阿司匹林诱导人恶性睾丸生殖细胞瘤NTera-2细胞凋亡

阿司匹林,又称乙酰水杨酸,已证实有抑制肿瘤细胞增殖、诱导肿瘤细胞凋亡和抑制血管生成等多种抗癌功能.除已知对环氧合酶COX-2的活性有抑制外,阿司匹林抗癌分子机制尚不十分清楚.已报道阿司匹林可以降低多种癌症发生风险,但应用于人类睾丸肿瘤治疗的研究报道很少.本文研究了阿司匹林对人恶性睾丸肿瘤NTera-2细胞凋亡的机制.通过MTT方法检测细胞活力,发现阿司匹林以时间和剂量依赖方式抑制NTera-2细胞增殖.不同浓度阿司匹林处理NTera-2细胞后,采用Hoechest 33258染色方法和Annexin V-FITC/PI流式法分别检测NTera-2细胞的形态学变化、凋亡小体形成、细胞凋亡水平;RT-PCR结果显示,NTera-2细胞中Fas和caspase-8的表达以阿司匹林剂量依赖性上升;蛋白印迹结果显示,FasL的蛋白表达水平下降并活化caspase-8、caspase-3蛋白表达,PARP出现剪切体. 进一步的实验证明,caspase广谱抑制剂Z-VAD-FMK能够减弱阿司匹林诱导NTera-2细胞凋亡. 结果显示,阿司匹林能明显抑制NTera-2细胞活力,并通过激活caspase 通路诱导NTera-2细胞的凋亡,为进一步利用阿司匹林治疗人类睾丸肿瘤的研究奠定基础.     

Ferrous Iron Induces Nrf2 Expression in Mouse Brain Astrocytes to Prevent Neurotoxicity

Free radical damage caused by ferrous iron is involved in the pathogenesis of secondary brain injury after intracerebral hemorrhage (ICH). NF‐E2‐related factor 2 (Nrf2), a major phase II gene regulator that binds to antioxidant response element, represents an important cellular cytoprotective mechanism against oxidative damage. We hypothesized that Nrf2 might protect astrocytes from damage by Fe²⁺. Therefore, we examined cytotoxicity in primary astrocytes induced by iron overload and evaluated the effects of Fe²⁺ on Nrf2 expression. The results demonstrated that 24‐h Fe²⁺ exposure exerted time‐ and concentration‐dependent cytotoxicity in astrocytes. Furthermore, Fe²⁺ exposure in astrocytes resulted in time‐ and concentration‐dependent increases in Nrf2 expression, which preceded Fe²⁺ toxicity. Nrf2‐specific siRNA further knocked down Nrf2 levels, resulting in greater Fe²⁺‐induced astrocyte cytotoxicity. These data indicate that induction of Nrf2 expression could serve as an adaptive self‐defense mechanism, although it is insufficient to completely protect primary astrocytes from Fe²⁺‐induced neurotoxicity.     

Activation of the UPR Protects against Cigarette Smoke-induced RPE Apoptosis through Up-Regulation of Nrf2

Recent studies have revealed a role of endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR) in the regulation of RPE cell activity and survival. Herein, we examined the mechanisms by which the UPR modulates apoptotic signaling in human RPE cells challenged with cigarette smoking extract (CSE). Our results show that CSE exposure induced a dose- and time-dependent increase in ER stress markers, enhanced reactive oxygen species (ROS), mitochondrial fragmentation, and apoptosis of RPE cells. These changes were prevented by the anti-oxidant NAC or chemical chaperone TMAO, suggesting a close interaction between oxidative and ER stress in CSE-induced apoptosis. To decipher the role of the UPR, overexpression or down-regulation of XBP1 and CHOP genes was manipulated by adenovirus or siRNA. Overexpressing XBP1 protected against CSE-induced apoptosis by reducing CHOP, p-p38, and caspase-3 activation. In contrast, XBP1 knockdown sensitized the cells to CSE-induced apoptosis, which is likely through a CHOP-independent pathway. Surprisingly, knockdown of CHOP reduced p-eIF2α and Nrf2 resulting in a marked increase in caspase-3 activation and apoptosis. Furthermore, Nrf2 inhibition increased ER stress and exacerbated cell apoptosis, while Nrf2 overexpression reduced CHOP and protected RPE cells. Our data suggest that although CHOP may function as a pro-apoptotic gene during ER stress, it is also required for Nrf2 up-regulation and RPE cell survival. In addition, enhancing Nrf2 and XBP1 activity may help reduce oxidative and ER stress and protect RPE cells from cigarette smoke-induced damage.     

