title: Matrix metalloproteinase-9 regulates tumor cell invasion through cleavage of protease nexin-1.
abstract: Matrix metalloproteinase-9 (MMP-9) expression is known to enhance the invasion and metastasis of tumor cells. In previous work based on a proteomic screen, we identified the serpin protease nexin-1 (PN-1) as a potential target of MMP-9. Here, we show that PN-1 is a substrate for MMP-9 and establish a link between PN-1 degradation by MMP-9 and regulation of invasion. PN-1 levels increased in prostate carcinoma cells after downregulation of MMP-9 and in tissues of MMP-9-deficient mice, consistent with PN-1 degradation by MMP-9. We identified three MMP-9 cleavage sites in PN-1 and showed that mutations in those sites made PN-1 more resistant to MMP-9. Urokinase plasminogen activator (uPA) is inhibited by PN-1. MMP-9 augmented uPA activity in the medium of PC3-ML cells by degrading PN-1. Prostate cancer cells, overexpressing PN-1 or treated with MMP-9 shRNA, had reduced cell invasion in Matrigel. PN-1 siRNA restored uPA activity and the invasive capacity. PN-1 mutated in the serpin inhibitory domain, the reactive center loop, failed to inhibit uPA and to reduce Matrigel invasion. This study shows a novel molecular pathway in which MMP-9 regulates uPA activity and tumor cell invasion through cleavage of PN-1.
authors.affiliation: Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford, UK.
authors.forename: Danmei
authors.initials: D
authors.lastname: Xu
authors.forename: Chad M
authors.initials: CM
authors.lastname: McKee
authors.forename: Yunhong
authors.initials: Y
authors.lastname: Cao
authors.forename: Yunchuan
authors.initials: Y
authors.lastname: Ding
authors.forename: Benedikt M
authors.initials: BM
authors.lastname: Kessler
authors.forename: Ruth J
authors.initials: RJ
authors.lastname: Muschel
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D045744:Cell Line, Tumor; D006801:Humans; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009361:Neoplasm Invasiveness; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000473:pathology*; D058255:Protease Nexins; D034741:RNA, Small Interfering / Q000235:genetics; D011956:Receptors, Cell Surface / Q000378:metabolism*; D058258:Serpin E2; D015843:Serpins / Q000378:metabolism*; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
chemical_list: D016564:Amyloid beta-Protein Precursor; D058255:Protease Nexins; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; C545486:SERPINE2 protein, human; D058258:Serpin E2; C511869:Serpine2 protein, mouse; D015843:Serpins; D014568:Urokinase-Type Plasminogen Activator; D020780:Matrix Metalloproteinase 9