抑制PI3K通路增强CAHB对Jurkat细胞的凋亡作用

目的 探讨CAHB单独使用及与LY294002联合应用对Jurkat细胞体外作用的影响.方法 分别用不同剂量的CAHB(0、5、10、20、40mmol/L)诱导Jurkat细胞,用MTS法检测Jurkat细胞的增殖抑制效应,流式细胞术分析Jurkat细胞凋亡情况;取40mmol/L浓度的CAHB加入PI₃K抑制剂LY294002,流式细胞术分析Jurkat细胞凋亡情况.结果 CAHB对Jurkat细胞生长有显著的抑制作用,并能显著诱导Jurkat细胞发生凋亡,其作用呈明显剂量、时间依赖性.PI₃K抑制剂LY294002能显著增强CAHB对Jurkat细胞的凋亡作用.结论 CAHB能抑制Jurkat细胞增殖,并诱导其凋亡.抑制PI₃K通路能增强CAHB对Jurkat细胞的凋亡作用.     

Annexin Ⅱ siRNA对淋巴瘤Jurkat细胞凋亡的影响

目的观察沉默膜联蛋白Ⅱ（annexinⅡ,A2）基因对淋巴瘤Jurkat细胞凋亡的影响。方法采用A2 siRNA转染人淋巴瘤Jurkat细胞后应用RT-PCR和Western blot鉴定干扰效果。Annexin V-FITC/PI双染流式细胞术检测其对细胞凋亡的影响。结果Real-time PCR和Western blot检测结果表明,A2基因被成功抑制。流式细胞术检测得A2siRNA组细胞凋亡率为57.47%±2.10%,较阴性对照组（28.68%±1.21%）明显增加,差异有统计学意义（P〈0.05）。结论A2基因可增强Jurkat细胞抗凋亡作用,A2 siRNA可诱导Jurkat细胞凋亡。     

The MDR1 (P-glycoprotein) and MRP (P-190) transporters do not play a major role in the intrinsic multiple drug resistance of Jurkat T lymphocytes

The response of T cells in relation to the cell cycle has not been extensively studied. We have attempted to address this question using Jurkat T cells treated with cytostatic drugs known to arrest cells at various transition points of their cycle. We tested several concentrations of drugs that act at G1/S (hydroxyurea, lovastatin, thymidine), early S (aphidicolin, cyclosporin A, rapamycin) or G2+M (colchicine, nocodazole) in 24 h cultures. Cytofluorimetric analyses showed that cycling Jurkat cells were equally distributed between the G1 (44.9 ± 6.5%) and S (42.3 ± 8.0%) phases. Cell distribution in G2+M was 12.7 ± 2.8%. Hydroxyurea but not lovastatin increased the percentage of cells in S phase to ≈60–70% and both drugs decreased it to ≈30% in G1. Thymidine had no effects. Aphidicolin increased the distribution in S phase to ≈70% with a decrease in G1 to ≈30%. Cyclosporin A and rapamycin increased the percentage of the cells in G1 to ≈70% and decreased it to ≈25% in S phase. Nocodazole increased cell distribution in G2+M to ≈60% and induced a decrease in G1 to ≈10%. The effects of the drugs were not related to their toxicity and their limited efficiency raised the possibility that Jurkat cells possessed an intrinsic resistance to these xenobiotics. Time-course analysis showed (scanning electron microscopy) that the early morphological changes induced by colchicine were reversible. Drug efflux experiments (vinblastine) suggested that an ATP-dependent process could be involved. However, Northern blot analyses showed a weak signal for MDR1 (P-glycoprotein). In contrast, a probe for MRP (P-190) showed a strong signal in Jurkat and peripheral lymphocytes. The presence of drugs (cyclosporin A, nocodazole, thymidine) (24 h) did not upregulate its message and cell treatment with -butathione (S,R)-sulfoximine only moderately affected the efficiency of the glutathione S-conjugate MRP transporter. Our data suggest that the intrinsic multidrug resistance of leukemic Jurkat T cells does not appear to involve the MDR1 and MRP members of the ABC family of reverse drug transporters and these observations raise the possibility of the involvement of multifaceted mechanisms.     

