Characterization of a metastasis-deficient lectin-resistant human melanoma mutant.

A mutant (3S5), almost completely deficient in pulmonary metastatic ability in nude mice, was recently isolated from a human malignant melanoma cell line (MeWo). The WGA-resistance (WGAr) phenotype of 3S5 cells was accompanied by a collateral hypersensitivity to the lectin BSII (Bandeiraea simplicifolia), similar to that observed previously in class-I non-metastatic WGAr recessive genetic mutants isolated from a highly metastatic mouse tumor. The lectin-resistance/sensitivity profile of 3S5 cells was completely stable in tissue culture for 9 months when the cells were grown in the absence of WGA. Twenty independent clones of 3S5 were analyzed and all manifested a similar lectin-resistance pattern, and severe deficiency in pulmonary metastatic ability following i.v. or s.c. inoculation, when compared to the parent MeWo cells. Some heterogeneity in metastasis was noted, especially with respect to occasional extrapulmonary spread. The majority of the small number of metastases obtained after i.v. inoculation of 3S5 cells maintained the lectin-resistance profile and deficient metastatic potential characteristic of 3S5 cells upon re-inoculation into other nude mice. The results provide further evidence that cell-surface glycosylation changes can significantly after metastatic potential, including that of human tumors.