PI3K / Akt / mTOR 信号通路介导的N822K 突变对c-KIT 抑制剂诱导的AML 细胞凋亡的影响

目的:研究c-KIT N822K 突变对c-KIT 抑制剂诱导AML 细胞凋亡的影响,并初步探讨相关的分子机制。方法:以c-KIT N822K 突变的Kasumi-1 细胞为实验组,以HL-60、NB4 细胞为非c-KIT N822K 突变的对照组,分别用0、0.04、0.16、0.64 μmol/ L 的c-KIT 抑制剂舒尼替尼处理这三株AML 细胞24 h 后收集细胞,采用Western blot 检测凋亡相关蛋白和PI3K/ Akt/ mTOR 通路蛋白水平,比较各组细胞相关信号通路蛋白的变化。结果:随着舒尼替尼浓度的增加,HL-60 及NB4 细胞中Bax 及CytoC、Caspase-9、Actived-Caspase-3、PARP 蛋白剪切体等促凋亡相关蛋白表达均上调(P<0.05),抗凋亡蛋白Bcl-2表达均下调(P<0.01),在具有N822K 突变的Kasumi-1 细胞中这一变化趋势则明显减弱;Kasumi-1 细胞中c-myc 蛋白及PI3K、Akt、4EBP1、mTOR 等PI3K/ Akt/ mTOR 通路蛋白的磷酸化水平均出现剂量依赖性下调(P<0.05),而HL-60 细胞和NB4 细胞则无此变化。结论:N822K 突变引起的c-KIT 结构性激活可影响c-KIT 抑制剂舒尼替尼对Kasumi-1 细胞的凋亡诱导作用,其机制可能与PI3K/ Akt/ mTOR 通路抑制有关。

Effect of PI3K / Akt / mTOR signal pathway-mediated N822K mutation on apoptosis induced by c-KIT inhibitor in AML cells

Objective:To investigate the effect of c-KIT N822K mutation on the apoptosis of AML cells induced by c-KIT inhibitor and to explore the underlying molecular mechanisms.Methods: Kasumi-1 cells that carry the c-KIT N822K mutation were used as experimental group,and HL-60 and NB4 cells with non-c-KIT N822K mutation were used as control group.These AML cells were treated with 0,0.04,0.16 and 0.64 μmol/ L c-KIT inhibitor sunitinib for 24 h,respectively.Apoptosis-related proteins and PI3K/Akt/ mTOR pathway proteins were detected by Western blot,compared the changes of cell-related signal pathway proteins in each group.Results: With the increase of sunitinib concentration, the expression of apoptosis-related proteins Bax, CytoC, Caspase-9,Actived-Caspase-3 and PARP in HL-60 and NB4 cells were increased (P<0.05),and the expression of anti-apoptotic protein Bcl-2 was down-regulated (P<0.01).However,the trend of this change was obviously weakened in Kasumi-1 cells with N822K mutation.In Kasumi-1 cells,the phosphorylation levels of PI3K/ Akt/ mTOR pathway proteins such as PI3K,Akt,4EBP1 and mTOR were down-regulated in a dose-dependent manner (P<0.05),but not in HL-60 cells and NB4 cells.Conclusion: The constitutive activation of c- KIT induced by N822K mutation may affect the apoptosis induction of c-KIT inhibitor sunitinib to Kasumi-1 cells,which may be related to the inhibition of PI3K/ Akt/ mTOR pathway.