油茶皂苷通过内质网应激途径诱导Jurkat细胞凋亡的研究

目的探讨油茶皂苷在体外诱导人白血病细胞Jurkat凋亡的作用及作用机制。方法将1～4μg/mL的油茶皂苷作用于人白血病Jurkat细胞,应用细胞计数考察油茶皂苷对细胞增殖的影响;用Western blot方法分析油茶皂苷对caspase-3、PARP、Bipc、hop、Perk、ATF6和IRE1蛋白表达的影响。结果油茶皂苷(1～4μg/mL)对Jurkat细胞的增殖产生明显的剂量依赖性抑制作用。免疫印迹结果显示,油茶皂苷可以使caspase-3激活,增加Cleaved PARP的表达量,而诱导Jurkat细胞发生凋亡;其作用机制是通过下调Bip和chop的表达,触发Perk、ATF6和IRE1 3个内质网应激跨膜蛋白而产生细胞凋亡的。结论 1～4μg/mL油茶皂苷具有抑制人白血病细胞增殖和诱导其凋亡的作用,其作用机制参与了细胞凋亡的内质网应激途径。     

Prolactin is an autocrine growth factor for the Jurkat human T-leukemic cell line

Despite convincing evidence of cooperation between IL-2 and endogenous prolactin (PRL) during T cell activation, the individual role of PRL as a T-cell lineage cytokine remains to be defined. We have examined the production and function of PRL on the Jurkat human T-leukemic cell line, which does not constitutively produce IL-2. The majority of Jurkat cells expressed PRL receptor (R) under standard culture conditions, whereas appearance of the α chain of the IL-2-R required PHA–PMA stimulation, as did IL-2 synthesis. Western blotting revealed a predominant band at 23.5 kDa and a weaker band at 25.5 kDa in both Jurkat cell lysates and human (h) pituitary PRL. Metabolic labeling of the cell lysates with -methionine and immunoprecipitation with an antiserum against hPRL showed that both forms of PRL are actively synthesized by the Jurkat cell line. PRL released in the medium was biologically active in the rat Nb2 lymphoma mitogenic assay. Depletion of medium PRL with two polyclonal anti-hPRL antisera inhibited the growth of Jurkat cells in a dose-dependent manner, as evaluated by cell number and -TdR uptake. Purified pituitary or recombinant hPRL at a wide range of concentrations had no significant effect on their growth, but reversed the blocking activity of the anti-hPRL antibody. Recombinant IL-2 had no effect on the antibody-induced growth inhibition. Taken as a whole, these results demonstrate that PRL can act as an autocrine T cell growth factor independently of IL-2 and are the first evidence of its involvement in human leukemic growth and possibly in leukemic transformation.     

