鱼藤素对U937细胞细胞周期及核孔蛋白Nup98和Nup88的调控作用

目的研究鱼藤素对人类白血病细胞株U937细胞体外抗肿瘤作用，研究其引起细胞周期与核孔蛋白Nup98和Nup88的改变，探讨其抗癌作用的分子机制。方法采用MTT法检测细胞增殖活性，流式细胞术检测细胞周期分布，激光共聚焦显微镜检测Nup98和Nup88蛋白表达变化，免疫电镜和流式细胞术观测鱼藤素对Nup98和Nup88的调控，Western blot检测鱼藤素对U937细胞Nup98和Nup88蛋白表达的影响。结果①鱼藤素对U937细胞具有明显的增殖抑制作用，其抑制作用呈时间和剂量依赖性。②鱼藤素作用U937细胞后细胞周期发生变化，0、5、10、20、40、80nmol／L鱼藤素处理U937细胞24h，主要使细胞阻滞于S期和G2／M期，而G1／G0期细胞呈浓度依赖性降低。G1／G0期细胞比例依次为73．01％、71．15％、68．42％、52．45％、43．99％和22．82％，S期细胞比例依次为17．18％、16．30％、18．09％、27．56％、31．21％和46．85％，G2／M期细胞比例依次为9．75％、12．31％、13．09％、18．99％、24．83％和27．79％。③鱼藤素可以调节U937细胞Nup98和Nup88的表达，低浓度即可使Nup98表达上调，而使Nup88表达下调。结论鱼藤素能够抑制U937细胞增殖，使细胞阻滞于S期和G2／M期，而G1/G0期细胞呈浓度依赖性降低。其抗肿瘤机制可能通过参与调控U937细胞Nup98和Nup88的表达，使Nup98表达上调，而使Nup88表达下调有关。

Deguelin regulates cell cycle and nuclear pore complex protein Nup98 and Nup88 in U937 cells in vitro

OBJECTIVE: To investigate antitumor activity and molecular mechanism of deguelin to the human U937 leukaemia cells and to explore the mechanisms regulating cell cycle and nucleoporin 98 (Nup98) and nucleoporin 88 (Nup88) in vitro. METHODS: The effects of deguelin on the growth of U937 cells were studied by MTT assay, and the cell cycle of U937 cells by a propidium iodide method. The localization of the nuclear pore complex protein Nup98 and Nup88 was checked by immunoflurescence and immunoelectron microscopy. The expressions of Nup98 and Nup88 in U937 cells were checked by flow cytometry (FCM) and Western blot respectively. RESULTS: The proliferation of U937 cells was significantly inhibited in a time-dose dependent manner in deguelin-treated group with a 24 h IC50 value of 21.61 nmol/L and 36 h IC50 value of 17.07 nmol/L. U937 cells treated with deguelin showed reduction in the percentages of cells in G0/G1, whereas accumulation of cells in S and G2/M phase. The ratio of G1/G0 phase cells were 73.01%, 71.15%, 68.42%, 52.45%, 43.99% and 22.82%, and that of S phase cells were 17.18%, 16.30%, 18.09%, 27.56%, 31.21% and 46.85%, and that of G2/M phase cells were 9.75%, 12.31%, 13.09%, 18.99%, 24.83% and 27.79% at deguelin concentrations of 0, 5, 10, 20, 40, 80 nmol/L respectively. Nup88 and Nup98 were found on both the nuclear and cytoplasmic side of the U937 cells. The expression of Nup98 was up-regulated and Nup88 down-regulated in deguelin treated U937 cells. CONCLUSION: Deguelin is able to inhibit the proliferation of U937 cells by regulating the cell cycle. The antitumor activity of deguelin was related to up-regulating the expression of Nup98 and down-regulating Nup88 protein.