EXPRESSION OF 3 UDP-N-ACETYL-ALPHA-D-GALACTOSAMINE-POLYPEPTIDE GALNACN-ACETYLAGALACTOSAMINYLTRANSFERASES IN ADENOCARCINOMA CELL-LINES

The Levels of mRNA expression of three UDP-N-acetyl-alpha-D-galactosam ine:polypeptide GalNAc N-acetylgalactosaminyltransferases (GalNAc-tran sferases) were quantified for human adenocarcinoma cell lines from pan creas, colon, stomach, and breast. Two of the GalNAc-transferases, Gal NAc-T1 and GalNAc-T2, were expressed constitutively and at low levels in most or all cell lines examined. A third GalNAc-transferase, GalNAc -T3, was differentially expressed. Well-differentiated adenocarcinoma cell lines expressed high levels and moderately differentiated cell li nes expressed lower levels of GalNAc-T3. Cell lines classified as poor ly differentiated failed to express GalNAc-T3 mRNA at levels that coul d be detected by Northern blot analysis. Differential expression of th e GalNAc-T3 protein was confirmed in these cell lines by Western blott ing. We propose that glycosylation in tumor cell lines may be regulate d in part by differential expression of GalNAc-transferases, and we su ggest that GalNAc-T3 gene expression may be a molecular indicator of d ifferentiated adenocarcinoma.