维生素C联合硼替佐米对人T细胞淋巴瘤细胞株Jurkat细胞凋亡的应用

目的 研究维生素C联合硼替佐米对人T细胞淋巴瘤细胞株Jurkat细胞凋亡相关蛋白B淋巴细胞瘤-2(Bcl-2)与Bcl2相关X蛋白(Bax)表达调节的影响.方法 采用30 nmol/L的硼替佐米组,100 μg/mL的维生素C组及联合组分别作用于Jurkat细胞24、48、72 h,设立未加药物的对照组,应用倒置显微镜观察细胞的生长方式,免疫组织化学检测Bax及Bcl-2的表达,CCK-8及流式细胞技术检测Jurkat细胞凋亡率和细胞周期.结果 维生素C使Jurkat细胞的生长方式从对照组的局部聚集向近乎均匀分散变化;维C组及联合组在24 h至48 h期间,Bcl-2的表达降低较硼替佐米组快,Bax表达升高的亦快,且维C组24～48 h对Bax的表达增量远超过硼替佐米组.CCK-8检测发现,在72h时维C组、联合组、硼替佐米组Jurkat细胞的抑制率分别为25.72％、75.23％、56.81％;流式检测凋亡率在72 h分别为81.73％、67.06％与81.50％;维生素C组的早期凋亡率大于晚期凋亡率,而硼替佐米组与联合组均为早期凋亡率低,但维生素C的添加,联合用药组细胞的早期凋亡率得到了大约15.26％的提高.结论 维生素C抑制T细胞淋巴瘤细胞株Jurkat细胞的增殖,尤其是促进Jurkat细胞早期凋亡,且细胞凋亡调控蛋白Bax与Bcl-2参与了维生素C诱导Jurkat细胞凋亡机制.     

Wnt/β-catenin信号通路在白藜芦醇抗急性T淋巴细胞白血病中的作用机制研究

目的:通过细胞水平和动物模型探讨Wnt/β-catenin信号通路在白藜芦醇体内外抗急性T淋巴细胞白血病（T-cell acute lymphoblastic leukemia,T-ALL）中的作用及其可能机制。方法:细胞实验（人淋巴细胞白血病Molt-4和Jurkat细胞）分为空白对照组（Control组）、二甲基亚砜组（DMSO组）和白藜芦醇处理组（Res组）,动物实验分为正常对照组（Control组）、T-ALL模型组（T-ALL组）和白藜芦醇处理组（Res组）。采用CCK-8法检测白藜芦醇对Molt-4和Jurkat细胞增殖能力的影响,选取适合的给药浓度进行后续实验;尾静脉注射ICN1-GFP+ T-ALL细胞建立T-ALL小鼠模型;采用流式细胞术检测小鼠外周血中ICN1-GFP+ T-ALL细胞百分比,监测T-ALL小鼠造模后的一般情况;应用实时荧光定量PCR（RT-PCR）分别检测细胞和小鼠脾脏组织中c-Myc和Cyclin D1 mRNA的表达水平;应用蛋白免疫印迹法（Western Blot法）分别检测细胞和小鼠脾脏组织中β-catenin、TCF-1、LEF-1、c-Myc和Cyclin D1的蛋白表达水平。结果:白藜芦醇明显抑制Molt-4和Jurkat细胞增殖能力（P＜0.01）,抑制作用随白藜芦醇浓度增加逐渐增强（P＜0.01）;经白藜芦醇处理后,Molt-4和Jurkat细胞中c-Myc和Cyclin D1 mRNA表达水平明显降低（P＜0.01）,β-catenin、TCF-1、LEF-1及其靶蛋白c-Myc和Cyclin D1表达水平均显著降低（P＜0.05）;T-ALL小鼠脾脏组织中c-Myc和Cyclin D1 mRNA表达水平显著增高（P＜0.01）,β-catenin、TCF-1、LEF-1及靶蛋白c-Myc和Cyclin D1表达水平显著升高（P＜0.01）;经白藜芦醇处理后,小鼠外周血中GFP+白血病细胞比例明显下降（P＜0.01）,c-Myc和Cyclin D1 mRNA表达水平明显降低（P＜0.01）,各蛋白表达水平明显下调（P＜0.01）。结论:在T-ALL细胞株和动物模型中,白藜芦醇可能通过下调Wnt/β-catenin信号通路中β-catenin、TCF-1和LEF-1的表达进而抑制靶蛋白c-Myc和Cyclin D1水平,发挥抗急性T淋巴细胞白血病作用。     

The BH4 domain of Bcl-2 inhibits ER calcium release and apoptosis by binding the regulatory and coupling domain of the IP3 receptor

