羟基芫花素对UGTs及UGT1A1活性抑制作用种属差异的体外研究

考察羟基芫花素对尿苷二磷酸葡萄糖醛酸转移酶(UGTs)及UGT1A1活性的影响,为预测其与其他药物的代谢性相互作用提供理论借鉴。该实验采用体外肝微粒体孵育模型,以4-硝基酚(4-NP)为底物检测UGTs活性;β-雌二醇为底物检测UGT1A1活性,利用UV和HPLC测定底物或代谢物含量。结果表明,在大鼠、小鼠和人肝微粒体(HLM)孵育体系,羟基芫花素能显著抑制UGTs活性;对UGT1A1,在小鼠肝微粒体(MLM)孵育体系中,羟基芫花素几乎无抑制作用(IC50=190μmol·L-1);在大鼠肝微粒体(RLM)和重组酶(r UGT1A1)孵育体系中,羟基芫花素表现为中等强度的抑制作用(IC50=10.93,20.07μmol·L-1),抑制类型分别为竞争性抑制和线性混合型抑制;在HLM孵育体系中,羟基芫花素表现为弱抑制作用(IC50=76.31μmol·L-1),抑制类型为竞争性抑制;其抑制强弱顺序为RLMr UGT1A1HLMMLM。综上,羟基芫花素对不同肝微粒体孵育体系中UGTs及UGT1A1活性均可产生抑制作用且存在种属差异性,提示羟基芫花素可能存在基于UGT1A1酶的药物相互作用。该研究可为合理开发利用羟基芫花素提供实验依据,并为研究药物在临床上的联合用药提供理论借鉴。     

木犀草素和异荭草素对Caco-2细胞中α-葡萄糖苷酶及葡萄糖吸收的影响

目的:研究木犀草素和异荭草素对Caco-2细胞α-葡萄糖苷酶的抑制作用及对葡萄糖吸收的影响。方法:取对数生长期的Caco-2细胞,分别加入不同浓度的木犀草素和异荭草素孵育,CCK-8法检测细胞的存活率,酶标仪检测α-葡萄糖苷酶抑制率,RT-PCR法和Western blot法检测Caco-2细胞钠依赖性葡萄糖转运蛋白1(SGLT1)和葡萄糖转运蛋白2(GLUT2)的mRNA和蛋白表达。结果:100μmol/L木犀草素和异荭草素对α葡萄糖苷酶的抑制作用与阿卡波糖差异无统计学意义(P0.05);50、100μmol/L木犀草素和100μmol/L异荭草素能显著抑制SGLT1、GLUT2 mRNA及蛋白表达(P0.05或P0.01)。结论:木犀草素和异荭草素通过抑制Caco-2细胞的α-葡萄糖苷酶和SGLT1、GLUT2的mRNA和蛋白表达来延缓对碳水化合物水解和影响葡萄糖吸收,具有潜在的降血糖作用。在相同浓度下,木犀草素的效果要优于异荭草素。     

阿卡宁的氧葡萄糖醛酸化代谢通路研究

目的对紫草素的立体异构单体阿卡宁的氧葡萄糖醛酸代谢通路进行研究和表征。方法采用液相色谱和质谱联用方法检测阿卡宁和其葡萄糖醛酸化代谢产物;将阿卡宁在人肝微粒体(HLM)、人肾微粒体(HKM)以及重组人类葡萄糖醛酸转移酶(UGT)中孵育,观察代谢轮廓、筛选参与催化的重组单酶、考察酶动力学;通过相关性分析以及化学抑制实验阐明UGT单酶对阿卡宁的选择性。结果阿卡宁在含尿苷5’-二磷酸葡萄糖醛酸(UDPGA)的HLM孵育中,可以检测到1个UGT代谢产物。UGT单酶筛选发现UGT1A9高选择性催化阿卡宁。酶动力学研究显示在HLM、HKM和UGT1A9中阿卡宁的UGT代谢都呈底物抑制模式,并且表观亲和常数(Km)在3.75~4.50μmol/L。阿卡宁和已知UGT1A9探针底物异丙酚在12例个体人肝中的UGT代谢具有很好的相关性,R2为0.88。化学抑制实验显示在HLM中,厚朴酚和尼氟灭酸对阿卡宁的UGT代谢具有明显的抑制作用;睾酮、雷公藤红素和尼罗替尼对阿卡宁的UGT代谢均无明显抑制作用。结论 UGT代谢是阿卡宁(紫草素)在人体的重要代谢途径之一,阿卡宁是人类UGT1A9的一个高选择性探针底物。     

