Caspase 8和Caspase 3在TRAIL诱导神经母细胞瘤细胞凋亡中的作用(英文)

目的探讨Caspase8和Caspase3在肿瘤坏死因子相关凋亡诱导配体（TRAIL）诱导CHP212神经母细胞瘤细胞凋亡中的作用。方法应用流式细胞仪检测TRAIL、Caspase8／Caspase3抑制剂＋TRAIL对CHP212细胞的诱导凋亡作用。应用比色法测定Caspase8、Caspase3的相对活性。应用透射电镜对凋亡细胞进行形态学的观察。结果TRAIL可诱导CHP212细胞的凋亡，并存在剂量依赖性；Caspase8／Caspase3抑制剂能抑制TRAIL对CHP212细胞的诱导凋亡作用。随TRAIL作用时间的延长，Caspase8、Caspase3的活性逐步升高，分别于作用16h、8h后达高峰。透射电镜可见到典型的细胞凋亡特征。结论TRAIL通过Caspase信号传导通路诱导CHP212细胞凋亡并伴随Caspase8和Caspase3活性的增高。     

Synergy is achieved by complementation with Apo2L/TRAIL and actinomycin D in Apo2L/TRAIL-mediated apoptosis of prostate cancer cells: role of XIAP in resistance

BACKGROUND: Tumors have an inherent immunogenicity that can be exploited by immunotherapy. However, often tumors develop mechanisms that render them resistant to most immunologic cytotoxic effector mechanisms. This study examines the underlying mechanism of resistance to Apo2L/TRAIL (tumor necrosis factor-related apoptosis-inducing ligand)-mediated apoptosis. METHODS: We studied prostate tumor cell lines for their sensitivity to Apo2L/TRAIL-mediated apoptosis in the presence and absence of the sensitizing agent actinomycin D (Act D). Apoptosis was determined by flow cytometry and signaling for apoptosis by Western blot. RESULTS: Treatment with subtoxic concentrations of Act D significantly sensitizes the tumor cells (CL-1, DU-145, and PC-3 prostate tumor cells) to Apo2L/TRAIL-mediated apoptosis. The cytotoxicity of Act D-sensitized prostate tumor cells was a result of synergistic activation of caspases (caspase-3, -9, and -8), detectable after 6 hr of treatment. Treatment with Apo2L/TRAIL alone, although it was insufficient to induce apoptosis, resulted in the loss of mitochondrial membrane potential and release of cytochrome c from the mitochondria into the cytoplasm in the absence of significant caspases activation. These findings suggested that a major apoptosis resistance factor blocking the Apo2L/TRAIL apoptotic signaling events is present downstream of the mitochondrial activation. The expression of receptors and anti-apoptotic proteins were examined in Act D-sensitized CL-1 cells. The earliest and the most pronounced change induced by Act D was down-regulation of X-linked inhibitor of apoptosis (XIAP) and up-regulation of Bcl-xL/-xS proteins. The role of XIAP in resistance was demonstrated by overexpression of Smac/DIABLO, which inhibited inhibitors of apoptosis (IAPs) and sensitized the cells to Apo2L/TRAIL. Apo2L/TRAIL receptors (DR4, DR5, DcR1, and DcR2), c-FLIP, Bcl-2, and other IAP members (c-IAP1 and c-IAP2) were marginally affected at later times in the cells sensitized by Act D. CONCLUSION: This study suggests that the combination of Act D-induced down-regulation of XIAP (Signal I) and Apo2L/TRAIL-induced release of cytochrome c (Signal II) leads to the reversal of resistance to Apo2L/TRAIL-mediated apoptosis in the tumor cells. The sensitization of tumor cells to Apo2L/TRAIL by Act D is of potential clinical application in the immunotherapy of drug/Apo2L/TRAIL refractory tumors.     

