p,p′-DDE induces testicular apoptosis in prepubertal rats via the Fas/FasL pathway

1,1-Dichloro-2,2 bis(p-chlorophenyl) ethylene (p,p′-DDE), the major metabolite of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. It has antiandrogenic effect. However, the mechanism by which p,p′-DDE exposure causes male reproductive toxicity remains unknown. To elucidate the mechanism underpinning the testicular effects of p,p′-DDE, we sought to investigate Fas/FasL apoptotic pathway in the testis of prepubertal rats, including Fas, FasL, caspase-8, -3, and NF-κB. Animals were administered with different doses of p,p′-DDE (0, 20, 60, 100 mg/kg b.wt) every other day by intraperitoneal injection for 10 days. The results indicated that p,p′-DDE exposure at over 20 mg/kg b.wt showed the induction of apoptotic cell death. p,p′-DDE could induce increase in the MDA level, and decrease in SOD and GSH-Px activity. Significant elevations in the mRNA levels of Fas along with an increase in FasL, caspase-3, -8 were observed in 100 mg/kg b.wt group. In protein level, p,p′-DDE could induce increase of FasL and reduction of procaspase-8. NF-κB p65 was activated by p,p′-DDE treatment in rat testis. In addition, the activities of caspase-3, -8 were increased in 100 mg/kg b.wt group. Taken together, these results lead us to speculate that in vivo exposure to p,p′-DDE might induce testicular apoptosis in prepubertal rats through the Fas/FasL pathway.     

Celastrol induces apoptosis in non-small-cell lung cancer A549 cells through activation of mitochondria- and Fas/FasL-mediated pathways

Celastrol is a natural compound extracted from the traditional Chinese medicinal herb, Tripterygium wilfordii Hook. It has attracted interests for its potential anti-inflammatory and antitumor effects. However, the molecular mechanisms of celastrol-induced apoptosis in cancer cells remain unclear. In this study, we investigated the effects of celastrol on the human non-small-cell lung cancer (NSCLC) cell line A549 in vitro. Celastrol caused a dose- and time-dependent growth inhibition of A549 cells with an IC₅₀ of 2.12 μM at 48 h treatment. Celastrol induced A549 cells apoptosis as confirmed by annexin V/propidium iodide staining and DNA fragmentation. Celastrol-induced apoptosis was characterized by cleavage of caspase-9, caspase-8, caspase-3, and PARP protein, increased Fas and FasL expression, and a reduction in the mitochondrial membrane potential. Furthermore, celastrol induced the release of cytochrome c. Celastrol also up-regulated the expression of pro-apoptotic Bax, down-regulated anti-apoptotic Bcl-2, and inhibited Akt phosphorylation. These results demonstrate that celastrol can induce apoptosis of human NSCLC A549 cells through activation of both mitochondria- and FasL-mediated pathways.     

Intervention of selenium on apoptosis and Fas/FasL expressions in the liver of fluoride-exposed rats

Fluorosis is a major public health problem in numerous areas around the world, including China. To alleviate this problem, selenium has been used. In this study, we aimed to investigate the influence of selenium on apoptosis in fluorosis-affected rat livers and determine the optimal selenium concentration in drinking water to fight fluorosis. The protein levels of Fas in NaF and NaF + Se (0.375 and 0.75 mg/L) groups as well as FasL in NaF, Se (0.75 and 1.5 mg/L), and NaF + Se (0.375 mg/L) groups were significantly increased compared with those in the control group. The mRNA levels of Fas in NaF and Se (1.5 mg/L) groups as well as FasL in NaF and NaF + Se (0.375 mg/L) groups were significantly increased. The protein levels of Fas in NaF + Se (1.5 mg/L) group and FasL in three NaF + Se groups were significantly decreased compared with those in the NaF group. The mRNA levels of Fas in the three NaF + Se groups and FasL in NaF + Se (0.75 and 1.5 mg/L) groups were significantly decreased. Compared with the control group, activity of GSH-Px, and SOD in the NaF group decreased obviously and MDA content increased obviously; activity of SOD in 1.5 mg/L Se group decreased obviously. Compared with the NaF group, activity of GSH-Px in NaF + Se (1.5 mg/L) group significantly increased, and MDA content decreased obviously. Thus, fluoride induced apoptosis in the liver, thereby causing liver damage in the rats. Selenium could alleviate fluorosis-induced liver injury. In particular, selenium at 1.5 mg/L is considered the optimum concentration against fluorosis.     