芫花氯仿萃取物对大鼠及人肝微粒体UGTs及UGT1A1活性影响

考察芫花氯仿萃取物对尿苷二磷酸葡萄糖醛酸转移酶(UGTs)及UGT1A1活性的影响,为预测芫花致肝损伤可能发生机制提供实验依据。采用体外肝微粒体孵育模型,分别以4-硝基酚和β-雌二醇为底物检测UGTs及UGT1A1活性;利用UV和HPLC测定底物或代谢物含量。结果表明,HPLC测得氯仿萃取物中3种黄酮类成分芹菜素、羟基芫花素和芫花素质量分数分别为1.00%,6.40%,18.38%;UV法测得总二萜质量分数为37.39%。与空白组相比,在大鼠肝微粒体(RLM)孵育体系,氯仿萃取物能显著抑制UGTs活性,而在人肝微粒体(HLM)孵育体系,抑制作用不明显;对UGT1A1,在RLM和HLM孵育体系中,氯仿萃取物均表现为中等强度的抑制作用(以芫花素计,IC50=8.76,10.36μmol·L-1);抑制类型分别为非竞争性抑制和反竞争性抑制。综上,氯仿萃取物对UGTs及UGT1A1活性均可产生抑制作用且存在种属差异性,推测这种抑制作用可能是芫花致肝损伤的机制之一。     

木犀草素诱导非小细胞肺癌细胞株A549 凋亡和G2 周期阻滞

目的:研究木犀草素诱导非小细胞肺癌细胞株A549细胞凋亡和抑制其细胞周期(G2期)的分子机制。方法:MTT法分析木犀草素对A549细胞的生长抑制作用和半数抑制率IC50。Hoechst 33258核染色,Annexin V-FITC/PI双染,流式细胞术检测细胞周期和凋亡,Western blot分析木犀草素引起的周期相关蛋白和凋亡相关蛋白的变化。Western blot和免疫细胞化学推测可能存在的分子机制。结果:木犀草素对A549细胞有显著的生长抑制作用,48 h的IC50为45.2μmol.L-1,流式细胞术检测细胞周期发现A549细胞经木犀草素处理后主要阻滞在G2期,周期蛋白cyclin A,p-CDC2和p-Rb都呈低表达。Hoechst 33258核染色,Annexin V-FITC/PI双染发现木犀草素处理组细胞凋亡率明显高于未处理组。Western blot发现木犀草素可上调JNK的磷酸化,下调NF-κB(p65)的磷酸化水平。免疫细胞化学显示木犀草素可抑制TNF-α刺激的p65入核,抑制其入核发挥转录因子的作用,促进细胞凋亡。结论:木犀草素能显著诱导人非小细胞肺癌细胞A549细胞凋亡和细胞周期阻滞,其可能的分子机制是通过上调JNK磷酸化继而激活线粒体凋亡途径,同时抑制NF-κB入核使其不能发挥转录活性。     

木犀草素对小鼠T淋巴细胞体外增殖及凋亡的作用

目的:研究木犀草素对小鼠T淋巴细胞体外增殖及凋亡作用的影响。方法:设置刀豆蛋白A(Con A)组和空白组,设置3个木犀草素药物组,终质量浓度分别为2.5,5,10 mg·L-1,细胞毒性活性检测-8(CCK-8)法检测各组细胞增殖情况,末端脱氧核苷酸转移酶介导的d UTP缺口末端标记测定法(TUNEL)和Annexin V-FITC/PI双染法检测各组细胞凋亡情况,蛋白免疫印迹法(Western blot)检测各组细胞凋亡通路蛋白B淋巴细胞瘤-2(B-cell lymphoma-2,Bcl-2),Bcl-2相关X蛋白(Bcl-2-associated X protein,Bax)表达水平。结果:CCK-8实验结果显示3个木犀草素药物组细胞数明显低于Con A组和空白组(P0.01),差异有统计学意义。TUNEL实验结果显示,Con A组的凋亡细胞数量显著低于3个木犀草素药物组(P0.01),差异有统计学意义。流式细胞仪检测结果显示3个木犀草素药物组的细胞凋亡率显著高于Con A组和空白组(P0.01),细胞凋亡率随着药物浓度增加而增高,呈明显的量-效关系。Western blot检测结果显示,2.5,5 mg·L-1木犀草素药物组中Bcl-2表达量高于对照组,Bax表达量低于对照组;10 mg·L-1药物组中Bcl-2表达量低于对照组,Bax表达量高于对照组。结论:2.5,5,10 mg·L-1木犀草素能够抑制T淋巴细胞增殖,能够诱导T淋巴细胞凋亡,10 mg·L-1木犀草素可能主要通过下调Bcl-2,上调Bax影响线粒体凋亡通路诱导细胞凋亡,2.5,5 mg·L-1木犀草素可能通过其他通路诱导细胞凋亡。     

