STI571联合三氧化二砷对K562细胞增殖、凋亡及Caspase-3、Bcl-xL表达的影响

Effects of STI571 Combind with As_2O_3 on Proliferation,Apoptosis and Caspase 3,Bcl-xL Expression of K562 Cells

本研究旨在探讨STI571单独应用及与三氧化二砷(arsenic trioxide,As2O3)联合应用对K562细胞增殖、凋亡及凋亡相关因子caspase-3、bcl-xL mRNA表达的影响。用MTT法检测各组K562细胞在药物作用各时间点(24、48、72小时)的OD值,以评估药物对细胞增殖的作用;AnnexinV/PI荧光标记法检测K562细胞的凋亡率;实时荧光定量PCR检测K562细胞caspase-3、bcl-xL mRNA的表达。结果表明:STI571单独应用及与As2O3联用均可抑制K562细胞的增殖。各实验组的OD值随着实验时间的延长而降低,各时间点之间的差异具有显著性(p<0.05),且各实验组均在72小时时OD值降低最明显。在同一时间点,与对照组相比较,各实验组的OD值均逐渐降低(p<0.05),其中实验5组下降最明显。流式细胞仪检测发现,对照组的凋亡率随着时间的延长无明显变化;各实验组的凋亡率随着时间的延长逐渐上升,各时间点之间的差异具有显著性(p<0.05),以72小时时上升最为明显;在同一时间点,与对照组相比较,各实验组的凋亡率均逐渐上升(p<0.05),其中以实验5组的凋亡率上升最明显。实时荧光定量PCR检测发现,与对照组相比,各实验组bcl-xL mRNA的表达减弱,出现了2-ΔΔCT值的减小,且减小程度实验3组大于实验2组(p<0.05);与对照组相比,各实验组caspase-3 mRNA的表达增强,出现了2-ΔΔCT值的增大,且增大的程度实验3组大于实验2组(p<0.05)。结论:STI571单独应用时能够抑制K562细胞增殖,加速其凋亡。STI571联合As2O3对K562细胞抑制增殖及加速凋亡的作用加强。两药联合后Caspase-3 mRNA的表达较STI571单独应用时增强而bcl-xL mRNA的表达减弱。影响凋亡相关因子caspase-3、bcl-xL mRNA的表达,可能是As2O3与STI571联合抗白血病细胞产生协同作用的分子机制之一。

This study was aimed to explore the effects of STI571 alone or with As2O3 on proliferation, apoptosis and caspase 3, bcl-xL mRNA expression of K562 cells, and the molecular mechanisim of As2O3 enhancing the anti-leukemia effect of STI571 so as to provide the scientific basis for clinical treatment of chronic myeloid leukemia. The effect of drugs on proliferation of K562 cells was assayed by MTT method, the apoptosis rate of K562 cells was detected by flow cytometry with Annexin V/PI double staining, the caspase 3, bcl-xL rnRNA expressions of K562 cells were determined by real time quantitative PCR. The results showed that STI571 alone or with AS2O3 both could inhibit the proliferation of K562 cells. OD value in test groups reduced along with prolonging of action times, the OD values between different time points were significantly different （p 〈0.05）, furthermore the OD values at 72 hours in test groups were lowest, while as compared with control group, OD values at same time points in test groups all gradually decreased, among which decrease of OD value in test 5 group was most significant. The flow cytometric detection indicated that along with time prolonging, the apoptotic rate in control group not obviously changed, but the apoptotic rate in test groups gradually increased, the difference between time points was significant（p 〈 0.05 ）, moreover apoptofic rate increased most obviously at 72 hours, while as compared with control group, apoptotic rate at same time points in test groups was gradually enhanced（p 〈 0.05）, among which the apoptotic rate in test 5 group was highest. The real time qPCR assay revealed that as compared with control group, the bcl-xL mRNA expression in test groups reduced with decrease of 2-AACT value,furthermore the decrease of expression level in test 3 group was higher than that in test 2 group （p 〈 0.05 ）, while the caspase 3 mRNA expression in test groups was enhanced with increase of 2-AACT value, moreover the increase of expression level in test 3 group was higher than that in test 2 group （p 〈0.05）. It is concluded that the STI571 can inhibit the proliferation of K562 cells, accelerate the apoptosis of K562 cells. The STI571 combined with A203 can enhance these two effects, increase the expression of caspase-3 mRNA and decrease the expression of bcl-xL mRNA. Therefore, the effect of STI571 combined with As2O3 on expression of caspase 3 and bcl-xL mRNA may be one of molecular mechanisms underlvine their svnereic antileukemia efficacy.