去铁胺诱导K562细胞凋亡研究

目的：探讨铁螯合剂去铁胺（DFO）诱导白血病细胞凋亡的分子机制。方法：实验分为DFO组(终浓度分别为10、50、100 μM)、DFO+FeCl3（各10 μmol/L）组及空白对照组。用钙黄绿素检测K562细胞可变铁池。锥虫蓝活细胞拒染实验进行活细胞计数及细胞存活率测定；光镜形态学观察及流式细胞仪方法检测K562细胞凋亡；比色法检测caspase-3活性。结果：（1）DFO作用于K562细胞后，随培养时间延长及DFO浓度的增加，动态铁池降低，细胞生存率逐渐下降，凋亡率增加，显示一定的时间剂量依赖性；而DFO+FeCl3组细胞凋亡率与空白对照组差异无统计学意义。（2）50 μmo/L、100 μmol/L DFO作用于K562细胞24 h时，caspase-3酶活性升高明显，与对照组相比，差异有统计学意义(P<0.01)；相关分析结果显示，K562细胞铁池的荧光改变与caspase-3活性变化呈负相关(r=-0.894, P<0.05)。结论：DFO诱导白血病细胞凋亡的作用可能与螯合细胞内铁，降低细胞可变铁池，激活caspase-3有关。

Deferoxamine induces apoptosis of K562 cells

Objective To study the molecular mechanism of apoptosis of leukemic cells(K562 cells) induced by iron chelating agent deferoxamine(DFO). Methods The exponentially growing K562 cells were used(1×106/mL) in this study.The K562 cells were treated with different concentrations of DFO(10,50 and 100 mmol/L),DFO+FeCl3(10 μmol/L each) or normal saline(blank control).The cellular labile iron pool was measured with a fluorimetric assay using the metalsensitive probe calcein-AM.The viable count and cell viability were determined by typanblue assay.Cell apoptosis was determined by morphological study and flow cytometry assay.Caspase-3 activity in K562 cells was detected by colorimetry. Results After DFO treatment,the cellular labile iron pool and the viability of K562 cells were reduced and the cell apoptosis increased in a time-and dose-dependent manner compared with the blank control group.The apoptosis rate of K562 cells in the DFO+FeCl3 treatment group was not significantly different from that in the blank control group.The caspase-3 activity in K562 cells increased significantly 24 hrs after 50 and 100 μmmol DFO treatment when compared with the blank control group(P<0.01).There was a negative correlation between cellular labile iron pool and caspase-3 activity of K562 cells(r=-0.894,P<0.05). Conclusions DFO induces apoptosis of leukemic cells possibly through decreasing cellular labile iron pool and increasing caspase-3 activity of the cells.