Use of IHC and newly designed matriptase inhibitors to elucidate the role of matriptase in pancreatic ductal adenocarcinoma.
ABSTRACT Matriptase, also known as MT-SP1, is a type II transmembrane serine protease strongly implicated in both the development and progression of a variety of epithelial cancers. Evidence comes from studies of its expression in human cancers and from mouse models of spontaneous cancer. Matriptase is considered to be a major activator of two key stimulators of invasive growth, namely hepatocyte growth factor/scatter factor and urokinase-type plasminogen activator. The aim of this study was to examine the role of matriptase in pancreatic ductal adenocarcinoma by expression analysis and functional assays in vitro. Immunohistochemical analysis of matriptase performed on microtissue arrays and large samples of 55 pancreatic ductal adenocarcinomas and on 31 samples of normal pancreatic ducts revealed that although matriptase expression differed greatly in both malignant and normal ductal pancreatic tissue, matriptase scores were significantly (p=0.02) elevated in pancreatic ductal adenocarcinoma compared to normal pancreatic ducts. To evaluate the role of matriptase during development of pancreatic cancer, we studied the effects of newly designed matriptase inhibitors on the processing of the zymogen of urokinase-type plasminogen activator in the human adenocarcinoma cell lines AsPC-1 and BxPC-3. In both cell lines, at 1 microM, all matriptase inhibitors completely prevented zymogen activation. At lower inhibitor concentrations, the degree of inhibition of zymogen processing correlated with the affinities of the inhibitors towards matriptase indicating that this is a specific result of matriptase inhibition. Furthermore, matriptase inhibitors reduced the phosphorylation of the HGF receptor/cMet and the overall cellular invasiveness of the human pancreatic adenocarcinoma cell line AsPC-1. Our findings demonstrate for the first time that matriptase may be involved in the progression of pancreatic ductal adenocarcinoma and that matriptase inhibition may contribute to preventing the progression of this devastating disease.
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ABSTRACT: Cystine-knot miniproteins define a class of bioactive molecules with several thousand natural members. Their eponymous motif comprises a rigid structured core formed by six disulfide-connected cysteine residues, which accounts for its exceptional stability towards thermic or proteolytic degradation. Since they display a remarkable sequence tolerance within their disulfide-connected loops, these molecules are considered promising frameworks for peptide-based pharmaceuticals. Natural open-chain cystine-knot trypsin inhibitors of the MCoTI (Momordica cochinchinensis trypsin inhibitor) and SOTI (Spinacia oleracea trypsin inhibitor) families served as starting points for the generation of inhibitors of matriptase-1, a type II transmembrane serine protease with possible clinical relevance in cancer and arthritic therapy. Yeast surface-displayed libraries of miniproteins were used to select unique and potent matriptase-1 inhibitors. To this end, a knowledge-based library design was applied that makes use of detailed information on binding and folding behavior of cystine-knot peptides. Five inhibitor variants, four of the MCoTI family and one of the SOTI family, were identified, chemically synthesized and oxidatively folded towards the bioactive conformation. Enzyme assays revealed inhibition constants in the low nanomolar range for all candidates. One subnanomolar binder (Ki = 0.83 nM) with an inverted selectivity towards trypsin and matriptase-1 was identified.PLoS ONE 01/2013; 8(10):e76956. · 3.73 Impact Factor
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ABSTRACT: Epithelial architecture is formed in tissues and organs when groups of epithelial cells are organized into polarized structures. The epithelial function and integrity as well as signaling across the epithelial layer is orchestrated by apical junctional complexes (AJCs), which are landmarks for PAR/CRUMBS and lateral SCRIB polarity modules and by dynamic interactions of the cells with underlying basement membrane (BM). These highly organized epithelial architectures are demolished in cancer. In all advanced epithelial cancers, malignant cells have lost polarity and connections to the basement membrane and they have become proliferative, motile, and invasive. Clearly, loss of epithelial integrity associates with tumor progression but does it contribute to tumor development? Evidence from studies in Drosophila and recently also in vertebrate models have suggested that even the oncogene-driven enforced cell proliferation can be conditional, dependant on the influence of cell-cell or cell-microenvironment contacts. Therefore, loss of epithelial integrity may not only be an obligate consequence of unscheduled proliferation of malignant cells but instead, malignant epithelial cells may need to acquire capacity to break free from the constraints of integrity to freely and autonomously proliferate. We discuss how epithelial polarity complexes form and regulate epithelial integrity, highlighting the roles of enzymes Rho GTPases, aPKCs, PI3K, and type II transmembrane serine proteases (TTSPs). We also discuss relevance of these pathways to cancer in light of genetic alterations found in human cancers and review molecular pathways and potential pharmacological strategies to revert or selectively eradicate disorganized tumor epithelium.Advances in Cancer Research 01/2011; 111:97-161. · 6.35 Impact Factor
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ABSTRACT: Sunflower trypsin inhibitor-1 (SFTI-1), a bicyclic tetradecapeptide, has become a versatile tool as a scaffold for the development of the inhibitors of therapeutically relevant serine proteases, among them matriptase and kallikreins. Herein, we report the rational design of potent monocyclic and bicyclic inhibitors of human matriptase-1. We found that the presence of positive charge and lack of bulky residues at the peptide N-terminus is required for the maintenance of inhibitory activity. Replacement of the N-terminal glycine residue by lysine allowed for the chemical conjugation with a fluorophor via the ε-amino group without significant loss of inhibitory activity. Head-to-tail and side-chain-to-tail cyclization resulted in potent inhibitors with comparable activities against matriptase-1. The most potent synthetic bicyclic inhibitor found in this study (Ki = 2.6 nM at pH 7.6) is a truncated version of SFTI-1 (cyclo-KRCTKSIPPRCH) lacking a C-terminal proline and aspartate residue. It combines an internal disulfide bond with a peptide macrocycle that is formed through side-chain-to-tail cyclization of the ε-amino group of an N-terminal lysine and a C-terminal proline. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.Journal of Peptide Science 04/2014; · 2.07 Impact Factor