Elevation of seprase expression and promotion of an invasive phenotype by collagenous matrices in ovarian tumor cells

Abstract

Tumor cells do not constitutively exhibit invasive activity, but rather, can be transiently induced to adhere and form lesions. We report here that the expression of seprase, a dominant EDTA-resistant gelatinase in malignant tumors, is dependent on tumor cell exposure to type I collagen gel (TICg). The induced seprase expression of ovarian tumor cells influences their collagen contraction and invasion capability. Importantly, tumor cells with reduced seprase expression, due to manipulation by RNA interference, showed a reduction of TICg contraction in the gel contractility assay, inhibition of tumor cell invasion through TICg as shown by a transwell migration assay and inhibition of peritoneal membrane tumor lesion in a mouse model. In addition, mAb C27, an antibody against b1 integrin, which blocks cellular avidity to TICg, can induce seprase RNA expression and promote the invasive phenotype and metastatic potential of ovarian tumor cells. Thus, collagenous matrices in the tumor cell niche induce the expression of seprase and initiate tumor invasion and metastatic cascades. ' 2008 Wiley-Liss, Inc.Key words: seprase; FAP-a; gelatinase; collagen; ovarian tumor Epithelial ovarian cancer progresses by increased tumor cell proliferation and proteolytic activity that degrades the extracellular matrix (ECM) of the peritoneum. 1,2 Although blocking tumor progression by inhibiting protease activity is well-known, it is also possible that tumor progression could be suppressed by hindering the initial induction of these proteases.Type I collagen (TIC) is comprised of 3 strands of gelatin each of which contain adjoining glycine and proline residues. 3 It is this bond that is the known substrate for seprase. 4 Seprase was first described in the LOX human malignant melanoma cell line and is a type II transmembrane, 760 aa glycoprotein whose 97 kDa monomer homodimerizes to form a catalytically active complex of 170 kDa. 5-7 Molecular cloning of seprase revealed it to be identical to that of fibroblast activation protein a (FAP-a) in gene sequence, protein form, as well as dipeptidyl peptidase and gelatinase activities, even though FAP-a was independently identified in reactive stromal fibroblasts but not in tumor or endothelial cells. [6][7][8][9][10][11] In fact, seprase was found to be present on tumor cells of gastric, colon, melanoma, ovarian and breast cancers. [5][6][7][12][13][14][15] It is likely that activation, which involves the seprase dimer being shorn from the cell membrane to allow greater accessibility of its TICg substrate to the catalytic pore, is required prior to gelatinase activity. 16,17 Seprase is not only present on activated fibroblast during wound healing and active endothelial cells during angiogenesis, but also has been found to be constitutively expressed at high levels in some malignant melanoma, glioma and carcinoma cells; however, most epithelial tumor cell lines express little or no seprase (see gene expression profiles of NCI60 tumor cell lines http:// cgap.nci.nih.gov/Microarray/FNResults?O...

A Combination of Serum Markers for the Early Detection of Colorectal Cancer

“…An increased expression of seprase in cancer including CRC has been shown and our Western blot results from tissue confirmed this (21,(24)(25)(26). However, most surprisingly the concentrations in serum seemed to be reduced instead when we used an in-house ELISA to discriminate CRC from controls.…”

Expression levels of seprase/FAPα and DPPIV/CD26 in epithelial ovarian carcinoma

“…To the best of our knowledge, the study of DPPIV and seprase in ovarian carcinomas has so far been confined to cell lines (34)(35)(36). Furthermore, no large-scale comparative studies concerning seprase expression in specimens of ovarian carcinoma have been conducted.…”

Expression profiling of dipeptidyl peptidase 8 and 9 in breast and ovarian carcinoma cell lines

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