Differential expression of cell surface sialoglycoconjugates on wild-type and cultured Ehrlich tumor cells as revealed by quantitative lectin-gold ultrastructural cytochemistry.
Three variants of the classical Ehrlich ascites tumor (EAT) cell have been studied by quantitative, sialic acid-specific, lectin-gold ultrastructural cytochemistry. Electron microscopic examination revealed pronounced differences in the surface morphology of the three cell variants. The wild-type Ehrlich cells (EAT-wt), grown in the peritoneal cavity of mice, exhibited a smooth surface profile. A variant form selected for growth as monolayer on basement membrane (EAT-c) showed a complex surface profile with numerous microvilli. The third variant (EAT-c/m), the cultured cells reinoculated into mice and passaged 20-25 times as ascites, presented a smooth surface profile similar to the EAT-wt cells. Quantitative single as well as double lectin-gold labeling revealed significant differences in the nature of cell surface sialoglycoproteins. The most significant finding was the presence of cell surface Neu5Ac alpha 2-6Gal residues as detected with the Sambucus nigra lectin on EAT-c and EAT-c/m cells, whereas EAT-wt cells contained little or none of such carbohydrate sequences. On the contrary, labeling by Maackia amurensis lectin, which recognizes the Neu5Ac alpha 2-3Gal beta 1-4GlcNAc sequence, was intense on all three Ehrlich cell variants; it was 20-60 times greater than alpha-2,6-linked sialic acid-containing glycoconjugates. Specific cell surface lectin binding combined with morphologic study appears to have identified a small subpopulation of cells within the ascites tumor that are capable of attaching to and growing on a basement membrane.
Department of Pathology, University of Zurich, Switzerland.
J
J
Roth
W P
WP
Li
R N
RN
Knibbs
D K
DK
MacCallum
Z
Z
Song
I J
IJ
Goldstein
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism* / Q000473:pathology; D002462:Cell Membrane / Q000378:metabolism; D006001:Glycoconjugates / Q000378:metabolism*; D006046:Gold; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D037102:Lectins; D051379:Mice; D008854:Microscopy, Electron / Q000379:methods; D019158:N-Acetylneuraminic Acid; D012794:Sialic Acids / Q000378:metabolism*; D013499:Surface Properties; D014407:Tumor Cells, Cultured
D006001:Glycoconjugates; D037102:Lectins; D012794:Sialic Acids; D006046:Gold; D019158:N-Acetylneuraminic Acid