HSulf-2, an extracellular endoglucosamine-6-sulfatase, selectively mobilizes heparin-bound growth factors and chemokines: effects on VEGF, FGF-1, and SDF-1
© Uchimura et al; licensee BioMed Central Ltd. 2006
Received: 23 July 2005
Accepted: 17 January 2006
Published: 17 January 2006
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.
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.
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.
Heparan sulfate proteoglycans (HSPGs) abundantly exist in the ECM and on the cell surface of most cells [1, 2]. They are composed of a restricted set of core proteins to which one or more glycosaminoglycan chains (GAG) are covalently attached. It is established that HSPGs are involved in a wide range of biological functions through their ability to bind to and modify the activities of a diverse repertoire of ligands including growth factors, morphogens, cytokines, chemokines, proteases, lipases, matrix proteins, and cell adhesion molecules [3–6]. Heparan sulfate (HS) chains and heparins (chemical analogues of these chains) consist of repeating disaccharide units of glucuronic/iduronic acid and glucosamine that are subject to a complex set of modifications involving deacetylation, epimerization, and sulfation. Four different sites of sulfation are found in heparin/HS: the N-, 3-O, and 6-O positions of glucosamine and the 2-O position of the iduronic acid residue. Heparin is highly-sulfated throughout the polymer chain whereas in HS these modifications are concentrated mainly in the S-domains, which consist of contiguous clusters of N-sulfated disaccharide units variably sulfated at the other positions [7–9]. Interspersed with the S domains are regions with low (transition zones) or zero sulfation; however, the transition zones contain a considerable fraction of the 6-O-sulfates in HS . The ligand binding activities of HSPG/heparin depend on patterns of sulfation along the chains .
HS chains are dynamically regulated in development and during tumor progression [11, 12]. Since these changes are central to the ligand binding properties of HSPGs, there is considerable interest in mechanisms that generate diversity of the chains. One such mechanism is through regulated expression of enzymes involved in the biosynthesis of heparan sulfate, for example, the sulfotransferases that modify HS chains . Another potential mechanism is through the action of extracellular endosulfatases that remove specific sulfation modifications from intact GAG chains. The first enzyme identified in this category was QSulf-1, which was discovered in quail embryo . Stimulated by this work, we cloned cDNAs encoding Sulf-1 and a new member of the family, Sulf-2, in mouse and human . We showed that both Sulf-1 and Sulf-2 are secreted into conditioned medium when they are expressed in Chinese hamster ovary (CHO) cells. Both possess endoglucosamine-6-sulfatase activity against intact heparin with an optimum at neutral pH. The enzymes liberate sulfate groups from the C-6 position of glucosamine residues on trisulfated -IdoA(2-OSO3)-GlcNSO3(6-OSO3)- disaccharide units of heparin. A similar activity for QSulf-1 has now been confirmed on HS chains [16, 17]. This trisulfated disaccharide structure occurs within the S-domains and is known to be a key element in many of the protein ligand interactions of heparin and HS (see below).
The transcripts corresponding to QSulf-1 and its rat orthologue (RFP-Sulf-1) demonstrate complex spatiotemporal regulation during embryonic development [14, 18] and QSulf-1 plays an essential role in Wnt-dependent differentiation of somites into muscle in quail . In addition, in vitro assays have demonstrated that QSulf-1 promotes both Wnt  and bone morphogenetic protein  signaling via its sulfatase activity. Less is known about the distribution and function of the Sulfs in adult tissues. However, some interesting correlations have been revealed in tumors. Lai and colleagues have reported downregulation of Sulf-1 transcripts in human ovarian cancer and a subset of hepatocellular carcinomas [19–21]. These workers and others have stressed the potential role of the enzyme in down-modulating certain signaling pathways involved in cell proliferation, since over-expression of Sulf-1 reduces signaling by FGF-2, HB-EGF, or HGF [19–22]. In striking contrast to the results in ovarian cancer, increased levels of SULF1 or SULF2 transcripts are observed in other human cancers including breast and pancreatic carcinomas [23–25]. Upregulation of Sulf-2 at both the transcript and protein levels has been established in two mouse models of mammary carcinoma . Furthermore, cultured human breast carcinoma cells release enzymatically active Sulf-2 into conditioned medium. The upregulation of Sulf-2 raises the possibility that it may be involved in promoting tumor progression [24, 25]. Indeed, we have shown that Sulf-2 has pro-angiogenic activity, a relevant function for contributing to tumorigenesis .