毒毛花苷通过Nrf2抑制子宫内膜癌细胞增殖活性

摘要 目的：通过研究毒毛花苷对核因子2相关因子2 (nuclear factor erythroid 2-related factor 2, Nrf2)的抑制作用,深入探讨其抑制子宫内膜癌细胞增殖的作用机制。方法：（1）采用细胞增殖实验观察不同浓度的毒毛花苷对Ishikawa细胞增殖的影响;（2）通过克隆形成实验观察毒毛花苷对Ishikawa细胞增殖的作用;（3）采用蛋白免疫印迹法检测经毒毛花苷处理后,Ishikawa细胞Nrf2蛋白表达水平的变化。结果：经毒毛花苷处理后,Ishikawa细胞增殖受到显著抑制且呈剂量依赖性。Nrf2蛋白表达下调。结论：毒毛花苷可能通过下调Nrf2蛋白水平,从而抑制子宫内膜癌的恶性生物学行为。     

姜黄素诱导Nrf2核转位对脂多糖引起库普弗细胞分泌炎症细胞因子的影响

目的：研究姜黄素诱导大鼠Kupffer细胞Nrf2核转位对脂多糖（LPS）引起的炎症细胞因子分泌的影响。方法：分别用10μM、20μM和30μM干预Kupffer细胞8h,诱导Nrf2核转位水平;将Kupffer细胞随机分为对照组、LPS组和干预组,对照组正常培养未加姜黄素和LPS,LPS组用10μg／mL的LPS加入Kupffer细胞培养液共同培养2h;干预组用30μM姜黄素干预8h后,余处理同LPS组。Western blot检测Nrf2核转位水平,分光光度法检测细胞MDA、GSH水平,ELISA法检测上清液TNF-α和IL-6,放免法检测IL-1β。结果：①姜黄素诱导Kupffer细胞Nrf2核转位,核转位水平随浓度增加而增高。②LPS组MDA水平较对照组显著升高（P〈0．01）,干预组MDA水平较LPS组显著降低（P〈0．01）,仍显著高于对照组（P〈0．01）。LPS组GSH水平较对照组显著降低（P〈0．01）,干预组GSH水平较LPS组显著升高（P〈0．01）,仍显著低于对照组（P〈0．01）。③LPS组上清液TNF-α,IL-1β和IL-6显著高于对照组（P〈0．01）,干预组均显著低于模型组（P〈0．01）,但显著高于对照组（P〈0．01）。结论：姜黄素通过诱导Kupffer细胞Nrf2核转位,降低LPS诱导的氧化应激损伤,抑制Kupffer细胞分泌炎症细胞因子。     

Antioxidant activities of ginsenoside Rg1 against cisplatin-induced hepatic injury through Nrf2 signaling pathway in mice

Oxidative stress is mainly caused by reactive oxygen species (ROS). The damage causes a net stress on normal organs, leading to a gradual loss of vital physiological function. ROS, such as free radicals, represent a class of molecules which are derived from the metabolism of oxygen and exist inherently. However, excessive produced ROS can damage all aerobic organisms. Ginseng is one of the most commonly used alternative herbal medicines, also as a traditional Chinese medicine. The aim of this study is to investigate the antioxidant potential function of ginsenoside Rg1 against cisplatin-caused hepatic damage. Male mice were treated with cisplatin to induce oxidative stress to mimic the side effect of anti-cancer drug cisplatin. Ginsenoside Rg1 effectively prevented against cisplatin-induced hepatotoxicity, alleviating histological lesions. Antioxidant functions of Rg1 were restrained by the activation of p62–Keap1–Nrf2 signaling pathway, simultaneously accompanied with expression of protein products. Accumulative p62 and increased activation of JNK in hepatocytes promoted the activation of Nrf2. For the other, degradation of Nrf2 was guided by tyrosine phosphorylation, ubiquitin, and Keap1. In summary, Rg1 prevents hepatotoxicity mainly by inhibiting the binding of Keap1 and Nrf2, partly by p62 accumulation, and more importantly by increasing the production of antioxidative proteins associated to Nrf2. Pharmacological activation of Nrf2 is an effective way in combating against liver injury.     

Quercetin alleviated H2O2‐induced apoptosis and steroidogenic impairment in goat luteinized granulosa cells

Quercetin (Que) is a natural flavonoid in most plants. Luteinized granulosa cell (LGC) culture is necessary for the study of follicle growth/differentiation. In the present study, we analyzed the role of Que in steroid production and apoptosis in hydrogen peroxide (H₂O₂)‐treated goat LGCs. The results showed that treatment with H₂O₂ induced apoptosis in goat LGCs, and treatment with Que decreased LGC apoptosis induced by H₂O₂ (P < .05), accompanied with the different expressions of BAX, BCL‐2, Caspase 3, and Cleaved caspase 3. Meanwhile, the messenger RNA expressions of nuclear factor erythroid 2 like 2 (Nrf2) and its downstream genes were upregulated with H₂O₂ +Que treatment, accompanied by the increased cellular viability (P < .05). Furthermore, Que alleviated H₂O₂‐induced reduction in the secretion of progesterone (P₄) (P < .05); however, it had no effect on the secretion of estrogen (E₂). Simultaneously, the expressions of StAR and P450scc were increased when treated with Que +H₂O₂, compared with the group treated with only H₂O₂ (P < .05). In conclusion, it is observed that Que could alleviate the H₂O₂‐induced apoptosis and steroidogenic impairment in goat LGCs, which might be mediated by the Nrf2 pathway.     

