Aristolochic acid induces apoptosis of human umbilical vein endothelial cells in vitro by suppressing PI3K/Akt signaling pathway

Aim: To investigate whether aristolochic acid (AA) induced the apoptosis of human umbilical vein endothelial cells (HUVECs) in vitro and the underlying mechanism. Methods: HUVECs were treated with AA (5, 10 or 20 mu g/mL) for 12, 24 and 48 h. Cell viabilities were determined with MTT assay. Hoechst 33258 staining and flow cytometry were used to examine the apoptosis of HUVECs. Western blotting was used to evaluate Akt phosphorylation. Bcl-2 and Bax levels were measured using Western blotting and RT-PCR assays. Results: Treatment of HUVECs with AA significantly decreased the cell viabilities in dose-and time-dependent manners. Morphological changes of apoptosis were observed in AA-treated cells. AA inhibited Akt activation, which was attenuated by pretreatment of the cells with LY294002 (20 mu mol/L) or wortmannin (50 nmol/L). Furthermore, AA reduced Bcl-2 levels and increased Bax levels. Conclusion: AA induces apoptosis of HUVECs in vitro via the PI3K/Akt signaling pathway and by modulating the ratio Bcl-2 and Bax.