LPA abrogates TSP-1–mediated inhibition of angiogenic signaling via LPA_1,3 and PKD-1. MVECs were exposed to LPA (5μM) for 24 hours and then were treated with FGF-2 (50 ng/mL) with or without TSP-1 (2nM) for 30 minutes. Cell lysates were subjected to Western blot using antibodies to phospho-VEGFR-2Tyr1175 (P-VEGFR; A) or phospho-Akt (P-Akt; B). (C) Cells were pretreated with CID 755673 (25μM) or Ki14625 (2μM) for 30 minutes followed by LPA for 24 hours and then analyzed as in panel B. Blots were stripped and reprobed with antibodies to total VEGFR-2 or Akt as loading controls. Blots are representative of 2 independent experiments.