Carnosic acid induces apoptosis associated with mitochondrial dysfunction and Akt inactivation in HepG2 cells

Abstract

Carnosic acid (CA), a phenolic diterpene isolated from rosemary, shows potential benefits in health promotion and disease prevention. In the present study, the cytotoxic and apoptotic-inducing effects of CA on human hepatocellular carcinoma HepG2 cells were investigated. The MTT assay results indicated that CA decreased cell viability in HepG2 cells in a dose-dependent manner. Treatment with CA caused a rapid Caspase-3 activation and subsequently proteolytic cleavage of poly (ADP-ribose) polymerase (PARP), both of which were markers of cells undergoing apoptosis. CA also dissipated mitochondrial membrane potential and decreased the ratio of Bcl-2/Bax protein, which mediated cytosolic translocation of cytochrome c from the mitochondria. Furthermore, CA reduced the phosphorylation of Akt, which was partially inhibited by insulin, an activator of phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway. In conclusion, our data suggest that the mitochondrial dysfunction and deactivation of Akt may contribute to the apoptosis-inducing effects of CA.     

槐定碱通过PI3K/Akt/mTOR信号通路诱导自噬抑制胰腺癌细胞增殖

目的 探讨槐定碱对胰腺癌细胞增殖及自噬的影响,并分析其机制。方法 MTT法分析Sw1990细胞增殖, MDC染色法检测细胞自噬水平,western blot检测细胞自噬相关蛋白、PI3K/Akt/mTOR信号通路相关蛋白表达水平,运用自噬抑制剂（3 - MA）研究自噬对细胞增殖的影响;裸鼠成瘤实验检测体内胰腺癌细胞增殖情况,并分析瘤组织中LC3 II、p - mTOR蛋白水平。结果 槐定碱抑制胰腺癌Sw1990细胞的增长,促进自噬小泡的形成,上调LC3 II/ LC3 I、Beclin - 1水平,下调p - PI3K、p - AKT、p - mTOR水平（P＜0.05）;与槐定碱40 μmol/L组比较,槐定碱40 μmol/L + 3 - MA 5 μmol/L组细胞抑制率升高,LC3 II/ LC3 I降低,p - mTOR蛋白水平升高（P＜0.05）; 40 mg/kg槐定碱下调裸鼠瘤体体积、瘤体质量,上调LC3 II/ LC3 I水平,下调p - mTOR蛋白水平（P＜0.05）。结论 槐定碱能抑制Sw1990细胞增殖,与调控PI3K/Akt/mTOR信号通路影响自噬有关。     

植酸通过线粒体途径诱导人肝癌细胞凋亡

目的 探讨植酸（IP₆）如何通过线粒体途径诱导人肝癌HepG2细胞凋亡,为研究IP₆的抗肿瘤作用提供理论依据。方法 应用Hoechst 33258荧光染色法和流式细胞仪Annexin-FITC/PI双染法观察不同浓度IP₆作用HepG2细胞后的凋亡情况;流式细胞仪检测IP₆作用HepG₂细胞后线粒体膜电位（ΔΨm）的变化;RT-PCR法检测HepG2细胞内caspase-3mRNA的表达变化;Western blot法检测IP₆作用HepG2细胞后Cyt-c的表达变化。结果 荧光显微镜下可观察到IP₆作用后细胞出现明显的凋亡形态;与对照组相比,IP₆可升高细胞凋亡率（F=342.15,q=2.9～28.53,P<0.05）,且随着浓度增加,凋亡率逐渐升高（P<0.05）;IP₆可降低线粒体膜电位（F=14802.610,q=101.531～209.237,P<0.05）,且随着浓度增加,膜电位逐渐降低（P<0.05）;IP₆可增加caspase-3 mRNA的表达（F=30.474,q=3.406～9.103,P<0.05）,且随着浓度增加,表达逐渐增加（P<0.05）;IP₆可上调细胞色素C（Cyt-c）的表达（F=87.194,q=5.246～15.218,P<0.05）,且随着浓度增加,表达逐渐上调（P<0.05）。结论 IP₆可通过降低线粒体膜电位,上调细胞色素C水平,激活caspase-3途径,促进人肝癌HepG2细胞发生凋亡。     

