雷公藤内酯醇诱导T淋巴细胞凋亡时Fas/FasL的表达

目的 检测Fas/FasL在雷公藤内酯醇诱导的T淋巴细胞凋亡中的表达。 方法 培养人T淋巴细胞，10、20、30μg/L的雷公藤内酯醇分别刺激细胞4、8、16 h，流式细胞仪DNA分析、FITC-Annexin Ⅴ binding/PI染色检测细胞凋亡，Western blot分析检测Fas/FasL蛋白的表达。 结果 雷公藤内酯醇以剂量和时间依赖的形式诱导T细胞凋亡，雷公藤内酯醇诱导T细胞凋亡的同时伴随有Fas和FasL表达的上调，同样，雷公藤内酯醇诱导Fas和FasL表达呈现剂量和时间依赖性。结论 雷公藤内酯醇以剂量和时间依赖的形式诱导人T细胞凋亡，雷公藤内酯醇诱导T细胞凋亡的信号通路可能是通过Fas/FasL途径激活的。     

New disease-modifying antirheumatic drug 2 acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid (KE-298) selectively augments activation-induced T cell death.

We examined in this study whether the newly developed disease-modifying antirheumatic drug (DMARD) 2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid (KE-298) augments activation-induced T cell death. Peripheral blood (PB) T cells, isolated from healthy donors, were activated by incubation with interleukin-2 (IL-2) followed by further culture with 12-0-tetradecanoyl phorbol 13-acetate (PMA) and ionomycin in the presence or absence of KE-298. The apoptosis of activated T cells was examined by flow cytometric determination of hypodiploid DNA. Fas expression and caspase-3 activity in activated T cells were also examined by flow cytometry, and expression of Fas ligand (FasL), Bcl-2-related proteins, and X chromosome-linked inhibitor of apoptosis protein (XIAP) was determined by Western blot analysis. Apoptosis was not obvious in resting T cells and was not augmented by KE-298. In contrast, apoptosis was clearly detected in activated T cells (activation-induced T cell death) with the increment of caspase-3 activity, and incubation of these cells with KE-298 further enhanced apoptosis. Treatment of activated T cells with KE-298 increased Bax expression but decreased XIAP expression without affecting the expression of Fas/FasL. Thus caspase-3 activity in activated T cells appeared to be increased by KE-298. Our results suggest that the newly developed DMARD, KE-298, selectively augmented activation-induced T cell death. This finding may contribute to the therapeutic efficacy of KE-298 in rheumatoid arthritis (RA) patients and provide new insight into the pharmacologic action of DMARDs.     

TRAIL诱导白血病细胞凋亡的分子机制研究

目的　检测TRAIL引起的T淋巴白血病细胞凋亡及与之相关的蛋白和信号通路 ,为探索T淋巴细胞凋亡分子机制打下基础 ,为相关肿瘤的治疗提供依据。方法　用TRAIL( 1μg/ml)刺激Jurkat细胞 3 6h以诱导细胞发生凋亡 ,用流式细胞术和MTS比色法检测细胞存活率 ,计算细胞凋亡率 ;用免疫印迹 (Westernblot)检测NF κB的表达和胱天肽酶 (caspase) 3、cas pase 8的变化。 结果　TRAIL能诱导Jurkat细胞凋亡并伴随NF κB表达增加及caspase 3和caspase 8的活化。 结论　TRAIL诱导的T淋巴白血病细胞凋亡的分子机制涉及NF κB及caspase 3、caspase 8,为TRAIL用于治疗白血病提供实验基础。     

