人参皂苷单体Rb1对人慢性粒白血病细胞K562增殖和分化的影响及其信号转导机制

Inhibition of proliferation and differentiation of human chronic granulocyte leukemia K562 cells by ginsenoside monomer Rb1 and relevant mechanism of signal transduction

目的 探讨人参皂苷单体Rb1对人慢性粒白血病细胞K562增殖和分化的影响及其细胞内信号转导机制。方法 取对数生长期的K562细胞,分别加入不同浓度（20、40、80、160、320μmol/L）的Rb1,MTT法检测其对K562细胞增殖的影响;加入浓度为160μmol/L Rb1,收集培养24、48和72 h的细胞,经Wright染色后,镜下观察Rb1诱导K562细胞成熟分化情况;Western blot法检测培养12、24、48和72 h的细胞中JAK2、STAT5、p-JAK2及p-STAT5的表达水平。结果 浓度为20～160μmol/L的Rb1对K562细胞的增殖具有明显的抑制作用,且呈剂量±赖性,作用48 h时抑制率达最高;经Rb1诱导后,K562细胞体积缩小,核直径减小,核和浆的比例降低,细胞向成熟方向分化;JAK2的表达水平随Rb1作用时间的延长而提高,p-JAK2的表达随着作用时间的延长而降低;各组间STAT5蛋白的表达水平无明显变化（P〉0.05）,但p-STAT5表达于作用48 h时开始降低,并持续至72 h。结论 人参皂苷单体Rb1可抑制人慢性粒白血病细胞K562增殖并诱导其向成熟方向分化,JAK2和STAT5的酪氨酸磷酸化在细胞增殖及诱导分化的信号转导过程中发挥重要作用。本实验为治疗白血病天然中药的研发提供了实验依据。

Objective To investigate the effect of ginsenoside monomer Rbl on proliferation and differentiation of human chronic granuloeyte leukemia K562 cells as well as the intracellular signal transduetion mechanism of Rbl. Methods The K562 cells at logarithmic growth phase were treated with Rbl at various concentrations （20, 40, 80, 160 and 320 μmol/L）, and determined for proliferation level by MTT method. The K562 cells at logarithmic growth phase were treated with 160 μmol/L Rbl, of which those cultured for 12, 24, 48 and 72 h were collected, subjected to Wright staining and observed for differentiation level by microscopy. The expression levels of JAK2, STATS, p-JAK2 and p-STATS in the cells 12, 24, 48 and 72 h after culture were determined by Western blot. Results Rbl at a concentration of 20 - 160 μmol / L showed significantly inhibitory effect on the proliferation of K562 cells in dose-dependent manner, while the inhibition rate reached a peak value 48 h after treatment. Both the size and nucleus diameter of K562 cells after induction with Rb1 decreased, while the ratio of nucleus to cytoplasm decreased, indicating the differentiation to erythroid cells. The expression level of JAK2 increased, while that of p-JAK2 decreased, with the increasing time for treatment with Rb1. The expression levels of STATS protein at various time points showed no significant difference （P 〉 0. 05 ）, while that of p-JAK2 decreased from 48 h until 72 h after treatment. Conclusion Ginsenoside Rbl may inhibit the proliferation andinduce the differentiation of K562 cells. However, the phosphorylation of tyrosine in JAK2 and STAT5 plays an essential role in signal transduction of proliferation and induction of differentiation of K562 cells. It provided a theoretical and practical basis for development of naturally traditional Chinese medicine for leukemia.