紫草素诱导A375-S2细胞凋亡的分子机制研究

目的　研究紫草素诱导人黑色素瘤A375 S2细胞凋亡的分子机制。方法　MTT法、Hoechst33258荧光染色、DNA片段化分析、Westernblot、流式细胞分析以及caspase活力分析等。结果　10μmol·L-1紫草素可明显地抑制A375 S2细胞的生长,其半数有效抑制浓度IC50为 (10 9±1 8)μmol·L-1。10μmol·L-1紫草素可诱导A375 S2细胞凋亡,并经历了caspase 9和caspase 3的激活。紫草素促进p53蛋白的积聚,Bax蛋白表达的上调和Bcl xL蛋白表达的下调,进而导致细胞色素C的释放,致使细胞凋亡。紫草素可使细胞周期停止在G1 期。结论　紫草素可诱导A375 S2细胞周期停止在G1 期,其诱导细胞凋亡的途径经过p53介导的Bax和caspase 9的激活。     

冬凌草甲素通过激活caspase诱导HeLa细胞凋亡

目的　研究冬凌草甲素诱导人子宫颈癌HeLa细胞凋亡的作用机制。方法　采用形态学观察、DNA凝胶电泳及LDH法。结果　冬凌草甲素能显著诱导HeLa细胞发生凋亡 ,其作用呈明显的量效关系和时间依赖性。形态学观察可见凋亡小体的形成 ,琼脂糖凝胶电泳可见凋亡典型的DNA梯带 ;caspase家族抑制剂 ,caspase 1和 3抑制剂能抑制冬凌草甲素诱导HeLa细胞的凋亡 ,6 8 7μmol·L-1冬凌草甲素作用HeLa细胞 12h使caspase 3的活力提高 2倍。 结论　适宜浓度以下 ,冬凌草甲素 (6 8 7μmol·L-1)诱导HeLa细胞凋亡具有浓度与时间依赖性 ,大剂量 (137 4 μmol·L-1)时 ,冬凌草甲素诱导HeLa细胞坏死的程度强于凋亡 ,且通过激活caspase途径诱导HeLa细胞凋亡。     

冬凌草甲素通过诱导人宫颈癌HeLa细胞自噬下调凋亡的机制

研究冬凌草甲素通过诱导人宫颈癌HeLa细胞自噬拮抗凋亡的机制。MTT法测定冬凌草甲素对HeLa细胞的细胞毒作用。通过相差显微镜观察细胞形态学变化，用琼脂糖凝胶电泳检测DNA片段化，用流式细胞仪检测细胞自噬和凋亡水平，用Western blotting检测分析药物对蛋白质表达的影响。冬凌草甲素明显抑制HeLa细胞的增殖，诱导HeLa细胞凋亡，同时诱导HeLa细胞发生自噬。Western blotting检测结果表明，冬凌草甲素作用24 h后，促凋亡蛋白Bax、细胞色素c和控制Bax活力的去乙酰化酶SIRT-1的表达明显改变。冬凌草甲素(64 μmol·L^-1)诱导的自噬通过影响SIRT-1和线粒体途径蛋白的表达下调凋亡。     

去甲斑蝥素诱导人黑色素瘤A375-S2细胞凋亡

目的:研究去甲斑蝥素(NCTD)诱导人黑色素瘤A375-S2细胞凋亡的机制.方法:采用MTT法、形态学观察、DNA凝胶电泳及Western blot检测法.结果:去甲斑蝥素可诱导A375-S2细胞发生凋亡.半胱氨酸天冬氨酸酶(caspase)-3,-9抑制剂可以部分的抑制NCTD诱导的细胞死亡.细胞凋亡时caspase-3,8,-9酶活力升高,caspase-3底物-caspase-3激活的DNA酶抑制物(ICAD)蛋白表达下降,同时Bcl-2/Bax、Bcl-xL/Bax蛋白表达比率明显降低.结论:去甲斑蝥素通过激活caspase和Bcl-2家族诱导A375-S2细胞凋亡.     

