Characterization of expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in prostate cancer cell lines

Stromal expression of some matrix metalloproteinases (MMPs) has been associated with increasing tumour burden in prostate cancer. We investigated the expression of mRNA (by RT-PCR) and protein (by zymography and western blotting) of MMPs and endogenous inhibitors (tissue inhibitors of metalloproteinases, TIMPs) in two parent epithelial prostate cancer cell lines and sublines of increasing invasive/metastatic potential. Expression of membrane type MMPs, MT1-MMP and MT3-MMP mRNA was higher in PC3-derived than in LNCaP-derived lines, whereas MT2-MMP mRNA expression was higher in the LNCaP derived than in PC3-derived cell lines. Active MT1, MT2 and MT3-MMP protein levels were similar in all lines, but processed MT-MMPs, indicative of latent MMP activation, were increased in more aggressive sublines. Expression of MMP-1, MMP-13 and TIMP-1 was higher in the more aggressive sublines and may be implicated in invasive/metastatic ability. Regulation of MMP-1 and MMP-13 expression may offer important therapeutic options for treating patients with prostate cancer.