Premium
Effect of tunicamycin on synthesis and secretion of carcinoembryonic antigen by human colonic adenocarcinoma cells
Author(s) -
Miura Soichiro,
Kim Young S.
Publication year - 1986
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910380209
Subject(s) - tunicamycin , carcinoembryonic antigen , glycosylation , glycoprotein , secretion , chemistry , biochemistry , microbiology and biotechnology , membrane glycoproteins , cell culture , biology , cancer , endoplasmic reticulum , genetics , unfolded protein response
The effect of the glycosylation inhibitor, tunicamycin, on synthesis and secretion of the membrane‐associated glycoprotein carcinoembryonic antigen (CEA), was studied in the LSI74T human colon cancer cell line. Tunicamycin treatment inhibited total cellular glycoprotein synthesis but did not affect CEA levels of cellular homogenate, membrane or cytosol fractions as determined by enzyme immunoassay. Control cells metabolically labelled with 3 H‐glucosamine, 3 H‐leucine or 35 S‐cysteine exhibited membranous and extracellular ( i.e . secreted) CEA with an MW of 200 kDa as judged by SDS‐gel electrophoresis following immuno‐precipitation. However, in the tunicamycin‐treated cells several forms of CEA with lower MWs and representing molecules with decreased glycosylation could be detected in addition to the original CEA molecule of 200 kDa present in control cells. The rates of synthesis, secretion and turnover of the lower‐molecular‐weight forms of poorly glycosylated CEA that appear after tunicamycin treatment are similar to those of CEA in control cells. These data suggest that the carbohydrate portion of the CEA molecule is not essential in synthesis, incorporation into the membrane, and secretion of CEA by colon cancer cells in vitro .