冬凌草甲素诱导HL-60细胞凋亡

目的　研究冬凌草甲素诱导人白血病HL 6 0细胞凋亡的作用。方法　形态学观察 ,DNA凝胶电泳及流式细胞术。结果　冬凌草甲素能显著地诱导HL 6 0细胞发生凋亡 ,其作用呈明显的浓度效应关系和时间依赖性。形态学观察可见凋亡小体的形成 ,琼脂糖凝胶电泳可见明显的DNA梯带 ;流式细胞仪检测到G1亚峰。结论　冬凌草甲素能诱导HL 6 0细胞凋亡 ,并与其细胞杀伤活性相互平行 ,提示冬凌草甲素的抗癌活性与诱导肿瘤细胞凋亡相关     

吴茱萸碱部分通过人白介素1所介导的途径诱导人黑色素瘤A375-S2细胞死亡

目的研究吴茱萸碱(evodiamine)诱导人黑色素瘤A375S2细胞死亡的作用机制及其与细胞因子人白介素1(interleukin1,IL1)信号转导途径之间的关系。方法MTT检测法,DNA凝胶电泳法及Westernblot法。结果IL1受体拮抗因子(IL1receptorantagonist,IL1ra)在24h时能够部分抑制吴茱萸碱诱导的A375S2细胞死亡。吴茱萸碱在诱导A375S2细胞死亡的过程中,Fas配体(Fasligand,FasL)的蛋白表达量升高,激活其下游的caspase8和caspase3,进而引起DNA的损伤并激活p53蛋白,同时Bax/Bcl2的蛋白表达比例被上调。在经过IL1ra预处理后,这些变化均被部分的抑制或逆转。结论吴茱萸碱诱导A375S2细胞死亡的作用是部分通过IL1介导的信号转导途径而实现的。     

水飞蓟素和Fas激动性抗体CH11共同作用诱导A375-S2细胞凋亡

目的水飞蓟素和CH11共同作用诱导人黑色素瘤细胞A375-S2凋亡的分子机制。方法结晶紫法测定细胞生长抑制率;细胞凋亡的形态学观察,LDH法测定凋亡与坏死的比率;用免疫印迹法检测凋亡抑制性的去乙酰化酶SIRT1、Bc l-2家族成员(抗凋亡蛋白Bc l-2,Bc l-xL和促凋亡蛋白Bax)、细胞色素C和Caspase-3的表达。结果水飞蓟素和CH11共同作用能诱导A375-S2细胞发生凋亡;形态学观察可见凋亡小体的形成;免疫印迹法检测发现水飞蓟素和CH11共同作用的A375-S2细胞中Bax蛋白的表达增加,Bc l-2蛋白和Bc l-xL蛋白的表达降低,细胞色素C释放增加,pro-caspase-3表达量明显降低。结论水飞蓟素协同CH11能明显促进A375-S2细胞的凋亡。     

人白细胞介素1β(IL-1β)在诱导人黑色素瘤A375-S2细胞凋亡过程中的细胞周期阻滞作用和对线粒体Bcl-2家族蛋白的调节

目的研究人白细胞介素1β(interleukin-1β,IL-1β)体外诱导人黑色素瘤A375-S2细胞凋亡的机制。方法通过Hoechst33258荧光染色,观察A375-S2细胞在IL-1β作用下的形态学变化。使用琼脂糖凝胶电泳法检测IL-1β对细胞DNA降解的影响。应用流式细胞分析技术研究IL-1β对A375-S2细胞周期的影响。利用Westernβlot方法检测IL-1β对细胞线粒体内Bcl-2家族蛋白表达的调节作用。结果IL-1β(1nM)能够诱导A375-S2细胞凋亡,72h时细胞体变小,细胞核呈现固缩、断裂,并出现因凋亡引起的DNA梯状条带。IL-1β可将细胞周期阻滞在G0/G1期,并具有时间依赖性。IL-1β诱导细胞凋亡过程中,抗凋亡蛋白Bcl-2和Bcl-xL的表达减少,促凋亡蛋白Bax的表达增加。结论IL-1β通过将细胞周期阻滞在G0/G1期,上调线粒体内Bax/Bcl-2和Bax/Bcl-xL的表达比例诱导A375-S2细胞凋亡。     

冬凌草甲素上调人肝癌HepG2细胞 PTEN基因表达与诱导凋亡作用

［摘要］目的研究冬凌草甲素诱导人肝细胞癌HepG2细胞凋亡及与PTEN基因表达的关系。方法四甲基偶氮唑蓝（MTT）比色法测定冬凌草甲素诱导HepG2细胞的增长抑制；流式细胞术分析DNA倍体测定细胞凋亡；琼脂糖凝胶电泳观察DNA碎片；逆转录 聚合酶链式反应（RT PCR）半定量分析冬凌草甲素诱导人肝细胞癌HepG2细胞后PTEN mRNA的表达情况。结果MTT比色法测得冬凌草甲素对HepG2细胞增殖具有明显抑制作用，并随冬凌草甲素浓度的升高及作用时间的延长而增强；流式细胞术分析HepG2细胞经冬凌草甲素诱导后，细胞凋亡率随作用时间延长而增加；DNA电泳呈梯状条带。RT PCR测得PTEN基因mRNA的表达随细胞凋亡增加而逐渐增高。 结论冬凌草甲素能够明显抑制HepG2细胞增殖，并诱导肝癌细胞凋亡， 其作用途径可能与上调PTEN mRNA表达有关。     