赛莱西布对肝癌HepG2细胞增殖与凋亡影响

目的探讨选择性环氧合酶-2（cox-2）抑制剂赛莱西布（celecoxib）对人肝癌细胞株HepG2细胞增殖、凋亡的影响及其可能的作用机制。方法用不同浓度的赛来西布处理HepG2细胞，分别应用四甲基偶氮噻唑蓝试验、DNA梯度电泳法、放射免疫法检测赛亚西布对HepG2细胞增殖和凋亡及其COX-2活性的影响；应用免疫印迹法和比色法检测赛莱西布对HepG2细胞胱氨酸蛋白酶3（clasepase-3）蛋白质的表达及活性的影响。结果12．5，25，50μmol／L的赛莱西布作用于HepG2细胞后，HepG2细胞增殖受抑制，与对照组比较，差异有统计学意义（P〈0．01）；赛莱西布干预组HepG2细胞DNA明显降解，可见细胞凋亡特征性梯状DNA条带；干预组HepG2细胞caspase3蛋白表达及活性均明显升高。与对照组比较，差异均有统计学意义（P〈0．01）；赛莱西布明显抑制HepG2细胞cox-2活性。与对照组比较，差异有统计学意义（P〈0．01）。结论赛莱西布可通过cox-2通路和easpase3通路抑制HepG2细胞增殖并诱导其凋亡。     

镉暴露对HepG2细胞NRF2信号通路影响

目的 探讨镉暴露对HepG2细胞转录因子NF-E2相关因子2（NRF2）信号通路的影响。方法 采用甲臢比色法测定CdCl₂（0、1、2.5、5、10、25、50、100、200 μmol/L）处理24 h后,HepG2细胞活力变化;应用蛋白免疫印迹法检测CdCl₂（1、2、5、10、20 μmol/L）处理细胞6 h后,NRF2蛋白水平;采用RT-qPCR方法检测10 μmol/L CdCl₂处理细胞2、4、6、12、24 h后,GCLC、GCLM、HO1 和 AKR1C1 mRNA水平变化,检测CdCl₂（1、2、5、10、20 μmol/L）处理细胞6 h后,GCLC、GCLM、HO1和AKR1C1 mRNA水平变化。结果 HepG2细胞活力随镉处理剂量升高而降低（P<0.05）;与对照组（0.60±0.01）比较, 1、2、5、10、20 μmol/L镉处理组HepG2细胞NRF2蛋白表达水平[分别为（0.65±0.01）、（1.37±0.04）、（1.94±0.05）、（2.24±0.07）、（2.22±0.05）]均明显升高（P<0.05）;与对照组比较,镉处理6 h时,HepG2细胞内GCLC、GCLM、HO1和AKR1C1 mRNA水平[分别为（45.76±7.04）、（114.21±5.23）、（59.52±1.50）、（674.13±27.12）]明显升高（P<0.05）;与对照组比较,5 μmol/L镉处理组HepG2细胞内GCLC和GCLM mRNA水平[分别为（24.77±2.16）、（29.93±0.67）]升高,2 μmol/L镉处理组HepG2细胞内HO1和AKR1C1 mRNA水平[分别（28.55±2.02）、（186.32±12.63）]升高（P<0.05）。结论 镉暴露能激活HepG2细胞系中NRF2信号通路。     

Quercetin induces apoptosis via caspase activation, regulation of Bcl-2, and inhibition of PI-3-kinase/Akt and ERK pathways in a human hepatoma cell line (HepG2)