5-氟尿嘧啶诱导Jurkat细胞凋亡及Fas、FasL的表达

目的探讨5-氟尿嘧啶（5-FU）诱导Jurkat细胞株的凋亡和Fas、FasL的表达。方法不同浓度的5-FU分别处理Jurkat细胞12h和24h后,流式细胞仪检测细胞表达CD95、CD95L的百分率。结果与对照组相比,5-FU在10、20、40μg.mL-1浓度下明显促进Jurkat细胞表达Fas、FasL;且5-FU在24h比处理12h有更强的诱导效果。结论 5-FU可显著提高Jurkat细胞凋亡率,并增强Fas、FasL的表达率。     

地塞米松对SLE患者外周血淋巴细胞凋亡及Fas、FasL表达的影响

目的观察活动期系统性红斑狼疮(SLE)患者外周血淋巴细胞(PBL)凋亡状态及Fas、FasL的表达,探讨地塞米松(Dex)对其的影响。方法分离19例SLE患者及10例健康人PBL,植物血凝素(PHA)刺激培养72h,流式细胞仪检测其凋亡率及Fas、FasL的表达。SLE患者的PBL,再经Dex作用后检测上述指标。结果SLE患者PBL在PHA刺激培养72h后凋亡率(42.81±7.52)%,较健康对照组(4.74±0.59)%明显升高(P<0.01),Fas表达SLE组(47.67±4.80)MFI,较健康对照组(21.70±5.16)MFI增高(P<0.01),FasL表达阳性细胞百分率与健康对照无明显差别(2.48±0.24)%,(2.64±0.31)%(P>0.05);SLE患者PBL经Dex培养后凋亡率(63.92±7.58)%较未处理组增高;Fas表达、FasL阳性细胞百分率两组间差异无统计学意义。结论SLE患者存在PBL凋亡及Fas、FasL表达的异常;Dex可加速SLE患者PBL的凋亡,且可能是通过Fas/FasL以外的途径实现。     

BPA-induced apoptosis of rat Sertoli cells through Fas/FasL and JNKs/p38 MAPK pathways

Bisphenol-A was examined for its effects on cultured Sertoli cells established from 18 to 22-day-old rat testes. Results indicated that exposure to BPA (0, 30, 50 and 70 μM) decreased the cell viability in a concentration-dependent manner and induced cell apoptosis. Apoptosis-caused cell death was observed in cells exposed to 50 and 70 μM BPA. The mRNA expressions of Fas, FasL and caspase-3 were all elevated, and the protein expressions of FasL and cleaved caspase-3 were also increased. In addition, levels of phosphorylation of JNKs/p38 MAPK were also increased and then activated JNKs/p38 MAPK up regulated target gene expressions, such as c-jun and CHOP. Translocation of NF-κB into nuclei indicated the activation of NF-κB after treatment with BPA. Taken together, observed results suggest that BPA induces apoptosis of Sertoli cells by the activation of JNKs/p38 MPAK and translocation of NF-κB, and Fas/FasL system plays a critical role in the initiation of apoptosis.     