冬凌草甲素上调人前列腺癌PC-3细胞PTEN基因的表达及其诱导凋亡作用

目的：研究冬凌草甲素诱导人前列腺癌PC-3细胞凋亡及与PTEN基因表达的关系。方法：MTT比色法测定冬凌草甲素诱导PC-3细胞的增长抑制;流式细胞术分析DNA倍体测定细胞凋亡;RT-PCR半定量分析冬凌草甲素诱导人前列腺癌PC-3细胞后PTENmRNA的表达情况。结果：MTT比色法测得冬凌草甲素对PC-3细胞具有明显的增殖抑制作用,并随冬凌草甲素浓度的升高及作用时间的延长而增强;流式细胞术分析PC-3细胞经冬凌草甲素诱导后,细胞凋亡比率随作用时间延长而增加。RT-PCR测得PTEN基因mRNA的表达随细胞凋亡的增加而逐渐增高。结论：冬凌草甲素能够明显抑制PC-3细胞的增殖,并诱导前列腺癌细胞凋亡,其作用途径可能与上调PTENmRNA表达有关。     

Oridonin induced A375-S2 cell apoptosis via bax-regulated caspase pathway activation, dependent on the cytochrome c/caspase-9 apoptosome

Two diterpenoids, oridonin (1) and ponicidin (2), were isolated from the 95% ethanol extract of Rabdosia rubescens and were evaluated for antiproliferative activity on cancer cells and human peripheral blood mononuclear cells (PBMC) in vitro. Oridonin has much more potent cytotoxic effects on four tumor cells (human melanoma A375-S2, human cervical cancer HeLa, human breast adenocarcinoma MCF-7, murine fibrosarcoma L929) than does ponicidin. The growth-inhibitory activity of oridonin for A375-S2 cells was more potent than that for the other cell lines, with an IC₅₀ of 15.1±1.2 μmol L^-1. Treatment with oridonin (34.3 μmol L_-1) for 12 h significantly inhibited A375-S2 cell growth, and showed weaker cytotoxicity against PBMC. By contrast, ponicidin markedly inhibited the growth of PBMC under the same conditions. When caspases-3 and -8 were activated at early stages after treatment of A375-S2 cells with oridonin (34.3 μmol L_-1), apoptotic bodies were formed, nuclear damage was observed by Hoechst 33258 staining and DNA fragmentation was exhibited. In addition, oridonin increased the expression of the apoptosis inducer, Bax, promoted the release of cytochrome c without affecting Bcl-2 expression, and activated down-stream caspase-9 in the mitochondrial pathway. These observations indicated that an appropriate dose of oridonin gave an initial premitochondrial phase that involved the Bcl-2 family of the pro-apoptotic protein Bax that required the participation of caspase-9 and caspase-3. However, on treatment with oridonin (137.4 μmol L_-1) for 12 h, the majority of A375-S2 cells underwent necrosis as measured by an LDH activity-based assay. Our results suggest that oridonin induces A375-S2 cell death on the balance of apoptosis and necrosis.     

Oridonin induces human epidermoid carcinoma A431 cell apoptosis through tyrosine kinase and mitochondrial pathway

Oridonin, a diterpenoid isolated from the plant Rabdosia rubescens, induces human epidermoid carcinoma A431 cell death through apoptosis and tyrosine kinase pathway. To examine the pathway of oridonin-induced A431 cell death, morphologic observation, lactate dehydrogenase activity-based assay, DNA agarose gel electrophoresis and Western blot analysis were carried out. When A431 cells, which overexpress epidermal growth factor receptor (EGFR), were treated with oridonin, caspase-3 was activated followed by the degradation of caspase-3 substrates, inhibitor of caspase-activated DNase (ICAD) and poly(ADP-ribose) polymerase (PARP) in a time-dependent manner. Oridonin promoted the release of cytochrome c and the down-regulation of mitochondrial transmembrane potential (DeltaPsim). Oridonin up-regulated the expression ratio of mitochondrial proteins, Bax/Bcl-2. In addition, the total tyrosine kinase activity of A431 cellular proteins and the expression of EGFR were markedly reduced after oridonin treatment. Taken together, oridonin induced apoptosis in A431 cells via mitochondrial pathway, activation of caspase-3 and inhibition of tyrosine kinase activities.     

