自噬与凋亡被认为是细胞程序性死亡的两种重要途径,二者的交互联系对阐明药物的抗肿瘤机理有重要价值.众多的研究表明,雷公藤甲素对多种肿瘤细胞都具有显著的抑制作用.细胞凋亡与自噬可被相同的因素所诱导,p53蛋白可以同时对二者起调控作用,在自噬与凋亡的交互作用(crosstalk)中扮演着重要角色.本文以He La细胞为模型,研究雷公藤甲素诱导He La细胞发生自噬和凋亡的机制,并通过抑制p53依赖的转录,研究雷公藤甲素诱导He La细胞p53依赖的自噬和凋亡交互联系.
Autophagy and apoptosis are considered as two main kinds of programmed cell death. The crosstalk between autophagy and apoptosis is crucial for illustration of anti-tumor drug's effects. Triptolide, a diterpene compound extracted from Tripterygium wilfordii Hook F, attracts increasing attention from researchers worldwide for its broad anti-tumor spectrum. Triptolide could bind to XPB(a subunit of the transcription factor TF ⅡH) and leads to RNA polymerase Ⅱ-mediated transcription inhibition. Also, triptolide induces autophagy and apoptosis processes in cancer cells. Through regulating different kinds of related proteins, tumor repressor p53, plays key roles in the crosstalk between autophagy and apoptosis. Thus, in this study, the authors focused on triptolide induced p53-dependent autophagy and apoptosis processes in He La cells, and to demonstrate the regulation of crosstalk through p53-dependent transcription inhibitor and autophagy inhibitors treatment. Using CCK-8 assay and clonogenic assay, triptolide shows significant inhibition effect on He La cells. The apoptosis analysis by Western blot has shown that triptolide induces the cleavage of caspase3 and nuclear poly(ADP-ribose) polymerase(PARP). Immuno-fluorescence and Western blot assay have shown that triptolide also leads to LC3- Ⅱaccumulation and p62 degradations. Collectively, triptolide induces autophagy and apoptosis in a time- and dose-dependent manner. Meanwhile, p53 is significantly up-regulated and the mammalian target of rapamycin(m TOR) is down-regulated with triptolide treatment, and ultimately results in activation of autophagy and apoptosis. Western blot assay have shown that triptolide-induced autophagy and apoptosis are partly inhibited by utilizing p53-dependent transcription inhibitor(Pifithrin-α). Furthermore, the combination treatment of autophagy inhibitors with triptolide enhances triptolide induced apoptosis, and significantly improves inhibition effect of triptolide in He La cells. Triptolide induces p53