[Anti-cancer action by PPARgamma ligand].

Accumulating evidences have shown that thiazolidinediones (TZDs), PPARgamma ligands, could exert anti-cancer actions in several human cancer cells. TZDs are capable to inducing growth inhibition, apoptosis and inhibition of cell invasion, thereby leading to their anti-cancer effects. The growth inhibition was mediated by a cyclin-dependent kinase inhibitor, p27(Kip1), accumulation which is induced by both inhibition of ubiquitylation of p27(Kip1) and reduction of degradation activity of p27(Kip1) by proteasome. In addition, a recent clinical observation has showed a 33% reduction in lung cancer risk among TZD users who have diabetes mellitus compared with nonusers, strongly suggesting TZDs possess clinically relevant actions. These results suggest that TZDs may be novel agents to treat malignant tumor.