Tanshinone: an inhibitor of proliferation of vascular smooth muscle cells.

Tanshinone (Tan) is one of the active components of Radix Salvia miltiorrhiza (Lamiaceae), which is clinically used to treat cardiovascular diseases in China. The aim of this study was to estimate the effect of Tan on the proliferation of cultured vascular smooth muscle cells (VSMCs) induced by fatal bovine serum (FBS). It was shown that various concentrations of Tan inhibited the VSMCs proliferation in a dose-dependent manner. Tan significantly blocked VSMCs cell cycle in G(0)/G(1) phase. The anti-proliferative effect of Tan was associated with the inhibition of the extracellular signal-regulated kinase1/2 (ERK1/2). On the other hand, the decrement of Tan on the cyclin D1 protein may be related to the high expression of p21(waf/cip1). The data suggest that the anti-proliferative effect of Tan on VSMCs proliferation was associated with ERK1/2 signaling pathway.