Even before the discovery of the Sulfs, the glucosamine-6-sulfate modification of HS was the focus of considerable interest. Thus, it has been shown that suppressing the expression of heparan sulfate 6-O-sulfotransferases via gene silencing strategies has pronounced developmental consequences in both Drosophila and Zebrafish development [26, 27]. Secondly, binding studies with heparin/HS fragments and chemically modified heparins point to an essential contribution of the glucosamine-6-sulfate modification to their interaction with various protein ligands, including FGF-1 , FGF-10 , PDGF , VEFG , hepatocyte growth factor , lipoprotein lipase , herpes simplex glycoprotein C , noggin , and L- and P-selectin . Here, we have taken advantage of recombinant Sulf-2 generated in 293 cells and of native Sulf-2 obtained from conditioned medium of a breast carcinoma cell line to explore the range of activities for this enzyme. We have established an ELISA to examine the effects of Sulf-2 from these two sources on the interaction of several growth factors and chemokines with immobilized heparin/HS. We found that pre-treatment of heparin with Sulf-2 significantly reduced its reactivity with certain ligands but not others ("pre-binding effect") and the enzyme also dissociated heparin-ligand complexes ("post-binding effect") raising the possibility that it may be involved in mobilizing HS-bound ligands in the ECM and basement membranes.
Effect of recombinant HSulf-2 on the binding of VEGF165, FGF-1 and FGF-2 to heparin
Estimated dissociation constants for the interaction of ligands with immobilized heparin-BSA and heparan sulfate (HS)-BSA
Kd value (nM)
Comparison of rHSulf-2 requirements for mobilization of heparin-bound ligands
Concentration required for 50% release of heparin-bound ligand
Effects of HSulf-2 on chemokine binding to heparin-BSA
Analysis of the activity of native HSulf-2 in MCF-7 conditioned medium
Effects of HSulf-2 on heparan sulfate interactions
The Sulfs are 6-O endosulfatases that act on the trisulfated disaccharide unit (-IdoA(2-OSO3)-GlcNSO3(6-OSO3)-) which is the most common unit in heparin but is largely confined to the S-domains of HS [15–17]. As the heterogeneous pattern of sulfation within S domains is known to dictate the binding specificity of many proteins for heparin/HS , the Sulfs could potentially regulate those interactions with a dependence on the presence of trisulfated disaccharides within the binding motif. Here, we have employed Sulf-2 as a tool to explore the binding requirements of several proteins, some of which had been previously characterized and others whose binding requirements were largely unknown. Previous work has shown that QSulf-1 treatment of soluble recombinant form of an HSPG (Glypican-1) reduced its ability to bind a Wnt ligand . Also, the interaction of Noggin with cell surface HSPGs was diminished by the overexpression of QSulf-1 in the cells . In the present study we have taken advantage of two sources of soluble HSulf-2: recombinant enzyme purified from stably transfected 293 cells and a natural form of the enzyme in CM of a human breast carcinoma cell line (MCF-7). It should be noted that we have not been able to obtain expression of high level of Sulf-1 in CM of transfected 293 cells, nor have we yet identified a soluble form of this enzyme from a native source.
We have previously shown that native Sulf-2 in MCF-7 CM has arylsulfatase activity . In the present study, we have used HPLC to demonstrate that MCF-7 CM possesses endosulfatase activity against intact heparin. This result has also been established by an alternative approach using mass spectroscopy . Employing an ELISA based on binding of protein ligands to heparin-BSA conjugate, we found that rHSulf-2 strongly modulated the binding of VEGF165, FGF-1, and SDF-1 to porcine intestinal heparin. In the case of FGF-1, the inhibitory effect of Sulf-2 was also demonstrated for heparan sulfate chains as well, using a HS-BSA conjugate. All of the effects obtained with the recombinant enzyme were observed for MCF-7 CM, and we confirmed that the activity in the CM was due to Sulf-2. The porcine intestinal heparin used in this study contained 70% trisulfated disaccharides, 18% disulfated disaccharides, 7% monosulfated disaccharides and 5% unsulfated disaccharides (data not shown). Based on our previous work  and the present study, we estimate that about 80% of the total trisulfated disaccharides in heparin-BSA was converted into disulfated disaccharides by Sulf-2. Thus, only about 22% of the overall sulfate moieties were removed by the enzyme treatment, arguing against the possibility that the reduced binding of selective protein ligands to treated heparin was due to a reduction in overall charge. As heparan sulfates have limited S-domains , Sulf-2 would be predicted to have an even smaller effect on the global sulfation of HSPGs. A further indication of the selectivity of Sulf-2 is that there is no relationship between the estimated Kd for binding of each ligand to heparin-BSA (Table 1) and the susceptibility of the interaction to the enzyme (Table 2).
