RNA expression of the five membrane-type matrix metalloproteinases MTI-MT5 in human prostatic cell lines and their down-regulation in human malignant prostatic tissue

BACKGROUND. The aim of this study was to assess the expression of membrane-type matrix metalloproteinases (MT-MMPs) 1-5 in the human prostatic cell lines BPH-1, LNCaP, DU 145, PC-3, in malignant and non-malignant prostatic tissue samples, and in epithelial cells cultured from these tissue samples. METHODS. Matched malignant and non-malignant tissue specimens were obtained from 12 men with untreated prostate carcinoma after radical prostatectomy. Expression of mRNA for the five MT-MMPs was quantified by real-time PCR technique and normalized to the expression of the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH). RESULTS. The expression of the five MT-MMPs was distinctly different not only between the prostate cell lines but also varied in the same cell line. There was a general higher expression of all MT-MMPs except for MT3-MMP in the androgen-insensitive cells DU 145 and PC-3 compared with that in the androgen-sensitive LNCaP cells. Their relatively high expression in the benign prostatic cell line BPH-1 and also in the primary cell cultures from malignant and nonmalignant tissue samples argues against a simple association between MT-MMP expression and invasiveness. In malignant tissue samples and their corresponding cell cultures, the expression of most MT-MMPs was down-regulated in comparison to the normal counterparts. There was no correlation between tumor classification data and the MT-MMP expression results. CONCLUSIONS. In contrast to other carcinoma, the down-regulation of most MT-MMPs is typical for prostate carcinoma. It seems to occur mainly in epithelial cells and has to be examined as special characteristic of this tumor entity in further studies. (C) 2003 Wiley-Liss, Inc.