木犀草素增强顺铂诱导的人肺癌细胞A549凋亡作用

目的 观察木犀草素与顺铂联合应用诱导体外培养的人肺癌细胞A549凋亡作用及对细胞周期的影响.方法 将木犀草素与顺铂单独及联合作用于A549细胞,AO/EB荧光染料染色,流式细胞仪检测细胞凋亡和细胞周期,Western blotting检测p53蛋白表达情况.结果 木犀草素(40 μmol/L)和顺铂(10 μg/mL)联用组诱导的A549细胞凋亡率和S期阻滞作用均显著强于木犀草素组或顺铂组,Western blotting发现,木犀草素和顺铂联用组p53蛋白水平也明显高于单独木犀草素组或顺铂组.结论 木犀草索能显著增强顺铂诱导的人肺癌细胞A549细胞凋亡和细胞周期阻滞;p53蛋白可能参与调节木犀草索和顺铂联合诱导的肿瘤细胞凋亡.     

人尿苷二磷酸葡糖醛酸转移酶参与马钱子碱和士的宁体外代谢研究北大核心CSCD

目的考察参与士的宁和马钱子碱Ⅱ相代谢的主要人尿苷二磷酸葡糖醛酸转移酶(UGTs)亚型,为预测其与其他药物代谢性相互作用提供理论借鉴。方法士的宁和马钱子碱分别与大鼠肝微粒体(RLMs)、人肝微粒体(HLMs)和12种主要人重组UGTs亚酶进行孵育,采用高效液相色谱-串联质谱(HPLC-MS/MS)法检测士的宁和马钱子碱葡糖醛酸代谢产物,考察参与其体外Ⅱ相代谢UGTs亚酶类型。结果马钱子碱和士的宁均在HLMs里生成1个单葡糖醛酸代谢产物,而在RLMs中未产生,单酶试验中二者均只在UGT1A4重组酶中发生代谢。结论马钱子碱和士的宁在人鼠代谢中存在种属差异,UGT1A4为其主要代谢亚酶。该研究结果可为临床预防马钱子因药物代谢性相互作用引发的不良反应提供理论和实验依据。     

白杨黄素和天然香豆素类对大鼠和人原代培养的肝细胞UGT1A1和UGT1A6活性的影响

二磷酸尿核苷葡萄糖醛酸基转移酶(UGTs)是许多组织细胞内质网中的一种二相药物代谢酶,其家族中的UGT1和UGT2亚型在有毒物质的代谢过程中具有重要的生理意义。研究了白杨黄素和6种天然香豆素类化合物(缴形酮、香豆素、勒素、cis- avicennol、香柠檬烯和前胡醚)对人和大鼠原代培养的肝细胞中UGT1A1和(或)UGT1A6的影响。     

木犀草素通过调控JAK2/STAT3信号通路对Hela细胞增殖和凋亡的影响

目的探究木犀草素通过调控JAK2/STAT3信号通路对Hela细胞增殖和凋亡的影响。方法木犀草素(10、20、30、40μmol/L)、JAK2抑制剂AG490(40μmol/L)单独或共同处理Hela细胞24 h。利用MTT检测Hela细胞增殖能力,流式细胞仪检测细胞凋亡,Western blot检测Bax、Bcl-2、p-JAK2/JAK2、p-STAT3/STAT3蛋白表达。结果木犀草素(30、40μmol/L)处理24 h后可抑制Hela细胞的增殖,促进Hela细胞凋亡(P0.01)。与对照组比较,AG490、木犀草素(40μmol/L)单独处理Hela细胞24 h,p-JAK、p-STAT3及Bcl-2蛋白表达降低,Bax蛋白表达增加。与AG490组相比, AG490与木犀草素(40μmol/L)共同处理Hela细胞,细胞增殖能力下降(P0.01)。结论木犀草素可能通过JAK2/STAT3信号通路来调控Hela细胞的增殖和凋亡。     

