自噬在吉西他滨诱导肺癌细胞A549凋亡中的作用及其相关机制

  目的  研究自噬对吉西他滨(gemcitabine, GEM)诱导的肺癌细胞A549凋亡的影响并探讨其可能机制。  方法  MDC染色后采用荧光显微镜对自噬进行形态观察; 以CCK8检测3-MA抑制自噬前后经吉西他滨诱导的A549细胞存活率; RT-PCR检测自噬相关基因Beclin-1表达的变化。Western blot分别检测自噬相关性蛋白Beclin-l及凋亡活化蛋白Caspase-3的变化。  结果  吉西他滨可诱导肺癌细胞A549产生自噬, 自噬在基因及蛋白水平表达均增加; 3-MA和吉西他滨联合用药可增强肺癌A549细胞凋亡。  结论  吉西他滨诱导肺癌细胞A549凋亡的过程中自噬可能起到保护作用, 3-MA特异性抑制自噬后可增强吉西他滨诱导的A549细胞凋亡。      

长春瑞滨及联合热疗抗血管生成作用的实验

目的探讨长春瑞滨及联合热疗对血管生成的抑制作用。方法以人肺癌A549细胞为对照,采用MTT法观察长春瑞滨及联合热疗对人脐静脉内皮细胞（HUVEC）增殖的影响;通过Transwell趋化实验、小管形成实验及流式细胞术观察长春瑞滨对HUVEC迁移、小管形成及细胞凋亡的影响;利用鸡胚绒毛尿囊膜（CAM）模型,观察长春瑞滨对体内CAM新生血管的影响。结果小剂量（0.1～1 ng/ml）长春瑞滨对HUVEC和A549增殖抑制具有差异细胞毒性（P=0.000）。0.1～1 ng/ml 长春瑞滨呈剂量依赖性抑制HUVEC增殖（r=0.993,P=0.000）,联合热疗具有抑制HUVEC增殖的叠加或协同效应。小剂量长春瑞滨能够抑制HUVEC迁移和小管形成,诱导HUVEC凋亡,遏制CAM新生血管形成。结论小剂量长春瑞滨具有抗血管生成作用,联合热疗具有协同或叠加效应。     

CyclinL2在化疗药物诱导肺癌细胞凋亡中的作用

目的:探讨cyclinL2基因在化疗药物顺铂(DDP)、长春瑞滨(NVB)和多西紫杉醇(DOC)诱导的肺癌细胞凋亡中的作用。方法:用肺腺癌A549细胞株进行培养传代,MTT试验检测DDP、NVB和DOC不同药物浓度对肺癌细胞生长的抑制作用,以及CyclinL2转染后对该细胞生长的抑制作用的影响。同时利用流式细胞术定量检测细胞凋亡。结果:不同浓度DDP、NVB和DOC对肺癌细胞生长均有明显的抑制作用,并有浓度的依赖性。细胞凋亡率和CyclinL2基因表达率成正相关。结论:CyclinL2基因在化疗药物诱导肺癌细胞凋亡中起重要作用。     

sCD40L联合长春瑞滨对肺腺癌A549细胞的作用

背景与目的 CD40信号对肿瘤细胞化疗敏感性的影响存在争议.本研究旨在观察可溶性CD40配体(sCD40L)联合长春瑞滨对肺腺癌A549细胞的作用.方法 以sCD40L处理AS49细胞,MTT法和流式细胞仪检测CD40激发前后长春瑞滨作用下A549细胞的生长、细胞周期及凋亡率等生物学行为的变化,同时用Caspase-3检测试剂盒分析Caspase-3活性的改变.结果 sCD40L对CD40分子的激发可增强长春瑞滨对表达CD40肺癌细胞株A549增殖的抑制率(P＜0.05),但并不显著影响细胞周期时相和细胞凋亡率(P＞0.05),Caspase-3活性反而显著下降(P＜0.05).结论 以sCD40L激发CD40信号可增强肺腺癌细胞A549对长春瑞滨的敏感性,可能通过非凋亡的、Cas-pase非依赖性的机制,且可能与抑制细胞周期进程无关.     