The Sulf-2 effects on FGF-1 binding were anticipated based on a number of correlative studies [28, 39], which have implicated the trisulfated disaccharide motif as a binding element in HS chains. Our VEGF165 results are compatible with a previous study in which chemical 6-O-desulfation of heparin strongly weakened its ability to interact with VEGF165 . However, our findings provide the first direct evidence that 6-O-sulfation of heparin within the context of the trisulfated disaccharide motif is essential for the interaction. The majority of VEGF isoforms are able to bind to heparin/HS , and it is anticipated that our results will generalize to these other forms as well. With respect to SDF-1, it has long been known that this highly basic chemokine binds relatively strongly to heparin , but the fine specificity of the interaction has not previously been explored. SLC and IL-8 showed a partial sensitivity to the desulfation effects of Sulf-2 on heparin. This partial susceptibility implies that the 6-O-sulfation of the trisulfated disaccharide can contribute but is not absolutely required for a measurable binding interaction with heparin. One important avenue for future investigation is based on our observation that Sulf-2 strongly modulated the interactions of two chemokines (SDF-1 and SLC) with heparin. SDF-1 has been implicated in a diverse range of processes such as lymphocyte chemotaxis, stem cell homing and retention, tissue repair, angiogenesis, and organ-specific metastasis , whereas SLC is important in lymphoid organ homeostasis and inflammation . Thus, Sulf-2 though effects on the ECM-association of chemokines could have important roles in a number of normal and pathophysiologic processes. HSulf-1 with an apparently indistinguishable enzymatic activity  may exert similar effects on HSPG-bound growth factors and chemokines.
It is well established that one function of heparan sulfate proteoglycans in the ECM and basement membranes is to sequester protein ligands away from signal transduction receptors [44, 45]. A known mechanism to regulate the mobilization of such factors is through the action of heparanase, an endo-ß-D-glucuronidase that degrades heparan sulfate chains into relatively large fragments . This enzyme is present in a number of normal cell types (e.g., leukocytes, platelets, cytotrophoblasts) and is upregulated in several cancers. Expression of heparanase in a number of settings elicits angiogenesis, apparently through the release of HSPG-bound angiogenic factors [44, 47]. Our finding that Sulf-2 can reverse the association between heparin and angiogenic factors (e.g., VEGF) suggests the possibility of functional parallels between these two enzymes. Sulf-2 may mobilize VEGF or other angiogenic factors sequestered in the ECM and increase their bioavailability to endothelial cells that express the appropriate signaling receptors. The ability of rHSulf-2 to promote angiogenesis in the chick chorioallantoic membrane (CAM) assay is consistent with such a scenario . Thus, the observed upregulation of Sulf-2 in mammary carcinomas and its secretion from these cells could directly contribute to tumor angiogenesis and thus tumor growth. Sulf-2 derived from a cancer cell could also conceivably mobilize HSPG-bound growth factors that then act back on the cancer cell and thus trigger its own proliferation. The ability of QSulf-1 to promote Wnt signaling within the cells that express the enzyme provides a plausible paradigm for this type of autocrine pathway [14, 16]. It should be borne in mind that in the context of some other signaling pathways (e.g., FGF-2 and HGF), Sulf-2 is likely to exert a negative effect.
As demonstrated in the present study, Sulf-2 can modulate the interaction of a number of important bioactive proteins with heparin/HS. A major finding of our study is that Sulf-2 completely disrupts the interaction of certain factors with heparin. As expected, the factors for which Sulf-2 strongly blocks binding to heparin in the pre-binding format are the most susceptible to reversal effects in the post-binding assays (VEGF, FGF-1, and SDF-1). These observations indicate that, irrespective of the engagement of a protein ligand, Sulf-2 has access to the 6-O-sulfate group of the trisulfated disaccharide units of intact heparin. Recombinant Sulf-2 provides a valuable tool for investigating the specific sulfation requirements for heparin/HS interactions of interest. Furthermore, future application of the assays described herein will certainly expand the range of interactions that can be modulated by Sulf-2 and should enhance our understanding of the potential functional roles served by this enzyme in situ.
The following materials were obtained commercially from the source indicated. Heparin conjugated with bovine serum albumin (Heparin-BSA), BSA, heparinases (I, II and III) were from Sigma (St Louis, Mo., USA); heparan sulphate (porcine intestinal mucosal) from Organon (Oss, The Netherlands); DEAE-Sephacel from Sigma (Poole, UK); Phenyl-Sepharose CL-4B from Amersham Biosciences (Little Chalfont, UK); Protein A Sepharose beads from RepliGen (Needham, MA); recombinant human VEGF165, human CXCL12 (SDF-1), anti-human VEGF antibody (Ab), anti-human FGF-1 Ab, anti-human FGF-2 Ab, anti-human CXCL12 Ab, anti-CXCL8 Ab and anti-human CCL21 Ab from R&D Systems. All are polyclonal antibodies produced in goats. Recombinant human FGF-1 (acidic FGF), human FGF-2 (basic FGF), human CCL21 (SLC) and CXCL8 (IL-8) were from Leinco Inc. A biotinylated swine anti-goat IgG (H+L) antibody and a streptavidin conjugated with alkaline phosphatase were from Caltag. FLAG-tagged versions of HSulf-2 and the inactive mutant designated ΔCCHSulf-2 were produced in 293 cells and purified as previously described . Polyclonal rabbit anti-bodies against HSulf-2 (H2.1 and H2.3) were generated and prepared as previously described .
