天花粉蛋白诱导NB4人白血病细胞凋亡研究

为了研究单链核糖体失活蛋白天花粉蛋白(trichosanthin，TCS)诱导人类白血病细胞株NIM细胞的凋亡及增长抑制的影响，采用流式细胞术分析NB4细胞经TCS诱导后细胞膜联蛋白V(annexin V)表达及线粒体膜电位(△ψm)的改变：用MTT比色法测定TCS对NB4细胞的增长抑制率，用琼脂糖凝胶电泳做细胞凋亡DNA分析。结果表明：小TCS对NB4细胞具有明显的增长抑制作用，并随TCS浓度的升高及作用时间的延长，抑制现象愈加显著；②NB4细胞经TCS诱导后，annexin V呈阳性表达，随作用时间延长阳性率进一步升高；③线粒体△ψm随着凋亡细胞的增加而逐渐降低；④DNA电泳呈梯状条带，表明TCS对NB4细胞确实存在诱导凋亡作用。结论：天花粉蛋白在体外能够明显抑制NB4细胞的增长，并诱导细胞凋亡，为今后TCS应用于急性早幼粒白血病的临床治疗提供重要的实验依据。

Study on NB4 Cell Apoptosis Induced by Trichosanthin

In order to study the influence of trichosanthin (TCS) on apoptosis and growth inhibition of human NB4 cells in vitro, the expression of annexin V and the change of DeltaPsim of NB4 cells induced by TCS was analyzed by FACS, and MTT assay was adopted to measure the growth inhibition ratio of NB4 cells treated with TCS. Apoptosis was assayed by agarose gel electrophoresis. The results showed the higher concentration of TCS and the longer the acting time, the stronger growth inhibition of NB4 cells. The expression of annexin V was positive, and the positive ratio was greatly enhanced with prolongation of acting time. DeltaPsim reduced gradually while the apoptosis cells increasing. DNA agarose gel electrophoresis showed a gradient, which confirmed that TCS could induce NB4 cells apoptosis. In conclusion, taken together, data show that TCS can inhibit NB4 growth in vitro, and induce apoptosis. Experiment provides an important evidence for application of TCS in clinical treatment of acute promyelocytic leukemia.