ABSTRACT
Objective To study the inductive effect of Cortex Periplocae extract(CPE) on apoptosis of human gastric cancer cells BGC-823 and its mechanism.Methods The cell morphology and super-microstructural changes of apoptosis were analysed by Giemsa staining and electric microscope,respectively.The BGC-823 apoptosis ratio,cell cycles,and changes of apoptosis in DNA level were studied by Flow Cytometry and agarose gel electrophoresis.The genes mRNA and protein expression of apoptosis-related genes bcl-2,bax,and survivin were studied by RT-PCR and immunology cell chemistry method.Results After treatment with CPE,BGC-823 cells showed some typical morphologic features and super-microstructural changes of apoptosis.DNA agarose gel electrophoresis showed characteristic "DNA ladder" pattern.Most BGC-823 cells were arrested at G_2/M phase.Some typical subdiploid peaks before G_0/G_1 phase were observed.The apoptotic rate of BGC-823 was 18.9% after 250 ?g/mL CPE treated for 48 h.The gene mRNA and protein expression of bcl-2 and survivin were inhibited by CPE,whereas that of bax was up-regulated.CPE could enhance the life span of S_(180) bearing mice in a dose-dependent manner.Conclusion(CPE can) inhibit the tumor growth by arresting the BGC-823 cell cycle at G_2/M phase and inducing BGC-823 apoptosis.Its mechanism is related to the inhibition on gene mRNA and protein expression of bcl-2 and survivin,and enhancement of those of bax.