姜黄素诱导Nrf2 核转位对脂多糖引起库普弗细胞分泌炎症 细胞因子的影响

目的:研究姜黄素诱导大鼠Kupffer细胞Nrf2核转位对脂多糖(LPS)引起的炎症细胞因子分泌的影响。方法:分别用10μM、20μM和30μM干预Kupffer细胞8h,诱导Nrf2核转位水平;将Kupffer细胞随机分为对照组、LPS组和干预组,对照组正常培养未加姜黄素和LPS,LPS组用10μg/mL的LPS加入Kupffer细胞培养液共同培养2 h;干预组用30μM姜黄素干预8h后,余处理同LPS组。Western blot检测Nrf2核转位水平,分光光度法检测细胞MDA、GSH水平,ELISA法检测上清液TNF-α和IL-6,放免法检测IL-1β。结果:①姜黄素诱导Kupffer细胞Nrf2核转位,核转位水平随浓度增加而增高。②LPS组MDA水平较对照组显著升高(P<0.01),干预组MDA水平较LPS组显著降低(P<0.01),仍显著高于对照组(P<0.01)。LPS组GSH水平较对照组显著降低(P<0.01),干预组GSH水平较LPS组显著升高(P<0.01),仍显著低于对照组(P<0.01)。③LPS组上清液TNF-α,IL-1β和IL-6显著高于对照组(P<0.01),干预组均显著低于模型组(P<0.01),但显著高于对照组(P<0.01)。结论:姜黄素通过诱导Kupffer细胞Nrf2核转位,降低LPS诱导的氧化应激损伤,抑制Kupffer细胞分泌炎症细胞因子。     

Nrf2及天然产物导向的Nrf2激活剂研究进展

氧化应激能够破坏细胞内氧化还原平衡,造成系统和组织损伤,最终引起一系列疾病的产生.转录因子E2相关因子2(Nrf2),受Kelch样环氧氯丙烷相关蛋白1(Keap1)蛋白的调控,是细胞氧化应激反应中的关键因子,在氧化应激条件下,Nrf2从Keap1中分离,然后进入细胞核与抗氧化反应元件(ARE)结合,增加了Ⅱ相解毒酶的...     

Disulfiram Suppresses Growth of the Malignant Pleural Mesothelioma Cells in Part by Inducing Apoptosis

Dithiocarbamate compound Disulfiram (DSF) that binds with copper and functions as an inhibitor of aldehyde dehydrogenase is a Food and Drug Administration approved agent for treatment of alcoholism. Copper complexed DSF (DSF-Cu) also possesses anti-tumor and chemosensitizing properties; however, its molecular mechanisms of action remain unclear. Here we investigated malignant pleural mesothelioma (MPM) suppressive effects of DSF-Cu and the molecular mechanisms involved. DSF-Cu inhibited growth of the murine as well as human MPM cells in part by increasing levels of ubiquitinated proteins. DSF-Cu exposure stimulated apoptosis in MPM cells that involved activation of stress-activated protein kinases (SAPKs) p38 and JNK1/2, caspase-3, and cleavage of poly-(ADP-ribose)-polymerase, as well as increased expression of sulfatase 1 and apoptosis transducing CARP-1/CCAR1 protein. Gene-array based analyses revealed that DSF-Cu suppressed cell growth and metastasis-promoting genes including matrix metallopeptidase 3 and 10. DSF inhibited MPM cell growth and survival by upregulating cell cycle inhibitor p27Kip1, IGFBP7, and inhibitors of NF-κB such as ABIN 1 and 2 and Inhibitory κB (IκB)α and β proteins. DSF-Cu promoted cleavage of vimentin, as well as serine-phosphorylation and lysine-63 linked ubiquitination of podoplanin. Administration of 50 mg/kg DSF-Cu by daily i.p injections inhibited growth of murine MPM cell-derived tumors in vivo. Although podoplanin expression often correlates with metastatic disease and poor prognosis, phosphorylation of serines in cytoplasmic domain of podoplanin has recently been shown to interfere with cellular motility and migration signaling. Post-translational modification of podoplanin and cleavage of vimentin by DSF-Cu underscore a metastasis inhibitory property of this agent and together with our in vivo studies underscore its potential as an anti-MPM agent.     

