title: 37-kDa laminin receptor precursor mediates GnRH-II-induced MMP-2 expression and invasiveness in ovarian cancer cells.
abstract: GnRH-II enhances ovarian cancer cell invasion in an autocrine manner. We have now found that GnRH-II increases 37-kDa laminin receptor precursor (LRP) production in GnRH receptor (GnRHR)-positive OVCAR-3 and CaOV-3 ovarian cancer cells, while small interfering RNA (siRNA)-mediated depletion of GnRH-II or GnRHR mRNA abrogates this. The invasiveness of ovarian cancer cells is also reduced >85% by siRNA-mediated knockdown of LRP levels and >50% by pretreatment of Matrigel with a synthetic peptide that blocks interactions between laminin and the 67-kDa nonintegrin laminin receptor which comprises two LRP subunits. Conversely, overexpressing LRP in CaOV-3 cells increases their invasiveness 5-fold, while overexpressing LRP with a nonfunctional laminin-binding site does not. Depletion of LRP by siRNA treatment reduces CaOV-3 cell attachment to laminin-coated plates by ∼80% but only reduces their binding to Matrigel by ∼20%. Thus, while LRP influences CaOV-3 cell adhesion to laminin, LRP must act in other ways to enhance invasion. Matrix metalloproteinases (MMPs) are key mediators of invasion, and LRP siRNA treatment of OVCAR-3 and CaOV-3 cells inhibits MMP-2 but not MMP-9 mRNA levels. Overexpressing LRP in these cells increases MMP-2 production specifically, while a laminin-binding deficient LRP does not. Importantly, LRP siRNA treatment abolishes GnRH-II-induced MMP-2 production, and invasion in OVCAR-3 and CaOV-3 cells, which was also seen after MMP-2 siRNA treatment. These results suggest that GnRH-II-induced LRP expression increases the amount of the 67-kDa nonintegrin laminin receptor, which appears to interact with laminin in the extracellular matrix to promote MMP-2 expression and enhance ovarian cancer cell invasion.
authors.affiliation: Department of Obstetrics and Gynecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Song Ling
authors.initials: SL
authors.lastname: Poon
authors.forename: Christian
authors.initials: C
authors.lastname: Klausen
authors.forename: Geoffrey L
authors.initials: GL
authors.lastname: Hammond
authors.forename: Peter C K
authors.initials: PC
authors.lastname: Leung
mesh_terms: D002448:Cell Adhesion; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003094:Collagen / Q000378:metabolism; D004338:Drug Combinations; D005260:Female; D015870:Gene Expression; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007797:Laminin / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000235:genetics* / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D009361:Neoplasm Invasiveness; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017474:Receptors, Laminin / Q000235:genetics / Q000378:metabolism*
chemical_list: D004338:Drug Combinations; D007797:Laminin; D011498:Protein Precursors; D011509:Proteoglycans; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017474:Receptors, Laminin; C059485:matrigel; D007987:Gonadotropin-Releasing Hormone; D003094:Collagen; C047717:LHRH, His(5)-Trp(7)-Tyr(8)-; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9