磷酸肌醇依赖性蛋白激酶-1在Notch1诱导的小鼠急性T淋巴细胞白血病发展中的作用

Effect of PDK 1 on Notch1-Induced Mouse T-cell Acute Lymphoblastic Leukemia

目的:应用Mx1-cre;Lox P系统,建立可诱导敲除PDK1的Notch1诱导的急性T淋巴细胞白血病小鼠模型,观察PDK1在急性T淋巴细胞白血病发展过程中的作用。方法:用流式细胞术检测小鼠骨髓白血病细胞的周期和凋亡率,应用实时荧光定量PCR检测小鼠白血病细胞中肿瘤相关基因和转录因子的表达水平。结果:成功建立诱导敲除PDK1的T-ALL小鼠模型;体内诱导PDK1敲除后,与对照组相比,敲除组白血病小鼠的生存期明显延长(P<0.01);PDK1敲除对白血病细胞的周期无影响;敲除组小鼠骨髓白血病细胞的凋亡率显著高于对照组(P<0.001);PDK1的敲除引起肿瘤相关基因和转录因子c-Myc和NF-κB表达水平降低(P<0.01)以及P53表达水平升高(P<0.01)。结论:PDK1的敲除可抑制T-ALL的发展,推测其机制可能是通过调控白血病细胞的凋亡和多种转录因子的表达来影响白血病的进程。

Objective: To explore the role of PDK1 in T-ALL development through establishing the Notch1-induced T-ALL mouse model by using Mx1-cre; Lox P system to knock-out PDK1. Methods: Cell cycle and apoptosis of leukemic cells w ere detected by flow cytometry,and relative expression of tumor-related genes and transcription factors of leukemic cells w ere determined by quantitative real-time PCR. Results: Notch1-induced T-ALL mouse model w ith inducible knock-out of PDK1 w as established successfully. Compared to T-ALL control mouse model,PDK1 knock-out mice show ed a significant longer survival time( P < 0. 01). There w as no difference of cell cycle betw een control and PDK1 knock-out mice,and the apoptosis rate of leukemic cells in PDK1 knock-out mice w as higher than that of control mice( P < 0. 001). PDK1 knock-out resulted in decreased expression of tumor-related genes and transcription factors,such as c-Myc and NF-κB( P < 0. 01),and increased expression level of P53( P < 0. 01). Conclusion: PDK1 knock-out can inhibit the development of T-ALL,and its mechanism may be the leukemia progression inhibited by regulating the apoptosis and expression of multiple related genes and transcription factors.