雷帕霉素对人淋巴瘤细胞株Raji细胞增殖抑制与自噬的机制研究

Rapamycin inhibits proliferation and induces autophagy of human Burkitt lymphoma cells

摘要:

目的  探讨雷帕霉素（宜欣可）对人淋巴瘤细胞株Raji细胞体外生长影响及诱导自噬的发生，并探讨可能的分子机制。方法  MTT法检测不同浓度（0、1、5、10、20、40、50及100 nmol/L）雷帕霉素作用不同时间（24、48及72 h）对Raji细胞增殖的影响。流式细胞仪测定雷帕霉素对Raji细胞周期分布和凋亡的影响。透射电镜观察Raji细胞形态学变化。Western blot方法检测雷帕霉素处理前后对Raji 细胞自噬蛋白Beclin1的影响。结果  雷帕霉素对Raji细胞增殖有明显的抑制作用（P <0.01或P <0.05）。呈现明显的剂量-效应和时间-效应依赖关系。雷帕霉素明显抑制Raji细胞周期发展（P <0.05），但没有发生明显的凋亡（P >0.05）。透射电镜观察到经100 nmol/L雷帕霉处理72 h后的Raji细胞胞质内有大量自噬体和自噬溶酶体。Western blot方法检测到0、1、10及100 nmol/L雷帕霉处理72 h后Beclin1蛋白表达逐渐上升，且呈浓度依赖性。结论  雷帕霉素通过阻滞细胞周期发展抑制Raji细胞增殖，诱导Raji细胞发生自噬但不能诱导其凋亡。

Abstract:

Objective To investigate the effect of Rapamycin on growth and autophagy of human Burkitt lymphoma cell line Raji cells and the possible mechanism. Methods Effect of Rapamycin in different concentrations (0, 1, 5, 10, 20, 40, 50 and 100 nmol/L) on proliferation of Raji cells at different time (24, 48 and 72 h) was detected by MTT assay. Apoptosis and cell cycle were analyzed using flow cytometry. The morphological changes were confirmed using transmission electron microscopy. The expression of Beclin1 protein was examined by Western blot technique in the Rapamycin-treated and untreated Raji cells. Results Rapamycin inhibited the proliferation of Raji cells at concentrations higher than 5 nmol/L (P < 0.05) and in a dose- and time-dependent manner. After treatment with Rapamycin, the number of cells in S phase and G2/M phase gradually decreased (P < 0.05), but that in G0/G1 phase significantly increased in a dose- and time-dependent manner (P < 0.05). However, it did not cause evident apoptosis in Raji cells. Using electron microscope, some large autolysosomes and vacuoles were observed in Raji cells treated with 100 nmol/L Rapamycin for 72 h. Raji cells treated with 0, 1, 10 and 100 nmol/L Rapamycin showed a dose-dependent up-regulation of expression of Beclin1 protein, the classic marker for antophagy. Conclusions Rapamycin inhibits Raji cell proliferation by cell cycle arrest in G0/G1 phase and induces autophagy.