Comparison of sialyl-Lewis a-carrying CD43 and MUC1 mucins secreted from a colon carcinoma cell line for E-selectin binding and inhibition of leukocyte adhesion.
The colon carcinoma cell line COLO 205 has earlier been shown to express and secrete two mucin-type glycoproteins, the leukocyte-associated sialoglycoprotein CD43 or leukosialin (named L-CanAg) and the MUC1 mucin (named H-CanAg). Both glycoproteins carry sialyl-Lewis a epitopes and could bind transfected COS cells expressing E-selectin in a Ca(2+)- and E-selectin-dependent way. Using the monoclonal antibodies C50, C241 (both against sialyl-Lewis a), and CSLEX1 (against sialyl-Lewis x), the MUC1 mucin was shown to express both sialyl-Lewis a and sialyl-Lewis x epitopes, while the CD43 mucin expressed sialyl-Lewis a and almost no sialyl-Lewis x epitopes. These two secreted glycoproteins could inhibit human polymorphonuclear leukocyte or HL-60 cell adhesion to E-selectin-transfected COS cells or IL-1 beta-stimulated human endothelial cells in vitro. The inhibitory efficiency of the MUC1 mucin was 5-10 times larger than that of the CD43 mucin, when studied on endothelial cells and comparable amounts of sample were used. Removing the sialic acids from the MUC1 or CD43 mucins by sialidase treatment abolished the inhibitory effect. Monoclonal antibodies against sialyl-Lewis a greatly and equally inhibited the binding of the MUC1 or CD43 mucins, whereas an antibody against sialyl-Lewis x (CSLEX1) showed almost no inhibitory effect. The result proposes that the sialyl-Lewis a epitope on at least some mucin-type molecules bind E-selectin better than sialyl-Lewis x and that the potency of tumor-secreted mucins to interfere with leukocyte attachment to E-selectin could be dependent on the apoprotein size or its presentation of the carbohydrate epitopes.
Zhang
K
K
Department of Medical Biochemistry, University of Göteborg, Sweden.
Baeckström
D
D
Brevinge
H
H
Hansson
G C
GC
D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018395:CA-19-9 Antigen; D019556:COS Cells; D002448:Cell Adhesion; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology; D019040:E-Selectin / Q000378:metabolism*; D000939:Epitopes; D005732:Gangliosides / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007962:Leukocytes / Q000378:metabolism; D051917:Leukosialin; D018396:Mucin-1 / Q000737:chemistry / Q000378:metabolism*; D009844:Oligosaccharides / Q000276:immunology / Q000378:metabolism; D012795:Sialoglycoproteins / Q000737:chemistry / Q000378:metabolism*; D000080506:Sialyl Lewis X Antigen; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018395:CA-19-9 Antigen; D019040:E-Selectin; D000939:Epitopes; D005732:Gangliosides; D051917:Leukosialin; D018396:Mucin-1; D009844:Oligosaccharides; C465014:SPN protein, human; D012795:Sialoglycoproteins; D000080506:Sialyl Lewis X Antigen; C064564:sialyl Le(a) ganglioside