蟾蜍灵诱导人胃癌SGC7901细胞自噬与凋亡的研究

目的：探讨自噬在蟾蜍灵（bufalin）诱导人胃癌SGC7901细胞死亡中的作用.方法：不同浓度的bu-falin处理人胃癌SGC7901细胞,采用MTT法检测bufalin对SGC7901细胞增殖的抑制作用.透射电镜观察给药后SGC7901细胞的自噬现象;流式细胞术检测细胞凋亡.Western blot检测自噬标志LC3蛋白表达.结果：Bufalin对胃癌SGC7901细胞生长有显著的抑制作用,且此作用呈明显的时间-剂量依赖性.Bufalin给药后可诱导SGC7901细胞发生自噬;并且在bufalin给药前用氯喹阻断自噬明显提高了bufalin对SGC7901的细胞毒性（P＜0.05）.结论：Bufalin能明显抑制SGC7901细胞的生长,并且诱导其发生保护性自噬.Bufalin和自噬抑制剂的联合应用可能为胃癌治疗提供新的策略.     

FUNDC1调控肺癌A549细胞及其干细胞的生长、自噬、凋亡和细胞干性的研究

目的:本实验旨在阐明线粒体自噬受体蛋白FUNDC1(FUN 14 domain containing 1)在肺癌病理进程中对肿瘤细胞生长死亡以及细胞干性的调控作用。方法:使用RT-qPCR分析FUNDC1在肺癌组织和细胞中的表达情况。siRNAs和过表达载体转染A549细胞以及诱导形成的A549干细胞团(A549/CSC)。采用CCK-8增殖试剂盒及集落形成实验分析不同处理对肺癌细胞增殖的影响。Western blotting检测FUNDC1、细胞自噬相关蛋白(Beclin-1、LC3-Ⅱ、p62)、凋亡相关蛋白(Bax、Bcl-2、caspase3)和细胞干性相关蛋白(CD133、Sox2、Oct4)的表达。细胞凋亡试剂盒(Elisa)用于测定细胞凋亡水平。流式细胞术分析CD133细胞阳性率。结果:FUNDC1在肺癌组织及细胞中表达上调,干扰FUNDC1抑制A549细胞增殖和保护性自噬,同时诱导细胞凋亡。此外,FUNDC1与CD133表达显著正相关,干扰FUNDC1可显著抑制细胞干性相关基因CD133、Sox2、Oct4的表达。A549/CSC细胞的FUNDC1表达高于正常A549细胞。干扰FUNDC1同样会抑制A549/CSC细胞增殖和保护性自噬,促进细胞凋亡。结论:FUNDC1调控肺癌细胞及CSC细胞的生长、自噬、凋亡及细胞干性。     

吉西他滨对人非小细胞肺癌A549细胞增殖与凋亡的影响

目的研究吉西他滨体外对人非小细胞肺癌A549细胞增殖及凋亡的作用。方法应用MTT法,流式细胞仪,Annexin V-PI双标法,Tunel法等多项方法,体外研究吉西他滨对A549细胞的促凋亡作用;采用免疫组化的方法,观察药物作用后bcl-2表达的变化。结果吉西他滨对A549细胞生长具有抑制作用,并有促凋亡效应,对细胞周期的影响表现为S期的阻滞,药物处理的细胞凋亡,可见伴有bcl-2的下调。结论吉西他滨可抑制人非小细胞肺癌A549细胞的生长,并诱导细胞发生凋亡,其诱导凋亡是吉西他滨抗肿瘤作用机制的原因之一,而且凋亡与bcl-2的表达有一定关系。     

