Expression of intestinal MUC17 membrane-bound mucin in inflammatory and neoplastic diseases of the colon

Abstract

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.