Caspase-8 activation is necessary but not sufficient for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in the prostatic carcinoma cell line LNCaP

BACKGROUND: The differential sensitivity of tumor cells to TRAIL-induced apoptosis may be mediated by different intracellular inhibitors of apoptosis, and only a few reports have described the pathway(s) that are activated in response to TRAIL in prostate cells. METHODS: LNCaP was transfected with a dominant-negative form of FADD (FADD-DN) and cells were selected in the presence of hygromycin. Cell viability was estimated by calcein assay. Apoptosis was estimated by caspase activation using both fluorogenic substrates and Western blot analysis of activated caspases. To detect cytochrome c release, mitochondria-free cytosol was prepared and Western blot analysis was performed. RESULTS: LNCaP is resistant to TRAIL but TRAIL transiently induces DEVDase activity and activation of caspase-8; caspase-2, -3, -7, and -9 were not activated. Wortmannin, an inhibitor of the PI3K/Akt pathway, converted the phenotype of LNCaP from TRAIL-resistant to -sensitive. In the presence of wortmannin TRAIL induced activation of caspase-2, -3, -7, -8, and -9, as well as dissipation of mitochondrial transmembrane potential and release of cyto-chrome c from mitochondria into the cytosol. In addition, combined TRAIL and wortmannin treatment resulted in cleavage of several proteins: PARP, Akt, p21/WAF1, and MDM2 as well as dephosphorylation of Akt. The proteolysis of p21/WAFI and Akt, which are known survival factors, presumably amplify the apoptotic cascade in LNCaP. Transfection of FADD-DN in LNCaP resulted in inhibition of caspase activation as well as in resistance to combined treatment with TRAIL and wortmannin. CONCLUSIONS: These results suggest that caspase-8 activation is necessary but not sufficient for TRAIL-mediated apoptosis and is presumably blocked downstream of caspase-8 by the PI3K/Akt pathway.     

Upregulation of osteoblast apoptosis by malignant plasma cells: a role in myeloma bone disease

Typical features of multiple myeloma (MM) are osteolytic lesions and severely affected bone regeneration. This study of 53 MM patients demonstrates an enhancement of osteoblast cytotoxicity by malignant myeloma cells via the upregulation of apoptogenic receptors, including Fas ligand (Fas-L) and tumour-necrosis-factor-related apoptosis inducing ligand (TRAIL). Both were significantly increased in the marrow myeloma cells of patients with extensive osteolytic lesions in a fashion similar to the highly malignant human myeloma cell line MCC-2. Osteoblasts from these subjects over-expressed Fas and death receptor (DR) 4/5 and underwent dramatic apoptosis when co-cultured with either MCC-2 or autologous myeloma cells. In osteoblast and myeloma cell co-cultures, monocyte chemoattractant protein 1 (MCP-1) mRNA was upregulated in osteoblasts from patients with severe bone disease in parallel with increased CC-chemokine receptor R2 (CCR2) expression, the ligand of MCP-1, in the myeloma cells. This chemokine was shown to activate malignant cell migration in vitro. An upregulation of ICAM-1 expression occurred in osteoblasts from patients with active skeleton disease. This upregulation appeared to be an effect of malignant plasma cell contact, as MCC-2 co-culture greatly enhanced ICAM-1 production by resting osteoblasts from patients without skeleton involvement. Our results suggest that osteoblasts in active myeloma are functionally exhausted and promptly undergo apoptosis in the presence of myeloma cells from patients with severe bone disease. It is suggested that this cytotoxic effect plays a pivotal role in the pathogenesis of defective bone repair.     

肿瘤坏死因子凋亡诱导配体联合顺铂对人横纹肌肉瘤细胞株凋亡的影响

目的探讨肿瘤坏死因子相关凋亡诱导配体（TRAIL）蛋白及TRAIL基因和顺铂联合应用对人横纹肌肉瘤细胞生长抑制和诱导凋亡作用，并分析细胞线粒体膜电位和细胞内cFLIPmRNA表达的改变对凋亡的的影响。方法将TRAIL蛋白、TRAIL基因和顺铂作用于培养的人横纹肌肉瘤细胞，通过MTT比色法、流式细胞仪（FCM）检测细胞凋亡和线粒体跨膜电位的改变、RT-PCR检测cFLIPmRNA表达，观察和分析TRAIL蛋白及TRAIL基因单独对横纹肌肉瘤细胞的作用及和顺铂联合作用的效果和机制。结果TRAIL基因和100μg／L的TRAIL蛋白对横纹肌肉瘤细胞的生长抑制率分别为52．5％和43．5％，凋亡诱导率为12．95％和10．26％，联合应用顺铂，生长抑制率和凋亡诱导率均显著高于单独应用，FCM分析显示联合应用降低了线粒体跨膜电位，RT—PCR显示cFLIPmRNA表达下降，与联合应用细胞凋亡率增加相一致。结论TRAIL蛋白和TRAIL基因能有效诱导横纹肌肉瘤细胞的凋亡从而抑制横纹肌肉瘤细胞的生长，联合应用顺铂可显著提高疗效。     