神经节苷脂钠联合亚低温治疗重度颅脑损伤对神经细胞Fas/FasL信号通路以及细胞凋亡的影响

目的　探究与分析神经节苷脂钠联合亚低温治疗重度颅脑损伤对神经细胞Fas/FasL信号通路以及细胞凋亡的影响。方法　选取晋城市人民医院2020年2月至2022年2月收治的重度颅脑损伤患者118例,按照不同治疗方案分为对照组与观察组,每组59例,其中对照组有7例,观察组有5例患者因死亡、中途退出研究者导致临床资料缺失,最终对照组有52例,观察组有54例纳入到最后研究。对照组中男30例,女22例,年龄（35.69±3.14）岁;观察组中男28例,女26例,年龄为（35.77±3.20）岁。对照组给予常规降低颅内压、保护脑细胞、抗感染以及解痉挛等治疗,观察组在其基础上给予神经节苷脂钠联合亚低温治疗,对比两组临床疗效、治疗前后格拉斯哥昏迷评分法（GCS）评分、大脑中动脉（MCA）血流速度及脑脊液中肿瘤坏死因子-α（TNF-α）、Fas、Fas配体（FasL）、半胱天冬氨酸酶-9（Caspase-9）蛋白水平和住院时间。采用χ²检验、t检验、F检验。结果　对照组总有效率为82.69%（43/52）、住院时间为（44.05±13.52）d,观察组总有效率为96.30%（52/54）、住院时间为（35.36±14.11）d,观察组与对照组相比临床总有效率较高,住院时间较短,差异均有统计学意义（χ²=5.271,P=0.022,t=3.236,P=0.002）。治疗后1周、2周、4周对照组GCS评分分别为（6.96±0.87）分、（7.54±1.02）分、（8.98±1.12）分,观察组分别为（7.43±0.86）分、（8.58±0.99）分、（10.58±1.24）分,两组治疗后1周、2周、4周分别与治疗前相比GCS较高,观察组治疗后1周、2周及4周分别与对照组治疗后1周、2周及4周相比,GCS较高,差异均有统计学意义（t=2.796,P=0.006;t=5.324,P<0.001;t=6.977,P<0.001）。治疗后1周、2周、4周对照组MCA分别为（88.47±7.58）cm/s、（81.98±12.84）cm/s、（72.87±12.84）cm/s,观察组分别为（85.33±8.10）cm/s、（75.45±14.15）cm/s、（66.86±13.78）cm/s,两组治疗后1周、2周、4周分别与治疗前相比MCA血流速度较低,观察组治疗后1周、2周、4周分别与对照组治疗后1周、2周、4周相比,MCA血流速度较低,差异均有统计学意义（t=2.062,P=0.042;t=2.490,P=0.014;t=2.234,P=0.022）。治疗后2周、4周对照组的TNF-α、Fas、FasL及Caspase-9分别为（1.04±0.51）mg/L、（0.79±0.32）mg/L,（34.55±7.25）μg/L、（27.10±5.58）μg/L,（89.34±5.77）μg/L、（20.87±6.55）μg/L,（23.54±5.47）pmol/L、（14.23±4.69）pmol/L;观察组分别为（0.83±0.41）mg/L、（0.36±0.12）mg/L,（40.14±8.20）μg/L、（10.35±4.14）μg/L,（102.47±5.78）μg/L、（17.53±5.28）μg/L,（40.69±6.78）pmol/L、（8.69±0.25）pmol/L,两组治疗后4周与治疗后2周相比,TNF-α、Fas、FasL及Caspase-9较低,观察组治疗后2周与对照组治疗后2周相比,TNF-α较低,Fas、FasL及Caspase-9较高,观察组治疗后4周与对照组治疗后4周相比,TNF-α、Fas、FasL及Caspase-9较低,差异均有统计学意义（均P<0.05）。结论　神经节苷脂钠联合亚低温治疗重度颅脑损伤可改善患者的昏迷程度,临床效果突出,通过作用于神经Fas/FasL信号通路的过程,对细胞凋亡的发生产生抑制效果,缩短住院时间,获得良好预后。     

Baicalin protects sertoli cells from heat stress-induced apoptosis via activation of the Fas/FasL pathway and Hsp72 expression

Certain Chinese herbal medicines have antipyretic effects in both animal and human clinical practice. However, no report indicates their antipyretic effects on heat-stressed cells. The present study aimed to identify the protective effects of baicalin on the apoptosis of primary cultured bovine sertoli cells (SCs) subjected to heat stress (HS). The results demonstrated that HS induced apoptosis in the SCs exposed to 43 °C for 1 h as Fas/FasL was activated and caspase-3 was cleaved, the cells apoptotic rate was decreased. Moreover, the mRNA and protein levels of Hsp72 increased, whereas the cells apoptotic rate and expression of Fas, FasL, caspases 8 and 3 decreased in the SCs pretreated with various concentrations (0.1, 1, 10, 20 μg/mL) of baicalin prior to HS. In conclusion, baicalin ameliorates heat stress-induced cell apoptosis via the modulation of the cell survival rate through Fas/FasL pathway activation and the upregulation of Hsp72 expression in bovine SCs.     

