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.     

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。     

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。     

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。     

薯蓣苷元诱导人黑素瘤细胞A375-S2凋亡依赖半胱天冬酶和MAPK途径

目的　研究薯蓣苷元诱导人黑素瘤细胞A375 S2凋亡的机制。方法　MTT法测定细胞生长抑制率及半胱天冬酶和有丝分裂原活化的蛋白激酶(MAPK)抑制剂对薯蓣苷元诱导细胞凋亡的影响。电镜观察细胞形态变化。流式细胞仪检测细胞凋亡及周期分布。用半胱天冬酶活力检测试剂盒测定半胱天冬酶活力。结果　薯蓣苷元抑制A375 S2细胞的生长呈时间 剂量依赖性。经薯蓣苷元处理后的A375 S2细胞表现出典型的凋亡特征 :细胞表面微绒毛消失、胞质空泡化、染色质浓集、边聚。流式细胞仪检测表明薯蓣苷元导致DNA片段化和细胞周期阻滞在G0 /G1期。半胱天冬酶家族抑制剂 (z VAD fmk )和p38MAPK抑制剂 (SB2 0 35 80 )可部分抑制薯蓣苷元诱导的A375 S2细胞凋亡。结论薯蓣苷元可诱导A375 S2细胞凋亡。其诱导凋亡作用与半胱天冬酶及MAPK的活化相关。     

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。     

吴茱萸碱在诱导人黑色素瘤A375-S2细胞凋亡过程中对SIRT1和p53蛋白的影响

目的研究吴茱萸碱(evodiamine)在诱导A375-S2细胞凋亡过程中对SIRT1和p53蛋白表达的调控。方法电镜观察吴茱萸碱诱导细胞凋亡过程中细胞形态的变化。Western blot方法分析药物作用后对SIRT1蛋白和p53及其下游p21蛋白表达的影响。结果经15μmol.L-1吴茱萸碱处理24 h的A375-S2细胞表现出典型的凋亡特征,即细胞表面微绒毛消失、胞质空泡化、染色质浓集、边聚。在吴茱萸碱诱导A375-S2细胞凋亡过程中,SIRT1蛋白的表达下降,p53和p-p53的表达有所上升,其下游p21蛋白也被激活。结论在吴茱萸碱诱导的A375-S2细胞凋亡中,p53及其下游p21蛋白被活化,SIRT1蛋白表达被下调。     

高良姜素对H_2O_2诱导A375细胞氧化损伤的保护作用

目的探讨高良姜素对人A375黑素瘤细胞氧化损伤的保护作用。方法以700μmol·L-1的H2O2处理人A375黑素瘤细胞,建立氧化损伤模型,并以1,5和10μg·mL-1的高良姜素拮抗其作用。用倒置显微镜观察细胞形态;采用MTT比色法检测细胞存活率;并检测各组细胞上清液中丙二醛(MDA)、总抗氧化能力(T-AOC)、过氧化氢酶(CAT)、一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-PX)。结果高良姜素能明显改善H2O2损伤后的A375细胞形态,显著提高人A375黑素瘤细胞的存活率。与模型组相比,高良姜素给药后均能提高A375细胞T-AOC、CAT、SOD和GSH-Px活力(P<0.05),而MDA和NOS明显降低(P<0.05)。结论高良姜素对H2O2诱导的A375细胞氧化损伤具有保护作用。     

Silymarin enhanced cytotoxic effect of anti-Fas agonistic antibody CH11 on A375-S2 cells

Silymarin is a polyphenolic flavonoid from milk thistle (Silybum marianum), which has anti-inflammatory, cytoprotective as well as antioxidant effects. Our previous study demonstrated that silymarin has anti-apoptotic effect against UV irradiation. In this study, we assessed the effect of silymarin on anti-Fas agonistic antibody CH11-treated human malignant melanoma, A375-S2 cells. Pretreatment with silymarin (3 × 10^- 4 mol/L) significantly induced cell apoptosis in CH11-treated A375-S2 cells. Mitochondrial transmembrane potential (ΔΨ_m) was also down-regulated by silymarin pretreatment. Caspase-8, -9, -3 and pan-caspase inhibitors partially reversed silymarin-induced apoptosis of CH11-treated cells. The expression of Fas-associated proteins with death domain (FADD), a downstream molecule of the death receptor pathway, was increased by silymarin pretreatment, followed by cleavage of procaspase-8, whose activation induced cell apoptosis. Moreover, cleavage of procaspase-3 and digestion of its substrate, the inhibitor of caspase-activated DNase (ICAD), were also increased by silymarin pretreatment. These results suggested that silymarin could also exaggerate the apoptotic effect of anti-Fas agonistic antibody CH11 on A375-S2 cells.     

