Inhibition of lysophosphatidic acid receptor-2 expression by RNA interference decreases lysophosphatidic acid-induced urokinase plasminogen activator activation, cell invasion, and migration in ovarian cancer SKOV-3 cells

Abstract

Aim: To explore the role of lysophosphatidic acid receptor-2 (LPA 2) in regulating lysophosphatidic acid (LPA)-induced urokinase plasminogen activator (uPA) activation, cell invasion, and migration in human ovarian cancer cell line SKOV-3. Methods: SKOV-3 cells were stimulated with LPA. Cell supernatant uPA level and activity were measured using enzyme-linked immunosorbent assay. LPA2 mRNA expression was inhibited with LPA 2-specific small interfering RNA (siRNA) and examined using semiquantitative reverse transcriptase-polymerase chain reaction. LPA-induced cell invasion and migration in transfected cells were evaluated by a Matrigel invasion chamber and a Transwell chemotaxis chamber, respectively. Results: LPA stimulation significantly enhanced in vitro uPA activity in time- and dose-dependent manner. The levels of LPA-induced uPA protein decreased by 55% in LPA2 siRNA-transfected cells compared with negatively transfected cells at 24 hours after being treated with 80 μmol/L LPA (0.75 ± 0.03 vs 0.34 ± 0.04, P = 0.004). In the LPA2 specific siRNA-transfected SKOV-3 cells, LPA treatment at 80 μmol/L induced considerably less invasion and migration compared with negative control siRNA-transfected SKOV-3 cells (invasion: 178 ± 17.2 vs 36.2 ± 3.3, P = 0.009; migration: 220.4 ± 25.5 vs 57 ± 7.6, P = 0.009). Conclusion: LPA2 has an essential role in LPA-induced uPA activation and tumor cell invasion in ovarian cancer SKOV-3 cells.