LECTIN BINDING GLYCOPROTEINS IN HUMAN-MELANOMA CELL-LINES WITH HIGH OR LOW TUMORIGENICITY

Lectin binding glycoproteins of 5 human malignant melanoma cell lines (HMMCL), differing in their ability to grow subcutaneously in athymic nude mice, were compared by electrophoresis of total cellular proteins and subsequent incubation of SDS-poly-acrylamide gel with 125I-labelled lectins. Despite the similarity between the protein profiles of the different HMMCL, Concanavalia ensiformis agglutinin (ConA), wheat-germ agglutinin (WGA) and peanut agglutinin (PNA) revealed differences in their glycoprotein expression, in contrast with Ulex europaeus agglutinin I (UEA I). A great diversity was observed in the electrophoretic mobilities and/or staining intensities of ConA and WGA binding glycoproteins of HMMCL. However, neither ConA-reactive glycoproteins nor WGA-reactive glycoproteins could be detected that were characteristic of HMMCL with high tumorigenicity (HT) or low tumorigenicity (LT). In contrast, the expression of two cell-surface PNA binding glycoproteins appeared to be related to the tumorigenic phenotype of HMMCL. One of them, with an apparent molecular weight of 190 kDa, was only detected in the LT cell lines. The other, with an apparent molecular weight of 60 kDa, was detected in all HMMCL but became strongly labelled after neuraminidase treatment only the HT cell lines. Thus, the expression of glycoproteins rich in terminal galactose resides may characterize human melanoma cells with different tumorigenic behavior.