As a key protein,annexin A5 involves in the process of invasion,metastasis and immune tolerance of tumors.And annexin A5 can not only promote the tumor,but also inhibit it.It has been widely concerned in the basic research targeting annexin AS.Because of the high affinity of annexin A5 for phosphatidylserine,annexin A5 is expected to be a new diagnostic marker and anti-tumor target.

ObjectiveTo study the inhibitory effect of Celastrus orbiculatus extract （COE） on gastric cancer cells， to clarify the specific mechanism of COE promoting the apoptosis of gastric cancer cells by affecting the mitochondrial structure and function， and to provide an experimental basis for the further development and clinical application of C. orbiculatus. MethodBrdu staining combined with flow cytometry and Annexin V-fluorescein isothiocyanate （AnnexinV-FITC） staining combined with flow cytometry were employed to detect the effects of COE （20， 40， 80 mg·L^-1） on the proliferation and apoptosis of gastric cancer cells， respectively. The changes in mitochondrial membrane potential were detected with JC-1 mitochondrial membrane potential assay kit. The expression of apoptosis-associated proteins including B-cell lymphoma-2 （Bcl-2）， B-cell lymphoma-xL （Bcl-xL）， Bcl-2-associated X （Bax）， and cysteine aspartutespecific protease-3 （Caspase-3） in gastric cancer cells was determined by Western blot. Transmission electron microscopy was employed to detect changes in the mitochondrial microstructure of gastric cancer cells exposed to COE. Western blot was employed to measure the expression of mitochondrial marker proteins ［superoxide dismutase 1 （SOD1）， voltage-dependent anion channel （VDAC）， prohibitin 1 （PHB1）， and heat shock protein 60 （HSP60）］ in gastric cancer cells. ResultCompared with the control group， COE （40， 80 mg·L^-1） inhibited the proliferation and promoted the apoptosis of gastric cancer cells （P<0.05）. Furthermore， COE reduced the mitochondrial membrane potential of gastric cancer cells. Compared with the control group， COE （20， 40， 80 mg·L^-1） up-regulated the expression of Bax and Caspase-3 which promoted apoptosis of gastric cells （P<0.05， P<0.01）， and COE at 40 and 80 mg·L^-1 down-regulated the expression of Bcl-2 and Bcl-xL which inhibited the apoptosis of gastric cancer cells （P<0.01）. The results of transmission electron microscopy showed that COE changed the microstructure of gastric cancer cells， which led to the appearance of vacuoles in the cell membrane and mitochondria and damaged the mitochondrial structure. Compared with the control group， COE （20， 40， 80 mg·L^-1） changed the expression of mitochondrial marker proteins. Specifically， it up-regulated the expression of SOD1 involved in stress response （P<0.05， P<0.01） and down-regulated that of VDAC， PHB1， and HSP60 associated with mitochondrial stability and permeability （P<0.01）. ConclusionCOE can significantly inhibit the proliferation and promote the apoptosis of gastric cancer cells. It may activate the mitochondrial apoptosis pathway by destroying the mitochondrial structure and function of gastric cancer cells.