DOV13 cells were plated and serum starved, as described in methods, and treated with the indicated S1P concentrations in SFM for 6 hours before CM was collected and (A) applied to the DQ gelatinase activity assay; and (B) separated on 15% SDS-PAGE zymography gels and stained. (C) Cell were treated as above for 4 or 24hrs, then cell surface proteins were biotin labeled and isolated from cell extracts through affinity streptavidin binding and separated on gradient 12.5% SDS PAGE gels, and analyzed by western analysis. Bars represent average of 2–3 assays, and gelatinolytic activity is represented relative to control (vehicle for S1P). Error bars=SEM. * Indicates p<0.05; ** = p<0.005.