Expression of collagenase-3 (matrix metalloproteinase-13) in transitional-cell carcinoma of the urinary bladder

Expression of collagenase-3 [matrix metalloproteinase-13 (MMP-13)] has been previously demonstrated in squamous-cell carcinomas of both the head and n eck and the vulva, cutaneous basal-cell carcinomas, chondrosarcomas and mel anomas. Using in situ hybridization, MMP-13 mRNA expression was detected in 13 of 23 (52%) urinary bladder transitional-cell carcinomas (TCCs). Expres sion was restricted to cells in the invading edges of tumors. No expression of MMP-13 mRNA could be detected in normal urothelium. As detected by immu nohistochemistry, MMP-13 protein showed an expression pattern similar to th at of MMP-13 mRNA. Expression of MMP-13 mRNA and protein was also detected in 2 bladder carcinoma cell lines (RT4 and T24). In these cell lines, TNF-a lpha potently induced MMP-13 mRNA expression. Retinoids and a selective p38 inhibitor, SB203580, potently inhibited MMP-13 mRNA expression. Our result s demonstrate MMP-13 expression in human urinary bladder carcinoma cells in vivo and in vitro and suggest that MMP-13 may serve as a marker for transf ormation and invasion in urinary bladder TCCs. Int. J. Cancer 88:417-423, 2 000. (C) 2000 Wiley-Liss, Inc.