Relationship of beta-glucuronidase to differentiation and invasion of human colorectal carcinoma

Abstract

Objective: To investigate the relationship between beta-glucuronidase and tumor differentiation and invasion in human colorectal carcinoma.

Methods: The expression of beta-glucuronidase in human colorectal carcinoma tissue was determined by streptavidin-peroxidase immunohistochemical method. Four human colorectal carcinoma cell lines were analysed for beta-glucuronidase in the medium by spectrophotometry method.

Results: Compared with well differentiated colorectal carcinomas, beta-glucuronidase expression was higher in poorly differentiated tumors. An association was found between beta-glucuronidase overexpression in colorectal carcinoma and more advanced tumor Dukes' stage (P < 0.05). With increasing maximum depth of invasion, tumors more frequently show higher beta-glucuronidase expression (P < 0.05). The analysis of colorectal carcinoma cell lines for beta-glucuronidase showed that low levels of beta-glucuronidase (activity range, 1.29 to 1.96 micrograms/10(6) cells per hour) were associated with the well differentiated cell lines which have low invasiveness (CX1, CCL187), and this was in contrast to the elevated level of the enzyme (2.46 to 2.73 micrograms/10(6) cells per hour) present in the medium derived from the poorly differentiated cells with high invasiveness (CCLI227, CCL228) (P < 0.05).

Conclusions: Poorly differentiated human colorectal carcinoma cells could synthesize more beta-glucuronidase, enhance local invasion. Immunohistochemical staining for beta-glucuronidase might be helpful to diagnosing the differentiation degree and invasiveness of human colorectal carcinomas, and the secreted beta-glucuronidase might provide a useful measurement of the differentiation degree and invasiveness of cultured human colorectal carcinoma cells.