Heparin and heparan sulfate binding sites on B-16 melanoma cells.
We have reported previously that the production of a tumor cell factor that stimulates synthesis of fibroblast collagenase is influenced by a fibroblast-deposited matrix component, possibly heparan sulfate-proteoglycan. In this study, binding sites for heparin and heparan sulfate on mouse B-16 melanoma cells have been demonstrated. Binding of 3H-heparin and 35S-heparan sulfate has been shown to occur to whole cells, isolated membranes, and to a component(s) of detergent extracts of the membranes. Scatchard analysis of binding of 3H-heparin yielded a Kd of 2-5 x 10(-8) M and a Bmax of 0.5 x 10(7) heparin molecules bound per cell. Binding of 35S-heparan sulfate was of at least an order of magnitude lower affinity than heparin, but the Bmax was similar to that for heparin. Competition studies showed that 35S-heparan sulfate binding was inhibited totally by heparin and heparan sulfate and partially by dermatan sulfate, but no inhibition was obtained with hyaluronate or chondroitin sulfate. Binding of 3H-heparin was inhibited totally by heparin but to different extents by preparations of heparan sulfate from different tissue sources. The heparin/heparan sulfate binding activity is a protein(s) because it is destroyed by treatment with trypsin. Binding of 3H-heparin to transblots of the detergent extract of the B-16 cell membranes indicated that at least part of the binding activity is a 14,000-dalton protein.
Biswas
C
C
Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, Massachusetts.
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002809:Chondroitin Sulfates / Q000378:metabolism; D003871:Dermatan Sulfate / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology*; D006497:Heparan Sulfate / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism; D007700:Kinetics; D008545:Melanoma / Q000378:metabolism*; D008566:Membranes / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism
D002809:Chondroitin Sulfates; D003871:Dermatan Sulfate; D006025:Glycosaminoglycans; D006493:Heparin; D006497:Heparan Sulfate; D006820:Hyaluronic Acid; D011956:Receptors, Cell Surface; C037680:heparin receptor