Dietary polyphenols have been associated with the reduced risk of chronic diseases such as cancer, but the precise underlying mechanism of protection remains unclear. The aim of this study was to investigate the effect of quercetin on the activation of the apoptotic pathway in a human hepatoma cell line (HepG2). Treatment of cells for 18 h with quercetin induced cell death in a dose-dependent manner; however, a shorter treatment (4 h) had no effect on cell viability. Incubation of HepG2 cells with quercetin for 18 h induced apoptosis by the activation of caspase-3 and -9, but not caspase-8. Moreover, this flavonoid decreased the Bcl-xL:Bcl-xS ratio and increased translocation of Bax to the mitochondrial membrane. A sustained inhibition of the major survival signals, Akt and extracellular regulated kinase (ERK), also occurred in quercetin-treated cells. These data suggest that quercetin may induce apoptosis by direct activation of caspase cascade (mitochondrial pathway) and by inhibiting survival signaling in HepG2.     

Black rice extract protected HepG2 cells from oxidative stress-induced cell death via ERK1/2 and Akt activation

BACKGROUND/OBJECTIVES

The objective of this study was to evaluate the protective effect of black rice extract (BRE) on tert-butyl hydroperoxide (TBHP)-induced oxidative injury in HepG2 cells.

MATERIALS/METHODS

Methanolic extract from black rice was evaluated for the protective effect on TBHP-induced oxidative injury in HepG2 cells. Several biomarkers that modulate cell survival and death including reactive oxygen species (ROS), caspase-3 activity, and related cellular kinases were determined.

RESULTS

TBHP induced cell death and apoptosis by a rapid increase in ROS generation and caspase-3 activity. Moreover, TBHP-induced oxidative stress resulted in a transient ERK1/2 activation and a sustained increase of JNK1/2 activation. While, BRE pretreatment protects the cells against oxidative stress by reducing cell death, caspase-3 activity, and ROS generation and also by preventing ERKs deactivation and the prolonged JNKs activation. Moreover, pretreatment of BRE increased the activation of ERKs and Akt which are pro-survival signal proteins. However, this effect was blunted in the presence of ERKs and Akt inhibitors.

CONCLUSIONS

These results suggest that activation of ERKs and Akt pathway might be involved in the cytoprotective effect of BRE against oxidative stress. Our findings provide new insights into the cytoprotective effects and its possible mechanism of black rice against oxidative stress.     

Alpha-linolenic acid attenuates high glucose-induced apoptosis in cultured human umbilical vein endothelial cells via PI3K/Akt/eNOS pathway

OBJECTIVE: High glucose-induced apoptosis in vascular endothelial cells contributes to the acceleration of atherosclerosis associated with diabetes. We hypothesized that alpha-linolenic acid (ALA) might attenuate high glucose-induced apoptosis in cultured human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were cultured at 5.5 and 33 mmol/L for 72 h. ALA with different concentrations was added with defatted bovine serum albumin as a carrier for 18 h before incubation with high glucose. RESULTS: Exposure of HUVECs to high glucose media for 72 h significantly increased the number of apoptotic cells compared with normal glucose control, as evaluated by flow cytometry and terminal deoxyuridine triphosphate nick end labeling assay. Pretreatment with low concentrations of ALA (10, 50, and 100 micromol/L) significantly attenuated high glucose-induced apoptosis of HUVECs, but increasing ALA to 200 micromol/L exerted the opposite effect. Furthermore, high glucose reduced phosphorylation of Akt and endothelial nitric oxide synthase (eNOS) with subsequent nitric oxide production, whereas ALA treatment attenuated the reduction caused by high glucose. Pretreatment with phosphatidylinositol 3' -kinase kinase inhibitor LY294002 and eNOS inhibitor N(G)-nitro-arginine methyl ester eliminated ALA' antiapoptotic effect. CONCLUSION: ALA exerts an antiapoptotic effect by the phosphatidylinositol 3'-kinase/Akt/eNOS pathway in HUVECs exposed to high glucose and thus may represent a candidate therapeutic agent for diabetic cardiovascular complications.     

