FUCOSYL-TRANSFERASE-III AND SIALYL-LE(X) EXPRESSION CORRELATE IN CULTURED COLON-CARCINOMA CELLS BUT NOT IN COLON-CARCINOMA TISSUE

The potential contribution of fucosyltransferases to the overexpressio n of sialyl-Le(x) antigen was investigated in the colon carcinoma cell line HT-29 and in human colon carcinoma tissue. In HT-29 cells as wel l as in normal or malignant colonic tissues Fuc-TIII, Fuc-TIV, Fuc-TVI but not Fuc-TV nor Fuc-TVII were detectable after RT-PCR. Sodium buty rate treatment of HT-29 cells increased (to about 200%) and DMSO treat ment decreased (to about 20%) the expression of sialyl-le(x). This mod ulation of sialyl-Le(x) was concomitant with the analogous increase/de crease of mRNA of Fuc-TIII but not Fuc-TIV. Fuc-TVI was not detectable by Northern blotting in HT-29 cells. In six human colon carcinomas wh ich exhibited strong overexpression of sialyl-Le(x), the expression of Fuc-TIII-mRNA was the same or lower than in the corresponding normal colonic tissue. Thus Fuc-TIII expression may be affecting the expressi on of the sialyl-le(x) moiety in HT-29 cells but not in human colon ca rcinoma tissue.