Heparan sulfate-BSA conjugate
Porcine intestinal mucosal heparan sulfate was coupled, via its reducing end, to BSA based on the procedure of Najjam et al. . Briefly, 2 mg of sodium cyanoborohydride was added to a mixture of 50 mg of HS and 2 mg of BSA in 2 ml of 0.2 M potassium phosphate buffer pH 8. The mixture was then incubated for 2 days at 37°C. After dilution to 10 ml with 0.15 M NaCl, 20 mM phosphate, pH7.4, it was applied to a 5 ml column of DEAE-Sephacel equilibrated in the same solution. After washing with 0.15 M NaCl solution, followed by buffered 0.4 M NaCl, to remove reagents and any non-conjugated BSA, the HS-containing material was then step-eluted with 0.5 ml aliquots of buffered 1.5 M NaCl. HS-containing fractions were identified by spotting aliquots onto Whatman filter paper and staining with Azure A. The pooled fractions were adjusted to 3 M in (NH4)2SO4, by addition of solid (NH4)2SO4, and then applied to a 2 ml column of Phenyl-Sepharose CL-4B equilibrated in 3 M (NH4)2SO4. After washing with 3 M (NH4)2SO4 to elute free HS, the bound HS-BSA conjugate was step-eluted with 0.5 ml aliquots of 0.15 M NaCl, 20 mM phosphate pH7.4. Fractions containing conjugated BSA were identified by their absorbance at 280 nm. The final product ran as a diffuse band, stainable with both Coomassie Blue and Azure A, close to the top of a 10% polyacrylamide SDS-PAGE gel and with a higher apparent MW than free BSA. The BSA content of the conjugate was assessed by absorbance at 280 nm. The HS content was determined by digestion with a mixture of heparinases I, II and III, and measurement of the resulting increase in absorbance at 232 nm. It was estimated that the average level of conjugation was 1–2 HS chains/BSA molecule.
Preparation of recombinant Sulf-2 and CM from MCF-7 cells
FLAG-tagged versions of active Sulf-2 (rHSulf-2) and inactive enzyme (rΔCCHSulf-2) were produced in stably transfected kidney 293 cells as described previously . The purities of rHSulf-2 and rΔCCHSulf-2 were estimated to be 90% and 80%, respectively based on Coomassie blue staining of SDS-PAGE gels. The amount of Sulf-2 protein was quantified by the BCA assay (Pierce). The amounts of rHSulf-2 and rΔCCHSulf-2 were equalized by an ELISA employing an anti-FLAG M2 antibody (Sigma) as the capture reagent and a mix of H2.1 and H2.3 antibodies for detection. The human breast carcinoma cell line, MCF-7, was grown in RPMI-1640 containing 10% fetal calf serum in a 150 mm-flask. Cells (80% confluent) were rinsed with PBS and OptiMEM (Invitrogen) and then incubated in 25 ml of OptiMEM at 37°C in 5% CO2 for 72 h. The CM was collected and then 100-fold concentrated on a Centricon-30. Subsequently, the concentrated CM was dialyzed into 50 mM HEPES, pH 8.0.
