Activation of Pro-gelatinase B by Endometase/Matrilysin-2 Promotes Invasion of Human Prostate Cancer Cells

Abstract

This work has explored a putative biochemical mechanism by which endometase/matrilysin-2/matrix metalloproteinase-26 (MMP-26) may promote human prostate cancer cell invasion. Here, we showed that the levels of MMP-26 protein in human prostate carcinomas from multiple patients were significantly higher than those in prostatitis, benign prostate hyperplasia, and normal prostate glandular tissues. The role of MMP-26 in prostate cancer progression is unknown. MMP-26 was capable of activating pro-MMP-9 by cleavage at the Ala 93 -Met 94 site of the prepro-enzyme. This activation proceeded in a time-and dose-dependent manner, facilitating the efficient cleavage of fibronectin by MMP-9. The activated MMP-9 products generated by MMP-26 appeared more stable than those cleaved by MMP-7 under the conditions tested. During the initial phases of carcinoma cell invasion, as tumor cells begin to spread and infiltrate into the surrounding normal tissues, these cells must first degrade the basement membrane and other elements of the extracellular matrix (ECM), 1 including type IV collagen, laminin, and fibronectin (FN) (1). Multiple protease families, including the matrix metalloproteinases (MMPs), serine proteases, and cysteine proteases, are suspected of contributing to the invasive and metastatic abilities of a variety of malignant tumors (2-5), but the specific biochemical mechanisms that facilitate these invasive behaviors remain elusive.More than 23 human MMPs, and numerous homologues from other species, have been reported (5), and matrix metalloproteinase-26 (MMP-26)/endometase/matrilysin-2 is a novel member of this enzyme family that was recently cloned and characterized by our group (6) and others (7-9). MMP-26 mRNA is primarily expressed in epithelial cancers, such as lung, breast, endometrial, and prostate carcinomas, in their corresponding cell lines (6 -9), and in a very limited number of normal adult tissues, such as the uterus (6, 8), placenta (7,8), and kidney (9). Recently, we have found that the levels of MMP-26 gene and protein expression are higher in a malignant choriocarcinoma cell line (JEG-3) than in normal human cytotrophoblast cells (10). Our preliminary studies indicate that expression of MMP-26 may be correlated with the malignant transformation of human prostate and breast epithelial cells. The specific expression of MMP-26 in malignant tumors and the proteolytic activity of this enzyme against multiple components of the ECM, including fibronectin, type IV collagen, vitronectin, gelatins, and fibrinogen, as well as non-ECM proteins such as insulin-like growth factor-binding protein 1 and ␣1-protease inhibitor (6 -9), indicate that MMP-26 may possess an important function in tumor progression.Another member of the MMP family considered to be an important contributor to the processes of invasion, metastasis, and angiogenesis exhibited by tumor cells is gelatinase B (MMP-9) (11-14). Uría and López-Otín (8) have demonstrated that MMP-26 is able to cleave MMP-9, and here we examine the possibility that MMP...

Coordinated peak expression of MMP-26 and TIMP-4 in preinvasive human prostate tumor

“…No peptide with >45% level of identity to these selected sequences was found as determined using the BLAST search method at the National Center for Biotechnology Information website (http://ncbi.nih.gov/ BLAST/). These rabbit polyclonal and mono specific antibodies were tested and verified to be highly specific for MMP 26 [12]. A goat polyclonal antibody against the C-terminal sequence region of MMP-26 (E-14) was obtained from Santa Cruz Biotechnology, and was utilized for the detection of MMP-26 following immunoprecipitation.…”

“…The samples were then incubated with primary antibody diluted to 25 mg/ml in blocking buffer (0.2% Triton X-100, 5% normal goat serum, and 3% bovine serum albumin in TBS) for 1 h at room temperature. The primary antibodies used were affinity purified polyclonal rabbit anti human pro MMP 26 and TIMP-4 [12,25], or were obtained from commercial sources and derived from different species. Purified preimmune IgG from rabbit was used as a negative control.…”

“…Once active, MMP-26 has been shown to cleave multiple components of the ECM, including fibronectin, type IV collagen, vitronectin, gelatins, and fibrinogen, as well as non ECM proteins such as insulin-like growth factor-binding protein-1 and α-1 protease inhibitor [7][8][9][10][11]. MMP-26 is also able to activate progelatinase B (pro-MMP-9), an enzyme that plays a critical role in ECM remodeling [12].…”

“…Our previous studies have shown that MMP-26 expression in human prostate carcinoma is significantly higher than that in prostatitis, benign prostate hyperplasia (BPH), and normal prostate tissue [12]. In addition, our group has shown that the expression of MMP 26 in human breast tissue is significantly higher during preinvasive ductal carcinoma in situ (DCIS) when compared to infiltrating ductal carcinoma (IDC), atypical intraductal hyperplasia (AIDH), and normal breast epithelia adjacent to DCIS and IDC [13].…”

Peaking of MMP-26 and TIMP-4 marks invasive transition in prostate cancer

“…Progression of the disease from noninvasive high-grade prostatic intraepithelial neoplasia (HGPIN) to invasive adenocarcinoma is linked to the action of a group of proteolytic enzymes called matrix metalloproteinases (MMPs), which digest various components of the extracellular matrix and thus open ways for tumor metastasis. Previous studies have shown that one MMP, MMP-26, is expressed at a significantly higher level in human prostate carcinoma than in normal prostate tissues, and that it appears to play an important role in promoting invasion of prostate cancer cells [1]. In this issue of Cell Research, Lee et al report detailed analyses of the expression pattern of MMP-26, along with its most potent endogenous inhibitor, TIMP-4 (TIMP stands for tissue inhibitor of metalloproteinases), in a number of prostate cancer samples derived from human patients [2].…”