title: Fibroblast growth factor-2 can mediate cell attachment by linking receptors and heparan sulfate proteoglycans on neighboring cells.
abstract: The myeloid 32D cell line, which grows in suspension and does not express FGF receptors or heparan sulfate proteoglycans, was transfected with the cDNA encoding FGF receptor-1 (32D-flg cells). When co-cultured with glutaraldehyde-fixed Chinese hamster ovary (CHO) cells, the 32D-flg cells remained in suspension in the absence of FGF-2 but attached to the CHO monolayer in the presence of 10 ng/ml FGF-2. In contrast, 32D cells transfected with the vector alone did not attach to the CHO monolayer in the presence of FGF-2. FGF-2-dependent attachment of 32D-flg cells was prevented by inclusion of 10 micrograms/ml heparin in the incubation medium and was diminished when CHO mutants in glycosaminoglycan synthesis or wild-type CHO cells treated with heparinase were used, indicating that the attachment occurred through FGF-2 interactions with heparan sulfates on the CHO cells. Attachment of 32D-flg cells to wild-type CHO cells was half-maximal at 0.4 ng/ml FGF-2 and was also observed with FGF-1 but not FGF-4. 32D-flg cells also attached to living CHO cells in a FGF-2-dependent manner, but attachment was transient at 37 degrees C. Induction of new proteins was not required for FGF-2-dependent attachment, since attachment occurred when the co-cultures were incubated at 4 degrees C and when the 32D-flg cells were preincubated with cycloheximide. FGF-2-dependent attachment of 32D-flg cells was also observed with Balb/C 3T3, NIH 3T3, and bovine capillary endothelial cells. We conclude that attachment is due to FGF-2 binding simultaneously to receptors on the 32D-flg cells and heparan sulfates on the CHO monolayers; thus, the FGF-2 acts as a bridge between receptor-expressing cells and heparan sulfate-bearing cells. In addition, induction of DNA synthesis in 32D-flg cells in response to FGF-2 was potentiated by the CHO-associated heparan sulfates to the same extent as by soluble heparin, indicating that this interaction has functional significance.
authors.affiliation: Department of Cell Biology, New York University Medical Center, New York 10016, USA.
authors.forename: C
authors.initials: C
authors.lastname: Richard
authors.forename: J P
authors.initials: JP
authors.lastname: Liuzzo
authors.forename: D
authors.initials: D
authors.lastname: Moscatelli
mesh_terms: D016475:3T3 Cells; D000818:Animals; D016466:CHO Cells; D002196:Capillaries; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D002450:Cell Communication; D002455:Cell Division; D002478:Cells, Cultured; D002810:Chondroitinases and Chondroitin Lyases / Q000494:pharmacology; D006224:Cricetinae; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism* / Q000494:pharmacology*; D006025:Glycosaminoglycans / Q000494:pharmacology; D006493:Heparin / Q000031:analogs & derivatives* / Q000378:metabolism; D019763:Heparin Lyase; D006497:Heparan Sulfate / Q000096:biosynthesis; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D011133:Polysaccharide-Lyases / Q000494:pharmacology; D011509:Proteoglycans / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism*; D051497:Receptor, Fibroblast Growth Factor, Type 2; D017468:Receptors, Fibroblast Growth Factor / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins / Q000187:drug effects / Q000378:metabolism; D014162:Transfection
chemical_list: D002810:Chondroitinases and Chondroitin Lyases; D016222:Fibroblast Growth Factor 2; D006025:Glycosaminoglycans; D006493:Heparin; D019763:Heparin Lyase; D006497:Heparan Sulfate; D011133:Polysaccharide-Lyases; D011509:Proteoglycans; D020794:Receptor Protein-Tyrosine Kinases; D051497:Receptor, Fibroblast Growth Factor, Type 2; D017468:Receptors, Fibroblast Growth Factor; D011994:Recombinant Proteins; C036090:heparin proteoglycan; C496354:Fgfr2 protein, mouse