ELISAs for "pre-binding" and "post-binding" effects of HSulf-2
The experimental design for these ELISA is schematically shown in Fig 2A. To immobilize heparin, 100 ng/ml of heparin-BSA in phosphate-buffered saline (PBS) was added to the wells (100 μl/well) of a 96-well plate (Immulon 2HB, Dynex Labs). The plate was placed at 4°C overnight. The wells were washed 3 times with PBS containing 0.1% Tween-20 (PBS-T) and then blocked with 3% BSA (Sigma) in PBS-T at 25°C for 2 h. To determine the effects of Sulf-2 on the ligand-binding activities of heparin ("pre-binding" effects), the wells were washed as above and then incubated with 100 μl of a reaction mixture containing 5 μmol of HEPES, pH 7.6, 1 μmol of MgCl2 and enzyme (rHSulf-2, rΔCCHSulf-2 or MCF-7 CM) at 37°C for 4 h. In the cases where we carried out dose response studies with protein ligands, incubation with the enzyme was overnight. The wells were washed 3 times with PBS-T and then incubated with 25 μl of heparin-binding factors (25 nM VEGF, 12.5 nM FGF-2, 12.5 nM FGF-1, and 100 nM CXCL12) in PBS at 25°C for 30 min. The wells were washed 3 times and incubated with 1 μg/ml of each primary antibody in 0.1% BSA/PBS (100 μl/well) at 25°C for 1 h. The wells were washed as above and incubated with 1.2 μg/ml of a biotinylated secondary antibody in 0.1% BSA/PBS (100 μl/well) at 25°C for 30 min. Then, the wells were washed and incubated with 2 μg/ml of an alkali phosphatase-conjugated streptavidin in 0.1% BSA/PBS (100 μl/well) at 25°C for 30 min. Finally, the wells were incubated with PNPP (Pierce) in cacodylate buffer, pH 9.2 (100 μl/well) at 25°C for 5 minutes, and then OD 405 nm was read on a microplate reader. For the analysis of "post-binding" effects (i.e. dissociation of heparin-ligand complexes), 25 μl of each heparin-binding factor was added to plates coated with heparin-BSA after blocking with 3% BSA. The plates were incubated at 25°C for 30 min to form the heparin-factor complex. The wells were washed as above and then incubated with 100 μl of the enzyme reaction mixture as described above. After washing the wells, the amount of bound factor was determined with the antibody detection procedures described above. For the "pre-binding" study of FGF-1 binding to heparan sulfate-BSA, 1 mg/ml of heparan sulfate-BSA was coated on a 96-well plate (100 μl/well). Other procedures are the same as described above for the heparin-BSA assay. Representative data are shown from one of 2–3 independent experiments in all cases.
A purified FLAG-tagged HSulf-2 (10 ng) or concentrated MCF-7 CM (10 μl) was separated by electrophoresis on a reducing SDS-7.5% polyacrylamide gel (Bio-Rad), and blotted onto ProBlott™ membrane (Applied Biosystems, Foster City, CA). The membrane was blocked with 5% skim milk/PBS-T for 1 h and then incubated overnight with an anti-HSulf-2 peptide antibody (see below) at a concentration of 1 μg/ml in 5% skim milk/PBS-T at 4°C. The membrane was washed and incubated with horseradish peroxidase-conjugated goat anti-rabbit IgG (Jackson ImmunoResearch Laboratories Inc, West Grove, PA) (0.2 μg/ml) for 1 h. Bound antibodies were visualized with SuperSignal West Pico Chemiluminescent reagent (Pierce).
Immunoprecipitation of HSulf-2 in MCF-7 CM
A mixture of anti-HSulf-2 peptide antibodies, H2.1 (5 μg) and H2.3 (5 μg) , or a rabbit IgG (10 μg), 10 μl of a 50% (v/v) suspension of protein A-Sepharose (IPA-400HC, RepliGen) and 100 μl of 100-fold concentrated CM of MCF-7 cells were mixed in a total volume of 1 ml with 150 mM NaCl and 50 mM Tris-HCl, pH 7.4. The mixture was rocked overnight at 4°C. The immunocomplexes bound to the protein A beads were removed by centrifugation. The "pre-binding" and "post-binding" ELISA activities remaining in the supernatant were assayed as described above.
Endoglucosamine-6-sulfatase activity of rHSulf-2 and MCF-7 CM was determined by previously established procedures . The standard reaction mixture contained 5 μmol of HEPES, pH7.8, 1 μmol of MgCl2, 5 μg of porcine intestinal heparin (Sigma), and a purified FLAG-tagged HSulf-2 or a 100-fold concentrated MCF-7 CM in a total volume of 100 μl. The mixture was incubated at 37°C. The reaction was stopped by heating at 100°C for 2 min. The heparin was digested into disaccharides by a mix of heparinase I, heparinase II and heparinase III . The disaccharides were then analyzed by HPLC on a Partisil-10 SAX column (Whatman, Fairfield, NJ) . The enzymatic activity was defined by calculating the increase in the moles of unsaturated disulfated disaccharide, IdoA(2S)-Glc(NS), in the digested heparin.
List of abbreviations used
Chinese hamster ovary, CM, conditioned medium
fibroblast growth factor
heparan sulfate proteoglycan
recombinant flag-tagged human Sulf-2
recombinant inactive mutant of human Sulf-2
serial analysis of gene expression
stromal cell-derived factor
vascular endothelial growth factor.
This work was supported by National Institutes of Health (NIH) Grants R01 GM57411 and R37 GM23547 (SDR), P01 AI53196 (ZW), a Mizutani Foundation Grant for Glycoscience (SDR), a UCSF Comprehensive Cancer Center Intramural Award from the Alexander and Margaret Stewart Trust (SDR). KU and MM-T are Research Fellows of the Japan Society for the Promotion of Science.
