title: Cancer-associated glycoforms of gelatinase B exhibit a decreased level of binding to galectin-3.
abstract: Gelatinase B (MMP-9) and galectin-3 are widely known to participate in tumor cell invasion and metastasis. Glycans derived from MMP-9 expressed in MCF-7 breast cancer and THP-1 myeloid leukemia cells were compared with those from MMP-9 expressed in natural neutrophils. The many O-linked glycans of neutrophil gelatinase B presented a cluster of mainly galactosylated core II structures, 46% of which were ligands for galectin-3; 11% contained two to three N-acetyllactosamine repeating units that are high-affinity ligands for the lectin. The glycan epitopes thus provide MMP-9 with both high-affinity and (presumably) high-avidity interactions with galectin-3. In contrast, the O-glycans released from MMP-9 expressed in MCF-7 and THP-1 cells were predominantly sialylated core I structures. Only 10% of MCF-7 and THP-1 gelatinase B O-glycans were ligands for galectin-3 and contained only a maximum single N-acetyllactosamine repeat. Consistent with the glycan analysis, surface plasmon resonance binding assays indicated that the cancer-associated glycoforms of MMP-9 bound galectin-3 with an affinity and avidity significantly reduced compared with those of the natural neutrophil MMP-9. Galectin-3 exists as a multimer that also binds laminin, providing a means of localizing neutrophil MMP-9 in the extracellular matrix (ECM). The analytical data presented here suggest that MMP-9 glycoforms secreted by tumor cells are unlikely to be tethered at the site of secretion, thus promoting more extensive cleavage of the ECM and providing a rationale for the contribution that gelatinase B makes to cancer cell metastasis.
authors.affiliation: Glycobiology Institute, Department of Biochemistry, University of Oxford, UK.
authors.forename: Simon A
authors.initials: SA
authors.lastname: Fry
authors.forename: Philippe E
authors.initials: PE
authors.lastname: Van den Steen
authors.forename: Louise
authors.initials: L
authors.lastname: Royle
authors.forename: Mark R
authors.initials: MR
authors.lastname: Wormald
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Leathem
authors.forename: Ghislain
authors.initials: G
authors.lastname: Opdenakker
authors.forename: James M
authors.initials: JM
authors.lastname: McDonnell
authors.forename: Raymond A
authors.initials: RA
authors.lastname: Dwek
authors.forename: Pauline M
authors.initials: PM
authors.lastname: Rudd
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D002236:Carbohydrate Conformation; D002417:Cattle; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000502:physiology*; D005109:Extracellular Matrix / Q000201:enzymology; D037502:Galectin 3 / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D007951:Leukemia, Myeloid / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009504:Neutrophils / Q000201:enzymology; D011134:Polysaccharides / Q000037:antagonists & inhibitors / Q000378:metabolism; D011485:Protein Binding; D020349:Surface Plasmon Resonance
chemical_list: D037502:Galectin 3; D007527:Isoenzymes; D061965:Matrix Metalloproteinase Inhibitors; D011134:Polysaccharides; D020780:Matrix Metalloproteinase 9