W146 TFA is a selective sphingosine-1-phosphate receptor 1 ( S1PR1 ) antagonist with an EC 50 value of 398 nM.

W146 is a S1PR1 antagonist with a K i of ~70-80 nM [1]. W146 pretreatment significantly increases activated cleaved caspase-3 levels. The reduced apoptosis of EPCs induced by S1P is completely abolished after treatment with W146 [2]. Apoptosis Analysis [2] Cell Line: Endothelial progenitor cells (EPCs). Concentration: 10 μM. Incubation Time: 30 min before the addition of S1P. Result: Increases activated cleaved caspase-3 levels.

W146 (5 mg/kg, ip, prior to AMD3100 administration) pre-treatment exhibits an approximately 8-fold increase of KSL-HSPC mobilization, measured by the CFU-G/M colony forming assays, compared to that in mice treated with AMD3100 alone [3] The W146-mediated augmentation of KSL-HSPC mobilization is specific, because pretreatment of mice with W140 is unable to produce any effect on AMD3100-stimulated KSL-HSPC mobilization. Injections of W146, W140, JTE013, or Cay10444 do not alter the basal WBC count in mice [3]. Animal Model: Mice (4-6-week-old) [3]. Dosage: 5 mg/kg. Administration: IP, 1 hour prior to AMD3100 (ADM) administration. Result: Significantly increased in KSL-HSPC mobilization compared to that in mice pretreated with dextran followed by AMD3100 administration.