Matrix metalloproteinases (MMPs) in bladder cancer: the induction of MMP9 by epidermal growth factor and its detection in urine.

OBJECTIVES: To investigate the matrix metalloproteinases (MMPs) 2 and 9 in bladder cancer cell lines stimulated with epidermal growth factor (EGF), and to investigate the presence of gelatinases in the urine of patients with bladder tumours, in relation to the stage and grade of tumour and the EGF receptor (EGFR) status. PATIENTS, SUBJECTS AND METHODS: Conditioned media from cultured tumour cells were analysed by zymography. Urine samples from 28 patients with transitional cell carcinoma and 12 normal volunteers were also analysed. Western blotting was used to verify the bands of gelatinolytic activity. The EGFR status of the tumours was assessed by immunohistochemistry.
RESULTS: MMP9 was induced by EGF in the RT112 but not the RT4 bladder tumour cell line, whereas MMP2 production was unaffected by EGF. Gelatin zymography of urine samples from patients with bladder tumours showed high levels of MMP activity, with 78% positive for MMP9 and 28% positive for MMP2. The total gelatinolytic and MMP9 activity were significantly higher in patients with high-stage invasive tumours than in those with superficial tumours (P < 0.05), and were higher than in normal controls. Gelatinolytic activity at 130 and 200 kDa in urine was identified as MMP9 and MMP2. There was no significant relationship of urinary MMP9 activity to EGFR status of the tumour.
CONCLUSION: EGF induces MMP9 but not MMP2 in bladder cells. Analysis of urinary gelatinases is a useful noninvasive technique and both total gelatinase and MMP9 activity are associated with high stages of bladder tumours.