title: Expression and functional characterization of the cancer-related serine protease, human tissue kallikrein 14.
abstract: Human tissue kallikrein 14 (KLK14) is a novel extracellular serine protease. Clinical data link KLK14 expression to several diseases, primarily cancer; however, little is known of its (patho)-physiological role. To functionally characterize KLK14, we expressed and purified recombinant KLK14 in mature and proenzyme forms and determined its expression pattern, specificity, regulation, and in vitro substrates. By using our novel immunoassay, the normal and/or diseased skin, breast, prostate, and ovary contained the highest concentration of KLK14. Serum KLK14 levels were significantly elevated in prostate cancer patients compared with healthy males. KLK14 displayed trypsin-like specificity with high selectivity for P1-Arg over Lys. KLK14 activity could be regulated as follows: 1) by autolytic cleavage leading to enzymatic inactivation; 2) by the inhibitory serpins alpha1-antitrypsin, alpha2-antiplasmin, antithrombin III, and alpha1-antichymotrypsin with second order rate constants (k(+2)/Ki) of 49.8, 23.8, 1.48, and 0.224 microM(-1) min(-1), respectively, as well as plasminogen activator inhibitor-1; and 3) by citrate and zinc ions, which exerted stimulatory and inhibitory effects on KLK14 activity, respectively. We also expanded the in vitro target repertoire of KLK14 to include collagens I-IV, fibronectin, laminin, kininogen, fibrinogen, plasminogen, vitronectin, and insulin-like growth factor-binding proteins 2 and 3. Our results indicate that KLK14 may be implicated in several facets of tumor progression, including growth, invasion, and angiogenesis, as well as in arthritic disease via deterioration of cartilage. These findings may have clinical implications for the management of cancer and other disorders in which KLK14 activity is elevated.
authors.affiliation: Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada.
authors.forename: Carla A
authors.initials: CA
authors.lastname: Borgoño
authors.forename: Iacovos P
authors.initials: IP
authors.lastname: Michael
authors.forename: Julie L V
authors.initials: JL
authors.lastname: Shaw
authors.forename: Liu-Ying
authors.initials: LY
authors.lastname: Luo
authors.forename: Manik C
authors.initials: MC
authors.lastname: Ghosh
authors.forename: Antoninus
authors.initials: A
authors.lastname: Soosaipillai
authors.forename: Linda
authors.initials: L
authors.lastname: Grass
authors.forename: Dionyssios
authors.initials: D
authors.lastname: Katsaros
authors.forename: Eleftherios P
authors.initials: EP
authors.lastname: Diamandis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D014408:Biomarkers, Tumor; D002356:Cartilage / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D007118:Immunoassay; D007610:Kallikreins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009389:Neovascularization, Pathologic; D009928:Organ Specificity; D011471:Prostatic Neoplasms / Q000097:blood / Q000201:enzymology; D011817:Rabbits; D011994:Recombinant Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000032:analysis / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity
chemical_list: D014408:Biomarkers, Tumor; D016326:Extracellular Matrix Proteins; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; C425336:KLK14 protein, human; D007610:Kallikreins; D012697:Serine Endopeptidases