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。     

冬凌草甲素通过改变Bax/Bcl-xL表达激活caspase-3诱导A375-S2细胞凋亡

目的　研究冬凌草甲素诱导人黑色素瘤A375 S2细胞凋亡的作用原理。方法　形态学观察 ,DNA凝胶电泳法及WesternBlot法。结果　冬凌草甲素能明显诱导A375 S2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 3的抑制剂能阻止caspase 3的活力升高 ;免疫印迹结果显示冬凌草甲素作用A375 S2细胞 12h改变Bax与Bcl xL蛋白的表达 ;且发现caspase 3的底物PARP蛋白在 12h时被降解。结论　冬凌草甲素 (34 3μmol·L-1)诱导A375 S2细胞凋亡 ,这种作用是通过改变了Bax/Bcl xL的表达比率 ,激活caspase 3而实现的。     

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。     

吴茱萸碱诱导人黑色素瘤A375-S2细胞的两种死亡机制吴茱萸碱诱导人黑色素瘤A375-S2细胞的两种死亡机制

目的研究吴茱萸碱诱导A375-S2细胞死亡机制。方法MTT法测定吴茱萸碱对A375-S2的细胞毒作用。通过倒置光显微镜，荧光染色， DNA电泳观察细胞形态学变化。应用流式细胞分析技术研究药物对细胞周期的影响。结果吴茱萸碱明显抑制A375-S2生长，在24 h前可诱导A375-S2凋亡，亚二倍体峰出现，caspase蛋白酶被激活， 24 h后启动坏死途径，caspase蛋白酶抑制剂不能抑制细胞死亡。结论吴茱萸碱诱导A375-S2死亡时早期启动了caspase依赖性的非经典凋亡途径，后期则启动了坏死途径。     

吡唑啉酮衍生物镉(Ⅱ)配合物诱导食管癌细胞凋亡与Bax和Bcl-2的关系

目的 研究吡唑啉酮衍生物镉(Ⅱ)配合物(Ls-17)对人食管癌细胞(Eca-109)的凋亡诱导作用及对细胞Bax和Bcl-2蛋白表达的影响.方法 MTT法检测Ls-17对Eca-109细胞的增殖抑制作用,流式细胞术检测细胞凋亡、周期分布变化及线粒体膜电位的改变,caspase活性法检测caspase-3和9的变化,Western blot法分析Bax和Bcl-2蛋白的表达.结果 Ls-17对Eca-109细胞增殖抑制的IC50值为25.12 mg·L-1,使细胞周期阻滞在G2/M期而导致细胞凋亡;能降低线粒体膜电位水平并激活caspase-3和9,使Bax/Bcl-2的比值增大.结论 Ls-17能够抑制Eca-109细胞增殖和诱导细胞凋亡,其机制可能与下调Bcl-2的表达,使Bax/Bcl-2的比值升高有关.     

去甲斑蝥素诱导人肾癌786-0细胞凋亡的体外研究

目的探讨去甲斑蝥素（NCTD）诱导人肾癌细胞株786—0凋亡的机制。方法实验分NCTD组和对照组．分别应用MTT法、流式细胞术和实时定量PCR检测NCTD对体外培养786—0细胞的生长抑制率、细胞周期和凋亡率以及肿瘤凋亡控制因子Bcl-2、Bax mRNA的表达。结果NCTD能抑制786—0细胞生长,随着NCTD浓度升高、处理时间延长作用增强,有明显的时间-剂量依赖性。流式分析显示,786—0细胞的S期细胞减少,G2/M期细胞增多,凋亡率上升。实时定量PCR结果表明,在80μmol／L NCTD处理24h后,Bcl-2 mRNA表达量明显减少、Bax mRNA表达水平则升高,Bcl-2／Bax比值明显下降,与对照组比较差异有统计学意义（P〈0．05）。结论NCTD可明显抑制786—0细胞的增殖和生长,诱导其凋亡,其机制可能与干扰786—0细胞生长周期、抑制DNA合成代谢以及影响凋亡相关基因Bcl-2和Bax的表达有关。     

