Expression of mucin genes and carbohydrate epitopes in 19 human colon carcinoma cell lines

The levels of mRNA corresponding to the MUC1, MUC2, MUC5AC, MUC5B, and MUC6 genes were determined in 19 human colon adenocarcinoma cell lines by the r everse transcriptase-polymerase chain reaction method using specific primer s in an attempt to correlate to the levels of cell surface carbohydrate epi topes. All 19 cell lines expressed MUC1 and MUC5B mRNA, whereas MUC2, MUC5A C, or MUC6 mRNA were only detected in 8, 3, or 2 of 19 cell lines, respecti vely. Sialyl Lewis a carbohydrates, identified by the monoclonal antibody ( mAb) CA19-9, and sialyl Lewis X carbohydrates, identified by mAb KM93, were observed, with most of the cell lines expressing multiple mucin core polyp eptide genes but with few cell lines expressing only MUC1 and MUC5B. Sialyl Tn epitopes identified by mAb B195.3R11 and by mAb TKH-2 were strongly exp ressed on both of two MUC6-positive cells, whereas only a small portion of MUC6-negative cells expressed these epitopes. Strict correlation between mu cin gene expression and any carbohydrate epitopes examined was not observed .