关键词: 乳腺肿瘤, 凋亡细胞, MCF-7, caspase-8

Abstract: To study the effect of 20(S)-ginsendoside Rg3(SPG-Rg3) on apoptosis of human mammary carcinoma line MCF-7 cells and its possible mechanism. Methods Human mammary carcinoma line MCF-7 cells were divided into experiment group of SPG-Rg3 and control group. The inhibition of SPG-Rg3 on the growth of MCF-7 cells was detected by MTT assay,IC₅₀ was calculated to obtain the effective concentration; flow cytometry was used to observe the cell cycle of MCF-7 cells; AO/EB fluorescence double-dye technology was performed to observe the apoptosis of cells in morphology,immunocellularchemistry and RT-PCR were utilized to investigate the apoptosis of MCF-7 cells and its relationship with caspase-8 from protein level and molecule level. Results The IC₅₀ of SPG-Rg3 was (155.7±0.71) mg•L^-1,when the concentration of SPG-Rg3 was arranged from 37.5 to 600.0 mg•L^-1,the growth inhibitory rate of MCF-7 cells was higher following the increase of its concentration,the cell growth was greatly inhibited compared with control group(P<0.05); cell cycle was changed,the cell number of S period increased compared with control group(P<0.01),the cell number of G₂/M period decreased compared with control group(P<0.01),in experiment group there was an apoptotic apex before G1 apex,and the number of apoptotic cells increased; most of cell nuleus in SPG-Rg3 (150 mg•L^-1)experiment group appeared yellow or chrysoidine fluorescence,contracted,beaded and crescent; the result of immunocellularchemical staining of caspase-8 indicated that caspase-8 protein had no expression in control group,but stronger expression in SPG-Rg3 group. HSCORE scores of the two groups were 1.894±0.027 and 2.869±0.043,the difference was markable(P<0.01). MCF-7 cells mRNA was extraited and caspase-8 primers were designed to perform RT-PCR,caspase-8 expressed strongly in experiment group and nothing in control. Conclusion SPG-Rg3　 could induce MCF-7 cell apoptosis,and the possible mechanism may be related to activating caspase-8.

Key words: breast neoplasms, apoptosis, MCF-7, caspase-8