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。     

蛋白激酶C在吴茱萸碱诱导A375-S2细胞死亡中的作用

目的研究蛋白激酶C(protein kinase C，PKC)在吴茱萸碱(evodiamine)诱导的A375-S2细胞死亡过程中的作用。方法TUNEL法检测吴茱萸碱诱导细胞凋亡的比例。MTT法测定药物对A375-S2细胞的细胞毒作用。Western blotting法分析药物作用后对ERK及其磷酸化蛋白和Bcl-2家族蛋白的影响。结果吴茱萸碱诱导A375-S2细胞的死亡在24 h以前以凋亡为主。PKC抑制剂staurosporine和ERK抑制剂PD98059均能促进吴茱萸碱诱导的A375-S2细胞死亡。吴茱萸碱能够抑制PKC的活力，下调ERK及其磷酸化蛋白的表达水平，并使Bax/Bcl-2表达比例上升。而staurosporine对吴茱萸碱抑制PKC活力，降低ERK及其磷酸化蛋白和Bcl-2的表达有进一步增强的作用。结论在吴茱萸碱诱导的A375-S2细胞死亡中，PKC位于ERK和Bcl-2的上游发挥其调节作用。     

盐酸小檗碱对人黑色素瘤A375-S2细胞增殖、凋亡的影响及其机制研究

摘要：目的:探讨盐酸小檗碱对人黑色素瘤A375-S2细胞增殖、凋亡以及核因子κB（NF-κB）通路相关蛋白表达的影响。方法:体外培养A375-S2细胞,实验分为对照组（不添加任何药物处理）、盐酸小檗碱高、中、低剂量组(25,50,100μmol·L-1)、阳性对照组(顺铂,0.01 mmol·L-1)。采用CCK-8法检测细胞增殖情况;流式细胞仪检测细胞凋亡以及周期分布情况;免疫印迹法（WB）检测细胞中NF-κB的抑制蛋白α（IκB-α）、p-NF-κB、NF-κB、B细胞淋巴瘤-2（Bcl-2）、Bcl-2相关X蛋白（Bax）、剪切的半胱氨酸天冬氨酸蛋白酶3（cleaved-caspase3）蛋白表达情况。结果:与对照组相比,盐酸小檗碱不同剂量组A375-S2细胞增殖抑制率、凋亡率、G1期DNA量、IκB-α、Bax、cleaved-caspase3蛋白表达均显著升高,p-NF-κB、Bcl-2蛋白表达显著降低（P<0.05）,且盐酸小檗碱高剂量组、阳性对照组与盐酸小檗碱中、低剂量组比较,差异有统计学意义（P<0.05）,高剂量组与阳性对照组间比较差异无统计学意义（P>0.05）。结论:盐酸小檗碱可明显抑制人黑色素瘤A375-S2细胞增殖并诱导细胞凋亡,其可能与引起细胞周期G1期阻滞及抑制NF-κB信号通路激活有关。     

姜黄素对肝癌SMMC-7721细胞增殖和凋亡的影响及其机制研究

目的研究姜黄素对肝癌SMMC-7721细胞增殖和凋亡的影响及其机制研究。方法选取肝癌细胞系SMMC-7721(50株),根据处理方式的不同分为对照组、姜黄素组。细胞计数试剂盒(CCK-8)方法检测两组细胞的增殖,流式细胞仪检测两组细胞的凋亡。比色法检测半胱氨酸天冬氨酸蛋白(caspase)-3酶的活性,用Western印迹方法检测Bax、Bcl-2蛋白的表达。结果姜黄素组的细胞增殖率低于对照组(P<0.05)。姜黄素组的细胞凋亡率高于对照组(P<0.05)。姜黄素组的caspase-3酶的活性高于对照组(P<0.05)。姜黄素组的Bax表达高于对照组,Bcl-2的表达低于对照组(P<0.05)。结论姜黄素能诱导SMMC-7721细胞凋亡,其机制可能与caspase活性升高、Bax表达增加、Bcl-2表达减少有关。     

Magnolol induces apoptosis via activation of both mitochondrial and death receptor pathways in A375-S2 cells

Magnolol inhibited proliferation of human malignant melanoma A375-S2 cells. The drug induced oligonucleosomal fragmentation of DNA in A375-S2 cells and increased caspase-3, 8, 9 activities followed by the degradation of caspase-3 substrates, inhibitor of caspase dependent DNase (ICAD) and poly-(ADP-ribose) polymerase (PARP). Pan-caspase inhibitor (z-VADfmk), caspase-3 inhibitor (z-DEVD-fmk), capase-8 inhibitor (z-IETD-fmk), caspase-9 inhibitor (z-LEHD-fmk) and caspase-10 inhibitor (z-AEVD-fmk) inhibited magnolol-induced A375-S2 cell apoptosis. The level of anti-apoptotic mitochondrial protein Bcl-2 was up-regulated while the level of pro-apoptotic protein Bax was down-regulated. Taken together, our results indicate that magnolol induces apoptosis by activation of both mitochondrial and death receptor pathways in A375-S2 cells.     