In Vitro Characterization of Glucuronidation of Vanillin: Identification of Human UDP‐Glucuronosyltransferases and Species Differences

Vanillin is a food flavoring agent widely utilized in foods, beverages, drugs, and perfumes and has been demonstrated to exhibit multiple pharmacological activities. Given the importance of glucuronidation in the metabolism of vanillin, the UDP‐glucuronosyltransferase conjugation pathway of vanillin was investigated in this study. Vanillin glucuronide was identified by high‐performance liquid chromatography‐tandem mass spectrometry (HPLC‐MS/MS) and a hydrolysis reaction catalyzed by β‐glucuronidase. The kinetic study showed that vanillin glucuronidation by HLMs and HIMs followed Michaelis‐Menten kinetics and the kinetic parameters were as follows: 134.9 ± 13.5 μM and 81.3 ± 11.3 μM for K_m of HLMs and HIMs, 63.8 ± 2.0 nmol/min/mg pro and 13.4 ±2.0 nmol/min/mg pro for V_max of HLMs and HIMs. All UDP‐glucuronosyltransferase (UGT) isoforms except UGT1A4, 1A9, and 2B7 showed the capability to glucuronidate vanillin, and UGT1A6 exerted the higher V_max/K_m values than other UGT isoforms for the glucuronidation of vanillin when assuming expression of isoforms is similar in recombinant UGTs. Kinetic analysis using liver microsomes from six studied speices indicated that vanillin had highest affinity for the monkey liver microsomes enzyme (K_m = 25.6 ± 3.2 μM) and the lowest affinity for the mice liver microsomes enzyme (K_m = 149.1 ± 18.4 μM), and intrinsic clearance was in the following order: monkey > dog > minipig > mice > rat ~ human. These data collectively provided important information for understanding glucuronidation of vanillin. Copyright © 2012 John Wiley & Sons, Ltd.     

Identification and interspecies characterization of UDP-glucuronosyltransferase isoforms catalyzing acacetin glucuronidation using recombinant UGT enzymes and microsomes

ObjectiveTo explore the glucuronic acid metabolism of acacetin in human liver and intestinal microsomes to better characterize human uridine 5′-diphospho (UDP)-glucuronosyltransferase (UGT) isoforms. In addition, interspecies comparisons were performed to identify the most appropriate experimental animal model for an in vivo study.MethodsLiquid chromatography tandem mass spectrometry (LC-MS/MS) and nuclear magnetic resonance (NMR) were used to confirm the successful biosynthesis of acacetin-7-O-glucuronide. Human isoforms of UGT and isozyme-specific chemical inhibitors were used for recombinant assays. Acacetin glucuronidation kinetics were assessed by combining acacetin with recombinant human UGT isoforms or with microsomes from humans or experimental animals. Kinetic differences between species were assessed in vitro using the same approach.ResultsWe identified multiple UGT isoforms that facilitated acacetin glucuronidation, and found that UGT1A1 was the major isoform that catalyzed this process. Acacetin-7-O-glucuronide formation exhibited clear substrate inhibition kinetics when combined with recombinant UGTs or with liver/intestinal microsomes derived from humans, monkeys, rats, mice, dogs, or pigs. Intrinsic metabolic clearance values of human intestinal microsomes were two-fold greater than those of human liver microsomes. Among the evaluated species, the K_m value of dog microsomes (0.86 μM) was greatest in acacetin glucuronidation, while mice exhibited the highest CL_int value, 5.05 mL/min/mg. The CL_int values of microsomes derived from monkeys and minipigs were 1.99 mL/min/mg and 2.12 mL/min/mg, respectively, exhibiting similar intrinsic metabolic clearance activity to that observed in humans.ConclusionMonkey may represent a suitable model for experimental studies of acacetin pharmacokinetics owing to a high sequence homology of UGT1A1 and similar UGT1A1 glucuronidation activity to humans.     

Up-regulatation of CYP3A expression through pregnent X receptor by praeruptorin D isolated from Peucedanum praeruptorum Dunn

Ethnopharmacological relevance

Qianhu, the dried roots of Peucedanum praeruptorum DUNN (Umbelliferae), is a well-known traditional Chinese medicinal herb which was officially listed in the Chinese Pharmacopoeia. Praeruptorin D (PD) is one of the major active constituents of Peucedanum praeruptorum Dunn (Qianhu). The Pregnane X receptor (PXR) is an orphan nuclear receptor and plays a pivotal role in the activation of human cytochrome P450 3A4 (CYP3A4) gene.

