中文摘要：

目的研究紫草素对人白血病NB4细胞增殖的影响及其作用机制。方法CCK-8法检测NB4细胞增殖。流式细胞术检测细胞周期和凋亡。Westernblot检测细胞c-MYC、ERK、P-ERK蛋白表达。用SPSS17．0软件包进行单因素方差分析及t检验。结果NIM细胞经紫草素处理后，细胞活力受到明显抑制（P〈0．01）；G，期细胞增多（P〈0．01），G2期和S期细胞减少（P〈0．01）；细胞凋亡率明显增加（P〈0．01）；c-MYC蛋白表达水平明显降低（P〈0．05），p-ERK水平明显升高（P〈0．01）。结论紫草素抑制NB4细胞增殖，可能机制是通过下调c．MYC蛋白的表达，EKR信号通路蛋白可能参与了这一过程。

英文摘要：

Objective To investigate the effect of shikonin on proliferation of leukemic NB4 cells and the potential mechanism. Methods CCK-8 assay was used to examine the proliferation inhibition of shikonin on NB4 cells. Cell cycle and apoptosis were detected by flow cytometry. The expression of c-MYC, ERK and p-ERK were detected by Western blot. Results Shikonin inhibited NB4 cell proliferation in concentration and time dependent manner（P 〈 0. 01 ）. The percentage of cells in G1 phase increased while decreased in G2 and S phases（P 〈0. 01 ）. The rate of apoptosis in the shikonin group was obviously higher than that of control group （P 〈 0. 01 ）. The expression of c-MYC decreased（P 〈 0. 05 ） and p-ERK increased（P 〈 0. 01 ）. Conclusions Shikoin can inhibit NB4 prolifera- tion through down-regulation of c-MYC with involvement of ERK pathways.