Adrenal Carcinoma Tumor Progression and Penultimate Cell Surface Oligosaccharides1

Many previous studies have implicated cell surface saccharides, and sialylglycoconjugates in particular, as important mediators of tumor cell metastasis. In this report, we have used three different specific sialidases and a highly sensitive high-performance liquid Chromatographie sialic acid assay to probe the cell surfaces of several murine adrenal carcinoma variants. In contrast to several earlier studies on other metastatic variants, we find no significant differences in the overall levels of cell surface or total cellular sialic acid among three Yl murine adrenal carcinoma variants with widely different metastatic phenotypes. However, using highly purified, linkage-specific sialyltransferases, in conjunction with K cholerae sialidase, to probe the cell surface saccharide topography of specific penultimate Oligosaccharides, we do find striking differences in oligosaccharide structures underlying the sialic acid moieties. Two tumorigenic and metastatic variants (F2 and F4) contain about 6-fold more penultimate Gal01—»4GlcNAc sialylation sites than a related tumorigenic but nonmetastatic variant (HSR) when CMP-|3H)-Ar-acetylneuraminic acid and the Gal/31—»4GlcNAc «2,6sialyltransferase are used to probe the adrenal carcinoma cell surfaces. The metastatic variants also are found to contain 4to 4.5-fold more Gal|81—>3GalNAcsialylation sites than the nonmetastatic variant when the Gal/Jl—»3GalNAc »2,3sialyl transferase is used as a cell surface probe. Earlier work, which used the same sialyltransferase probes on sialidase-treated murine melanoma variants (A. Passaniti and G. W. Hart, J. Biol. Chem., 263: 7591-7603, 1988), also showed similar quantitative differences in penultimate struc tures between metastatic variants. However, in contrast to the adrenal carcinoma cells, the highly metastatic melanoma cells have severalfold lower levels of sialylatable penultimate Gal/31—>4GlcNAcand Gal£l—» 3GalNAc saccharides compared to their nonmetastatic counterparts. Thus, while the precise structural alterations or surface accessibilities of penultimate saccharides appear to be cell type dependent, these results suggest that pronounced changes in penultimate cell surface sialo-oligosaccharide moieties occur during progression to a malignant phenotype in two widely different tumor systems. These types of alterations in the underlying penultimate oligosaccharide structures of cell surface sialoglycoconjugates may be a common feature of highly metastatic cells arising from very different tumor cell types.