High expression of HSP47 in ulcerative colitis-associated carcinomas: proteomic approach

BACKGROUND: Ulcerative colitis (UC) is a chronic relapsing inflammatory bowel disease, known to be associated with a markedly increased risk of colorectal carcinoma development. METHODS: Using proteomic analysis with two-dimensional gel electrophoresis and mass spectrometry, differentially expressed proteins were assessed between UC-associated cancer and sporadic colon cancer cell lines. Western blot and immunostaining were performed for confirming the expression. RESULTS: Heat-shock protein of 47 kDa (HSP47) was identified as one of the proteins expressed more highly in UC-associated cancer cell lines, and an immunohistochemical examination confirmed significantly higher levels of HSP47 in UC-associated colon cancers than in sporadic counterparts, the expression increasing with a progression of neoplastic lesions. Heat-shock protein of 47 kDa was further found to be coexpressed with type I collagen in the cytoplasm, and both HSP47 and type I collagen were released from cultured cells into the culture medium. CONCLUSION: These results suggest that overexpression of HSP47 is a unique characteristic of UC-associated carcinoma related to type I collagen synthesis, with possible clinical applications.