siRNA抑制NFBD1基因表达对人肝癌HepG2细胞凋亡的影响

目的:研究siRNA抑制NFBD1基因表达对人肝癌HepG2细胞凋亡的作用原理及caspase途径在此过程中的作用。方法:应用流式细胞法及RT-PCR检测沉默NFBD1对人肝癌HepG2细胞凋亡及凋亡基因组表达水平的影响。MTT法检测NFBD1 siRNA对HepG2细胞的抑制作用。结果:转染48 h后,转染组与阴性对照组和空白组相比,NFBD1mRNA表达明显减弱,转染组NFBD1 mRNA较空白组相对下降74.75%;HepG2细胞组中促凋亡基因Bc1-xl表达减少,Bid及caspase-3表达量增加(P<0.05)。MTT结果显示NFBD1 siRNA能明显抑制HepG2细胞增殖,抑制率达到92.131±0.893%。流式法检测结果显示转染组细胞凋亡明显高于阴性对照组和空白组。结论:NFBD1可通过改变Bc1-xl/Bid的表达比,激活caspase-3来诱导HepG2细胞凋亡。     

茶多酚联合原花青素改善AD大鼠记忆作用及机制

  目的  探讨三七皂苷Rg1（NRg1）对大鼠肾缺血再灌注损伤（RIRI）的保护作用及其对氧化应激水平和外周血Th1/Th2细胞因子的调节作用。  方法  健康雄性SD大鼠60只,随机分为假手术组、模型组及NRg1 2.5、5.0、10.0 mg/kg组,每组12只;建立RIRI模型再灌注后24 h后处死大鼠,检测尿蛋白及血清肌酐和尿素氮含量,苏木精 – 伊红（HE）染色和末端脱氧核苷酸转移酶介导的dUTP缺口末端标记测定法（TUNEL）染色检测各组大鼠肾脏组织病理损伤和细胞凋亡,酶联免疫吸附实验（ELISA）检测超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）含量,蛋白印迹法检测凋亡相关蛋白B细胞淋巴瘤因子2（Bcl-2）和Bcl-2相关X蛋白（Bax）的表达及核转录相关因子2（Nrf2）、谷胱甘肽 – S – 转移酶（GST）和醌氧化还原酶1（NQO1）的表达,流式细胞仪检测外周血中Th1（iNOS⁺）和Th2（IL-10⁺）细胞因子的含量。  结果  与模型组比较,NRg1 2.5、5.0、10.0 mg/kg组大鼠尿蛋白含量[分别为（34.1 ± 6.3）、（25.2 ± 4.5）、（11.7 ± 3.4）mg/24 h]均减少、血清肌酐含量[分别为（1.04 ± 0.15）、（0.84 ± 0.09）、（0.62 ± 0.12）mg/dL]均减少、尿素氮含量[分别为（28.6 ± 4.6）、（19.4 ± 3.4）、（15.2 ± 3.2）mg/dL]均减少、肾脏细胞凋亡率[分别为（43.6 ± 7.5）%、（32.4 ± 8.1）%、（11.7 ± 6.3）%]均降低、Bcl-2蛋白表达[分别为（0.12 ± 0.03）、（0.07 ± 0.02）、（0.04 ± 0.01）]均减少、Bax蛋白表达[分别为（0.06 ± 0.03）、（0.09 ± 0.04）、（0.16 ± 0.04）]均增加、GSH-Px含量[分别为（55.29 ± 9.31）、（80.14 ± 11.58）、（106.41 ± 14.16）U/mL]均增加、SOD含量[分别为（0.71 ± 0.13）、（1.26 ± 0.15）、（1.50 ± 0.23）U/mL]均增加、Nrf2蛋白表达[分别为（0.04 ± 0.03）、（0.10 ± 0.04）、（0.18 ± 0.05）]均增加、GST蛋白表达[分别为（0.07 ± 0.02）、（0.14 ± 0.03）、（0.22 ± 0.06）]均增加、NQO1蛋白表达[分别为（0.04 ± 0.02）、（0.09 ± 0.04）、（0.14 ± 0.05）]均增加、Th1（iNOS⁺）含量[分别为（9.13 ± 1.05）%、（5.26 ± 0.84）%、（2.63 ± 0.61）%]均减少、Th2（IL-10⁺）含量[分别为（0.92 ± 0.34）%、（2.93 ± 0.57）%、（4.41 ± 0.62）%]均增加（均P < 0.01）。  结论  NRg1能通过减轻氧化应激水平和炎性损伤,改善大鼠肾缺血再灌注造成的损伤。     

