氧化应激在TRAIL诱导Hela细胞凋亡中的作用

目的 探讨氧化应激在肿瘤坏死因子相关凋亡诱导配体(tumor necrosis factor related apoptosis inducing ligand,TRAIL)诱导人宫颈癌Hela细胞凋亡中的作用.方法 40μg·L-1 TRAIL处理细胞后,用MTT法检测TRAIL对细胞增殖的抑制作用;用分光光度法检测细胞内还原型谷胱甘肽(GSH)、丙二醛(MDA)含量;流式细胞仪检测胞浆内的活性氧(ROS)水平;激光共聚焦测定细胞线粒体膜电位(△Ψm);蛋白质印迹法检测Bcl-2、Cyt C、DR 4、DR 5蛋白量.结果 40 μg·L-1 TRAIL对Hela细胞的生长具有显著的抑制作用;使抗氧化因子GSH含量明显下降,氧化应激产物ROS、MDA含量明显增多;到6h时△Ψm不断降低,能明显下调抗凋亡蛋白Bcl-2的表达,引起线粒体Cyt C向细胞质的释放;同时上调死亡受体DR 5的表达.而抗氧化剂N-乙酰半胱氨酸(NAC)能抑制TRAIL引起的这些变化.结论 氧化应激在TRAIL诱导的Hela细胞凋亡中起着重要作用,可能与ROS激活线粒体途径和上调DR 5的表达密切相关.     

葫芦素B通过激活线粒体途径诱导人肺癌NCI-H460细胞凋亡

目的探讨葫芦素B对人肺癌NCI-H460细胞增殖及凋亡的影响,并探讨其机制。方法体外培养NCI-H460细胞,MTT法观察葫芦素B对细胞增殖的影响,倒置相差显微镜观察细胞形态的变化,采用流式细胞术检测细胞凋亡率。采用罗丹明123(Rhodamine 123)染色,通过流式细胞仪检测线粒体膜电位(△ψm),采用Western blot方法检测线粒体内和胞浆内的细胞色素C。结果葫芦素B对NCI-H460细胞的增殖有抑制作用,且呈剂量、时间依赖性;葫芦素B处理组细胞形态发生显著改变,细胞皱缩、变圆,可见胞核染色质浓缩;流式细胞仪检测结果显示葫芦素B诱导NCI-H460细胞凋亡,呈剂量依赖性。葫芦素B处理后线粒体膜电位显著下降,细胞色素C由线粒体释放到胞浆中。结论葫芦素B可以抑制人肺癌NCI-H460细胞的增殖并诱导细胞凋亡,线粒体途径参与葫芦素B诱导的NCI-H460细胞凋亡。     

2-甲氧基雌二醇抑制骨髓增生异常综合征SKM-1细胞增殖和诱导细胞凋亡

目的 探讨2-甲氧基雌二醇(2-ME)对骨髓增生异常综合征SKM-1细胞增殖和细胞凋亡的影响.方法 常规培养的SKM-1细胞分为2-ME处理组与非处理对照组,SKM-1细胞分别与不同浓度2-ME(1、2、4和8 μmol/L)和对照组共同培养,MTT法检测2-ME对SKM-1细胞增殖抑制作用;光学显微镜观察瑞氏-姬姆萨染色后的细胞形态;流式细胞术分析细胞周期和凋亡;荧光探针JC-1检测细胞线粒体膜电位(△Ψm).结果 2-ME对SKM-1细胞的生长抑制作用具有浓度和时间依赖性;光学显微镜下可见典型的凋亡细胞形态特征;SKM-1细胞被阻滞于G2/M期,表现为Go/G期细胞和S期细胞逐渐减少,G2/M期细胞逐渐增多(P＜0.05＝;2-ME降低细胞△Ψm具有时间依赖性(P＜0.05＝.结论 2-ME对人骨髓增生异常综合征SKM-1细胞的增殖具有显著的抑制作用并可诱导细胞凋亡.其机制可能与细胞G2/M期阻滞和△Ψm下调有关.     

