辐射增敏剂Wortmannin促进组蛋白去乙酰化酶抑制剂诱导的MOLT-4细胞凋亡

Wortmannin Enhances Trichostatin A-Induced Tumor Cells Apoptosis Through Downregulation of Survivin and Acceleration of Caspase-cascades

关键词:  Wortmannin  组蛋白去乙酰化酶抑制剂  曲古抑菌素A  肿瘤  凋亡

Key words:  Wortmannin  histone deacetylase inhibitor  trichostatin A(TSA)  tumor  apoptosis

摘要:

目的 探讨选择性磷脂酰肌醇激酶相关蛋白激酶家族(PIKKs)的小分子抑制剂Wortmannnin对组蛋白去乙酰化酶抑制剂(HDIs)诱导的细胞凋亡的影响，并探讨DNA损伤功能信号级联在HDIs类药物抗肿瘤效应中的功能机制。方法 流式细胞术分析加药后不同时间点的细胞周期分布和细胞凋亡情况；荧光显微镜下观察用药后的细胞核形态；免疫印迹法检测加药前后Caspase-2，Caspase-3，Caspase-7和Survivin蛋白表达情况。结果 低剂量Wortmannin单独作用对肿瘤细胞生存率未见显著影响，但能够激活G₁/S细胞周期阻滞、抑制TSA引发的G₂/M阻滞、并显著促进肿瘤细胞凋亡。在此过程中，Wortmannin促进凋亡效应分子Caspase-2，Caspase-3和 Caspase-7的激活并抑制Survivn的表达。结论 PIKKs家族的小分子抑制剂Wortmannnin 通过下调Survivin并促进Caspase信号级联而促进TSA诱导的肿瘤细胞凋亡。

Abstract:

OBJECTIVE To study the interaction between Wortmannnin, a selective inhibitor of PIKKs, and TSA, to explore the role of DNA damage signals in HDIs induced tumor cell death. METHODS The cell cycle distribution and cell apoptosis were detected by flow cytometry. The expression level of Caspase-2, 3, 7 and Survivin were determined by Western blotting with the antibody against each protein. RESULTS While low-dose Wortmannin alone had little effect on the tumor cell viability, it inhibited Trichostatin A (TSA) induced G₂/M arrest and enhanced TSA induced apoptosis. TSA induced human acute lymphoblastic leukemia (MOLT-4) cells apoptosis through activation of Caspase-2, 3, 7. When pretreatment with Wortmannin, activation of Caspase-2, Caspase-3, and Caspase-7 by TSA was accelerated, and Survivin, a member of inhibitor of apoptosis protein (IAP) family, was also significantly decreased coincident with the acceleration of cells apoptosis. CONCLUSION As a PIKKs inhibitor, wortmannnin has been proposed as a potential anti-neoplastic agent. Wortmannin enhances TSA-induced tumor cells apoptosis through down-regulation of Survivin and activation of Caspase-cascades.