鼠角膜TRAIL mRNA表达与角膜移植排斥反应

目的观察正常鼠眼角膜组织中“肿瘤坏死因子相关凋亡诱导配体（TRAIL）的表达分布情况。方法采用RT-PCR技术和免疫组化技术检测TRAIL，定性、定位分析TRAIL在正常BALB／c鼠角膜组织中的表达。结果TRAIL mRNA在正常BALB／c鼠角膜组织中表达，免疫组织化学检测显示：角膜上皮层、内皮层强表达，闻质层弱表达。结论TRAIL广泛存在于角膜组织中，有抑制或减轻角膜移植免疫排斥反应的作用，但其机制有待进一步深入研究。     

Antitumor Effects of Soluble TRAIL in Human Hepatocellular Carcinoma

TNF related apoptosis inducing ligand(TRAIL) is a promising cancer therapeutic agent,which appears to specifically kill transformed cells,and spare most normal cells[1, 2]. In the presentstudies, we investigated the expression of TRAILand TRAIL receptors in 60 HCC tissues, 20 nor mal liver samples and two HCC cell lines (HepG2and SMMC 7721). The effects of TRAIL on pro moting apoptosis in the HCC cell lines were ana lyzed after the cells exposed to the…     

Tumor Necrosis Factor-related Apoptosis Ligand Induces Apoptosis in Prostate Cancer PC-3M Cell Line

Summary： To study the effect of tumor necrosis factor-related apoptosis inducing ligand （TRAIL） on PC-3M cell line, PC-3M cell line was incubated with gradient concentrations of TRAIL for 4-24 h. Annixin-V fluorescence staining and TUNEL method were employed to detect the apoptosis of PC-3M cells. The morphology of apoptotic PC-3M cells was observed by electron microscopy. The relationship between TRAIL concentrations and the percentage of apoptotic cells was evaluated by flow cytometry. The proliferation inhibitory ratio was calculated by using MTT colorimetry. Our results showed that apoptosis of PC-3M cells could be induced by treatment with TRAIL for at most 4 h. The results of flow cytometry and MTT colorimetry demonstrated a time-and concentration-dependent relationship between cell apoptosis rate and TRAIL concentration. It is concluded that apoptosis of PC-3M cells can be induced by TRAIL. Because of the selective killing effect of TRAIL on tumor cells, it may become a potential alternative for the treatment of advanced prostate cancer.     

TRAIL促肿瘤细胞凋亡的研究进展

 目的笔者通过对TRAIL受体结构与功能进行综述,总结了TRAIL诱导肿瘤细胞凋亡途径以及TRAIL在肿瘤治疗方面的价值,表明TRAIL成为一种新型抗肿瘤药物的可能性。方法比较各型TRAIL受体在正常组织和肿瘤组织中分布的差异,多种细胞器在TRAIL诱导细胞凋亡应答中的效用及其细胞信号传递的通路。结果表明TRAIL对肿瘤组织具有选择性诱导细胞凋亡作用,对多种肿瘤均有诱导作用,但诱导的剂量和作用的量效关系存在差异,动物实验表明,TRAIL与传统放化疗药物具有一定的协同作用。结论TRAIL的生物学效用表明其有可能成为一种新型抗肿瘤药物,但其作用的许多方面还不十分清楚,有待进一步解决,如:①需进一步明确TRAIL表达的调控机制,特别是关于转录因子对TRAIL的调节,目前还知之甚少;②进一步探讨TRAIL的临床应用价值及所需条件等。     

rsTRAIL诱导人肺癌细胞系A549的细胞凋亡表达谱变化研究

 目的研究一定量的重组可溶性TRAIL作用于人肺癌系A549细胞培养物后,细胞凋亡基因表达谱变化。方法用50μg·L^-1的rsTRAIL处理人肺癌系A549细胞培养物,以未经药物处理的A549细胞培养物为对照,应用基因表达谱芯片技术进行细胞凋亡相关基因mRNA表达差异分析。结果经TRAIL处理后,所检测的96个细胞凋亡相关基因中,21个基因表达上调,17个基因表达水平下调。结论经TRAIL处理后,通过细胞凋亡相关的功能基因组群基因表达的正负调控,对人肺癌系A549细胞凋亡信号传导途径进行调控。药物处理不影响p53基因的表达变化。