Silymarin enhanced cytotoxic effect of anti-Fas agonistic antibody CH11 on A375-S2 cells

Silymarin is a polyphenolic flavonoid from milk thistle (Silybum marianum), which has anti-inflammatory, cytoprotective as well as antioxidant effects. Our previous study demonstrated that silymarin has anti-apoptotic effect against UV irradiation. In this study, we assessed the effect of silymarin on anti-Fas agonistic antibody CH11-treated human malignant melanoma, A375-S2 cells. Pretreatment with silymarin (3 x 10(- 4) mol/L) significantly induced cell apoptosis in CH11-treated A375-S2 cells. Mitochondrial transmembrane potential (DeltaPsi(m)) was also down-regulated by silymarin pretreatment. Caspase-8, -9, -3 and pan-caspase inhibitors partially reversed silymarin-induced apoptosis of CH11-treated cells. The expression of Fas-associated proteins with death domain (FADD), a downstream molecule of the death receptor pathway, was increased by silymarin pretreatment, followed by cleavage of procaspase-8, whose activation induced cell apoptosis. Moreover, cleavage of procaspase-3 and digestion of its substrate, the inhibitor of caspase-activated DNase (ICAD), were also increased by silymarin pretreatment. These results suggested that silymarin could also exaggerate the apoptotic effect of anti-Fas agonistic antibody CH11 on A375-S2 cells.     

Silymarin prevents UV irradiation-induced A375-S2 cell apoptosis

Silymarin, a plant flavonoid from milk thistle (Silybum marianum [L.] GAERTNER) was first evaluated for its protective effect against UV irradiation-induced apoptosis in human malignant melanoma cells (A375-S2 cells). Treatment with silymarin 500 microM for 12 h significantly inhibited UV irradiation (2.4 J/cm(2), 5 min)-induced apoptosis in A375-S2 cells. Activities of caspase-9 and caspase-3 in UV-irradiated A375-S2 cells were effectively reduced by silymarin in a dose-dependent manner, while the expression of the inhibitor of caspase-activated DNase (ICAD), protein expression of Bcl-x(L) (Bcl-2 family member), and the activity of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) were increased simultaneously. It is suggested that the inhibitory effect of silymarin is exerted by blockage of the caspase/ICAD pathway after increased expression of Bcl-x(L) protein and activation of the ERK/MAPK pathway.     

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。     

Evodiamine induced human melanoma A375-S2 cell death partially through interleukin 1 mediated pathway

We have reported that caspase cascade accompanied by the regulation of Bax/Bcl-2 and MAPK signaling were involved in evodiamine-induced A375-S2 cell death. In this study, pretreatment with interleukin 1 (IL-1) receptor antagonist (IL-1Ra) rescued the cell viability loss and reversed the ratio of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells induced by evodiamine. IL-1Ra was capable of attenuating the expression of Fas-ligand (Fas-L) and the cleavage of procaspas-8 and -3 caused by evodiamine. Subsequently, IL-1Ra reduced evodiamine-induced DNA degradation, p53 activation and up-regulation of Bax/Bcl-2 ratio. However, IL-1Ra attenuated the enhanced phosphorylation level of p38 mitogen-activated protein kinase (p38 MAPK) without affecting extracellular signal-regulated protein kinase (ERK) inactivation induced by evodiamine. In conclusion, IL-1-induced death cascade in melanoma A375-S2 cell might be one of the targets for natural product evodiamine, and increased Fas-L expression via IL-1 mediated pathway stands at the initiation phase, leading to consequent events that culminate in the death of the 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.