不同年龄白内障晶状体上皮细胞中caspase-3、Fas/FasL的表达及意义

目的：探讨不同年龄白内障晶状体上皮细胞（LECs）中caspase-3、Fas/FasL的表达及临床意义。方法选择2007年9月~2012年2月本院眼科收治的白内障患者50例为研究对象,其中25～49岁设为白内障中青年组,≥50岁设为白内障老年组,各25例,并收集20例成人尸体解剖非白内障眼球为对照组,其中25～49岁设为中青年对照组,≥50岁设为老年对照组,各10例。采用免疫组织化学法检测各组晶状体前囊膜组织中caspase-3、Fas、FasL的表达。结果白内障老年组、白内障中青年组、老年对照组和中青年对照组LECs中凋亡细胞百分率分别为34.0%、16.0%、2.0%、3.0%,白内障老年组显著高于白内障中青年和老年对照组,白内障中青年组显著高于中青年对照组,差异有统计学意义（P＜0.01）。白内障老年组LECs中caspase-3、Fas、FasL蛋白的阳性表达率分别为84.0%、60.0%、68.0%,白内障中青年组LECs中caspase-3、Fas、FasL蛋白的阳性表达率分别为44.0%、24.0%、32.0%,老年对照组LECs中caspase-3、Fas、FasL蛋白的阳性表达率分别为10.0%、10.0%、20.0%,中青年对照组LECs中caspase-3、Fas、FasL蛋白的阳性表达率分别为10.0%、0.0%、0.0%,4组caspase-3、Fas、FasL蛋白阳性表达率比较,差异有统计学意义（P＜0.01）。老年白内障患者和中青年白内障患者中,LECs凋亡与caspase-3和Fas、FasL表达水平均呈正相关（r=0.621、0.583、0.621,P＜0.01）。结论老年性白内障形成过程可能与LECs的凋亡及caspase-3、Fas/FasL的表达调控有关。     

Doxorubicin-induces NFAT/Fas/FasL cardiac apoptosis in rats through activation of calcineurin and P38 MAPK and inhibition of mTOR signalling pathways

This study investigated the role of NFAT/Fas/FasL axis in cardiomyocyte apoptosis following doxorubicin (DOX) treatment in rats and evaluated the involvement and regulation of all NFAT members in cardiac apoptosis. Forty adult male Wistar rats were divided equally into control or DOX-treated groups (15 mg/kg over 2 weeks). Cardiomyocytes were cultured and pre-incubated with various inhibitors and activators (10 μmol/L) prior to DOX exposure (1 μmol/L). In the left ventricles and cultured cells, DOX increased cytoplasmic protein levels of cytochrome C, Bax and increased the activities of caspase-8, caspase3, ERK1/2, JNK, and P38 mitogen-activated protein kinases (MAPKs), reducing levels of Bcl-2 and the activity of mTOR, and inducing cell death. In addition, DOX enhanced mRNA and protein levels of Fas and FasL. Furthermore, the nuclear and cytoplasmic levels of NFAT1 and nuclear accumulation of NFAT2-4were increased with DOX treatment. The inhibition of calcineurin with FK506 significantly inhibited the nuclear levels of NFAT2 and NFAT4 and the inhibition of P38 MAPK with SB203580 inhibited the nuclear and cytoplasmic accumulation of NFAT1. However, the activation of mTOR by IGF-1 significantly lowered NFAT3. In conclusion, NFAT/Fas/FasL-induced cell death in cardiac myocytes of DOX-treated rats is regulated, at least, by the activation of calcineurin and P38 MAPK and inhibition of mTOR.     

Proteasome inhibitor MG-132 induces C6 glioma cell apoptosis via oxidative stress

Aim:

Proteasome inhibitors have been found to suppress glioma cell proliferation and induce apoptosis, but the mechanisms are not fully elucidated. In this study we investigated the mechanisms underlying the apoptosis induced by the proteasome inhibitor MG-132 in glioma cells.

Methods:

C6 glioma cells were used. MTT assay was used to analyze cell proliferation. Proteasome activity was assayed using Succinyl-LLVY-AMC, and intracellular ROS level was evaluated with the redox-sensitive dye DCFH-DA. Apoptosis was detected using fluorescence and transmission electron microscopy as well as flow cytometry. The expression of apoptosis-related proteins was investigated using Western blot analysis.

Results:

MG-132 inhibited C6 glioma cell proliferation in a time- and dose-dependent manner (the IC₅₀ value at 24 h was 18.5 μmol/L). MG-132 (18.5 μmol/L) suppressed the proteasome activity by about 70% at 3 h. It induced apoptosis via down-regulation of antiapoptotic proteins Bcl-2 and XIAP, up-regulation of pro-apoptotic protein Bax and caspase-3, and production of cleaved C-terminal 85 kDa PARP). It also caused a more than 5-fold increase of reactive oxygen species. Tiron (1 mmol/L) effectively blocked oxidative stress induced by MG-132 (18.5 μmol/L), attenuated proliferation inhibition and apoptosis in C6 glioma cells, and reversed the expression pattern of apoptosis-related proteins.