特发性血小板减少性紫癜患者外周血T细胞Fas-FasL和caspase-3凋亡相关蛋白的表达及其意义

目的 探讨Fas、FasL及caspase-3凋亡相关蛋白在特发性血小板减少性紫癜(ITP)患者T淋巴细胞的表达及其意义.方法 应用流式细胞术测定T细胞亚群表面Fas、FasL的表达率及细胞质中活化caspase-3的表达率,用Western blot法检测T细胞亚群caspase-3蛋白的表达.结果 与健康对照组[(29.4±8.2)%]相比,ITP患者组CD4+ T细胞表面Fas的表达率显著增加[(42.1±9.5)%](P＜0.05),CD8+ T细胞表面Fas的表达率略有增加但差异无统计学意义[(9.3±6.0)%与(13.4±5.8)%](P＞0.05).ITP患者组T细胞亚群表面FasL的表达率均较健康对照组显著增加(P＜0.05).ITP患者组T细胞亚群胞质中活化caspase-3的表达率,明显高于健康对照组(P＜0.05).Western blot检测结果显示,与治疗前相比,ITP患者治疗后CD4+ T细胞表达pro-caspase-3和cleaved-caspase-3均明显减少(P＜0.05).结论ITP患者外周血T细胞Fas、FasL及caspase-3表达明显增加,激素治疗可干预Fas-FasL、caspase-3的表达水平,提示Fas、FasL及caspase-3信号通路在ITP发生机制中起一定作用.     

黄芩苷诱导T细胞淋巴瘤凋亡的初步研究

目的:探讨黄芩苷对T细胞淋巴瘤细胞的诱导调亡作用及其机制。方法:采用黄芩苷处理白血病细胞株Jurkat,3-(4,5-二甲基噻唑)-2,5-二苯基四氮唑溴盐法测定细胞生长抑制率,细胞甩片瑞氏染色法观察细胞形态学改变,流式细胞术检测细胞凋亡,蛋白印迹法检测凋亡相关蛋白天冬氨酸特异性半胱氨酸蛋白酶caspase-3、caspase-8、caspase-9及AKT/ERK-MYC信号通路的表达,并用Calcusyn软件分析其与阿霉素、环磷酰胺联合使用的药效。结果:黄芩苷作用于Jurkat细胞48 h后的半数抑制浓度(IC50)为(24.32±1.01)μg/mL,且其生长抑制作用呈药物浓度-时间依赖性。黄芩苷组细胞呈现细胞凋亡的形态学改变,流式细胞术检测凋亡细胞百分比亦明显高于对照组,且呈药物浓度依赖性,而这种作用可被pan-caspase抑制剂ZVAD-FMK逆转。黄芩苷作用于Jurkat细胞48 h后,活化剪切型caspase-3、caspase-8、caspase-9表达均上调,AKT/ERK-MYC通路被抑制。此外,黄芩苷与阿霉素联合使用具有显著的协同效应。结论:黄芩苷可有效抑制T细胞淋巴瘤细胞增殖,诱导内源性和外源性凋亡,抑制AKT/ERK-MYC信号通路,并与阿霉素有显著的协同效应,具有良好的临床应用前景。     

Bovine lactoferricin selectively induces apoptosis in human leukemia and carcinoma cell lines

Bovine lactoferricin (LfcinB) is a cationic, amphipathic peptide that is cytotoxic for human and rodent cancer cells. However, the mechanism by which LfcinB causes the death of cancer cells is not well understood. Here, we show that in vitro treatment with LfcinB rapidly induced apoptosis in several different human leukemia and carcinoma cell lines as determined by DNA fragmentation assays and phosphatidylserine headgroup inversion detected by Annexin V binding to the surface of cancer cells. Importantly, LfcinB treatment did not adversely affect the viability of untransformed human lymphocytes, fibroblasts, or endothelial cells. Studies with different LfcinB-derived peptide fragments revealed that the cytotoxic activity of LfcinB resided within the amino acid sequence FKCRRWQWRM. Treatment of Jurkat T leukemia cells with LfcinB resulted in the production of reactive oxygen species followed by caspase-2-induced dissipation of mitochondrial transmembrane potential and subsequent activation of caspase-9 and caspase-3. Selective inhibitors of caspase-2 (Z-VDVAD-FMK), caspase-9 (Z-LEHD-FMK), and caspase-3 (Z-DEVD-FMK) protected both leukemia and carcinoma cells from LfcinB-induced apoptosis. Conversely, a caspase-8 inhibitor (Z-IETD-FMK) had no effect, which argued against a role for caspase-8 and was consistent with the finding that death receptors were not involved in LfcinB-induced apoptosis. Furthermore, Jurkat T leukemia cells that overexpressed Bcl-2 were less sensitive to LfcinB-induced apoptosis, which was characterized by mitochondrial swelling and the release of cytochrome c from mitochondria into the cytosolic compartment. We conclude that LfcinB kills cancer cells by triggering the mitochondrial pathway of apoptosis at least in part through the generation of reactive oxygen species.     

