Potent PPARγ antagonist (IC50 values 3.3 nM, 32 nM and 2000 nM for PPARγ, PPARα, and PPARδ, respectively) which inhibits growth of breast tumour cells and promotes the anticancer effects of the PPARγ agonist rosiglitazone, independently of PPARγ activation. GW 9662 profoundly improved healing and induced angiogenesis in human mesenchymal stem cells (hMSCs), and reversed the protection of endotoxin (lipopolysaccharide, LPS) in a model of renal ischemia-reperfusion.