Conclusion:

MG-132 induced apoptosis of C6 glioma cells via the oxidative stress.     

Paraoxon induces apoptosis in EL4 cells via activation of mitochondrial pathways

The toxicity of organophosphorus compounds, such as paraoxon (POX), is due to their anticholinesterase action. Recently, we have shown that, at noncholinergic doses (1 to 10 nM), POX (the bioactive metabolite of parathion) causes apoptotic cell death in murine EL4 T-lymphocytic leukemia cell line through activation of caspase-3. In this study, by employing caspase-specific inhibitors, we extend our observations to elucidate the sequence of events involved in POX-stimulated apoptosis. Pretreatment of EL4 cells with the caspase-9-specific inhibitor zLEHD-fmk attenuated POX-induced apoptosis in a dose-dependent manner, whereas the caspase-8 inhibitor zIETD-fmk had no effect. Furthermore, the activation of caspase-9, -8, and -3 in response to POX treatment was completely inhibited in the presence of zLEHD-fmk, implicating the involvement of caspase 9-dependent mitochondrial pathways in POX-stimulated apoptosis. Indeed, under both in vitro and in vivo conditions, POX triggered a dose- and time-dependent translocation of cytochrome c from mitochondria into the cytosol, as assessed by Western blot analysis. Investigation of the mechanism of cytochrome c release revealed that POX disrupted mitochondrial transmembrane potential. Neither this effect nor cytchrome c release was dependent on caspase activation, since the general inhibitor of the caspase family zVAD-fmk did not influence both processes. Finally, POX treatment also resulted in a time-dependent up-regulation and translocation of the proapoptotic molecule Bax to mitochondria. Inhibition of this event by zVAD-fmk suggests that the activation and translocation of Bax to mitochondria is subsequent to activation of the caspase cascades. The results indicate that POX induces apoptosis in EL4 cells through a direct effect on mitochondria by disrupting its transmembrane potential, causing the release of cytochrome c into the cytosol and subsequent activation of caspase-9. Inhibition of this specific pathway might provide a useful strategy to minimize organophosphate-induced poisoning.     

Apoptosis induced by penta-acetyl geniposide in C6 glioma cells is associated with JNK activation and Fas ligand induction

In our previous study, penta-acetyl geniposide ((AC)(5)GP) is suggested to induce tumor cell apoptosis through the specific activation of PKCdelta. However, the downstream signal pathway of PKCdelta has not yet been investigated. It was shown that JNK may play an important role in the regulation of apoptosis and could be a possible downstream signal of PKCdelta isoforms. In the present study, we investigate whether JNK is involved in (AC)(5)GP induced apoptosis. The result reveals that (AC)(5)GP induces JNK activation and c-Jun phosphorylation thus stimulating the expression of Fas-L and Fas. Using SP600125 to block JNK activation shows that (AC)(5)GP-mediated apoptosis and related proteins expression are attenuated. Furthermore, we find that the (AC)(5)GP induces apoptosis through the activation of JNK/Jun/Fas L/Fas/caspase 8/caspase 3, a mitochondria-independent pathway. The JNK pathway is suggested to be the downstream signal of PKCdelta, since rottlerin impedes (AC)(5)GP-induced JNK activation. Therefore, (AC)(5)GP mediates cell death via activation of PKCdelta/JNK/FasL cascade signaling.     

Prevention by vitamin E of DNA fragmentation and apoptosis induced by fumonisin B1 in C6 glioma cells

Fumonisin B₁ (FB₁), produced by the fungus Fusarium moniliforme, belongs to a class of sphingosine analogue mycotoxins that occur widely in the food chain. Epidemiological studies have associated consumption of Fusarium moniliforme-contaminated food with human oesophageal cancer in China and South Africa. FB₁ also causes equine leucoencephalomalacia. Evidence for induction of apoptosis by FB₁ was first obtained when C6 glioma cells were incubated with fumonisin B₁ (3–27 μM) causing DNA fragmentation profiles showing DNA laddering in gel electrophoresis and apoptotic bodies revealed by chromatin staining with acridine orange and ethidium bromide. Further confirmation experiments and comet assays have been performed under similar conditions. The results of the comet test show that FB₁ at 9 and 18 μM induces respectively 50 ± 2% and 40 ± 1% of cells with a comet with an increased tail length of 93 ± 9 μm and 102 ± 17 μm respectively. Under these concentrations, FB₁ induced DNA fragmentation and laddering and many apoptotic bodies. Pre-incubation of the cells with vitamin E (25 μM) for 24 h before FB₁ (18 μM) significantly reduced DNA fragmentation and apoptotic bodies induced by FB₁. Received: 30 August 1999 / Accepted: 18 January 2000     