Aim of the study

The purpose of this study was to investigate the effect of PD on the PXR-mediated transactivation of CYP3A4, and thus to predict potential herb–drug interactions between PD, Qianhu, and the other co-administered drugs that metabolized by CYP3A4.

Materials and methods

The effect of PD on the Cyp3a11, mPXR mRNA expression in mice primary hepatocytes was measured using real-time PCR. The gene expression, protein expression, and catalytic activity of CYP3A4 in the LS174T cells after transfected with PXR expression plasmids were determined by real-time PCR, Western blot analysis, and LC–MS/MS based CYP3A4 substrate assay.

Results

The results revealed that the level of Cyp3a11 gene expression in mice primary hepatocytes was significantly increased by PD, but PD cannot induce the mPXR gene expression. On the other hand, CYP3A4 mRNA, protein expression and functional activity in PXR-over-expression LS174T cells were significantly increased by PD through PXR-mediated pathway; conversely, no significant change was found in the untransfected cells.

Conclusions

These findings suggest that PD can significantly up-regulate CYP3A4 expression and activity via the PXR-mediated pathway and this should be taken into consideration to predict any potential herb–drug interactions when PD and Peucedanum praeruptorum Dunn are co-administered with other drugs.     

姜黄素硒化衍生物的合成和抗肿瘤活性研究

 目的 合成姜黄素的硒化衍生物并研究其体外抗肿瘤活性。 方法 用姜黄素和氯氧化硒反应合成目标化合物,通过氢化物发生 - 石墨炉原子吸收光谱测定了合成物中的硒含量,用 UV 、 IR 、 MS 、 ¹ H-NMR 和 ¹³ C -NMR 表征其结构;用姜黄素和顺铂做对照,采用四氮唑盐（ MTT ）法考察目标化合物对胃癌（ human gastric cancer BGC823 cells , BGC823 ）细胞、鼻咽癌（ human nasopharyngeal carcinoma CNE cells , CNE ）、白血病（ human leukemic HL-60 cells , HL-60 ）、口腔上皮癌（ human oral epithelial carcinoma KB cell s , KB ）、结肠癌（ human colon carcinoma LS174T cells , LS174T ）、前列腺癌（ human prostate cancer PC3 cells , PC3 ）及宫颈癌（ human cervical cancer cell line HELA cells , HELA ）的细胞毒活性。 结果 确认目标化合物为一种新化合物二姜黄素硒氧配合物;对上述细胞株的 IC₅₀ 分别为 45.71 , >100 , 30.09 , 3.18 , >100 , 21.76 , 2.54 mg·L^-1 ,对 KB 和 HELA 均表现出比姜黄素强的抑制活性,对 HELA 的抑制活性比顺铂要高。 结论 合成出一个新化合物二姜黄素硒氧配合物;该化合物对部分肿瘤细胞有很强的抑制活性;有关其硒化衍生物对肿瘤细胞生长的抑制机制有待进一步研究。     

Raf and PI3K are the Molecular Targets for the Anti‐metastatic Effect of Luteolin

Metastases are the primary cause of human cancer deaths. Luteolin, a naturally occurring phytochemical, has chemopreventive and/or anticancer properties in several cancer cell lines. However, anti‐metastatic effects of luteolin in vivo and the underlying molecular mechanisms and target(s) remain unknown. Luteolin suppresses matrix metalloproteinase (MMP)‐2 and ‐9 activities and invasion in murine colorectal cancer CT‐26 cells. Western blot and kinase assay data revealed that luteolin inhibited Raf and phosphatidylinositol 3‐kinase (PI3K) activities and subsequently attenuated phosphorylation of MEK and Akt. A pull‐down assay indicated that luteolin non‐competitively bound with ATP to suppress Raf activity and competitively bound with ATP to inhibit PI3K activity. GW5074, a Raf inhibitor, and LY294002, a PI3K inhibitor, inhibited MMP‐2 and ‐9 activities and invasion in CT‐26 cells. An in vivo mouse study showed that oral administration (10 or 50 mg/kg) of luteolin significantly inhibited tumor nodules and tumor volume of lung metastasis induced by intravenous injection of CT‐26 cells. Luteolin also inhibited MMP‐9 expression and activity in CT‐26‐induced mouse lung tissue. These results suggest that luteolin may have considerable potential for development as an anti‐metastatic agent. Copyright © 2012 John Wiley & Sons, Ltd.     

