Hyaluronate-binding proteins in weakly and highly metastatic variants of rat rhabdomyosarcoma cells

Weakly (RMS8) and highly (RMS0) metastatic rat rhabdomyosarcoma cells were assayed for their interaction with hyaluronate. The cells in subconfluent cultures were incubated with 35S methionine, the cells were fractionated and the labelled proteins were separated by affinity chromatography on hyaluronate-Sepharose and by HPLC. The RMS8 cells expressed about twice the amount of labelled hyaluronate-binding proteins seen in the RMS0 cells. The molecular sizes of the main hyaluronate-binding proteins were similar in both cell types. Unlike the RMS0 cells, the RMS8 cells took up exogenous, radioactively labelled hyaluronate at 4 degrees C in a saturable and specific way with high affinity. Cells were also incubated with 3H glucosamine. The isolation of the glycosaminoglycans from these cultures by ion-exchange chromatography indicated that the RMS8 cells retained more endogenous 3H hyaluronate in their pericellular domain than did the RMS0 cells. The attachment of trypsinized cells could be inhibited with exogenous hyaluronate, indicating that the proteins with affinity for hyaluronate may act as hyaluronate-binding sites on these cells.