去铁胺对白血病细胞K562/A02的影响及机制研究

本研究旨在探讨铁螯合剂去铁胺对人白血病耐阿霉素细胞K562/A02的影响及其作用机制。采用四甲基偶氮唑蓝法(MTT)检测不同浓度去铁胺作用48小时对K562/A02细胞增殖的抑制效应;流式细胞术检测去铁胺25、50、100和200μmol/L作用K562/A02细胞48小时后细胞的凋亡率;半定量RT-PCR检测各组细胞凋亡基因BAX、BCL-2以及多药耐药基因1(MDR1)mRNA表达变化;Western blot检测各组细胞P-糖蛋白(P-gp)表达变化。结果显示,随着去铁胺药物浓度的增加,细胞活力逐渐下降,凋亡率明显增加,呈剂量依赖性;随着去铁胺浓度增加,BAX表达水平逐渐升高,但MDR1 mRNA与P-gp的表达受到显著抑制。结论:去铁胺可以通过螯合细胞内铁,影响细胞DNA的合成;同时去铁胺可抑制阿霉素诱导的MDR1、P-gp表达,增加白血病细胞对化疗药物的敏感性,进而诱导凋亡。

Effect of Desferioxamine on K562/A02 Cell Line and Its Mechanism

Iron is an essential element for cell growing including tumor cells.This study was purposed to explore the effect of desferioxamine（DFO） on cell line K562/A02 and its mechanism.K562/A02 cells were cultured with different concentrations of DFO.The inhibitory effects of adriamycin（ADM） used alone or combined with DFO on the proliferation of K562/A02 was evaluated by MTT assay.The apoptosis rate of K562/A02 cells after treatment with 0,12.5,25 and 50 μmol/L DFO alone or in combination with 1 mg/L ADM were analyzed by flow cytometry.ADM accumulation in K562/A02 cells after treatment with different concentrations of 0,12.5,25 and 50 μmol/L DFO were also analyzed by flow cytometry.The levels of BAX/BCL-2 and MDR1 mRNA were determined by RT-PCR,and then the protein level of P-glycoprotein（P-gp） was detected by Western blot.The results showed that the IC50 of ADM for K562 and K562/A02 cells were（1.46±0.07）mg/L and（40.98±3.05）mg/L respectively.The resistance of K562/A02 cells to ADM was 28.06 times as that of K562 cells.After treatment of K562/A02 cell with DFO of 12.5,25 and 50 μmol/L for 48 hours,the resistance of K562/A02 cells to ADM were increased by 24.95,16.11 and 9.99 times respectively.When K562/A02 cells were incubated with different concentrations of DFO of 12.5,25,50 μmol/L for 48 hours,the apoptosis rat were（3.50±0.30）%,（7.27±0.32）% and（12.53±1.21）% respectively.After co-culture with DFO and ADM for 48 hours,apoptosis rate were（6.13±0.29）%,（9.57±0.40）% and（18.97±1.10）% respectively.The above apoptosis rates was much higher than that of control group（p〈0.05） and they were dose-dependent.In comparison between DFO＋ADM group and DFO group,there was no significant difference（p〈0.05）.Expression rate of BAX/BCL-2 increased.The levels of MDR1 mRNA reduced.Furthermore,expression of P-gp also decreased in K562/A02 cells.It is concluded that iron increase can promote K562/A02 cells growth and inhibit their apoptosis.Otherwise,iron-deprivation can induce K562/A02 cells apoptosis.DFO disturbs the iron metabolism and inhibits DNA synthesis of K562/A02 cells.This action of DFO may enhance the suscepibility of K562/A02 cells to apoptosis induced by chemotherapeutic drugs.The iron-deprivation may play a role in the treatment of leukemia with combination of DFO with other anticancer agents.