Urokinase type plasminogen activator receptor is involved in insulin-like growth factor-induced migration of rhabdomyosarcoma cells in vitro.
Urokinase-type plasminogen activator (uPA) binds to its receptor, uPAR, on the surface of cancer cells, leading to the formation of plasmin. Rhabdomyosarcoma (RMS) cell lines secrete high levels of insulin-like growth factor II (IGF-II), suggesting autocrine IGFs play a major role in the unregulated growth and metastasis of RMS. In vitro, IGF-II and IGF-I increased migration of RD cells to 124+/-9% (P<0.01) and 131+/-8% (P<0.05) of control, respectively. IGF-II-induced migration was abolished by insulin-like growth factor binding protein-6 (IGFBP-6) (P<0.01), a relatively specific inhibitor of IGF-II, and by plasminogen activator inhibitor type 1 (PAI-1) (P<0.05). Aprotinin, a plasmin inhibitor, and mannosamine, which inhibits the synthesis of glycosylphosphatidylinositol (GPI), thereby preventing anchorage of GPI-linked proteins such as uPAR to the cell membrane, also decreased IGF-II- (P<0.05 for both) but not IGF-I-induced migration. [Arg54,Arg55]IGF-II and [Leu27]IGF-II, which preferentially bind to the IGF-I and IGF-II/mannose-6-phosphate receptors (IGF-II/M6PR), respectively, both induced RD cell migration to 146+/-8% (P<0.01) and 120+/-7% (P<0.05) of control, respectively. An anti-uPAR anti-serum reduced IGF-II- and IGF-I-induced migration (P<0.05 for both). An anti-low density lipoprotein-related protein (LRP) anti-serum reduced IGF-I-induced migration (P<0.05). IGF-I and -II both increased specific 125I-single chain uPA (scuPA) binding to RD cells in a dose-dependent manner (P<0.01). These results suggest involvement of the PA/plasmin system in IGF-induced migration and indicate important roles these systems may have in RMS metastasis.
Gallicchio
Marisa A
MA
Department of Medicine, University of Melbourne, Austin and Repatriation Medical Centre (Austin Campus), Heidelberg, Victoria, Australia.
Kaun
Christoph
C
Wojta
Johann
J
Binder
Bernd
B
Bach
Leon A
LA
D007611:Aprotinin / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D004797:Enzyme-Linked Immunosorbent Assay; D006595:Hexosamines / Q000378:metabolism; D006801:Humans; D018976:Insulin-Like Growth Factor Binding Protein 6 / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D012208:Rhabdomyosarcoma / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000096:biosynthesis / Q000187:drug effects; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000187:drug effects / Q000378:metabolism
D006595:Hexosamines; D018976:Insulin-Like Growth Factor Binding Protein 6; C524898:PLAUR protein, human; D017395:Plasminogen Activator Inhibitor 1; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; C008322:mannosamine; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D007611:Aprotinin; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator