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Characterization of a sialic‐acid‐rich mucus glycoprotein secreted by a premalignant human colorectal adenoma cell line
Author(s) -
Corfield Anthony P.,
Clamp John R.,
Casey Angela D.,
Paraskeva Christos
Publication year - 1990
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.2910460619
Subject(s) - sialic acid , mucus , biochemistry , glycoprotein , gel electrophoresis , mannose , mucin , polyacrylamide gel electrophoresis , chemistry , threonine , centrifugation , cell culture , microbiology and biotechnology , neuraminic acid , fucose , biology , serine , enzyme , ecology , genetics
The human colonic cell line PC/AA, derived from an adenoma, retains in vitro colonic cell differentiation, notably the production of mucus glycoproteins. The PC/AA adenoma cells produce an extracellular gel layer in culture. The PC/AA gel could be isolated by extraction of the cell cultures with guanidine hydrochloride. The extracted material was purified by gel filtration and caesium chloride density‐gradient centrifugation and showed properties typical of mucus glycoproteins, namely, a carbohydrate content above 60% of dry weight rich in N‐acetylgalactosamine and sialic acid and low in mannose; an amino acid composition with high serine threonine and proline content; a molecular weight above 1,000 kDa on Sepharose CL 4B chromatography and on SDS‐polyacrylamide gel electrophoresis under reducing conditions (>200 kDa); a buoyant density of approximately 1.48 g/ml and the release of oligosaccharides by the alkaline β‐elimination reaction. Comparison of the gel mucus glycoprotein purified from premalignant PC/AA cells with normal human colon much showed that it has a higher sialic acid content. This suggests that higher sialic acid levels may precede the development of malignancy.