哇巴因诱导Jurkat细胞凋亡与胱冬酶-3及bcl-2基因家族的关系

本研究探讨哇巴因诱导Jurkat细胞凋亡及其机制。采用四甲基偶氮唑盐（MTT）法观察哇巴因对Jurkat细胞生长的抑制作用，应用流式细胞术、原位末端标记技术（TUNEL）等观察细胞凋亡，应用Western—blot测定胱冬酶-3（caspase-3）的活性亚单位及Bcl-2、Bax蛋白表达水平，用比色法检测caspase-3活性。结果表明：哇巴因能诱导Jurkat细胞凋亡，在细胞凋亡过程中，Bax蛋白表达增加，easpase-3活性明显升高。结论：哇巴因可能通过调节Bcl-2、Bax蛋白表达，从而激活caspase途径诱导Jurkat细胞凋亡。     

Involvement of Fas (CD95/APO-1) and Fas ligand in apoptosis induced by ganciclovir treatment of tumor cells transduced with herpes simplex virus thymidine kinase.

Transduction of cancer cells with herpes simplex virus thymidine kinase gene (HSVtk) followed by prodrug ganciclovir (GCV) treatment has been shown to induce apoptosis. In this study, four murine tumors including B16F10 melanoma, NG4TL4 sarcoma, H6 hepatoma and 1MEA 7R.1 hepatoma were found to vary in sensitivity to this gene therapy strategy in vitro but, at effective doses of GCV, the HSVtk-transduced cells of all four tumors showed similar kinetics of early rise in p53 protein levels, then cell cycle S-/G2-phase arrest and finally signs of apoptosis. Immunoblot analyses revealed that Fas (CD95/APO-1), Fas ligand (FasL) and two downstream mediators, RIP and caspase-3, (CPP32, YAMA, Apopain) were increased in GCV-treated HSVtk-transduced tumor cells the cell cycle arrest and before apoptosis. Increased expression of FasL could also be observed in vivo in HSVtk-transduced tumors induced to regress by GCV treatment. Enzyme measurements using specific substrate showed that the caspase-3 activation followed kinetically the FasL expression. More than half of the HSVtk/GCV-induced cell death could be abrogated by addition to the cell culture medium of a specific antisense oligonucleotide to block FasL synthesis, a recombinant Fas/Fc chimeric protein to compete with Fas receptor for FasL binding, or cell-permeable specific tetrapeptide inhibitors of caspase-3 or caspase-8.     

乌索酸诱导Jurkat细胞凋亡及其机制的初步研究

本研究旨在探讨乌索酸(ursolic acid,UA)对Jurkat细胞的诱导凋亡作用及其分子机制,为UA应用于血液系统恶性肿瘤治疗提供理论依据。培养Jurkat细胞,用Water Solubility Tetrazolium-8(WST-8)法检测不同浓度UA对Jurkat细胞的细胞毒作用,观察caspase-9抑制剂对UA细胞毒作用的抑制情况;分别收集20、40μmol/L UA处理2小时和4小时的Jurkat细胞,用Annexin/PI双染色、流式细胞仪检测细胞凋亡率;收集不同浓度UA作用不同时间的Jurkat对数生长期细胞,提取蛋白,用Western blot分析caspase-9和-3及细胞色素C活化、Akt磷酸化情况。结果表明:UA能明显降低Jurkat细胞的生存率,能够诱导Jurkat细胞凋亡,caspase-9抑制剂能够抑制UA的细胞毒作用。在UA诱导Jurkat细胞凋亡过程中,caspase-9、caspase-3和细胞色素C被活化,Akt磷酸化受到抑制。结论:UA对Jurkat细胞具有明显的细胞毒作用,并能诱导其凋亡;UA诱导Jurkat细胞凋亡是通过线粒体途径实现的,其机制可能与抑制细胞生存因子Akt磷酸化过程相关。     

