title: Secretion of protease nexin-II/amyloid beta protein precursor by human colorectal carcinoma cells and its modulation by cytokines/growth factors and proteinase inhibitors.
abstract: Trypsin inhibitors secreted by human colorectal adenocarcinoma cell lines were analyzed by reverse zymography. Among eleven cell lines analyzed, the major inhibitor secreted was protease nexin-II (PN-II), a secreted form of amyloid beta protein precursor (APP) containing a Kunitz-type serine proteinase inhibitor domain. Expression of the APP gene was also confirmed in the cell lines and the main APP mRNA species were PN-II types. The APP gene expression was constant during cell growth in vitro. On the other hand, the rate of extracellular PN-II accumulation markedly increased after long-term serum-free maintenance of the confluent culture. The extracellular accumulation of PN-II was also strongly stimulated either by interleukin-1beta (IL-1beta) treatment or to a lesser extent by basic fibroblast growth factor, tumor necrosis factor-alpha, hepatocyte growth factor or epidermal growth factor. Neither serum depletion- nor IL-1beta-induced stimulation of extracellular PN-II accumulation were accompanied by obvious alteration of the levels of APP mRNA and cellular APP holoprotein, suggesting that the enhanced extracellular accumulation of PN-II might result from up-regulation of the secretory pathway of APP. The IL-1beta-induced PN-II secretion was significantly inhibited by relatively high concentrations (50-200 microg/ml) of aprotinin, a serine proteinase inhibitor, in a dose-dependent manner without obvious cell-toxic effects.
authors.affiliation: Second Department of Pathology, Miyazaki Medical College, Kiyotake, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Seguchi
authors.forename: H
authors.initials: H
authors.lastname: Kataoka
authors.forename: H
authors.initials: H
authors.lastname: Uchino
authors.forename: K
authors.initials: K
authors.lastname: Nabeshima
authors.forename: M
authors.initials: M
authors.lastname: Koono
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D000595:Amino Acid Sequence; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D016895:Culture Media, Serum-Free; D017931:DNA Primers; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D008969:Molecular Sequence Data; D058255:Protease Nexins; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface; D014361:Trypsin Inhibitors / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: C545487:APP protein, human; D016564:Amyloid beta-Protein Precursor; D002352:Carrier Proteins; D016895:Culture Media, Serum-Free; D017931:DNA Primers; D006133:Growth Substances; D007375:Interleukin-1; D058255:Protease Nexins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D014361:Trypsin Inhibitors