LPA abrogates TSP-1–mediated inhibition of migration and tubelike structure formation in vitro. (A) MVECs treated with LPA (5μM) or the vehicle control for 22 hours were subjected to migration assays using a modified Boyden chamber assay in which cells were exposed to FGF-2 (50 ng/mL), TSP-1 (2nM), or their combination. Migration was assessed microscopically after 24 hours by staining nuclei with DAPI (NS, not significant; **P < .01). (B) MVECs were exposed to 5μM (left) or 1-5μM of LPA (right) and then cultured for 24 hours in Matrigel containing FGF-2 (50 ng/mL), TSP-1 (2nM), or their combination. Cells were imaged with a Leica DM-RXE fluorescence microscope equipped with a 20×/0.50 NA objective interfaced to a computer with QCapture Version 6.0 software and the extent of the tubelike (cordlike) structure was quantified microscopically using ImageJ Version 1.40g software. Representative images are shown in the top left panel (scale bar = 50 μm); bar graphs show mean ± SEM (**P < .01; *P < .05).