Fas配体在髓系白血病细胞中的表达及功能研究

为了解Fas配体 (FasL)在髓系白血病细胞中的表达水平及其诱导Fas+敏感细胞发生凋亡的功能 ,用流式细胞术检测 38例髓系白血病患者 (外周血白细胞 >10 0× 10 9/L)的白血病细胞在新鲜分离及IL 2和IFN γ刺激后表面膜FasL的表达水平 ,将白血病细胞 ( 1× 10 6/ml)与Jurkat细胞 ( 1× 10 5/ml)混合培养 2 4小时后 ,用DNA电泳和流式细胞术双标法检测Jurkat细胞发生凋亡的情况。结果表明 :白血病细胞表面FasL表达量 ( 3.5 9± 1.0 5 ) %高于正常人 ( 0 .36± 0 .16 ) % ,P <0 .0 0 1,经IL 2和IFN γ刺激后其表达量明显增加 ( 7.78± 3.4 0 ) % ,P <0 .0 1;白血病细胞刺激前后诱导Jurkat细胞发生的凋亡率分别为 ( 8.2 8± 1.6 1) % ,( 10 .73± 2 .16 ) % ,差异具有显著性意义。结论 :FasL在髓系白血病细胞表面高表达且对Fas+的敏感细胞具有杀伤功能 ,推测Fas/FasL途径可能在白血病的“免疫逃逸”中发挥作用     

Cyclooxygenase 2 Modulates Killing of Cytotoxic T Lymphocytes by Colon Cancer Cells

Although anti-cancer effects of cyclooxygenase 2 (COX2) inhibitors have been reported, most studies focused on the direct effects of COX2 inhibiters on colon cancer cells. On the other hand, several types of cancers express Fas ligand (FasL) and/or TRAIL and mediate apoptosis of T cells in vitro. The “counter-attack” machinery may account for the mechanisms by which tumors evade host immune surveillance. In this study we determined if COX2 inhibitor could modulate effector molecules of cell death on colon cancer cells changing their effects on cytotoxic T lymphocytes. Colon adenocarcinoma cells, HCA7 and HCT116, the former COX2-positive and the latter COX2-negative, were pre-incubated with/without a COX2 inhibitor, NS398. Subsequently, the cells were co-cultured with Jurkat T cell leukemia cells and damage to Jurkat cells was determined. Treatment with NS398 resulted in reduction of expression of FasL and TRAIL in HCA7 cells, whereas NS398 did not affect the expression of FasL and TRAIL in HCT116 cells. The number of viable Jurkat cells was diminished when cells were co-cultured with naive, non-pretreated HCA7 or HCA116 cells. Preincubation of HCA7 cells with NS398 before co-culture blunted the HCA7 cell-induced cell toxicity on Jurkat cells. In contrast, pretreatment with NS398 failed to inhibit the HCT116-induced Jurkat cell killing. Our results suggest that COX2 regulates the expression of FasL and TRAIL on COX2-positive colon cancer cells thereby evoking a counter-attack against cytotoxic T cells, which may lead to compromised host immune responses.     

反义Fas阻断激活T细胞凋亡的研究

目的：探索阻断激活Ｔ细胞凋亡的途径，增加激活的Ｔ细胞数量，提高肿瘤免疫治疗的疗效。方法：应用ＣＤ３诱导Ｊｕｒｋａｔ细胞的凋亡作为激活的Ｔ细胞凋亡模型，应用逆转录病毒载体将反义Ｆａｓ转染Ｊｕｒｋａｔ细胞，观察反义Ｆａｓ对ＣＤ３及抗Ｆａｓ单克隆抗体（单抗）对Ｊｕｒｋａｔ细胞凋亡的影响。结果：构建一个反义Ｆａｓ的逆转录病毒载体ｐＬＸＳＮ－反义Ｆａｓ，并转染Ｊｕｒｋａｔ细胞，发现Ｊｕｒｋａｔ细胞Ｆａｓ蛋白表达量下降，并部分阻断ＣＤ３及抗Ｆａｓ单抗诱导的Ｊｕｒｋａｔ细胞凋亡。结论：应用反义技术阻断Ｆａｓ基因表达，可部分阻断ＣＤ３及抗Ｆａｓ单抗诱导的Ｊｕｒｋａｔ细胞凋亡。     

