尖吻蝮蛇毒抑瘤组分I通过PERK/eIF2α通路诱导Tca8113细胞凋亡的机制研究

Mechanism of apoptosis of Tca8113 cells induced by AAVC-I through PERK/eIF2α pathway

目的:探讨内质网应激(ERS)相关的蛋白激酶R样内质网激酶(PERK)/真核翻译起始因子2α(eIF2α)通路在尖吻蝮蛇毒抑瘤组分I(AAVC-I)诱导人舌鳞癌Tca8113细胞凋亡中的作用及机制。方法:不同实验浓度(4. 0、8. 0和16. 0 mg/L)的AAVC-I处理Tca8113细胞24 h后采用苏木素-伊红(HE)染色观察细胞形态;流式细胞术(annexin V-FITC/PI双荧光染色法)检测细胞凋亡;Western blot检测ERS相关蛋白葡萄糖调节蛋白78(GRP78),PERK/eIF2α通路中的磷酸化PERK(p-PERK)、磷酸化eIF2α(p-eIF2α)及下游的活化转录因子4(ATF4)和CCAAT/增强子结合蛋白同源蛋白(CHOP),以及细胞凋亡相关蛋白Bcl-2和Bax的蛋白表达水平。结果:AAVCI各浓度组分别与正常对照组相比以及各浓度组之间相互比较的结果显示,随着AAVC-I浓度的增加,Tca8113细胞活力逐渐降低,细胞逐渐皱缩变小,间隙增大,胞核浓缩、碎裂,出现凋亡小体,细胞凋亡率增高(P<0. 05);GRP78、p-PERK、p-eIF2α、ATF4、CHOP及Bax蛋白水平上调,Bcl-2表达下调(P<0. 05)。结论:AAVC-I抑制Tca8113细胞活力的同时引发细胞发生ERS并诱导细胞凋亡,其诱导细胞凋亡的机制与PERK/eIF2α通路密切相关。

AIM:To investigate the role of endoplasmic reticulum stress(ERS)-related protein kinase R-like endoplasmic reticulum kinase(PERK)/eukaryotic translation initiation factor 2α(eIF2α)pathway on the apoptosis of hu⁃man tongue squamous carcinoma Tca8113 cells induced by anti-tumor component I from Agkistrodon acutus venom(AAVC-I).METHODS:Tca8113 cells were treated with the experimental concentrations(4.0,8.0 and 16.0 mg/L)of AAVC-I for 24 h.The morphological changes of the cells were observed by hematoxylin-eosin(HE)staining,and the apoptosis rates were analyzed by flow cytometry with annexin V-FITC/PI double fluorescence staining.The protein levels of ERS-related protein glucose-regulated protein 78(GRP78),PERK/eIF2αpathway-related proteins phospho-PERK(p-PERK)and phospho-eIF2α(p-eIF2α),PERK/eIF2αpathway downstream proteins activating transcription factor 4(ATF4)and CCAAT/enhancer-binding protein homologous protein(CHOP),and apoptosis-related proteins Bcl-2 and Bax were determined by Western blot.RESULTS:Increased concentration of AAVC-I gradually resulted in Tca8113 cell viability inhibition,cell shrinkage,cell size reduction,cell gap enlargement,nuclear condensation,and cell fragmenta⁃tion.The apoptotic bodies were observed with the increased apoptosis rate(P<0.05).The protein levels of GRP78,p-PERK,p-eIF2α,ATF4,CHOP and Bax were increased,while the protein level of Bcl-2 was decreased(P<0.05).CONCLUSION:AAVC-I inhibits the viability of Tca8113 cells and induces ERS-mediated apoptosis.The mechanism of the apoptosis is closely related to the ERS-related PERK/eIF2αpathway.