苦马豆素诱导人胃癌细胞SGC-7901凋亡作用机制的实验研究

目的:探讨SW体外诱导人胃癌细胞株SGC7901凋亡的机制。方法:应用MTT法确定SW对体外培养的SGC7901细胞的作用剂量,通过流式细胞术及凋亡相关调控基因p53、cmyc、Bcl2的检测对细胞凋亡及细胞周期的测定,观察SW对胃癌细胞SGC7901增殖周期的影响以及抑制肿瘤细胞增殖的方式,同时利用激光共聚焦显微镜对细胞内Ca2 浓度的监测,研究SW与细胞内Ca2 超载的关系。结果:SW体外抗SGC7901细胞的完全致死剂量为6.2μg·ml-l,高于0.05μg·ml-l时抑制作用明显(P<0.05),其LC50为0.84μg·ml-l;经SW0.5～1.5μg·ml-l处理24h可引起凋亡抑制基因p53、Bcl2的明显下降、凋亡促进基因cmyc的明显升高以及肿瘤细胞内Ca2 超载,最终诱导SGC7901细胞凋亡。实验还证实SW主要作用于肿瘤细胞的S期,使瘤细胞主要积聚在S期。结论:SW通过多种途径诱导细胞凋亡可能是其发挥抗癌作用的重要机制。

Research of mechanisms of swainsonine-induced apoptosis in the human gastric carcinoma cell line SGC-7901

AIM: To investigate the effects and mechanisms of swainsonine-induced apoptosis on SGC-7901 cells. METHODES: After being treated with swainsonine, effective dose and median inhibition concentration (IC50) of swainsonine to SGC-7901 cells were examined by MTT assay. Cell cycle distribution and apoptotic rates were analyzed by flow cytometry. Expression of p53, c-myc and Bcl-2 were determined by immunocyto- chemical method, and the concentration of Ca2+ intra-cellular (Ca2+]i ) was measured by the laser scanning confocal microscope (LSCM). RESULTS: Swainsonine inhibited cell growth of SGC-7901 in vitro, IC50 of 24 h was 0.84 μg·ml-l, and complete inhibition concentration of swainsonine was 6.2 μg·ml-l. Treated with swainsonine at the concentrations of 0.5, 1.5 and 4.5 μg·ml-l for 24 h, the expression of apoptosis inhibiting gene p53 and bcl-2 decreased, and apoptotic trigger gene c-myc increased (P<0.05), as well as Ca2+]i overloading, SGC-7901 cell was induced to apoptosis in the end. The percentage of S phase were 38.8%, 39.7% and 29.6%, respectively (20.0% in control group and 23.2% in 5-Fu group), the percentage of G2/M phase were 4.5%, 1.7% and 5.3%, respectively (5.5% in control group and 9.0% in 5-Fu group), and the percentage of G1/M phase was not altered. SGC-7901 cells were treated by swainsonine at the concentrations of 0.5, 1.5 and 4.5 μg·ml-l for 24 h. Compared with the control group, the percentage of S phase were increased and that of G2/M cells were decreased significantly in treatment groups (P<0.01). CONCLUSION: Swainsonine can inhibit the cell proliferation and induce apoptosis of SGC-7901 cells, the mechanisms of swainsonine-induced apoptosis may related with Ca2+]i overloading and expression of apoptosis-related genes.