Fangchinoline inhibits rat aortic vascular smooth muscle cell proliferation and cell cycle progression through inhibition of ERK1/2 activation and c- fos expression

Abstract

Fangchinoline (FAN; a plant alkaloid isolated from Stephania tetrandrae) is a nonspecific Ca 2+ channel blocker. The objective of the present study was to investigate the effect of FAN on the growth factor-induced proliferation of primary cultured rat aortic smooth muscle cells (RASMCs). FAN significantly inhibited both 5% fetal bovine serum (FBS)- and 50 ng/mL platelet-derived growth factor (PDGF)-BB-induced proliferation, [ 3 H ]thymidine incorporation into DNA and phosphorylation of extracellular signal-regulated kinase 1/2. In accordance with these findings, FAN revealed blocking of the FBS-inducible progression through G 0/G 1 to S phase of the cell cycle in synchronized cells and caused a 62% decrease in the early elevation of c- fos expression induced after 5% FBS addition. Furthermore, significant antiproliferative activity of FAN is observed at concentrations below those required to achieve significant inhibition of Ca 2+ channels by FAN. These results suggest that FAN reduced both FBS- and PDGF-BB-induced RASMCs proliferation by perturbing cell cycle progression. This antiproliferative effect of FAN is dependent on the MAP kinase pathway, but cannot be limited to its Ca 2+ modulation.