曲古抑菌素A阻断Stat3信号通路诱导前列腺癌细胞凋亡的实验研究

目的本实验研究组蛋白去乙酰化酶抑制剂曲古抑菌素A(TSA)对前列腺癌细胞DU145的抑制作用及其对信号传导与转录激活因子3(Stat3)信号通路的影响。方法采用不同浓度的TSA处理DU145不同时间后,四氮甲基唑蓝比色法测定TSA对细胞活力的抑制效应;流式细胞仪分析细胞周期的改变;蛋白印迹实验检测细胞凋亡相关蛋白半胱氨酸蛋白酶(Caspase)家族的Caspase-8、Caspase-9、Caspase-3、二磷酸腺苷核糖多聚酶(PARP)及Stat3信号蛋白活性(phospho-Stat3)的变化。结果 TSA时间和剂量依赖性地抑制DU145细胞的增殖,TSA处理细胞24 h和48 h后,细胞生存率分别是85.7%和68.7%;细胞经TSA处理后,细胞形态和细胞周期均发生明显的变化,细胞周期被阻断在G0/G1期,其细胞百分比从55.6%增加到68.5%;Western blot检测结果显示,TSA作用DU145细胞后,Stat3信号蛋白的磷酸化水平下降,同时IL-6对Stat3的刺激诱导作用也被TSA所阻断;Caspase-8、Caspase-9、Caspase-3、PARP等凋亡蛋白被TSA诱导活化,并发生显著剪切。结论 TSA能够通过抑制Stat3信号通路的活性来诱导DU145细胞凋亡。     

Iron deficiency down-regulates the Akt/TSC1-TSC2/mammalian Target of Rapamycin signaling pathway in rats and in COS-1 cells

Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity.     

PI3K/Akt信号通路在虾青素调节LX-2细胞活化中作用

目的 探讨磷脂酰肌醇3-激酶/蛋白激酶B（PI3K/Akt）信号通路在虾青素调节人肝星状细胞（LX-2细胞）活化中的作用。方法 实验设对照组、低、中、高剂量虾青素组（5、10、20 μmol/L）、抑制剂组（25 μmol/L LY294002）、抑制剂+虾青素组（25 μmol/L LY294002+20 μmol/L虾青素）,作用48 h后检测LX-2细胞中α-平滑肌肌动蛋白（α-SMA）和Ⅰ型胶原（col1a1）mRNA表达水平、各组细胞Akt及其磷酸化水平。结果 与对照组比较,虾青素组LX-2细胞中α-SMA和col1a1 mRNA表达明显降低,并呈剂量依赖关系（P<0.05）;与对照组比较,抑制剂组LX-2细胞中磷酸化Akt水平（0.42±0.05）、α-SMA和col1a1 mRNA表达水平[分别为（0.23±0.05）、（0.35±0.06）]均明显降低（P<0.05）;与对照组比较,虾青素组LX-2细胞中磷酸化Akt水平（0.60±0.07）、α-SMA和col1a1 mRNA表达水平[分别为（0.48±0.07）、（0.61±0.04）]均明显降低（P<0.05）;与抑制剂组比较,抑制剂+虾青素组LX-2细胞中磷酸化Akt水平（0.18±0.04）、α-SMA和col1a1 mRNA表达水平[分别为（0.11±0.05）、（0.20±0.03）]均明显降低（P<0.05）。结论 虾青素可通过PI3K/Akt信号通路抑制肝星状细胞活化,发挥抗非酒精性脂肪肝纤维化作用。     