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.     

p53-mediated cell cycle arrest and apoptosis induced by shikonin via a caspase-9-dependent mechanism in human malignant melanoma A375-S2 cells

Natural products regulate cell growth in response to oncogene activation that induces cell cycle arrest and apoptosis in tumor cell lines. We investigated the mechanisms of caspase activation in human malignant melanoma, A375-S2 cells, by the natural product shikonin, which was isolated from the plant Lithospermum erythrorhizon SIEB. et ZUCC. Shikonin inhibited cell growth in a time- and dose-dependent manner, which might be mediated through up-regulation of p53 and down-regulation of cyclin-dependent protein kinase 4. Caspase activation was detected in shikonin-induced cell apoptosis, which involved in a post-mitochondrial caspase-9-dependent pathway. Decreased Bcl-2 protein levels and increased Bax protein levels were positively correlated with elevated expression of p53 protein. Apoptosis-inducing factor, another apoptotic protein of mitochondria, partially contributed to shikonin-induced release of cytochrome c. Taken together, shikonin-induced DNA damage activates p53 and caspase-9 pathways.     

Cytochrome c release from oridonin-treated apoptotic A375-S2 cells is dependent on p53 and extracellular signal-regulated kinase activation

We have reported that oridonin isolated from Rabdosia rubescens induces apoptosis of human melanoma A375-S2 cells within 12 h. In this study, TUNEL assay and flow cytometric analysis also indicate that one of the causes of A375-S2 cell death induced by oridonin was apoptosis. The cell death was preceded by the release of cytochrome c from the mitochondria. Twelve hours after treatment with oridonin, the ratio of Bax/Bcl-xL protein expression was increased and release of cytochrome c was decreased by an extracellular signal-regulated kinase (ERK) MAPK inhibitor (PD98059) and a phosphoinositide 3-kinases (PI3-K) inhibitor (wortmannin). A mitochondrial permeability transition (MPT) inhibitor, decylubiquinone, suppressed the release of cytochrome c without affecting Bax expression. The activation of p53 by oridonin was also blocked by wortmannin. In addtion, PD98059 and wortmannin significantly decreased oridonin-induced DNA fragmentation, but the p38 MAPK inhibitor (SB203580) did not after DNA fragmentation. Oridonin induced A375-S2 cell apoptosis by activating parallel p53 and ERK pathways, increasing the ratio of Bax/Bcl-xL protein expression, and promoting the release of cytochrome c into the cytosol, resulting in apoptotic cell death.     

Butein, a plant polyphenol, induces apoptosis concomitant with increased caspase-3 activity, decreased Bcl-2 expression and increased Bax expression in HL-60 cells

In the present study we have investigated whether butein could induce apoptosis in human leukaemic HL-60 cells. The treatment of HL-60 cells with butein induced apoptotic cell death as determined by morphological and biochemical changes. Apoptotic DNA fragments in the butein-treated HL-60 cells were increased gradually as determined by flow cytometric analysis. The caspase-3 activity was increased during butein-induced apoptosis. However, caspase-3 inhibitor abrogated the butein-induced DNA fragmentation. Furthermore, the treatment of HL-60 cells with butein decreased the expression of Bcl-2 protein, but increased the expression of Bax protein. These results suggest that butein-induced apoptosis is mediated through the activation of caspase-3 and it is associated with changed expression of Bcl-2 and Bax proteins.     

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。     

Pseudolaric acid B induces apoptosis through p53 and bax/ Bcl-2 pathways in human melanoma a375-s2 cells

Pseudolaric acid B is a major compound found in the bark of Pseudolarix kaempferi Gordon. In our study, pseudolaric acid B inhibited growth of human melanoma cells, A375-S2 in a time- and dose-dependent manner. A375-S2 cells treated with pseudolaric acid B showed typical characteristics of apoptosis including morphologic changes, DNA fragmentation, sub-diploid peak in flow cytometry, cleavage of poly-ADP ribose polymerase (PARP) and degradation of inhibitor of caspase-activated DNase (ICAD). P53 protein expression was upregulated while cells were arrested at the G2/M phase of the cell cycle. There was a decrease in the expression of anti-apoptotic Bcl-2 and Bcl-xL proteins, whereas pro-apoptotic Bax was increased. The two classical caspase substrates, PARP and ICAD, were both decreased in a time-dependent manner, indicating the activation of downstream caspases.