title: A synthetic tissue kallikrein inhibitor suppresses cancer cell invasiveness.
abstract: Serine proteinases modulate the interaction of tumor cells with extracellular matrix components during extravasation and metastasis. The serine proteinase tissue kallikrein has been previously demonstrated in several human adenocarcinomas, and we presently report the localization of immunoreactive kallikrein and its mRNA in pancreatic adenocarcinoma. In addition, a synthetic peptide-based inhibitor specific for tissue kallikrein (FE999024) was used in our studies to explore a possible role for kallikrein in cancer cell invasiveness. Matrigel invasion assays were performed with a human breast-cancer cell line, MDA-MB-231, which expresses tissue kallikrein in culture. In the presence of FE999024 invasion through Matrigel was inhibited in a dose-dependent manner to a maximum of 39%. We also developed a novel ex vivo assay in which breast cancer cells are infused into the pulmonary circulation of artificially ventilated explanted rat lungs. At intervals up to 6 hours after infusion pulmonary invasion was quantified by bronchial alveolar lavage to recover human cancer cells from the airspace. Invading cells in the lung interstitium were also quantified after immunohistochemistry with a monoclonal antibody specific for human cytokeratin 18. The synthetic kallikrein inhibitor attenuates breast cancer cell invasion into the airspace by 33% when quantified by lavage recovery and up to 34% as quantified in the lung interstitium by cytokeratin 18 immunostaining. Our results indicate tissue kallikrein may participate in the invasion and metastasis of human adenocarcinomas. The newly developed explanted rodent lung assay should be useful for the study of cancer cells, neutrophils, or other extravasating cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
authors.forename: W C
authors.initials: WC
authors.lastname: Wolf
authors.forename: D M
authors.initials: DM
authors.lastname: Evans
authors.forename: L
authors.initials: L
authors.lastname: Chao
authors.forename: J
authors.initials: J
authors.lastname: Chao
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D001672:Biocompatible Materials; D003094:Collagen; D004338:Drug Combinations; D006801:Humans; D007797:Laminin; D008168:Lung / Q000473:pathology; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D010455:Peptides / Q000494:pharmacology*; D011509:Proteoglycans; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D020840:Tissue Kallikreins / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D004338:Drug Combinations; C440019:FE 999024; D007797:Laminin; D010455:Peptides; D011509:Proteoglycans; C059485:matrigel; D003094:Collagen; D020840:Tissue Kallikreins