Characterization of a Deficiency in Fucose Metabolism in Lectin- resistant Variants of a Murine Tumor Showing Altered Tumorigenic and Metastatic Capacities in Vivo1

Four wheat germ agglutiniti (WGA)-resistant variants of the highly metastatic murine tumor MDAY-D2 were found to have altered tumorigenic and metastatic capacities in the syngeneic DBA/2 host. The parental tumor metastasized to lungs (100%) and completely replaced the liver (100%) in the syngeneic DBA/2 host. In contrast, the variants formed large, discrete tumor nodules in the liver (100%) and formed gross métastases in the lungs less frequently (15 to 50%). The WGA-resistant variants were examined for alterations in their cell surface carbohydrate content which may affect either tumorigenicity or the metastatic capacity of the tumor cells. Three of the four variants were deficient (<2% of the parental strain) in the utilization of L-[3H]fucose for glycosylation of glycoproteins and glycolipids, while incorporation of D-[3H]glucosamine and A/-[3H]acetyl-D-mannosamine was unaltered. The monosaccharides /v-acetyl-o-glucosamine, D-galactose, and D-mannose were present on the surface of the variants in altered amounts compared to the parental strain, as indicated by the binding of the lectins WGA, ricin II, lentil, and concanavalin A. However, none of the changes in lectin binding were common to all the WGA-resistant variants. Fucosyltransferase activities A and B in cell homogenates were assayed using desialofetuin and desialodegalactofetuin as acceptors and were found to be normal. The cellular level of the acid-soluble products of L-[3H]fucose, following a 5-hr pulse label, were the same in all the lines. Chromatographie separation of the soluble products of L-[3H]fucose indicated that the salvage-deficient variants produced L-fucose 1-phosphate (>95%) and the pa rental strain converted the fucose to guanosine diphosphate fucose (>90%). Fucosylation in the variants was accomplished by conversion of D-[14C]mannose into L-[14C]fucosylated acidprecipitable products. The results suggest a relationship between resistance to WGA, altered fucose metabolism, and altered metastatic phenotype; in contrast, none of these were found to be related to tumorigenicity in this particular tumor system.