中国癌症杂志 ›› 2020, Vol. 30 ›› Issue (6): 401-406.doi: 10.19401/j.cnki.1007-3639.2020.06.001

• 论著 • 上一篇    下一篇

抑制PDK1经由ASK1/JNK/Bim通路诱导慢性粒细胞白血病细胞凋亡

王 方 1 ,王 昕 2 ,刘 哲 1 ,惠凌云 1 ,冯 艾 1 ,李 娜 1 ,王亚文 1,2   

  1. 1. 西安交通大学第一附属医院检验科,陕西 西安 710061 ;
    2. 西安交通大学第一附属医院生物样本资源中心,陕西 西安 710061
  • 出版日期:2020-06-30 发布日期:2020-07-15
  • 通信作者: 王亚文 E-mail: wfang1823@xjtu.edu.cn
  • 基金资助:
    国家自然科学基金青年项目(81600134)。

Inhibition of PDK1 induces apoptosis in CML cells via activation of ASK1/JNK/Bim cascade

WANG Fang 1 , WANG Xin 2 , LIU Zhe 1 , HUI Lingyun 1 , FENG Ai 1 , LI Na 1 , WANG Yawen 1,2   

  1. 1. Department of Laboratory Medicine, the First Affiliated Hospital of Xi’an Jiao Tong University, Xi’an 710061, Shannxi Province, China; 2. Biobank, the First Affiliated Hospital of Xi’an Jiao Tong University, Xi’an 710061, Shannxi Province, China
  • Published:2020-06-30 Online:2020-07-15
  • Contact: WANG Yawen E-mail: wfang1823@xjtu.edu.cn

摘要: 背景与目的:3-磷酸肌醇依赖性蛋白激酶1(3-phosphoinositide-dependent kinase-1,PDK1)在细胞的生长、增殖及存活中具有重要的生理作用,其功能异常参与多种肿瘤的发生。探讨PDK1在慢性粒细胞白血病(chronic myelogenous leukemia,CML)细胞中的表达及参与细胞凋亡的调节机制。方法:通过蛋白质印迹法(Western blot)检测蛋白水平;通过细胞计数试剂盒(cell counting kit-8,CCK-8)及克隆形成实验检测细胞增殖;通过流式细胞术检测细胞凋亡。结果:CML患者外周血白细胞中PDK1蛋白含量明显高于健康体检者(P<0.05);在细胞株中,抑制PDK1能明显降低K562和KU812的增殖活力及克隆形成能力;同时,细胞凋亡明显(P<0.01),凋亡执行分子caspase-3及底物多聚ADP核糖聚合酶[poly(ADP-ribose)polymerase,PARP]被切割活化。抑制剂GSK2334470降低PDK1的磷酸化水平(K562:P<0.05;KU812:P<0.01),但并不影响其表达丰度。蛋白激酶B(protein kinase B,AKT)及下游糖原合成酶激酶-3β(glycogen synthase kinase-3β,GSK-3β)磷酸化水平均明显下降,然而β-catenin及靶基因c-Myc表达均未受影响(P>0.05)。磷酸化凋亡信号调节激酶1(apoptosis signal-regulating kinase 1,ASK1)水平降低(P<0.001),下游c-Jun氨基末端激酶(c-Jun N-terminal kinase,JNK)及Bcl-2相互作用细胞凋亡介导因子(Bcl-2 interacting mediator of cell death,Bim)磷酸化水平明显升高,同时,Bim表达量也有所增加。最后,抑制PDK1能够增加CML细胞对伊马替尼(imatinib)的敏感性,与imatinib单独作用相比,联合GSK2334470能够显著提高细胞凋亡水平(P<0.01)。结论:PDK1抑制剂GSK2334470通过调节ASK1/JNK/Bim信号通路磷酸化水平激活CML细胞凋亡。

关键词: 慢性粒细胞白血病, 3-磷酸肌醇依赖性激酶, 凋亡信号调节激酶1, 细胞凋亡

Abstract: Background and purpose: 3-phosphoinositide-dependent kinase-1 (PDK1) plays vital role in cell growth, proliferation and survival. Dysfunctional PDK1 involves in various carcinogenesis. This study aimed to determine the abundance of PDK1 in chronic myelogenous leukemia (CML) cells and study the molecular basis of its contribution to anti-apoptotic phenotype. Methods: The expression of protein was detected by Western blot. Flow cytometry was conducted to analyze the apoptotic cells. Clone formation assay and cell counting kit-8 (CCK-8) were employed to examine the inhibition of proliferation. Results: In comparison with heathy donors, PDK1 in CML cells was significantly over-expressed (P<0.05). In K562 and KU812 cell lines, blockage of PDK1 resulted in remarkable reduction of growth and induction of apoptosis (P<0.01), which was further validated by cleavage of the caspase-3 and its substrate poly (ADP-ribose) polymerase (PARP). The PDK1 inhibitor, GSK2334470 lowered the phosphorylation, but not the total PDK1 level (in K562 cells, P<0.05; in KU812 cells, P<0.01). Besides, the decrease in protein kinase B (AKT) and downstream glycogen synthase kinase-3β (GSK-3β) phosphorylation was also found in two cell lines. However, no significant change of β-catenin was detected, consequently, no effect was found on the expression of c-Myc, the targeted gene of this pathway (P>0.05). Moreover, PDK1 inhibition caused evident decrease in apoptosis signal-regulating kinase 1 (ASK1) phosphorylation (P<0.001), which further led to activation of c-Jun N-terminal kinase (JNK) and Bcl-2 interacting mediator of cell death (Bim). Finally, GSK2334470 enhanced the sensitivity of imatinib (P<0.01). Conclusion: PDK1 inhibition triggered cell death by modulation of ASK1/JNK/Bim cascade.

Key words: Chronic myelogenous leukemia, 3-phosphoinositide-dependent kinase-1, Apoptosis signal-regulating kinase 1, Apoptosis