GJB2通过AMPK/mTOR信号通路促进宫颈癌细胞恶性增殖

目的 筛选宫颈癌中具有临床意义的潜在药物靶点并研究此靶点蛋白在宫颈癌发生发展中的功能和潜在分子机制.方法 收集2018年7月至2019年7月济南市人民医院妇科行宫颈癌手术的30例宫颈癌患者肿瘤组织标本及癌旁组织标本,通过临床数据库分别找到在宫颈癌中高表达的基因(tumor/normal>2)以及在宫颈癌中具有显著临床预...     

DEHP与BaP联合诱导Chang liver细胞线粒体 介导细胞凋亡作用

目的 研究邻苯二甲酸二(2-乙基)己酯(DEHP)与苯并(a)芘(BaP)联合染毒对Chang liver细胞的毒性。方法 DEHP(62.5、125、250、500和1 000 μmol/L)与BaP(64 μmol/L)单独或联合染毒Chang liver细胞24 h,检测细胞活力、细胞内活性氧(ROS)含量、线粒体膜电位(MMP)、细胞凋亡率和Bcl-2相关X蛋白(Bax)、B细胞淋巴瘤因子2(Bcl-2)以及半胱氨酸蛋白酶-3(caspase-3)蛋白表达量。结果 联合染毒各组细胞存活率均低于DEHP单独染毒组(t=6.22、4.64、6.64、5.84、7.29,P<0.01),但胞内ROS水平均升高(t=4.57、2.23、2.39、2.22、2.16,P<0.05或P<0.01);≥250 μmol/L DEHP与BaP联合染毒组的MMP分别为(80.12±6.41)%、(69.92±5.56)%和(53.76±1.88)%,均低于BaP单独染毒组的(165.93±5.09)%(t=10.92、12.51、14.62,P<0.01);细胞凋亡率分别为(7.73±1.91)%、(11.00±3.04)%和(14.20±3.96)%,均高于BaP单独染毒组的(1.55±0.21)%(t=3.96、6.06、8.11,P<0.01);此外,活化caspase-3的高表达和升高的Bax/Bcl-2比值也被检出。结论 较高浓度DEHP与BaP联合染毒Chang liver细胞促发ROS水平升高和线粒体膜电位降低,并导致了细胞凋亡;Bax、Bcl-2和活化caspase-3参与了此调控过程。     

硒诱导HepG2细胞凋亡与活性氧的关系

目的探讨亚硒酸钠(Na2SeO3)诱导细胞凋亡的可能作用机制。方法用0、2.5、5、10和20μmol/L的Na2SeO3以及加有N-乙酰基-L-半胱氨酸(NAC)的Na2SeO3(10μmol/L)处理HepG2。用四甲基偶氮唑盐(MTT)比色法测定细胞活性;流式细胞仪测细胞内活性氧(ROS)的水平以及细胞凋亡情况。结果5、10和20μmol/LNa2SeO3作用于HepG21h即引起ROS增加,12h后HepG2细胞活性降低,24h后细胞早期凋亡以及晚期凋亡/坏死率均增加,与对照组相比差异有显著性(P<0.05);抗氧化剂NAC有效抑制了ROS的增加,并增加了细胞活性,降低了细胞凋亡率,与未加NAC的Na2SeO3组(10μmol/L)相比差异有显著性(P<0.05)。结论一定浓度的亚硒酸钠使HepG2细胞活性下降,促进了细胞凋亡,ROS的增加在其中发挥了作用。     