^125IUdR对大鼠胶质瘤细胞靶点放疗后的细胞凋亡研究

目的 在建立C6／Wistar胶质瘤大鼠模型的基础上，研究^125IUdR介导俄歇电子释放对大鼠G6胶质瘤DNA靶点放疗后的肿瘤细胞凋亡。方法 建立C6／Wistar胶质瘤大鼠模型后，应用流式细胞仪检测研究C6胶质瘤细胞的增殖动力学指标。结果 实验组肿瘤细胞的S期百分比与对照组相比显著降低（P〈0．001），G2＋M期的细胞也随之减少，肿瘤细胞大量停滞在G0／G1期。实验组增殖指数明显低于对照组（P〈0．001），而凋亡指数则显著增加（P〈0．001）。结论 ^125IUdR通过电离作用导致G1期细胞增殖阻滞及DNA断裂、诱导肿瘤细胞凋亡。     

Glutathione modifies the toxicity of triethyltin and trimethyltin in C6 glioma cells

It has been demonstrated that exposure to mercury or cadmium compounds causes alterations in the glutathione system in a model glial cell line, C6. Here we report that two organic tin compounds, triethyltin (TET) and trimethyltin (TMT), are also toxic to these cells with EC₅₀ values for cell death of c. 0.02 μM and 0.8 μM respectively. Exposure for 24 h to either of these compounds at sub-toxic concentrations caused increases in the amount of reduced glutathione (GSH) per cell. Increases in glutathione-S-transferase enzyme activity were also demonstrated after TET or TMT exposure. This suggests that glutathione increases occur in glial cells after toxic insults below that required to cause cell death, possibly acting as a protective mechanism. To test whether GSH plays a role in organotin-induced cell death we manipulated GSH in the culture media or via intracellular GSH and looked at the effects on sensitivity to TET or TMT toxicity. Adding GSH to the culture media did not protect the cells. Depletion of intracellular GSH with buthionine-[S,R] sulphoximine did not alter cytotoxicity of TET or TMT. However, pre-treatment with (−)-2-oxo-4-thiazolidine carboxylic acid (OTC), which increases intracellular GSH levels, protected the cells against both compounds. The EC₅₀ for TMT was increased from 0.77 to 1.8 μM, a 2.3-fold shift, whereas the EC₅₀ for TET was increased >20-fold, from 0.022 to 0.47 μM. One interpretation of these results is that GSH protects cells against the toxicity of organic tin compounds without reacting directly with them to any significant extent. Under conditions where GSH is depleted, additional protective mechanisms may be active. Received: 26 May 1997 / Accepted: 21 October 1997     

Differential expression of protein kinase C subtypes during ginsenoside Rh2-induced apoptosis in SK-N-BE(2) and C6Bu-1 cells

We examined the modulation of protein kinase C (PKC) subtypes during apoptosis induced by ginsenoside Rh2 (G-Rh2) in human neuroblastoma SK-N-BE(2) and rat glioma C6Bu-1 cells. Apoptosis induced by G-Rh2 in both cell lines was confirmed, as indicated by DNA fragmentation and in situ strand breaks, and characteristic morphological changes. During apoptosis induced by G-Rh2 in SK-N-BE(2) cells, PKC subtypes alpha, beta and gamma were progressively increased with prolonged treatment, whereas PKC delta increased transiently at 3 and 6 h and PKC epsilon was gradually down-regulated after 6 h following the treatment. On the other hand, PKC subtype zeta markedly increased at 24 h when maximal apoptosis was achieved. In C6Bu-1 cells, no significant changes in PKC subtypes alpha, gamma, delta, epsilon and zeta were observed during apoptosis induced by G-Rh2. These results suggest the evidence for a possible role of PKC subtype in apoptosis induced by G-Rh2 in SK-N-BE(2) cells but not in C6Bu-1 cells, and raise the possibility that G-Rh2 may induce apoptosis via different pathways interacting with or without PKC in different cell types.     

