Lysophosphatidic Acid Stimulates Urokinase Receptor (uPAR/CD87) in Ovarian Epithelial Cancer Cells

Background/Aim: Lysophosphatidic acid (LPA) is a bioactive lipid positively linked with ovarian cancer progression. The multi-functional urokinase receptor (uPAR), a cell-surface glycoprotein, binds and facilitates activation of uPA and laterally regulates integrin and tyrosine kinase receptor activities in promotion of cell migration and invasion. We hypothesized that LPA stimulates uPAR expression and activity in ovarian epithelial cancer cells. Materials and Methods: Ovarian epithelial cancer cell lines OVCA 429 and OVCA 433 were stimulated with LPA and examined for uPAR mRNA expression and protein localization. uPA binding to OVCA plasma membranes was measured through enzymatic analysis of affinity-isolated cell-surface proteins. Results: LPA drove cell-surface uPAR aggregation and mRNA expression concomitant with increased cell-surface binding of uPA. Both control and LPA-stimulated uPAR expression and uPA cell-surface association involved phosphatidylinositol 3-kinase, but not p38 or p42 mitogen-activated protein kinase, signaling. Conclusion: These data provide mechanistic insight into ovarian epithelial cancer cell progression by demonstrating that LPA drives uPAR expression and uPA binding.