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Identification and characterization of a Kunitz‐type protease inhibitor in ascites fluid from patients with ovarian carcinoma
Author(s) -
Kobayashi Hiroshi,
Hirashima Yasuyuki,
Sun Gun W.,
Ohi Hidekazu,
Fujie Michio,
Terao Toshihiko
Publication year - 2000
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/1097-0215(20000701)87:1<44::aid-ijc7>3.0.co;2-q
Subject(s) - ascites , trypsin , ovarian carcinoma , extravasation , protease , ovarian cancer , microbiology and biotechnology , biology , protease inhibitor (pharmacology) , carcinoma , pathology , medicine , enzyme , cancer , immunology , biochemistry , human immunodeficiency virus (hiv) , antiretroviral therapy , viral load
Abstract Urinary trypsin inhibitor (UTI; Mr 40 kDa) is a Kunitz‐type protease inhibitor that efficiently inhibits cell‐associated trypsin and plasmin activities. The aim of this study is to examine the expression pattern of UTI in the human ovarian carcinoma ascites fluid by Western blotting, zymography, immunoprecipitation, immunohistochemistry, biochemical and gene analyses and animal experiments. We have identified and characterized the 40 kDa immunoreactive UTI (UTI 40 ) and 8 kDa degradation fragment (UTI 8 ) in ascites fluid. The levels of UTI 40 and UTI 8 are elevated in ascites fluid taken from patients with ovarian carcinoma relative to paired plasma samples. The UTI 40 and UTI 8 were identified immunologically by the reactivity with 2 different anti‐UTI antibodies recognizing different epitopes of the UTI molecule, functionally by its ability to bind trypsin and structurally by its apparent molecular mass with and without deglycosylation treatment. The purified polypeptides have been sequenced and were identical with sequences obtained from UTI and the carboxyl‐terminal domain of UTI, respectively. However, UTI mRNA was not detected in the ovarian carcinoma tissue and ovarian carcinoma cell lines examined. Based on extravasation experiments using intravenously injected biotinylated inter‐α‐trypsin inhibitor (IαI; a precursor of UTI), we conclude that UTI 40 and UTI 8 found in the ascites fluid may result from (i) the extravasation of plasma proteins such as IαI into the peritoneal cavity via hyperpermeable vessels and (ii) the subsequent degradation of IαI and UTI 40 by tumor cell‐associated trypsin‐like enzymes. Int. J. Cancer 87:44–54, 2000. © 2000 Wiley‐Liss, Inc.