K562细胞诱导分化过程中早期生长反应基因mRNA表达的研究

目的 通过12-0-十四酰基咐哌醇-13-乙酸酯(TPA)诱导K562细胞分化,探讨白血病细胞早期生长反应基因(EGR-1)的表达及与细胞分化的关系。方法应用体外细胞培养技术通过细胞形态、细胞化学染色观察细胞分化的情况;用流式细胞术、逆转录-聚合酶链反应等技术检测细胞周期、纽咆表面分化抗原CD33、CD14及EGR-1 mRNA的表达。结果 TPA作用后K562细胞形态趋向成熟分化,非特异性酯酶(NSE)染色阳性,多可被氟化钠抑制;多数细胞被阻滞在G0 G1期,S期细胞减少;随处理时间的延长细胞表面抗原CD33,表达有所减少,CD14表达逐渐增多;EGR1 mRNA仅在TPA诱导K562细胞分化过程中表达。结论 TPA可诱导K562细胞向单核或巨噬细胞分化;EGR1-mRNA在TPA诱导K562细胞分化过程中才有表达,它可能参与K562细胞向单核或巨噬细胞分化的过程,并在诱导和维持细胞分化方面可能发挥重要作用。

EGR-1 mRNA expression during 12-0-tetradecanoylphorbol-13-acetate-induced K562 cell differentiation

OBJECTIVE: 12-0-tetradecanoylphorbol-13 acetate (TPA) plays an important role in precipitating cell differentiation for various tumor cells, especially leukemic cells. Changes of many genes may be involved in this process. The purpose of this study was to observe the relationship between the EGR1mRNA expression and cell differentiation during TPA-induced K562 cell differentiation. METHODS: Incubation of human K562 cells in vitro was applied to cultivate K562 cells. The cells were treated in two different ways. K562 cells of experiment group were treated with TPA and those of control group were treated without TPA. Using morphology (Wright's staining and NSE staining) and flow cytometry (FCM), the investigators observed the differentiation characteristics of K562 cells, cell-cycle and the differentiation antigen expressions of CD33 and CD14 on cell membranes. RT-PCR was carried out to assay EGR1 mRNA expression. RESULTS: After treated with TPA for 7 d, the morphology of K562 cells obviously tended to mature differentiation, like monocytes. The differentiation rate of induced K562 cells was up to 95% in experiment group and 4.5% in control group, respectively. Using SPSS software, the above result showed statistical significance (P < 0.01). Using NSE staining, K562 cells showed positive reaction. Some of them were densely stained. The positive rate was up to 86%. More than half of the positive cells could be inhibited by NaF. The inhibiting rate of NaF was up to 58.72%, showing statistical difference when compared with that of control group. FCM analysis showed that most of K562 cells stimulated by TPA underwent G1/S phase cell-cycle arrest. The composing rate of cell-cycle in TPA-treated group showed that (53.7 +/- 1.25)% of cells were at G0 + G1 phase and (44.3 +/- 1.32)% were at S phase (P < 0.05). The level of CD33 expression on cell membranes was mildly decreased from 0.997% to 0.893% (P > 0.05). However, the level of CD14 expression was significantly increased from 0.049% to 0.387% (P < 0.05). CONCLUSION: K562 cells could express EGR1mRNA during TPA-induced differentiation, which suggested that EGR1mRNA might participate in the process of K562 cells differentiating into monocyte/macrophages, and might play an important role in precipitating and maintaining cell differentiation for leukemic cells.