白藜芦醇对人黑色素瘤细胞增殖及凋亡的影响

目的研究白藜芦醇(resveratrol,Res)对人黑色素瘤细胞增殖及凋亡的影响。方法 MTT法检测不同浓度(10、20、40、80、160μmol.L-1)Res对人黑色素瘤细胞株Mel-RM和MM200增殖的抑制作用,溴化丙啶(propidium iodide,PI)单染进行流式细胞仪分析,检测Res对黑色素瘤细胞凋亡的影响。通过JC-1染色法检测Mel-RM和MM200细胞线粒体膜电位(mitochondrial membrane potential,△Ψm)。试剂盒检测Caspase-3的活性变化。结果随着Res的浓度的增加,对人黑色素瘤细胞株的增殖产生明显的抑制作用,80、160μmol.L-1的Res可诱导Mel-RM和MM200细胞出现明显的凋亡,JC-1染色结果显示,Res处理后Mel-RM和MM200线粒体膜电位分别降低51.0%和68.8%。Caspase-3活性检测结果显示Res对Caspase-3具有激活作用。结论 Res具有抑制黑色素瘤细胞增殖诱导其凋亡的作用,其机制可能与降低细胞线粒体膜电位及激活Caspase-3有关。     

吉九里香碱体外诱导HCT-15细胞凋亡的研究

目的:探讨中药单体吉九里香碱是否通过诱导 HCT-15细胞凋亡而发挥其抑制肿瘤细胞增殖的作用。方法:采用 MTT法检测细胞增殖抑制作用;采用透射电子显微镜观察细胞凋亡的形态学变化;库尔特全自动颗粒粒度分析药物引起 HCT-15细胞体积大小分布的变化;琼脂糖凝胶电泳测定 DNA ladder 的发生;通过流式细胞仪应用 Annexin V-FITC 和 Rhodamine123检测磷脂酰丝氨酸(PS)及线粒体跨膜电位(△ψm)。结果:MTT 结果显示吉九里香碱以浓度和时间依赖方式抑制 HCT-15细胞的增殖,抑制率依赖于吉九里香碱的浓度和作用时间;50 μmol·L~(-1)吉九里香碱处理 HCT-15细胞24 h 时,细胞出现凋亡典型的形态学特征;50 μmol·L~(-1)吉九里香碱分别处理 HCT-15细胞6,12,24 h 及不同浓度吉九里香碱处理 HCT-15细胞24 h 时,能够使细胞产生明显的 DNA ladder 和体积大小变化,呈一定的量效和时效关系;细胞 PS 外翻随作用时间的延长而增加,分别为15.34%(6 h),20.20%(12 h),39.37%(24 h);50 μmol·L~(-1)吉九里香碱处理 HCT-15细胞导致线粒体△ψm以时间依赖方式下降。结论:吉九里香碱通过诱导 HCT-15细胞凋亡而发挥其抗 HCT-15细胞增殖的作用,致凋亡机理可能与线粒体△ψm快速下降有关。     

BAPTA-AM对MDCK细胞的保护作用及其机制

目的观察BAPTA-AM抗D-氨基半乳糖(D-GalN)诱导MDCK细胞损伤作用,探讨其作用机制。方法采用MTT法,Annexin V-EGFP/PI与Hoechst33342/PI荧光染色,罗丹明123(Rhodamine 123)荧光染色,Caspase-8、Caspase-9活性测定及钙离子载体A23187诱导细胞内高钙等方法,分别测定D-GalN攻击下MDCK细胞活性,细胞凋亡状况,线粒体膜电位(△Ψm)、Caspase-8、Caspase-9活性和细胞内游离钙浓度([Ca2+]i)变化等。结果 BAPTA-AM能明显抑制D-GalN所致的细胞活力下降、减少细胞凋亡、维持△Ψm,抑制Caspase-8、Caspase-9的激活,减轻A23187所致细胞损伤,降低[Ca2+]i。结论 BAPTA-AM通过减轻钙超载,保护线粒体、抑制外源及内源性凋亡通路的激活,发挥抗肾细胞凋亡作用。     

神经酰胺诱导人结肠癌细胞凋亡作用

目的探讨外源性神经酰胺诱导人结肠癌HT-29细胞的凋亡作用。方法采用光镜、电镜、荧光显微镜和琼脂糖凝胶电泳方法检测C2-神经酰胺诱导HT-29细胞凋亡。MTT法检测C2-神经酰胺对HT-29细胞线粒体功能的影响。结果C2-神经酰胺使HT-29细胞发生核染色质断裂、DNA Ladder、凋亡小体等典型凋亡表现,12和24 h凋亡细胞率分别为64.1%和81.3%,呈现时间-剂量依赖关系。同时C2-神经酰胺处理细胞6 h后,细胞线粒体功能即出现损伤。结论外源性神经酰胺能诱导人结肠癌HT-29细胞凋亡,参与其凋亡调控。     