MiRNA-326抑制人椎间盘退变髓核细胞活力和凋亡的机制

目的:探讨过表达miRNA-326对椎间盘退变(intervertebral disc degeneration,IDD)髓核(nucleus pulposus,NP)细胞凋亡的影响及其作用机制。方法:构建miRNA-326慢病毒表达载体,在293T细胞中获得重组慢病毒,经感染NP细胞得到稳定过表达细胞系GV369-miRNA-326-NP,同时设置空载体GV369-NP组与空白组。荧光显微镜观察慢病毒载体的标签蛋白[绿色荧光蛋白(green fluorescent protein,GFP)]的表达,实时荧光定量PCR(real-time quantitative polymerase chain reaction,RT-qPCR)方法检测miRNA-326的表达,流式细胞术检测细胞凋亡,荧光素酶报告基因分析验证miRNA-326与FasL的靶向关系,蛋白质印迹法检测细胞中凋亡相关蛋白FADD,caspase-3,Bcl-2及Bax的表达,使用试剂盒检测细胞线粒体膜电势的变化情况。结果:荧光显微镜下示,经慢病毒感染的过表达细胞系和空载体细胞系均出现绿色荧光,而空白组未见绿色荧光。与空白组相比,GV369-miRNA-326-NP组中miRNA-326的表达水平、Bcl-2表达水平和线粒体膜电位明显升高,而细胞凋亡率,FADD,caspase-3和Bax的表达水平明显下降,差异均有统计学意义(P<0.05);GV369-NP组与空白组相比,差异无统计学意义(P>0.05)。荧光素酶报告基因分析证实miRNA-326与FasL存在靶向关系。结论:MiRNA-326可抑制IDD NP细胞发生凋亡,既可通过靶向性调控外源性FasL/Fas通路参与caspase-3和FADD介导的细胞凋亡,也可通过线粒体途径对细胞凋亡发挥作用。     

中性粒细胞凋亡调控基因表达异常在全身炎症反应综合征中的作用

目的观察全身炎症反应综合征（SIRS）时中性粒细胞（PMN）凋亡的异常变化及其凋亡调控基因的表达情况，评价其临床意义。方法8例SIRS患者（均为急性胰腺炎患者）作为SIRS组。6名健康献血者作为正常对照组。分别观察两组外周血PMN凋亡率、凋亡调控基因Fas／FasL和凋亡信号转导分子天冬氨酸特异性半胱氨酸蛋白酶-3（caspase-3）及血清白细胞介素-6（IL-6）、IL8的水平。结果SIRS组外周血血清IL-6和IL-8水平均明显高于正常对照组（P均＜0．01）。SIRS组患者外周血PMN细胞凋亡率较正常对照组明显减少（P＜0．01）；两组PMN在体外培养24h后，用蛋白质免疫印迹法（Western blotting）没有检测到FasL表达；SIRS组患者外周血PMN的Fas、caspase-3表达水平与正常对照组比较明显降低（P均＜0．01）。结论SIRS患者存在PMN的凋亡异常和Fas、caspase-3表达水平下调，PMN凋亡延迟在SIRS的发生发展中有着重要意义。     

Caspase activation is required for T cell proliferation

Triggering of Fas (CD95) by its ligand (FasL) rapidly induces cell death via recruitment of the adaptor protein Fas-associated death domain (FADD), resulting in activation of a caspase cascade. It was thus surprising that T lymphocytes deficient in FADD were reported recently to be not only resistant to FasL-mediated apoptosis, but also defective in their proliferative capacity. This finding suggested potentially dual roles of cell growth and death for Fas and possibly other death receptors. We report here that CD3-induced proliferation and interleukin 2 production by human T cells are blocked by inhibitors of caspase activity. This is paralleled by rapid cleavage of caspase-8 after CD3 stimulation, but no detectable processing of caspase-3 during the same interval. The caspase contribution to T cell activation may occur via TCR-mediated upregulation of FasL, as Fas-Fc blocked T cell proliferation, whereas soluble FasL augmented CD3-induced proliferation. These findings extend the role of death receptors to the promotion of T cell growth in a caspase-dependent manner.     

