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Polymorphic expression of decay‐accelerating factor in human colorectal cancer
Author(s) -
Nakagawa Masahiro,
Mizuno Motowo,
Kawada Mikihiro,
Uesu Tokurou,
Nasu Junichirou,
Takeuchi Kazuaki,
Okada Hiroyuki,
Endo Yuichi,
Fujita Teizo,
Tsuji Takao
Publication year - 2001
Publication title -
journal of gastroenterology and hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.214
H-Index - 130
eISSN - 1440-1746
pISSN - 0815-9319
DOI - 10.1046/j.1440-1746.2001.02418.x
Subject(s) - decay accelerating factor , colorectal cancer , blot , mouse model of colorectal and intestinal cancer , cancer , western blot , glycosylation , northern blot , cancer research , cancer cell , messenger rna , medicine , microbiology and biotechnology , real time polymerase chain reaction , biology , gene , immunology , complement system , genetics , antibody
Background: We have previously shown that expression of decay‐accelerating factor (DAF), a complement regulatory protein, is enhanced immunohistochemically on the luminal surface of cancer glands in human colorectal cancer and is detected in stool specimens of patients with colorectal cancer. The amount of DAF present in the stools might be influenced by the stability of DAF on the cell surface which is regulated by biochemical properties such as glycosylation of the protein. In the present study, to help elucidate the mechanism for the release of DAF from human colorectal cancers, we biochemically analyzed DAF expression by western and northern blotting by using surgically resected specimens of colorectal cancers. Methods: Surgically resected colorectal cancer tissues were obtained from 10 patients. Expression of DAF was determined by western and northern blotting, and glycosylation of DAF protein was analyzed with glycosidase digestion. Results: Northern blot analysis demonstrated that the expression of DAF mRNA in colorectal cancer was enhanced two‐ to threefold compared with normal tissues. In western blotting, expression of DAF protein in the cancer tissue was increased, and heterogeneity in the apparent molecular weight of DAF was observed among patients. When o ‐linked sugars were removed, this heterogeneity of DAF size diminished. Conclusions: The polymorphic expression of DAF in colorectal cancer is likely to reflect variability in the o ‐glycosylation of the protein. We speculate that this variability could affect the stability of DAF on the surfaces of cancer cells and, in turn, the amount of DAF shed into the stools of colorectal cancer patients.