三氧化二砷联合化疗诱导肝癌HepG2细胞凋亡作用机制研究

目的探讨三氧化二砷(As2O3)联合化疗诱导肝癌HepG2细胞凋亡的作用机制。方法体外培养人肝癌HepG2细胞株,分别给予As2O3和顺铂单独或联合处理,用细胞免疫组化酶法检测Bax、Bcl-2、Fas蛋白的表达情况;采用流式细胞仪观察人肝癌HepG2细胞株的细胞周期变化,细胞DNA含量的分布,测定不同作用时间后端粒酶活性的变化情况。结果As2O3组肝癌HepG2细胞的Bax和Fas基因的表达明显增加,Bcl-2基因的表达明显降低;在DNA直方图上可见在G1期细胞前凋亡细胞呈现典型特征性的亚二倍体凋亡峰,使S期细胞减少,将细胞生长周期阻滞于G2/M期,联合用药组比单独用药组作用明显增强。结论As2O3及联合化疗能诱导肝癌细胞凋亡,其主要机制与增强Bax、Fas的表达,下调Bcl-2的表达,将细胞生长周期阻滞于G2/M期,阻止细胞的有丝分裂,抑制端粒酶活性有关。     

Diallyl trisulfide induces apoptosis of human basal cell carcinoma cells via endoplasmic reticulum stress and the mitochondrial pathway

Diallyl trisulfide (DATS), an active component of garlic oil, has attracted much attention because of its anticancer effect on several types of cancers. However, the mechanism of DATS-induced apoptosis of basal cell carcinoma (BCC) is not fully understood. In the present study, we revealed that DATS-mediated dose-dependent induction of apoptosis in BCC cells was associated with intracellular reactive oxygen species accumulation and disrupted mitochondrial membrane potential. Western analysis demonstrated concordant expression of molecules involved in mitochondrial apoptosis, including DATS-associated increases in phospho-p53, proapoptotic Bax, and decreases in antiapoptotic Bcl-2 and Bcl-xl in BCC cells. Moreover, DATS induced the release of cytochrome c, apoptosis-inducing factor, and HtrA2/Omi into the cytoplasm, and activated factors downstream of caspase-dependent and caspase-independent apoptosis, including nuclear translocation of apoptotic-inducing factor and endonuclease G and the caspase cascade. These results were confirmed by pretreatment with the antioxidant N-acetyl-L-cysteine and the caspase inhibitor (z-VAD-fmk), the latter of which did not completely enhance the viability of DATS-treated BBC cells. Exposure to DATS additionally induced endogenous endoplasmic reticulum stress markers and intracellular Ca2(+) mobilization, upregulation of Bip/GRP78 and CHOP/GADD153, and activation of caspase-4. Our findings suggest that DATS exerts chemopreventive potential via ER stress and the mitochondrial pathway in BCC cells.     

Carbon ion irradiation suppresses metastatic potential of human non-small cell lung cancer A549 cells through the phosphatidylinositol-3-kinase/Akt signaling pathway

We previously showed that carbon ion irradiation can inhibit the expression of the anillin (ANLN) gene, which is regulated by the activation of the phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway associated with metastasis. The purpose of this study is to compare the effects of carbon ion irradiation on the PI3K/Akt signaling pathway to those of photon irradiation. Our study showed that carbon ion irradiation of human lung adenocarcinoma cells A549 decreased their invasion more effectively than photon irradiation did. We found that carbon ion irradiation reduced the nuclear localization of ANLN at lower dose, but did not affect its expression. Low-dose carbon ion irradiation also reduced the level of phosphorylated Akt compared to untreated controls, whereas photon irradiation did not. These results suggest that carbon ion irradiation effectively suppresses the metastatic potential of A549 cells by suppressing the PI3K/Akt signaling pathway.