CHARACTERIZATION OF DEOXYGUANOSINE-RESISTANT HYPOXANTHINE GUANINE PHOSPHORIBOSYLTRANSFERASE- METASTATIC VARIANTS ALTERED IN SOYBEAN-AGGLUTININ-BINDING PROPERTIES AND CELL-SURFACE GLYCOPROTEINS

The isolation of deoxyguanosine-resistant 1OT1/2 mouse cell lines following stepwise selection in the presence of increasing concentrations of drug led to the identification of a highly metastatic line, as measured by the ability to form secondary tumors in syngenic mice after intravenous injection. This metastatic deoxyguanosine-resistant mutant was determined to be deficient in hypoxanthine-guanine phosphoribosyltransferase activity, accounting for the resistance to deoxyguanosine. Lectin-binding studies determined that the metastatic potential of high- and low-metastatic revertant clones of this deoxyguanosine-resistant mutant was negatively correlated to soybean agglutinin binding, but not to concanavalin A or wheat germ agglutinin binding. Examination of labelled cell-surface glycoproteins led to the identification of two glycoproteins, gp8O and gp48, which were present on the low-metastatic wild-type cell line but absent from the highly metastatic drug-resistant cells. Our studies suggest that these cell-surface glycoprotein alterations play a role in determining the malignant properties of the cells, and indicate that metastatic variants with the properties described in this report would be useful biological tools for investigations into the roles played by specific cell-surface structures in mechanisms of tumor progression.