- Bernfield M, Gotte M, Park PW, Reizes O, Fitzgerald ML, Lincecum J, Zako M: Functions of cell surface heparan sulfate proteoglycans. Annu Rev Biochem. 1999, 68: 729-777. 10.1146/annurev.biochem.68.1.729.PubMedView Article
- Esko JD, Lindahl U: Molecular diversity of heparan sulfate. J Clin Invest. 2001, 108: 169-173. 10.1172/JCI200113530.PubMed CentralPubMedView Article
- Ornitz DM: FGFs, heparan sulfate and FGFRs: complex interactions essential for development. Bioessays. 2000, 22: 108-112. 10.1002/(SICI)1521-1878(200002)22:2<108::AID-BIES2>3.0.CO;2-M.PubMedView Article
- Nakato H, Kimata K: Heparan sulfate fine structure and specificity of proteoglycan functions. Biochim Biophys Acta. 2002, 1573: 312-318.PubMedView Article
- Esko JD, Selleck SB: Order out of chaos: assembly of ligand binding sites in heparan sulfate. Annu Rev Biochem. 2002, 71: 435-471. 10.1146/annurev.biochem.71.110601.135458.PubMedView Article
- Witt DP, Lander AD: Differential binding of chemokines to glycosaminoglycan subpopulations. Curr Biol. 1994, 4: 394-400. 10.1016/S0960-9822(00)00088-9.PubMedView Article
- Gallagher JT: Heparan sulfate: growth control with a restricted sequence menu. J Clin Invest. 2001, 108: 357-361. 10.1172/JCI200113713.PubMed CentralPubMedView Article
- Lindahl U, Kusche-Gullberg M, Kjellen L: Regulated diversity of heparan sulfate. J Biol Chem. 1998, 273: 24979-24982. 10.1074/jbc.273.39.24979.PubMedView Article
- Powell AK, Yates EA, Fernig DG, Turnbull JE: Interactions of heparin/heparan sulfate with proteins: appraisal of structural factors and experimental approaches. Glycobiology. 2004, 14: 17R-30R. 10.1093/glycob/cwh051.PubMedView Article
- Murphy KJ, Merry CL, Lyon M, Thompson JE, Roberts IS, Gallagher JT: A new model for the domain structure of heparan sulfate based on the novel specificity of K5 lyase. J Biol Chem. 2004, 279: 27239-27245. 10.1074/jbc.M401774200.PubMedView Article
- Jayson GC, Vives C, Paraskeva C, Schofield K, Coutts J, Fleetwood A, Gallagher JT: Coordinated modulation of the fibroblast growth factor dual receptor mechanism during transformation from human colon adenoma to carcinoma. Int J Cancer. 1999, 82: 298-304. 10.1002/(SICI)1097-0215(19990719)82:2<298::AID-IJC23>3.0.CO;2-9.PubMedView Article
- Brickman YG, Ford MD, Gallagher JT, Nurcombe V, Bartlett PF, Turnbull JE: Structural modification of fibroblast growth factor-binding heparan sulfate at a determinative stage of neural development. J Biol Chem. 1998, 273: 4350-4359. 10.1074/jbc.273.8.4350.PubMedView Article
- Habuchi O: Diversity and functions of glycosaminoglycan sulfotransferases. Biochim Biophys Acta. 2000, 1474: 115-127.PubMedView Article
- Dhoot GK, Gustafsson MK, Ai X, Sun W, Standiford DM, Emerson CPJ: Regulation of Wnt signaling and embryo patterning by an extracellular sulfatase. Science. 2001, 293: 1663-1666. 10.1126/science.293.5535.1663.PubMedView Article
- Morimoto-Tomita M, Uchimura K, Werb Z, Hemmerich S, Rosen SD: Cloning and characterization of two extracellular heparin-degrading endosulfatases in mice and humans. J Biol Chem. 2002, 277: 49175-49185. 10.1074/jbc.M205131200.PubMed CentralPubMedView Article
- Ai X, Do AT, Lozynska O, Kusche-Gullberg M, Lindahl U, Emerson CPJ: QSulf1 remodels the 6-O sulfation states of cell surface heparan sulfate proteoglycans to promote Wnt signaling. J Cell Biol. 2003, 162: 341-351. 10.1083/jcb.200212083.PubMed CentralPubMedView Article
- Viviano BL, Paine-Saunders S, Gasiunas N, Gallagher J, Saunders S: Domain-specific modification of heparan sulfate by Qsulf1 modulates the binding of the bone morphogenetic protein antagonist Noggin. J Biol Chem. 2004, 279: 5604-5611. 10.1074/jbc.M310691200.PubMedView Article
- Ohto T, Uchida H, Yamazaki H, Keino-Masu K, Matsui A, Masu M: Identification of a novel nonlysosomal sulphatase expressed in the floor plate, choroid plexus and cartilage. Genes Cells. 2002, 7: 173-185. 10.1046/j.1356-9597.2001.00502.x.PubMedView Article