rm hTNF-α联合吉西他滨杀伤人肺腺癌细胞A549作用研究

背景与目的 目前,晚期非小细胞肺癌患者化疗效果已达平台,生物治疗与化疗联合使用可明显改善此类患者的治疗效果.本课题旨在研究rmhTNF-α联合吉西他滨对人肺腺癌细胞A549的杀伤作用及其作用机制.方法 应用CCK-8法检测不同浓度rmhTNF-α及吉西他滨对A549细胞抑制率,应用细胞生长曲线描述经rmhTNF-α、吉西他滨干预过的A549细胞增殖情况,应用流式细胞仪检测各药物处理组48 h的细胞周期分布及凋亡率,并用光学显微镜及透射电子显微镜观察A549细胞形态及超微结构.结果 CCK-8检测结果及细胞生长曲线均提示rmhTNF-α不仅具有抑制A549细胞生长作用,而且可以增强吉西他滨对A549细胞杀伤作用;FCM显示两药联合组可促使A549细胞阻滞在S期,降低G2/M期比率;凋亡比率以吉西他滨 rmhTNF-α组最明显,光镜及电镜下观察结果均能明显观察到A549细胞呈凋亡形态学改变.结论 rmhTNF-α通过诱导人肺腺癌细胞A549细胞凋亡及细胞周期阻滞,从而增强吉西他滨对其的杀伤作用.     

香菇菌C91-3凋亡相关蛋白24414对人肺癌细胞A549凋亡作用及其机制的研究

目的:研究香菇菌C91-3凋亡相关蛋白24414对人肺癌细胞A549的凋亡诱导作用,探讨其诱导肿瘤细胞凋亡的机制。方法:将用毕赤酵母GS115体系进行诱导表达并已鉴定的香菇菌C91-3凋亡相关蛋白24414作用于人肺癌细胞A549,用MTT法测定目的蛋白的抑瘤率,用流式细胞术检测目的蛋白对肿瘤细胞的诱导凋亡作用,用ELISA法测定目的蛋白对肿瘤细胞Caspase-3活性的影响,同时用MTT法检测目的蛋白对正常鸡胚成纤维细胞的毒性作用。结果:流式细胞术与MTT法检测结果显示,终浓度为7.5、15和30μg/mL的此蛋白对A549细胞凋亡作用与对照组比较差异有统计学意义。ELISA法检测结果显示以上浓度的此蛋白对A549细胞Caspase-3活性影响与对照组相比较差异也有显著性意义(7.5μg/mL组vs对照组:t=8.787,P=0.000;15μg/mL组vs对照组:t=13.429,P=0.000;30μg/mL组vs对照组:t=36.908,P=0.000)。同时此蛋白对正常鸡胚成纤维细胞无毒性作用。结论:香菇菌C91-3凋亡相关蛋白24414在对正常鸡胚成纤维细胞无毒性作用的同时对人肺癌细胞A549具有诱导凋亡作用,其凋亡途径可能通过Caspase-3通路。     

蝙蝠葛提取物对人肺癌细胞系A549诱导凋亡作用的研究

目的探讨蝙蝠葛提取物对人肺癌细胞系A549诱导凋亡和抗增殖作用及其机制,为开发抗肿瘤新中药提供实验依据。方法应用MTT法测定蝙蝠葛提取物对人肺癌细胞系A549的生长抑制作用;通过倒置显微镜、光学显微镜观察肿瘤细胞凋亡的形态学变化;采用流式细胞术检测A549细胞的凋亡率;应用免疫组织化学技术检测药物处理前后凋亡相关蛋白酶caspase-3、caspase-8、caspase-9的表达。结果 （1）MTT法检测结果：蝙蝠葛提取物对人肺癌细胞系A549有明显的抑制生长的作用,且呈现出浓度的依赖性;（2）倒置显微镜观察结果：实验组肿瘤细胞体积变小、变圆,核染色质凝集,细胞间连接疏松,贴壁能力减弱;（3）HE染色观察结果：实验组肿瘤细胞体积变小、变圆,核染色质浓缩或染色质块形成,有的细胞膜起泡形成凋亡小体;（4）流式细胞术检测结果显示：蝙蝠葛提取物可以诱导A549细胞发生凋亡,加药组出现亚二倍体峰。结论 （1）蝙蝠葛提取物在体外对人肺癌细胞系A549有显著的诱导凋亡作用;（2）蝙蝠葛提取物诱导凋亡作用机制可能通过上调caspase-3、caspase-8和caspase-9蛋白表达,经由细胞凋亡的死亡受体和线粒体通路完成凋亡的启动和执行;（3）蝙蝠葛提取物具有显著的体外抗肿瘤作用,有望开发成一种新的抗肿瘤药物。     