Although the presence of a BH4 domain distinguishes the antiapoptotic protein Bcl-2 from its proapoptotic relatives, little is known about its function. BH4 deletion converts Bcl-2 into a proapoptotic protein, whereas a TAT-BH4 fusion peptide inhibits apoptosis and improves survival in models of disease due to accelerated apoptosis. Thus, the BH4 domain has antiapoptotic activity independent of full-length Bcl-2. Here we report that the BH4 domain mediates interaction of Bcl-2 with the inositol 1,4,5-trisphosphate (IP3) receptor, an IP3-gated Ca²⁺ channel on the endoplasmic reticulum (ER). BH4 peptide binds to the regulatory and coupling domain of the IP3 receptor and inhibits IP3-dependent channel opening, Ca²⁺ release from the ER, and Ca²⁺-mediated apoptosis. A peptide inhibitor of Bcl-2-IP3 receptor interaction prevents these BH4-mediated effects. By inhibiting proapoptotic Ca²⁺ signals at their point of origin, the Bcl-2 BH4 domain has the facility to block diverse pathways through which Ca²⁺ induces apoptosis.     

Fas/FasL途径介导的人肺癌细胞免疫逃逸

目的：观察在3种人肺癌细胞（A549、EBC-1、LCSC）和人T细胞(Jurkat) Fas/FasL表达情况，探讨人肺癌细胞免疫逃逸及反杀伤作用与Fas/FasL途径的关系。 方法： 用FACScan、RT-PCR方法检测Fas/FasL蛋白及mRNA表达；以荧光染色法观察细胞调亡；用台盼蓝拒染法检测细胞存活。 结果： 3种人肺癌细胞及T-细胞系(Jurkat)均表达 Fas及 FasL；肺癌细胞与Jurkat细胞共培养时，肺癌细胞可导致Jurkat细胞生长抑制(P<0.05)及凋亡；在共培养体系中加入FasL中和性抗体NOK1，可封闭肺癌细胞对Jurkat细胞的生长抑制作用(P>0.05)。 结论： Fas/FasL途径可介导上述3种人肺癌细胞对Jurkat细胞的生长抑制及致凋亡作用；中和性抗体可有效阻断Fas信号转导途径，抑制肿瘤细胞的反杀伤作用，有效保护免疫系统。     

The influence of arsenic trioxide on the cell cycle,apoptosis and expression of cyclin D1 in the Jurkat cell line

Cyclin D1 drives cell cycle progression at the G1/S transition and is believed to play a significant role in tumorigenesis, contributing to efficient proliferation of many cancer cells. Consequently, it is also recognized as an end-point biomarker of therapeutic outcome for different treatment modalities in cancer. In this study we aimed to evaluate the expression and localization of cyclin D1 in arsenic trioxide (ATO) treated Jurkat cells (lymphoblastic leukemia cell line) and to correlate these results with the extent of cell death and/or cell cycle alterations. Jurkat cells were incubated with increasing concentrations of ATO (0.2, 0.6 and 1.0 μM) for 24 h in standard cell culture conditions. To reach our goal we performed annexin V/PI labeling for detection of cell death and RNase/PI labeling for evaluation of cell cycle distribution, which were followed by the respective flow cytometric analyses of ATO-treated Jurkat cells. Transmission electron microscopy was applied for visualization of the cell ultrastructure. For cyclin D1 estimation a biparametric cyclinD1/cell cycle assay was done and localization of the protein was shown after immuno-labeling using light microscopy (ABC procedure) and confocal fluorescence microscopy. We found that there were no significant changes in the percentages of cyclin D1-positive cells after the treatment with ATO, but at the same time mean fluorescence intensity reflecting cyclin D1 content was gradually increasing along with the cell cycle progression, irrespective of the applied dose of the drug. On the other hand, we found a nuclear-cytoplasmic shift of this protein as a major treatment-related response, which was in good accord with an increased rate of cell death and suggested that cyclin D1 cytoplasmic degradation is an important determinant of the therapeutic efficiency of ATO in the Jurkat cell line.