辛伐他汀诱导K562细胞凋亡过程中对线粒体膜电位的影响

目的:观察辛伐他汀诱导人红白血病K562细胞凋亡时线粒体膜电位(Δψm)的变化及其与时间的关系。方法:常规培养细胞24h,辛伐他汀(20μmol.L-1)处理K562细胞12、24、48、72h,观测细胞形态学改变;MTT法检测细胞增殖抑制情况;流式细胞术检测细胞凋亡率和线粒体膜电位改变,并与溶剂对照组比较。结果:与对照组比较,辛伐他汀作用K562细胞48h后细胞出现核固缩、核碎裂和凋亡小体等形态学改变;作用12、24、48、72h后细胞凋亡率分别增加(2.55±0.35)%、(6.1±0.35)%、(14.15±0.42)%、(30.70±0.65)%,K562细胞凋亡率随着药物作用时间延长而增加;细胞膜电位降低百分率分别为(0.7±0.24)%、(39.6±4.80)%、(24.4±2.45)%、(6.0±1.62)%,24h时膜电位降低百分率最大。结论:线粒体跨膜电位降低是凋亡发生的早期事件,辛伐他汀诱导K562细胞凋亡的可能机制是通过使线粒体跨膜电位崩溃,从而导致细胞凋亡。     

通关藤诱导白血病细胞U937,HL60细胞凋亡的实验研究

目的探讨通关藤抑制白血病细胞增殖作用及其机制。方法以不同浓度的通关藤提取物制剂处理白血病细胞U937、HL60,1~5 d,以四甲基偶氮唑盐(MTT)法检测对细胞增殖的影响,以Annexin V/PI双染法检测细胞的凋亡程度,Western blot检测凋亡相关蛋白caspase3,PARP改变,以JC-1染色法检测线粒体跨膜电位(ΔΨm)水平。结果通关藤提取物制剂呈时间和剂量依赖性抑制U937、HL60细胞增殖,50μL/mL时能明显降低线粒体跨膜电位(ΔΨm),活化caspase 3,剪切PARP,诱导细胞凋亡。结论通关藤提取物制剂对U937、HL60白血病细胞有显著的抑制和诱导凋亡作用,能通过降低线粒体跨膜电位途径触发白血病细胞凋亡。     

辛伐他汀通过线粒体途径诱导K562细胞凋亡

目的观察辛伐他汀诱导K562细胞凋亡不同时间的膜电位(Δψm),caspase-3、9和细胞色素C的改变,以推测其凋亡通路。方法采用浓度为20μmol.L-1的辛伐他汀处理K562细胞24、48、72 h,采用流式细胞技术检测细胞凋亡率和线粒体膜电位,分光光度法检测caspase-3、9蛋白活性,免疫组织化学法检测细胞色素C蛋白。结果浓度为20μmol.L-1辛伐他汀作用K562细胞24、48、72 h后,凋亡率分别为(6.1±0.35)%、(14.15±0.42)%(、30.70±0.65)%,随着凋亡率增加线粒体膜电位降低分别为(39.6±4.80)%,(24.4±2.45)%,(6.0±1.62)%;caspase-3、9蛋白活性与对照组相比上调,细胞浆内细胞色素C升高。结论辛伐他汀诱导K562细胞凋亡时线粒体膜电位下降,caspase-3、9活性增高和细胞色素C释放,推测辛伐他汀诱导K562细胞的凋亡可能经过线粒体凋亡途径。     

Role of hesperetin (a natural flavonoid) and its analogue on apoptosis in HT-29 human colon adenocarcinoma cell line--a comparative study

Colon cancer is one of the serious health problems in most developed countries and its incidence rate is increasing in India. Hesperetin (HN) (3',5,7-trihydroxy-4'-methoxyflavonone) and hesperetin analogue (HA) were tested for their apoptosis inducing ability. Methyl thiazolyl tetrazolium assay revealed a dose as well as duration-dependent reduction of HT-29 (colon adenocarcinoma) cellular growth in response to HN and HA treatment. At 24 h 70 μM of HN and 32 μM of HA showed 50% reduction of HT-29 cellular growth. Acridine orange/ethidium bromide staining showed apoptotic features of cell death induced by HN and HA. Rhodamine 123 staining showed significant reduction in mitochondrial membrane potential induced by HN and HA. HN and HA induced DNA damage was confirmed by comet tail formation. Lipid peroxidation markers (TBARS) and protein oxidation marker (PCC) were significantly elevated in HN and HA treated groups. Enzymic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) were slightly decreased in their activities compared to control (untreated HT-29 cells). Results of Western blot analysis of apoptosis associated genes revealed an increase in cytochrome C, Bax, cleaved caspase-3 expression and a decrease in Bcl-2 expression. These findings indicate that HN and HA induce apoptosis on HT-29 via Bax dependent mitochondrial pathway involving oxidant/antioxidant imbalance.     