桧木醇激活膀胱癌J82细胞自噬诱导细胞凋亡

背景与目的：膀胱癌是我国最常见的泌尿系统恶性肿瘤,近年来发病率逐年上升,严重威胁着人类的健康。本研究旨在探讨桧木醇对人膀胱癌J82细胞增殖、凋亡及自噬的作用,并初步阐明其作用机制。方法：采用CCK-8法检测细胞的增殖活力,采用流式细胞术检测细胞的凋亡状态,采用蛋白[质]印迹法(Western blot)检测cleaved caspase 3、LC3及P62蛋白的表达,转染EGFP-LC3后在激光共聚焦显微镜下观察细胞自噬状态。结果：桧木醇能够显著抑制J82细胞的增殖活力,通过激活caspase途径诱导肿瘤细胞凋亡,Z-VAD-FMK能够部分抑制桧木醇的凋亡诱导作用。桧木醇能够激活J82细胞发生自噬,上调LC3蛋白的表达,下调P62蛋白的表达。3-MA抑制自噬之后能够部分逆转桧木醇的抗肿瘤作用。结论：桧木醇可以显著抑制J82细胞增殖并通过过度激活自噬促进膀胱癌细胞凋亡。     

Inhibition of autophagy by 3-MA potentiates cisplatin-induced apoptosis in esophageal squamous cell carcinoma cells

Cisplatin (DDP)-based adjuvant chemotherapy is widely used for the treatment of esophageal cancer. However, DDP resistance has become more common and thus new approaches are required to be explored. Cisplatin was used to induce autophagy in the human esophageal cancer cell line, EC9706 cells, and the effect of autophagy on the survival of EC9706 cells was investigated using an autophagy inhibitor 3-MA. Cell viability was measured by CCK8 assay. Apoptosis and cell cycle were detected by flow cytometry. Monodansylcadaverine (MDC) was used to detect autophagy. Western blotting assay was used to investigate the molecular changes that occurred in the course of treatment. DDP inhibited cell proliferation, induced cell death and cell cycle arrest at S phage. Moreover, autophagy was activated through class III PI3K pathway. The expression of autophagy-related Beclin1 and LC3-I was up-regulated and part of LC3-I was converted into LC3-II. However, after the combination treatment of 3-MA and DDP, the cell inhibitory rate increased; the apoptosis rate and the numbers of cells in S phase also increased. Furthermore, the accumulation of autophagic vacuoles was decreased; the expression of Beclin1 and LC3 was significantly down-regulated and the release of cytochrome c was decreased. DDP-induced apoptosis in EC9706 cells can be enhanced by the inhibitor of autophagy, 3-MA. Autophagy might play a role as a self-protective mechanism in DDP-treated esophageal cancer cells, and its inhibition could be a novel strategy for the adjuvant chemotherapy of esophageal cancer.     