Plumbagin-induced apoptosis in lymphocytes is mediated through increased reactive oxygen species production, upregulation of Fas, and activation of the caspase cascade

Extracts from plants containing plumbagin (PLB) continue to be used as a treatment of a number of chronic immunologically-based diseases. However, most of these claims are supported only by anecdotal evidence with few scientific reports describing the mechanism of action or the efficacy of plumbagin in the suppression of the immune response. In the current study, we tested the hypothesis that plumbagin-induced suppression of the immune response was mediated through the induction of apoptosis. Splenocytes from C57BL/6 mice cultured in the presence of 0.5 µM or greater concentrations of PLB significantly reduced proliferative responses to mitogens, including anti-CD3 mAbs, concanavalin A (Con A), lipopolysaccharide (LPS) and staphylococcal enterotoxin B (SEB) in vitro. Exposure of naïve and activated splenocytes to PLB led to a significant increase in the levels of apoptosis. In addition, PLB treatment led to a significant increase in the levels of reactive oxygen species (ROS) in naïve and activated splenocytes. Furthermore, treatment with the ROS scavenger, N-acetylcysteine (NAC), prevented PLB-induced apoptosis, suggesting a role of ROS in PLB-induced apoptosis. PLB-induced apoptosis led to ROS-mediated activation of both the extrinsic and intrinsic apoptotic pathways. In addition, plumbagin led to increased expression of Fas. Finally, treatment of mice with PLB (5 mg/kg) led to thymic and splenic atrophy as well as a significant suppression of the response to SEB and dinitroflourobenzene (DNFB) in vivo. Together, these results suggest that plumbagin has significant immunosuppressive properties which are mediated by generation of ROS, upregulation of Fas, and the induction of apoptosis.     

MPP+和6-羟基多巴胺对C6胶质瘤细胞摄取谷氨酸的影响

目的：研究1-甲基4-苯基-吡啶离子(MPP^ )和6-羟基多巴胺(6-OHDA)对C6胶质瘤细胞摄取谷氨酸(Glu)的影响。方法：应用放射免疫法测定C6胶质瘤细胞对培养液中[^3H]-D，L-谷氨酸的摄取；应用四氮唑(MTY)比色法检测胶质瘤细胞的活性。结果：6-OHDA和MPP^ 均不同程度地抑制C6胶质瘤细胞摄取Glu；6-OHDA显抑制C6胶质瘤细胞活性，而MPP^ 却不影响细胞活性；蛋白激酶C(PKC)激动剂TPA显增强C6细胞对Glu的摄取，并拮抗：MPP^ 对C6细胞摄取Glu的抑制。结论：6-OHDA抑制C6胶质瘤细胞对Glu的摄取，可能与其抑制细胞活性有关，而MPP^ 的抑制作用可能与直接影响转运体的摄取功能有关，并可能由PKC途径介导。     

漆黄素对胶质瘤C6细胞侵袭、迁移、增殖及细胞周期的影响

目的 研究漆黄素对胶质瘤C6细胞侵袭、迁移、增殖及细胞周期的影响.方法 以不同浓度的漆黄素(12.5、25、50μmol/L)处理C6细胞,以DMSO作为对照组.分别采用Transwell体外侵袭实验、Transwell体外迁移实验检测漆黄素对C6细胞侵袭、迁移能力的影响,采用流式细胞术检测漆黄素对C6细胞增殖及细胞周期的影响.结果 Transwell侵袭实验显示:漆黄素处理24 h后与对照组相比,漆黄素处理组的C6细胞侵袭率明显降低.Transwell侵袭实验显示:漆黄素处理C6细胞12h后与对照组相比,漆黄素处理组的C6细胞迁移率显著降低.流式细胞术检测细胞增殖结果显示:与对照组相比,漆黄素处理组的C6细胞增殖率明显降低.流式细胞术检测细胞周期结果显示:与对照组相比,漆黄素处理组的G1期细胞比例逐渐增高,而G2期和S期的细胞比例相应降低,将细胞周期阻滞在G1期.结论 漆黄素能够明显抑制胶质瘤C6细胞的侵袭、迁移能力;并可通过阻滞C6细胞的细胞周期进程来抑制其增殖.