- Lai J, Chien J, Staub J, Avula R, Greene EL, Matthews TA, Smith DI, Kaufmann SH, Roberts LR, Shridhar V: Loss of HSulf-1 up-regulates heparin-binding growth factor signaling in cancer. J Biol Chem. 2003, 278: 23107-23117. 10.1074/jbc.M302203200.PubMedView Article
- Lai JP, Chien JR, Moser DR, Staub JK, Aderca I, Montoya DP, Matthews TA, Nagorney DM, Cunningham JM, Smith DI, Greene EL, Shridhar V, Roberts LR: hSulf1 Sulfatase promotes apoptosis of hepatocellular cancer cells by decreasing heparin-binding growth factor signaling. Gastroenterology. 2004, 126: 231-248. 10.1053/j.gastro.2003.09.043.PubMedView Article
- Lai JP, Chien J, Strome SE, Staub J, Montoya DP, Greene EL, Smith DI, Roberts LR, Shridhar V: HSulf-1 modulates HGF-mediated tumor cell invasion and signaling in head and neck squamous carcinoma. Oncogene. 2004, 23: 1439-1447. 10.1038/sj.onc.1207258.PubMedView Article
- Wang S, Ai X, Freeman SD, Pownall ME, Lu Q, Kessler DS, Emerson CPJ: QSulf1, a heparan sulfate 6-O-endosulfatase, inhibits fibroblast growth factor signaling in mesoderm induction and angiogenesis. Proc Natl Acad Sci U S A. 2004, 101: 4833-4838. 10.1073/pnas.0401028101.PubMed CentralPubMedView Article
- Li J, Kleeff J, Abiatari I, Kayed H, Giese N, Felix K, Giese T, Buchler MW, Friess H: Enhanced levels of Hsulf-1 interfere with heparin-binding growth factor signaling in pancreatic cancer. Mol Cancer. 2005, 4: 14-10.1186/1476-4598-4-14.PubMed CentralPubMedView Article
- Morimoto-Tomita M, Uchimura K, Rosen SD: Novel Extracellular Sulfatase: Potential Roles in Cancer. Trends in Glycoscience and Glycotechnology. 2003, 15: 159-164.View Article
- Morimoto-Tomita M, Uchimura K, Bistrup A, Lum DH, Egeblad M, Boudreau N, Werb Z, Rosen SD: Sulf-2, a proangiogenic heparan sulfate endosulfatase, is upregulated in breast cancer. Neoplasia. 2005, 7: 1001-1010. 10.1593/neo.05496.PubMed CentralPubMedView Article
- Kamimura K, Fujise M, Villa F, Izumi S, Habuchi H, Kimata K, Nakato H: Drosophila heparan sulfate 6-O-sulfotransferase (dHS6ST) gene. Structure, expression, and function in the formation of the tracheal system. J Biol Chem. 2001, 276: 17014-17021. 10.1074/jbc.M011354200.PubMedView Article
- Bink RJ, Habuchi H, Lele Z, Dolk E, Joore J, Rauch GJ, Geisler R, Wilson SW, den Hertog J, Kimata K, Zivkovic D: Heparan sulfate 6-o-sulfotransferase is essential for muscle development in zebrafish. J Biol Chem. 2003, 278: 31118-31127. 10.1074/jbc.M213124200.PubMedView Article
- Kreuger J, Salmivirta M, Sturiale L, Gimenez-Gallego G, Lindahl U: Sequence analysis of heparan sulfate epitopes with graded affinities for fibroblast growth factors 1 and 2. J Biol Chem. 2001, 276: 30744-30752. 10.1074/jbc.M102628200.PubMedView Article
- Ashikari-Hada S, Habuchi H, Kariya Y, Itoh N, Reddi AH, Kimata K: Characterization of growth factor-binding structures in heparin/heparan sulfate using an octasaccharide library. J Biol Chem. 2004, 279: 12346-12354. 10.1074/jbc.M313523200.PubMedView Article
- Feyzi E, Lustig F, Fager G, Spillmann D, Lindahl U, Salmivirta M: Characterization of heparin and heparan sulfate domains binding to the long splice variant of platelet-derived growth factor A chain. J Biol Chem. 1997, 272: 5518-5524. 10.1074/jbc.272.40.24850.PubMedView Article
- Ono K, Hattori H, Takeshita S, Kurita A, Ishihara M: Structural features in heparin that interact with VEGF165 and modulate its biological activity. Glycobiology. 1999, 9: 705-711. 10.1093/glycob/9.7.705.PubMedView Article
- Lyon M, Deakin JA, Mizuno K, Nakamura T, Gallagher JT: Interaction of hepatocyte growth factor with heparan sulfate. Elucidation of the major heparan sulfate structural determinants. J Biol Chem. 1994, 269: 11216-11223.PubMed
