Research article

HSulf-2, an extracellular endoglucosamine-6-sulfatase, selectively mobilizes heparin-bound growth factors and chemokines: effects on VEGF, FGF-1, and SDF-1

Kenji Uchimura¹ , Megumi Morimoto-Tomita¹ , Annette Bistrup² , Jessica Li¹ , Malcolm Lyon³ , John Gallagher³ , Zena Werb¹ and Steven D Rosen¹

¹  Department of Anatomy and the UCSF Comprehensive Cancer Center, University of California, San Francisco, CA 94143-0452, USA

²  Thios Pharmaceuticals, 5980 Horton Street, Emeryville, CA 94608, USA

³  Department of Medical Oncology, University of Manchester, Paterson Institute for Cancer Research, Manchester, UK

author email corresponding author email

BMC Biochemistry 2006, 7:2doi:10.1186/1471-2091-7-2

Published:	17 January 2006

Abstract

Background

Heparin/heparan sulfate (HS) proteoglycans are found in the extracellular matrix (ECM) and on the cell surface. A considerable body of evidence has established that heparin and heparan sulfate proteoglycans (HSPGs) interact with numerous protein ligands including fibroblast growth factors, vascular endothelial growth factor (VEGF), cytokines, and chemokines. These interactions are highly dependent upon the pattern of sulfation modifications within the glycosaminoglycan chains. We previously cloned a cDNA encoding a novel human endosulfatase, HSulf-2, which removes 6-O-sulfate groups on glucosamine from subregions of intact heparin. Here, we have employed both recombinant HSulf-2 and the native enzyme from conditioned medium of the MCF-7-breast carcinoma cell line. To determine whether HSulf-2 modulates the interactions between heparin-binding factors and heparin, we developed an ELISA, in which soluble factors were allowed to bind to immobilized heparin.

Results

Our results show that the binding of VEGF, FGF-1, and certain chemokines (SDF-1 and SLC) to immobilized heparin was abolished or greatly diminished by pre-treating the heparin with HSulf-2. Furthermore, HSulf-2 released these soluble proteins from their association with heparin. Native Sulf-2 from MCF-7 cells reproduced all of these activities.

Conclusion

Our results validate Sulf-2 as a new tool for deciphering the sulfation requirements in the interaction of protein ligands with heparin/HSPGs and expand the range of potential biological activities of this enzyme.