姜黄素对HepG2细胞蛋白质组的影响

目的:应用双向电泳和质谱技术研究姜黄素对HepG2细胞蛋白质组的影响。方法:双向电泳分离HepG2细胞和经过30μmol/L姜黄素处理的HepG2细胞蛋白质,经银染后扫描得到蛋白质组图谱,用Image Master2D 6.0软件进行差异蛋白质组分析,筛选差异在2倍以上的蛋白质作为差异蛋白,进行质谱鉴定,并用RT-PCR方法进行初步验证。结果:经姜黄素处理后,HepG2细胞中蛋白质二硫键异构酶、复制蛋白A2、肉碱缺乏症相关蛋白、细胞周期蛋白依赖性激酶抑制因子表达量增加,而增殖细胞核抗原、内质网60蛋白酶、Ran结合蛋白1、Stathmin 1/oncoprotein 18、Nm23蛋白表达量降低。结论:姜黄素可以通过干扰细胞周期变化、抑制肿瘤细胞的生长、促进细胞凋亡、抑制肿瘤浸润与转移及促进细胞损伤修复而起到抗肿瘤作用,此外,姜黄素降血脂和抗动脉粥样硬化作用可能与促进脂肪酸跨膜转运、维护细胞膜稳定性相关。     

姜黄素调控MicroRNA-1246及对膀胱癌T24细胞的放疗增敏机制探究

目的:研究在膀胱癌化疗中使用姜黄素的增敏功能原理。方法:在T24细胞经过姜黄素及放射处理后,探讨分析其细胞活力(细胞增殖试验试剂盒)、microRNA表达(miRNA芯片测序)、集落形成、凋亡(AnnexinV-F)分析、miR-1246及p53 mRNA及蛋白质(Westernblot)表达、ITC/7-AAD流式细胞计数(ITC/7-AAD)。结果:通过测试,发现17个异常microRNA表达,细胞在经过姜黄素处理后,T24细胞活力相较于常规组明显下降,并出现浓度依赖性的现象。在T24细胞中,miR-1246相较于人膀胱上皮永生化细胞(SV-HUC-1细胞)表达明显较高。姜黄素的浓度较高时,T24细胞miR-1246的表达会受其影响并明显下降。研究组使用浓度为20μg/mL的姜黄素,并结合放疗处理的方式,与常规组相比,研究组在控制miR-1246的表达、集落形成及细胞活力方面,效果更为显著,T24细胞比例会因转染antagomiR-1246而增加,细胞死亡现象一般发生于转染antagomiR-NC细胞时期。结论:膀胱癌细胞中,姜黄素和放射治疗都可促进microRNA-1246表达下调,在对肿瘤的治疗中可以使姜黄素及放疗结合,共同产生抗肿瘤作用。     

Caspase-8和Bcl-2在脑肿瘤干细胞肿瘤坏死因子相关凋亡诱导配体耐药中的作用研究

 目的 探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)对脑肿瘤干细胞生长的影响,研究Caspase-8和Bcl-2在肿瘤坏死因子相关凋亡诱导配体耐药中的作用。方法 应用CD133免疫磁珠分选法获得脑肿瘤干细胞,流式细胞术检测分选阳性率;亚神经球形成实验分析脑肿瘤干细胞的自我更新能力和增殖能力;四甲基偶氮唑盐法检测肿瘤坏死因子相关凋亡诱导配体对脑肿瘤干细胞生长的影响;Western blot法检测DR5、FADD、Caspase-8和Bcl-2蛋白的表达。结果 分选后CD133⁺细胞即脑肿瘤干细胞可达71%;脑肿瘤干细胞以神经球的方式生长;肿瘤坏死因子相关凋亡诱导配体作用前后,脑肿瘤干细胞都有极强的形成神经球的能力;肿瘤坏死因子相关凋亡诱导配体可以引起脑肿瘤干细胞死亡,加入Caspase-8或Caspases抑制剂,可明显阻断肿瘤坏死因子相关凋亡诱导配体所引起的细胞死亡(P<0.05);Western blot结果显示,脑肿瘤干细胞表达Caspase-8 蛋白水平降低,表达Bcl-2蛋白水平增加(P<0.05)。结论 脑肿瘤干细胞是脑肿瘤对肿瘤坏死因子相关凋亡诱导配体耐药的根源,Caspase-8蛋白表达减少及Bcl-2蛋白表达增强使Caspase-8不能活化,导致了脑肿瘤干细胞发生肿瘤坏死因子相关凋亡诱导配体耐药。