- Parthasarathy N, Goldberg IJ, Sivaram P, Mulloy B, Flory DM, Wagner WD: Oligosaccharide sequences of endothelial cell surface heparan sulfate proteoglycan with affinity for lipoprotein lipase. J Biol Chem. 1994, 269: 22391-22396.PubMed
- Feyzi E, Trybala E, Bergstrom T, Lindahl U, Spillmann D: Structural requirement of heparan sulfate for interaction with herpes simplex virus type 1 virions and isolated glycoprotein C. J Biol Chem. 1997, 272: 24850-24857. 10.1074/jbc.272.40.24850.PubMedView Article
- Wang L, Brown JR, Varki A, Esko JD: Heparin's anti-inflammatory effects require glucosamine 6-O-sulfation and are mediated by blockade of L- and P-selectins. J Clin Invest. 2002, 110: 127-136. 10.1172/JCI200214996.PubMed CentralPubMedView Article
- Ishihara M: Structural requirements in heparin for binding and activation of FGF-1 and FGF-4 are different from that for FGF-2. Glycobiology. 1994, 4: 817-824.PubMedView Article
- Turnbull JE, Fernig DG, Ke Y, Wilkinson MC, Gallagher JT: Identification of the basic fibroblast growth factor binding sequence in fibroblast heparan sulfate. J Biol Chem. 1992, 267: 10337-10341.PubMed
- Saad OM, Ebel H, Uchimura K, Rosen SD, Bertozzi CR, Leary JA: Compositional profiling of heparin/heparan sulfate using mass spectrometry: assay for specificity of a novel extracellular human endosulfatase. Glycobiology. 2005, 15: 818-826. 10.1093/glycob/cwi064.PubMedView Article
- Pye DA, Vives RR, Turnbull JE, Hyde P, Gallagher JT: Heparan sulfate oligosaccharides require 6-O-sulfation for promotion of basic fibroblast growth factor mitogenic activity. J Biol Chem. 1998, 273: 22936-22942. 10.1074/jbc.273.36.22936.PubMedView Article
- Houck KA, Leung DW, Rowland AM, Winer J, Ferrara N: Dual regulation of vascular endothelial growth factor bioavailability by genetic and proteolytic mechanisms. J Biol Chem. 1992, 267: 26031-26037.PubMed
- Bleul CC, Fuhlbrigge RC, Casasnovas JM, Aiuti A, Springer TA: A highly efficacious lymphocyte chemoattractant, stromal cell-derived factor 1 (SDF-1). J Exp Med. 1996, 184: 1101-1109. 10.1084/jem.184.3.1101.PubMedView Article
- Kucia M, Jankowski K, Reca R, Wysoczynski M, Bandura L, Allendorf DJ, Zhang J, Ratajczak J, Ratajczak MZ: CXCR4-SDF-1 signalling, locomotion, chemotaxis and adhesion. J Mol Histol. 2004, 35: 233-245. 10.1023/B:HIJO.0000032355.66152.b8.PubMedView Article
- Christopherson KW, Hood AF, Travers JB, Ramsey H, Hromas RA: Endothelial induction of the T-cell chemokine CCL21 in T-cell autoimmune diseases. Blood. 2003, 101: 801-806. 10.1182/blood-2002-05-1586.PubMedView Article
- Elkin M, Ilan N, Ishai-Michaeli R, Friedmann Y, Papo O, Pecker I, Vlodavsky I: Heparanase as mediator of angiogenesis: mode of action. Faseb J. 2001, 15: 1661-1663.PubMed
- Bergers G, Brekken R, McMahon G, Vu TH, Itoh T, Tamaki K, Tanzawa K, Thorpe P, Itohara S, Werb Z, Hanahan D: Matrix metalloproteinase-9 triggers the angiogenic switch during carcinogenesis. Nat Cell Biol. 2000, 2: 737-744. 10.1038/35036374.PubMed CentralPubMedView Article
- Vlodavsky I, Friedmann Y: Molecular properties and involvement of heparanase in cancer metastasis and angiogenesis. J Clin Invest. 2001, 108: 341-347. 10.1172/JCI200113662.PubMed CentralPubMedView Article
- Goldshmidt O, Zcharia E, Abramovitch R, Metzger S, Aingorn H, Friedmann Y, Schirrmacher V, Mitrani E, Vlodavsky I: Cell surface expression and secretion of heparanase markedly promote tumor angiogenesis and metastasis. Proc Natl Acad Sci U S A. 2002, 99: 10031-10036. 10.1073/pnas.152070599.PubMed CentralPubMedView Article
- Najjam S, Gibbs RV, Gordon MY, Rider CC: Characterization of human recombinant interleukin 2 binding to heparin and heparan sulfate using an ELISA approach. Cytokine. 1997, 9: 1013-1022. 10.1006/cyto.1997.0246.PubMedView Article
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.