pemt2-cDNA的转染抑制大鼠CBRH-7919肝癌细胞c-Met及Bcl-2的表达并诱发凋亡

为探讨磷脂酰乙醇胺 N 甲基转移酶 2 (phosphatidylethanolamine N methyltransferase 2 ,PEMT2 )的转染抑制大鼠肝癌CBRH 7919细胞增殖的分子机理 ,构建了带有完整的pemt2 cDNA基因质粒载体 ,经转染和鉴定 ,确知其在大鼠肝癌细胞系CBRH 7919细胞中稳定高表达 .用细胞培养、免疫细胞化学、Western印迹、流式细胞仪和琼脂糖凝胶电泳等技术研究c Met(HGF的受体 )及抗凋亡蛋白Bcl 2在此过程中的表达和是否诱发凋亡 .免疫组织化学及Western印迹分析显示在转染高表达细胞中 ,c Met及Bcl 2的表达下调 .流式细胞仪分析表明 ,在转染pemt2 cDNA的高表达细胞中 ,G1期细胞增加 ,S期细胞减少 ,并在G0 期出现一个凋亡峰 .琼脂糖凝胶电泳谱显示梯状条带 .结果表明 :pemt2的转染可使大鼠肝癌细胞的c Met及Bcl 2的表达下调 ,并发生凋亡 .     

转录因子Nrf2在肝脏疾病中的作用

NF-E2相关因子2(nuclear erythroid 2-related factor 2,Nrf2)是一种能调节肝脏中大量解毒和抗氧化防御基因表达的重要转录因子.氧化应激与各种形式的肝损伤有密切的关系.Nrf2由亲电体压力或氧化应激激活,并通过结合抗氧化反应元件(antioxidant response element,ARE)诱导其靶基因,从而对细胞产生保护作用.因此,Nrf2通路在肝脏疾病中的作用已被深入研究.多种动物模型研究结果表明,Nrf2通路通过靶基因表达,在对抗病毒性肝炎、药物性肝损伤、酒精性肝病、非酒精性脂肪肝及肝癌方面表现出了不同的生物功能.根据Nrf2及其信号通路在对抗肝损伤中产生保护作用的相关文献,本文综述并讨论了其作为治疗肝损伤的药物作用靶点方面可能的应用前景.     

淋巴细胞凋亡与p53蛋白表达关系的研究

培养B95-8细胞,分离EB病毒,转染外周血和扁桃体淋巴细胞,建立永生化的LCLs和TLCL细胞株; 带有wt P₅₃基因的LCLs在DNA损伤剂——顺铂处理前未检出p53蛋白,经顺铂处理后,LCLs随作用时间延长细胞存活率明显下降、p53蛋白水平升高、DNA电泳显出梯状带;含mt P₅₃基因的淋巴瘤细胞在顺铂处理前可检出高浓度的p53蛋白,经顺铂处理后,细胞存活率与p53蛋白并无明显改变.这些结果表明：顺铂引起细胞DNA损伤、激活wt p53蛋白的表达、继而wt p53蛋白又促进了DNA损伤细胞凋亡.     

Clusterin抑制人肾近曲小管上皮HK-2细胞的凋亡

Clusterin是一种硫酸糖蛋白.最近研究发现,clusterin具有抗凋亡作用,同时对肾细胞具有保护作用,但抗凋亡的具体机制仍不清楚.为研究clusterin及其不同功能区域在人肾近曲小管上皮HK-2细胞中的抗凋亡作用,构建了含有全长及缺失前导序列的clusterin重组质粒（分别命名为pIRES2-EGFP/cluac和pIRES2-EGFP/clubc）.将重组质粒转染人肾近曲小管上皮HK-2细胞后,检测转染细胞中clusterin的表达及其抗Na₂SeO₃（10μmol/L）诱导的凋亡作用.Western印迹显示,转染pIRES2-EGFP/cluac的HK-2细胞培养上清及细胞裂解液中均可检测到clusterin蛋白表达,但转染pIRES2-EGFP/clubc的HK-2细胞仅在裂解液中检测到clusterin,在培养上清液中未检测到该蛋白表达.流式细胞术检验显示,HK-2 /clubc细胞实验组出现明显凋亡峰,而 HK-2 /cluac细胞组则未见凋亡;两组的凋亡百分率之间也存在显著性差异（P<0.05）.以Cy3标记的Annexin V染色后于荧光显微镜下观察细胞凋亡情况与FCM检测结果基本一致.上述结果证明,clusterin有明显的抑制人肾近曲小管上皮HK-2细胞凋亡的作用;clusterin前导序列是其发挥抗凋亡作用的必需功能区域,提示clusterin抗凋亡作用是通过细胞外途径产生的.