ABSTRACT
Aim Toinvestigatetheeffectsoftriptonot-erpene methyl ether ( TME ) , a diterpene derived from the medicinal plant Triptergium wilfordii, on human gastric cancer AGS cell proliferation inhibition and ap-optosisinducedinvitro.Methods MTTassaywas used for screening tumor spectrum and detecting the vi-ability of AGS cells and normal human gastric epitheli-al cells GES-1 . Cell morphology was observed by light microscopy and AO / EB staining. Flow cytometry was used to detect cell apoptotic rate and cell cycle. JC-1 staining and fluorescence probe DCFH-DA were em-ployed to detect the changes of mitochondrial mem-brane potential and reactive oxygen species ( ROS ) . The effect of inhibiting AGS clonogenic survival was as-sayed by the method of plate clone formation. Western blot was used to analyse the expression of caspase-3 , caspase-8,Bcl-2andBax.Results MTTresults showed that TME exhibited significantly higher cytotox-icity to gastric cancer AGS cell line than to noncancer-ous cell line GES-1. IC50 for AGS of 48 h treatment was 23 . 85 μmol · L-1 . TME significantly inhibited colony formation and caused morphological changes in AGS cells. Annexin V-FITC / PI double staining showed the apoptotic rate increased. DCFH-DA stai-ning showed TME resulted in an increase in intracellu-lar ROS levels. Mitochondrial membrane potential de-creased after TME treatment. Western blot results showed that TME increased the proportion of Bax /Bcl-2 , with the activation of caspase-8 and caspase-3 . The broad-spectrum caspase inhibitor z-VAD-fmk pre-treatment reduced the expression of caspase-8 and caspase-3. TME enabled AGS cell cycle arrest in G0/G1phase.Conclusion TMEpossessespotenttumor selected toxicity and can induce apoptosis of AGS cells through cell cycle arrest, which is associated with Bcl-2 protein family.