000 m −1s−1), termed “slow/low.” Most of the species of HS possessed the latter binding site, which was able to activate bFGF in HS-deficient fibroblasts. However, the HS from the culture medium of the mammary fibroblasts and the myoepithelial-like cells possessed both a fast/high and a slow/low binding site and could not activate bFGF, although it could potentiate the growth-stimulatory activity of aFGF. Treatment of the HS possessing two binding sites for bFGF with heparitinase 1 released oligosaccharides that were able to restore the activity of bFGF in HS-deficient fibroblasts.
Footnotes
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↵* This work was supported by the Cancer and Polio Research Fund, the Cancer Research Campaign, the Medical Research Council, the Mizutani Foundation for Glycoscience, and the North West Cancer Research Fund.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵¶ To whom correspondence should be addressed. Tel.: 44-151-794-4388; Fax: 44-151-794-4349; E-mail:dgfernig{at}liv.ac.uk.
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↵1 The abbreviations used are: FGF, fibroblast growth factor; aFGF (FGF-1), acidic FGF; bFGF (FGF-2), basic FGF; DMEM, Dulbecco’s modified Eagle’s medium; FGFR, fibroblast growth factor receptor; HGF/SF, hepatocyte growth factor/scatter factor; HS, heparan sulfate; Huma, human mammary; PBS, phosphate-buffered saline; PBST, PBS with Tween 20; Rama, rat mammary; SDM, step-down medium.
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↵2 H. Rahmoune, H.-L. Chen, J. T. Gallagher, P. S. Rudland, and D. G. Fernig, submitted for publication.
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- Received June 19, 1997.
- Revision received January 12, 1997.
- The American Society for Biochemistry and Molecular Biology, Inc.