A glycoprotein from Laminaria japonica induces apoptosis in HT-29 colon cancer cells

We isolated a novel glycoprotein from the brown alga Laminaria japonica that has antiproliferative effects on HT-29 colon cancer cells. We also identified the mechanism by which this glycoprotein, named LJGP, induces apoptosis. MTS assays showed that LJGP inhibited the proliferation of several cancer cell lines (AGS, HepG2, HT-29) in a dose-dependent manner. Especially in HT-29 cells, proliferation was significantly decreased. LJGP treatment on HT-29 displayed several apoptotic features, such as DNA fragmentation, sub-G1 arrest, caspase-3 activation, and PARP degradation. Consistent with sub-G1 arrest, LJGP decreased the expression of Cdk2, cyclin E, cyclin D1, PCNA, E2F-1, and phosphorylated pRb. Furthermore, the increase of p27 expression was observed. We also determined that LJGP-induced apoptosis leads to the formation of a death-induced signaling complex of Fas, FADD, and procaspase-8. LJGP induced the reduction of mitochondrial membrane potential with activation of the Bcl-2 family of proteins and caspase-9. These findings suggest that LJGP inhibits HT-29 cell proliferation by inducing apoptosis, which may be mediated via multiple pathways, including the Fas signaling pathway, the mitochondrial pathway, and cell cycle arrest. Therefore, LJGP can be a useful treatment option for colon cancer in humans.     

岩大戟内酯B对人乳腺癌Bcap37细胞凋亡的影响

目的:探讨岩大戟内酯B(jolkinolide B)诱导人乳腺癌Bcap37细胞凋亡及其可能机制。方法:分别应用MTT和AnnexinV-FITC/PI双染法检测jolkinolide B对Bcap37细胞的生长抑制率和细胞凋亡率;用流式细胞仪检测线粒体膜电位和细胞内游离Ca2+浓度的变化;RT-PCR检测jolkinolide B对Bcap37细胞caspase-3mRNA表达的影响。结果:jolkinolide B可显著抑制Bcap37细胞的增殖,呈剂量和时间效应关系;随jolkinolide B剂量增加,细胞凋亡率明显增加;线粒体膜电位下降,并伴有细胞内游离钙浓度增加,与对照组相比差异显著(P<0.01),同时caspase-3mRNA表达水平明显增高。结论:jolkinolide B可通过提高细胞游离Ca2+水平,激活内源性线粒体信号转导途径而诱导Bcap37细胞凋亡。     

Potential Role of Individual and Combined Effects of T-2 Toxin,HT-2 Toxin and Neosolaniol on the Apoptosis of Porcine Leydig Cells

T-2 toxin usually co-occurs with HT-2 toxin and neosolaniol (NEO) in the grains and feed. Our previous studies found that T-2 toxin and its metabolites’ binary or ternary combination exposure to porcine Leydig cells (LCs) displayed synergism in certain range of dosage and cannot be predicted based on individual toxicity. However, the possible mechanism of these mycotoxins’ combined exposure to cell lesions remains unknown. Based on 50% cell viability, the mechanism of apoptosis in porcine Leydig cells was investigated after exposure to T-2, HT-2, NEO individual and binary or ternary combinations. Compared with control, the adenosine triphosphate (ATP) content decreased, reactive oxygen species (ROS) level increased, and mitochondrial membrane potential (MMP) decreased in all treated groups. Additionally, the cell apoptosis rates were significantly increased in test groups (p < 0.05), and the B-cell lymphoma 2 (Bcl-2) Associated X (Bax)/Bcl-2 ratio and the expression of caspase 3, caspase 8, cytochrome c (Cytc) in the treated group are all significantly higher than the control group. Moreover, the expression of Cytc and caspase 8 gene in NEO and T-2+NEO groups was significantly higher than that in other individual and combined groups. It can be concluded that the toxicities of T-2, HT-2, and NEO individually and in combination can induce apoptosis related to the oxidative stress and mitochondrial damage, and the synergistic effect between toxins may be greater than a single toxin effect, which is beneficial for assessing the possible risk of the co-occurrences in foodstuffs to human and animal health.     

