关键词: 细胞黏附肽； 胃癌细胞系BGC823；细胞凋亡

Abstract:

Abstract:Objective To investigate the effect of cellular adhesion tripeptide  RGD on the growth and proliferation of human stomach cancer cells BGC823,and study the function of cellular adhesion tripeptide RGD in inducing BGC823 apoptosis.
Methods BGC823 cells cultivated in vitro were divided into control group,12.5,25.0,50.0 and 100.0 mg?L^-1  RGD groups. BGC823 cells were treated with cellular adhesion tripeptide RGD at various concentrations. MTT assay was used to examine the growth and proliferation of BGC823 cells after treatment with cellular adhesion tripeptide RGD for 48 h.Ordinary light microscope and transmission electron microscope were used to observe the morphology of apoptotic cells,and immunohistochemical method,flow cytometry were also used to analyze the BGC823 apoptosis.Results The results of MTT assay showed that in 12.5,25.0,50.0,100.0 mg·L^-1RGD groups after treated for 24,48 and 72 h,the inhibitory rates of  BGC823 were signiticantly higher then those in cortrol group  (P<0.01);with the increasing of the concentration of RGD,the inhibitory rate of  BGC823 cells increased.The results of ordinary light microscope showed that after treated with 50.0 mg·L^-1 RGD for 48 h,the morphology of BGC823 cells had some transmutations,the cells became smaller,nucleus was deeply stained,cytoplasm was red,and a lot of apoptotic cells were observed;the results of transmission electron microscopy observation  showed that the cell surface microvilli disappeared,and heterochromatin was aggregated toward the edge,they were all gathered on the nuclear membrane,formed a crescent-shaped cap structure,and the nuclear membrane was even disappeared,nucleus was fragmented,and  the  apoptotic bodies could be seen;the results of flow cytometry showed that BGC823 cells had undergone apoptosis,and the apoptotic peak became higher as the concentration increased;the electrophoresis results showed that the BGC823 cell’s DNA fragments had broken into various small fragments,limpid degradation of electrophoresis strips were observed.The result of immunohistochemistry showed that after  BGC823 cells were treated with 50.0 mg·L^-1  RGD,the Survivin expression was significantly  diminished,the average gray values were 196.56 ± 10.12 and 108.59 ± 14.26 respectively in control group and experimental group according to the results of the image analysis,there was significant difference(P<0.01),which indicated the apoptosis of BGC823 cells in experrmental group.
Conclusion Cellular　 adhesion tripeptide RGD may inhibit tumor cell growth and proliferation through inducing apoptosis,and the mechanism of inducing BGC823 apoptosis  is probably initiated mitochondria into this category.

Key words: RGD；BGC823 cells；apoptosis