Autophagy inhibition promotes paclitaxel-induced apoptosis in cancer cells

Paclitaxel has been demonstrated to be an effective mitotic inhibitor and apoptosis inducer to treat aggressive malignancies. In this paper, we have provided a line of evidence that promotion of apoptotic cell death by paclitaxel was accompanied with induction of autophagy in A549 cells. Paclitaxel treatment could lead to the formation of acidic vesicular organelles (AVOs), the induction of Atg5, Beclin 1 and microtubule-associated protein 1 light chain 3 (LC3) expressions, and the increase of punctate fluorescent signals in A549 cells pre-transfected with green fluorescent protein (GFP)-tagged LC3. Interestingly, paclitaxel-mediated apoptotic cell death was further potentiated by pretreatment with autophagy inhibitor 3-methyladenine (3-MA) or small interfering RNA against the autophagic gene beclin1. These findings suggest that paclitaxel-elicited autophagic response plays a protective role that impedes the eventual cell death, and inhibition of autophagy could be an adjunctive strategy for enhancing chemotherapeutic effect of paclitaxel as an antitumor agent.     

Tripchlorolide induces cell death in lung cancer cells by autophagy

It has been demonstrated that triptolide inhibits the growth of several types of cancer cells in vitro and prevents tumor growth in vivo by inducing apoptosis and autophagy. Here we showed that Tripchlorolide (T4) significantly suppressed the proliferation of A549 cells in a dose- and time-dependent manner. This suppressive effect was diminished when cells were pretreated with 3-Methylamphetamine (3-MA). After the cells were treated with T4, the LC3 II protein expression was significantly increased, and autophagosomes were observed by TEM. However, almost no apoptosis was observed in A549 treated with T4. These results suggest that T4 induces A549 cell death predominantly through the activation of the autophagy pathway instead of the apoptosis pathway.     

The BH3 mimetic S1 induces autophagy through ER stress and disruption of Bcl-2/Beclin 1 interaction in human glioma U251 cells

Previous results showed that a novel BH3 mimetic S1 could induce cell death in a wide range of cancer types in vitro through Bax/Bak-dependent apoptosis. We demonstrated that in addition to mitochondrial pathway apoptosis, endoplasmic reticulum (ER) stress-associated apoptosis was also induced by S1. Moreover, S1 can induce autophagy in U251 cells, which may occur through ER stress and disruption of the association of Bcl-2 and Beclin 1. Inhibition of autophagy by the autophagic inhibitors 3-methyladenine (3-MA) or chloroquine (CQ) increased S1-induced apoptosis. In conclusion, autophagy plays an important role in S1-induced U251 cell death.     

Inhibition of autophagy enhances DENSpm-induced apoptosis in human colon cancer cells in a p53 independent manner

Purpose

One of the recently developed polyamine (PA) analogues, N ¹ ,N¹¹-diethylnorspermine (DENSpm), has been found to act as an apoptotic inducer in melanoma, breast, prostate and colon cancer cells. Also, its potential to induce autophagy has been established. Unfolded protein responses and starvation of amino acids are known to trigger autophagy. As yet, however, the molecular mechanism underlying PA deficiency-induced autophagy is not fully clarified. Here, we aimed to determine the apoptotic effect of DENSpm after autophagy inhibition by 3-methyladenine (3-MA) or siRNA-mediated Beclin-1 silencing in colon cancer cells.

Methods

The apoptotic effects of DENSpm after 3-MA treatment or Beclin-1 silencing were determined by PI and AnnexinV/PI staining in conjunction with flow cytometry. Intracellular PA levels were measured by HPLC, whereas autophagy and the expression profiles of PA key players were determined in HCT116, SW480 and HT29 colon cancer cells by Western blotting.

Results

We found that DENSpm-induced autophagy was inhibited by 3-MA treatment and Beclin-1 silencing, and that apoptotic cell death was increased by PA depletion and spermidine/spermine N¹-acetyltransferase (SSAT) upregulation. We also found that autophagy inhibition led to DENSpm-induced apoptosis through Atg5 down-regulation, p62 degradation and LC3 lipidation in both HCT116 and SW480 cells. p53 deficiency did not alter the response of the colon cancer cells to DENSpm-induced apoptotic cell death under autophagy suppression conditions.

