Aim To determine the cellular location and expression of MUC17 mucin in specimens of normal, inflamed and neoplastic colon.
Methods Immunohistochemical analysis of human surgical resection specimens (n=106) was performed with a specific antibody to the MUC17 apomucin protein. A semi-quantitative scoring system was used to measure MUC17 expression. In various colon cancer cell lines, the MUC17 expression was examined by immunoblot analysis and normal RT-PCR.
Results MUC17 was highly expressed on the surface epithelium and crypts of colonic mucosa. In contrast, the expression of MUC17 was significantly decreased in colonic mucosa of chronic ulcerative colitis (p<0.0001) and ischaemic colitis (p=0.003). Similarly, MUC17 expression was decreased in hyperplastic polyps (p=0.0003), tubular and tubulovillous adenomas (p<0.0001) and colon cancers (p<0.0001). Furthermore, of eight different colon cancer cell lines, MUC17 expression was only detected in LS174T and LS180 cells.
Conclusion Results indicate that the potential protective effects of this membrane-bound mucin are primarily or secondarily diminished in inflammatory and neoplastic conditions. Further research is needed to determine the specific role of MUC17 in the pathogenesis of these conditions.
- inflammatory bowel disease
- ulcerative colitis
- ischaemic colitis
- colorectal neoplasia
- colorectal cancer
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Funding This work was supported by NIH grant CA78590, CA111294, CA133774, CA131944, Department of Defense PC081409 (SKB), a Veterans Affairs Merit Review Award (SBH), NIH Center grant DK080506 (SBH), and the Veterans Affairs Research Service.
Competing interests None.
Ethics approval This study was conducted with the approval of the Department of Medicine, University of California, San Diego and VA San Diego Healthcare System, San Diego, California, USA.
Provenance and peer review Not commissioned; externally peer reviewed.