RESUMEN
Objective To investigate the effects of periplocin from Cortex Periplocae (CPP) on apoptosis of human lung cancer A549 cells and expression of survivin, and demonstrate its anti-tumor effect and the possible mechanism. Methods Inhibitory effect of CPP at different concentrations (1. 25, 2. 50, 5. 00, 10. 00, 20. 00 ng·mL-1 ) and for different time length (24, 48, 72 h) on A549 cell proliferation was tested by MTT method. Apoptosis rate of A549 cells treated with CPP at different concentrations (2. 50, 5. 00, 10. 00 ng·mL-1 ) were measured using flow cytometry (FCM) for 6, 12, 24, 48, 72 h, respectively. The morphological and ultrastructural changes of the apoptosis cells were observed by acridine orange/ ethidium bromide (AO/ EB) staining and transmission electron microscopy (TEM). The effects of CPP on mRNA and protein expression of apoptosis associated gene survivin were assessed by RT-PCR and Western blotting. Results CPP could significantly inhibit the growth of A549, and the inhibition rate reached (93. 46±2. 35)% . The results of FCM showed that the apoptosis rate of A549 cells treated with CPP was increased significantly as compared to the control group ( P<0. 05). Meanwhile, typical apoptotic peaks were detected. The characteristic morphological changes of apoptosis were observed in A549 exposed to CPP, including cell shrinkage, the nuclei became yellow-red by AO/ EB staining, and typical ultrastructural changes, including nuclear chromatin condensation along the nuclear membrane, vacuolar degeneration of cytoplasm observed by TEM. The result of RT-PCR indicated that survivin mRNA expression decreased obviously in A549 cells exposed to CPP. The protein expression of survivin in A549 cells treated with 10. 0 ng·mL-1 CPP(0. 251±0. 012)was weaker than that in control group(0. 928±0. 016). Conclusion CPP can induce apoptosis in human lung cancer cell lines A549, and the probable mechanism is related to the down-regulation of survivin mRNA and protein.