Conclusions

From our results we conclude that DENSpm-induced apoptotic cell death is increased when autophagy is inhibited by 3-MA or Beclin-1 siRNA through PA depletion and PA catabolic activation in colon cancer cells, regardless p53 mutation status.

     

3-甲基腺苷对芹菜素诱导乳腺癌T47D细胞系自噬和凋亡的影响

研究自噬抑制剂3-甲基腺苷（3-methyladenine,3-MA）对芹菜素诱导乳腺癌T47D细胞系自噬和凋亡的影响。方法：常规培养人乳腺癌T47D细胞,分为对照组、3-MA组、芹菜素组、3-MA+芹菜素组。MTT法检测各组的细胞增殖抑制率;GFP-LC3质粒转染观察各组细胞自噬情况;Hochest/Mito-Red/YO-PRO-1染色法观察各组细胞凋亡形态;AnnexinV/PI双染法流式细胞仪检测各组细胞凋亡率;Western blot法检测LC3及PARP的变化。结果：MTT示3-MA+芹菜素组的增殖抑制率明显高于其他各组（P<0.05）;GFP-LC3质粒转染结果显示：对照组,3-MA组及3-MA+芹菜素组自噬不明显,而芹菜素组与其他各组相比自噬明显增多（P<0.05）;3-MA+芹菜素组的凋亡细胞增多,各组凋亡率分别为（12.73±0.05）%,（18.46±0.03）%,（23.27±0.07）%,（34.14±0.05）%,与对照组相比有统计学意义（P<0.05）;Western blot结果显示,芹菜素组LC3-Ⅱ增高,而3-MA组及3-MA+芹菜素组的LC3-Ⅱ显著减少,3-MA+芹菜素组PARP的剪切带相比其他各组明显增加。结论：自噬抑制剂3-MA抑制细胞自噬后,能够明显增强芹菜素对乳腺癌T47D细胞系的凋亡诱导效应。     

桧木醇对肾癌786-O细胞增殖及相关细胞因子的影响

目的从体外水平研究桧木醇(hinokitio1)的抗肾癌作用,探讨其作用机制。方法采用MTT法和流式细胞术检测桧木醇对肾癌786-O细胞增殖的抑制作用和促凋亡作用的影响;采用Western-blot检测桧木醇对人肾癌786-O细胞Caspase-3剪切体、LC3和P62蛋白表达水平的影响。以3-MA验证其抗癌作用与自噬作用的关系。结果桧木醇对肾癌786-O细胞增殖有显著抑制作用,主要是通过激活Caspase途径对细胞凋亡进行诱导。同时桧木醇可以对肾癌786-O细胞进行诱导自噬发生,使LC3蛋白的表达量出现显著上调,而P62蛋白表达则显著下调。结论桧木醇能够显著抑制肾癌786-O细胞的增殖,而且可以通过过度激活细胞自噬促进肾癌细胞凋亡。     

Steroidal Saponins from Paris polyphylla Induce Apoptotic Cell Death and Autophagy in A549 Human Lung Cancer Cells

Background: Paris polyphylla (Chinese name: Chonglou) had been traditionally used for a long time and shownanti-cancer action. Based on the previous study that paris polyphylla steroidal saponins (PPSS) induced cytotoxiceffect in human lung cancer A549 cells, this study was designed to further illustrate the mechanisms underlying.Materials and Methods: The mechanisms involved in PPSS-induced A549 cell death were investigated by phasecontrast microscopy and fluorescence microscopy, flow cytometry and western blot analysis, respectively. Results:PPSS decreased the proportion of viable A549 cells, and exposure of A549 cells to PPSS led to both apoptosis andautophagy. Apoptosis was due to activations of caspase-8, caspase-3, as well as cleavage of PARP, and autophagywas confirmed by up-regulation of Beclin 1 and the conversion from LC3 I to LC3 II. Conclusions: PPSS wasable to induce lung cancer A549 cell apoptosis and autophagy in vitro, the results underlining the possibility thatPPSS would be a potential candidate for intervention against lung cancer.