Lectin-binding characteristics of related high- and low-metastatic rat mammary adenocarcinoma cell lines

Abstract

Lectin-binding characteristics of a previously described highly metastatic variant (clone 4), derived in vivo from a poorly metastatic rat mammary adenocarcinoma (DMBA-8), have been investigated. of the lectins studied clone 4 cells, unlike the parent cells, bound Ulex europaeus agglutinin (UEA-1; specificity alpha-L-fucose) and peanut agglutinin (PNA; specificity D-galactose). These differences may be related to the greatly enhanced ability of clone 4 cells to form lung foci after intravenous injection. After neuraminidase treatment the differential binding of PNA, as shown by flow cytofluorography, was abrogated whereas that of UEA was unchanged. After separation by SDS-PAGE, four proteins in total cell extracts of clone 4 cells bound 125I-UEA applied to the gels. These had subunit molecular weights greater than 100,000 daltons and were also found in cellular extracts of another highly metastatic rat mammary adenocarcinoma (MAT 13762-B), but were missing from DMBA-8 cell extracts. In clone 4 and MAT 13762-B cells exogenous 3H-fucose was mainly incorporated into four fucoproteins of similar molecular weights to those which bound 125I-UEA. DMBA-8 cells, which incorporated slightly less exogenous fucose, showed a different pattern of fucoprotein labelling, which would seem to explain why DMBA-8 cells failed to bind UEA. Differences in cell surface protein iodination patterns were also noted between DMBA-8 and clone 4 cells.