Oridonin induces human epidermoid carcinoma A431 cell apoptosis through tyrosine kinase and mitochondrial pathway

Oridonin, a diterpenoid isolated from the plant Rabdosia rubescens, induces human epidermoid carcinoma A431 cell death through apoptosis and tyrosine kinase pathway. To examine the pathway of oridonin-induced A431 cell death, morphologic observation, lactate dehydrogenase activity-based assay, DNA agarose gel electrophoresis and Western blot analysis were carried out. When A431 cells, which overexpress epidermal growth factor receptor (EGFR), were treated with oridonin, caspase-3 was activated followed by the degradation of caspase-3 substrates, inhibitor of caspase-activated DNase (ICAD) and poly(ADP-ribose) polymerase (PARP) in a time-dependent manner. Oridonin promoted the release of cytochrome c and the down-regulation of mitochondrial transmembrane potential (ΔΨm). Oridonin up-regulated the expression ratio of mitochondrial proteins, Bax/Bcl-2. In addition, the total tyrosine kinase activity of A431 cellular proteins and the expression of EGFR were markedly reduced after oridonin treatment. Taken together, oridonin induced apoptosis in A431 cells via mitochondrial pathway, activation of caspase-3 and inhibition of tyrosine kinase activities.     

人参皂苷Rh2对人黑色素瘤A375—S2细胞的促凋亡作用

目的;研究人参皂苷G－Rh2诱导人黑色素肿瘤细胞A375－S2凋亡的分子生物学机制。方法：用结晶紫染色的方法测定细胞的死亡率。用置显微镜观察细胞形态学的变化。用琼脂糖凝胶电泳检测核酸片断。用流式细胞仪检测细胞凋亡和细胞周期。结果：G－Rh2抑制A375－S2细胞增殖并在20μmol/L可以诱导A375－S2细胞产生凋亡,Caspase抑制剂z-VAD-fmk(caspase家族）,z-DEVD-fmk(caspase-3)或z-IETD-fmk(caspase-8)能部分抑制细胞凋亡,但是Ac-YVAD-cmk(caspase-1)不能抑制A375－S2细胞凋亡。结论：GRh2在体外抑制A375－S2细胞的增殖,通过细胞形态学和核酸片断分析,G－Rh2能够诱导A375－S2细胞产生凋亡。这种作用是通过细胞内caspase一类半胱氨酸蛋白酶进行传导的,G－Rh2对A375－S2细胞的周期没有影响。     

Oridonin induces a caspase-independent but mitochondria- and MAPK-dependent cell death in the murine fibrosarcoma cell line L929

Oridonin, an active component isolated from Rabdosia rubescences, has been reported to exhibit antitumor effects, but little is known about its molecular mechanisms of action. In this study, the growth-inhibitory activity of oridonin for L929 cells is in time- and dose-dependent manner. After treatment with various concentrations of oridonin for 12 h, the majority of L929 cells underwent apoptosis as measured by an LDH activity-based assay. Although apoptotic bodies were observed in oridonin-treated L929 cells, DNA fragmentation as a hallmark of apoptosis was not found. The pan-caspase inhibitor, z-VAD, and caspase-3 inhibitor, z-DEVD, sensitized L929 cells to oridonin, however, a PARP inhibitor (DPQ) effectively blocked oridonin-induced cell death. After 12 h treatment, PARP proenzyme was significantly cleaved. This result indicated that oridonin-induced L929 cell death required PARP degradation in a caspase-independent manner. In addition, an MEK/ERK inhibitor (PD98059) markedly blocked oridonin-induced cell death, whereas a p38 inhibitor (SB203580) and JNK inhibitor (SP600125) weakly protected the cells against death. Treatment with 41.2 microM oridonin for 12 h induced significant and persistent ERK activation and p38 inactivation in L929 cells without evident changes in the protein levels. The responsiveness of ERK and p38 to oridonin suggests the involvement of these kinases in this apoptotic process. Moreover, oridonin increased the ratio of Bax/Bcl-2 protein expression, whereas it had no effect on the expression of Bcl-xL. These results indicate that regulation of the Bcl-2 and MAPK families maybe the effector mechanisms of oridonin-induced L929 cell death, independent of the caspase pathway.