ATX/LPC-regulated OPN expression is mediated by LPA2 receptor and activation of Akt and MAPK/ERK. SGC7901 cells were exposed to ATX, LPC, LPA, ATX/LPC2 or DMEM/0.1% BSA for 24 hours or 30 min, and then total RNA and protein were extracted for real time-PCR (A-D) and Western blot (E, F), respectively. (E) Immunoblotting was performed to detect the phosphorylation status of ERK and Akt. Total ERK and Akt levels were assessed as control. (F) The effects of the LPA inhibitor, ERK inhibitor and Akt inhibitor on ATX/LPC2-induced OPN expression in SGC7901 cells. SGC7901 cells were treated with Ki16425, PD98059, LY294002 or DMSO (0.1%; a solvent control) for 45 min prior to ATX/LPC2 treatment. 24 hours following stimulations, OPN expression was measured by Western blot analysis. All experiments were performed in triplicate and a representative result is shown here. Figure 2G showed the densitometric ratio of OPN protein/α-tubulin. Statistical analysis was performed using Student's t test. *p < 0.05.