Glioma apoptosis induced by macrophages involves both death receptor-dependent and independent pathways

Apoptosis of glioma may represent a promising intervention for tumor treatment. Macrophages are able to induce apoptosis in a number of tumor cells, including glioma. It is known that apoptosis of cells is executed on either a death receptor-dependent or independent pathway. Whether and how apoptosis of glioma cells induced by activated macrophages is involved in these two pathways simultaneously are not known. Using in vitro and in vivo experimental models, we investigated Bcl-2 system and Fas/FasL channel, representing the death receptor-dependent and independent pathways, respectively, in glioma cells treated with the supernatant from the activated macrophages, which was rich in tumor necrosis factor-alpha and interferon-gamma. We found that levels of Fas and FasL were up-regulated both in vitro and in vivo, accompanying an increase in the expression of caspase-8. The number of apoptotic cells was also increased significantly, although the percentage of death cells exceeded the number of tumor cells positive for Fas or FasL. It was also evident that the expression of Bax was increased, whereas the level of Bcl-2 was decreased, in glioma cells treated with the supernatant from the activated macrophages. The alteration of molecules related to both death pathways led to apoptosis of glioma and the inhibition of xenograft glioma growth in mice. Apoptosis of glioma induced by the activated macrophage is executed by way of both death receptor-dependent and independent pathways, and such an apoptosis-induced approach can effectively inhibit the growth of glioma in vivo.     

转染人livinα基因对Jurkat细胞增殖及凋亡的影响

目的：研究人livinα基因表达对Jurkat细胞增殖、凋亡的影响。方法基因转染获得稳定表达livinα的Jurkat细胞克隆（Jurkat/livinα）;MTT法测定细胞增殖,流式细胞仪分析细胞凋亡率,通过观察细胞生长和凋亡情况,探讨livinα对Jurkat细胞增殖及凋亡的影响;RT-PCR检测细胞中livinα和caspase-3 mRNA的表达。结果Jurkat/livinα组livinαmRNA表达高于对照组（Jurkat细胞组）（P＜0.05）,转染后caspase-3 mRNA受到抑制,表达减弱,细胞生长曲线显示Jurkat/livinα组细胞生长速度增快,倍增时间缩短9-10 h（P＜0.05）,细胞凋亡率计算显示Jurkat/livinα组细胞凋亡率较Jurkat细胞组明显减少（P＜0.01）。结论 livin α基因能促进Jurkat细胞生长,可能通过抑制细胞凋亡而在急性T淋巴细胞白血病发生发展中起重要作用,有望成为白血病治疗的新分子靶点。     

Helicobacter pylori-induced apoptosis in T cells is mediated by the mitochondrial pathway independent of death receptors

BACKGROUND: Chronic infection with Helicobacter pylori is related to the pathogenesis of the noncardia carcinoma of the stomach. In this study we investigated the mechanisms of H. pylori-induced apoptosis in T lymphocytes, which could explain a mechanism of immune evasion facilitating chronic inflammation of the mucosa and gastric carcinogenesis. MATERIALS AND METHODS: The supernatant of H. pylori culture was used to study the mechanism of apoptosis induction in human leukaemia T cell lines Jurkat and CEM and in primary T cells. The cytotoxin associated gene A (CagA) and vacuolating cytotoxin A (Vac A) positive bacterial strain H. pylori 60190 (CagA(+), VacA(+)) and as a control the less toxic H. pylori strain Tx30a (CagA(-), VacA(-)) were used to produce the supernatant. Cell death was determined by DNA fragmentation and protein expression by Western blot. RESULTS: H. pylori 60190-induced apoptosis was neither blocked by inhibition of the death ligands TRAIL (TNF-related apoptosis-inducing ligand), CD95L/FasL and TNF-alpha (tumour necrosis factor-a) in wild type Jurkat cells nor in FADD(def) (Fas-associated death domain protein) and caspase-8(def) subclones of the Jurkat cell line. Yet, the pancaspase inhibitor zVAD-fmk could inhibit up to 90% of H. pylori-induced apoptosis. Stable transfection of Jurkat wild type cells with Bcl-x(L and) Bcl-2 resulted in marked reduction of H. pylori-induced apoptosis, showing that the mitochondrial pathway is the key regulator. This is supported by the finding that surviving primary human lymphocytes upregulate Bcl-2 when exposed to H. pylori supernatant. CONCLUSIONS: H. pylori-induced apoptosis of T cells is mediated by the mitochondrial pathway and could create a local environment that facilitates life-long infection by immune evasion.