核因子-κB活化抑制增强高三尖杉酯碱诱导白血病细胞凋亡

目的　研究地塞米松 (DXM)和长春新碱 (VCR)对高三尖杉酯碱 (HH)诱导白血病细胞凋亡与核因子 κB (NF κB)活化的影响。方法　采用TdT介导的dUTP缺口末端标记技术(TUNEL)、DNA电泳方法观察HH诱导K5 6 2 n细胞凋亡 ,采用电泳迁移率变动分析 (EMSA)观察HH诱导K5 6 2 n细胞NF κB活化。结果　用 (0 5、5、5 0 ) μmol/L的HH均能诱导K5 6 2 n细胞凋亡率分别为 (30 0 0± 3 34,4 7 13± 3 18,6 8 6 3± 8 14 ) % ,与对照组相比 ,有良好的浓度依赖关系 (P <0 0 5 ) ;DXM 1μmol/L和VCR 0 1μmol/L本身无诱导K5 6 2 n细胞凋亡的作用 ,但均能增强HH 0 5μmol/L诱导的K5 6 2 n细胞凋亡 ,凋亡增加率分别为 85 8%和 114 6 % (P值均 <0 0 5 )。K5 6 2 n细胞未经药物诱导NF κB也有轻度活化 ;HH 0 5 μmol/L可明显诱导K5 6 2 n细胞NF κB活化 ,DXM 1μmol/L和VCR 0 1μmol/L能显著抑制HH 0 5 μmol/L诱导的NF κB活化 ,抑制率分别为 32 0 %和39 4 % (P值均 <0 0 5 )。结论　HH诱导K5 6 2 n细胞凋亡的同时激活NF κB ;DXM和VCR可通过抑制NF κB活化 ,增强其诱导K5 6 2 n细胞凋亡的作用。

Inhibition of activation of nuclear factor-kappaB enhanced apoptosis of leukemic cells induced by homoharringtonine

OBJECTIVE: To explore the effects of dexamethasone (DXM) and vincristine (VCR) on apoptosis of K562-n cells and activation of nuclear factor-kappaB-gene binding (NF-kappaB) in K562-n cells induced by homoharringtonine. METHODS: K562-n cells were cultured in RPMI-1640 medium. Homoharringtonine of various concentrations was added into the cultures. Twelve hours later, the apoptosis induced by homoharringtonine in K562-n cells was analysed by TdT-mediated X-dUTP nick and end labeling (TUNEL) and DNA electrophoresis. Another sample of K562-n cells was culture together with DXM (1 micro mol/L) or VCR (0.1 micro mol/L) for 2 hours, then homoharringtonine was added into the cultures. Twelve hours later, the apoptosis in K562-n cells was analysed by TUNEL and DNA electrophoresis. Still another sample of K562-n cells was cultured for 3 hours with homoharringtonine, then electrophoretic mobility shift assay (EMSA) was conducted to determine the DNA-binding activation of NF-kappaB. A fourth sample of K562-n cells was cultured together with DXM (1 micro mol/L) or VCR (0.1 micro mol/L) for 2 hours, then homoharringtonine was added into the cultures. Three hours later, EMSA was conducted. RESULTS: The apoptosis rates of K562-n cells induced by homoharringtonine of various concentrations were (30.00 +/- 3.34)%, (47.13 +/- 3.18)% and (68.63 +/- 8.14)%, respectively. The apoptosis rates of K562-n cells induced by homoharringtonine being pre-processed with DXM or VCR were (55.75 +/- 3.88)% and (64.38 +/- 4.60)%, respectively, being 85.8% and 114.6% higher than that induced by homoharringtonine alone (30.00 +/- 3.34)% (all P < 0.05). Activation of NF-kappaB in K562-n cells was induced significantly by homoharringtonine. Activation of NF-kappaB in K562-n cells induced by homoharringtonine could be suppressed by being pre-processed with 1.0 micro mol/L DXM or 0.1 micro mol/L VCR. The rate of suppression was 32.0% and 39.4% respectively. CONCLUSION: Homoharringtonine induces apoptosis of K562-n cells and induces NF-kappaB activation in K562-n cells. The mechanism of increased apoptosis of K562-n cells with DXM or VCR may be related to suppression of activation of NF-kappaB of K562-n cells.