Mitochondrial apoptosis contributes to the anti-cancer effect of Smilax glabra Roxb

Smilax glabra Roxb. (SGR), a member of the Smilacaceae family and a rhizome of the Liliaceae plant, has shown anti-inflammation and detoxification properties, and a few studies reported its anti-cancer effect. In this study, we showed that SGR inhibited growth of human breast cancer cell line MCF7, colon carcinoma cell line HT-29, and gastric cancer cell line BGC-823 in a dose-dependent manner. Furthermore, SGR could inhibit tumor growth of HT-29 in Balb/c nude mice and murine hepatoma H22 cells in ICR mice. SGR elicited apoptotic cell death, as confirmed by DNA ladder formation, changes in nuclear morphology, and the increased FITC-Annexin-V/PI staining. Permeabilization of mitochondrial membrane (MMP), production of reactive oxygen species (ROS), elevation of intracellular [Ca²⁺], relocation of cytochrome c, and the activation of caspase-3 were found to be associated with the initiation of apoptosis by SGR treatment. Using microarray analysis, we found the changes in expression profiles of genes related to apoptosis, proliferation and cell cycle control in the cells treated with SGR. Our results demonstrated the mitochondrial regulation of apoptosis by which SGR exerts the anti-cancer effect.     

A novel non-aromatic B-ring flavonoid: Isolation, structure elucidation and its induction of apoptosis in human colon HT-29 tumor cell via the reactive oxygen species-mitochondrial dysfunction and MAPK activation

The aim of the present study was to elucidate the chemical structure of a novel non-aromatic B-ring flavonoid (DHEC) isolated from Macrothelypteris viridifrons and to evaluate its putative molecular mechanism of action on induction of apoptosis in human colon HT-29 cancer cell. On the basis of MS, UV, IR, 1D and 2D NMR data, DHEC was identified as 2-(cis-1, 2-dihydroxy-4-oxo-cyclohex-5-enyl)-5-hydroxy-7-ethoxy-chromone. In addition, the cytotoxicity of DHEC and its effect on induction of apoptosis were confirmed by several assays. After treatment of HT-29 cell with DHEC, we observed the accumulation of intracellular reactive oxygen species, the loss of mitochondrial membrane potential, the alteration of expression of the Bcl-2 family members, the releasing of cytochrome c, the cleavage of poly (ADP-ribose) polymerase (PARP), and the activation of caspase-3, -8, and -9. Further analysis showed that the mitogen-activated protein kinase (MAPK) related proteins were stimulated by treatment with DHEC. These results suggest that DHEC exhibits potential anti-cancer activity in HT-29 cell through induction of apoptosis, which may highly be associated with reactive oxygen species-mitochondrial dysfunction as well as activation of MAPK signaling pathway.     

Disruption of mitochondrial complexes,cytotoxicity, and apoptosis results from Mancozeb exposure in transformed human colon cells

Ethylene bisdithiocarbamate pesticides, including Mancozeb (MZ), are used as fungicides. Effects of MZ on apoptosis induction and mitochondrial activity of HT-29 colon cells were investigated. MZ exposed cells exhibited blebbing and cellular membrane disruption in scanning electron micrographs. Positive fluorescent staining with Annexin V at doses of 60–140 μM supports apoptosis as the mechanism of cell death. Activity of all electron transport chain complexes were evaluated. Mitochondrial Complex I activity was decreased in 100 μM treated cells. Mitochondrial Complex III activity was decreased in 60 and 100 μM MZ treated cells. Mitochondrial Complex II and Complex IV activities were decreased in cells treated with 60, 100, and 140 μM. Cells treated with 60 μM exhibited a decrease in Complex V enzyme activity. It is concluded that MZ exposure inhibits all mitochondrial complexes of HT-29 cells and that positive fluorescent microscopy and blebbing support previous studies of cell death via apoptosis.     

Induction of apoptosis in HT-29 colon cancer cells by crude saponin from Platycodi Radix

This study examined the apoptotic effects of crude saponins acquired from the roots of Platycodon grandiflorum (SPR) in HT-29 human colon cancer cells.SPR decreased HT-29 cell proliferation in dose- and time-dependent manners by inducing apoptosis via DNA fragmentation and poly (ADP-ribose) polymerase (PARP) cleavage. The apoptosis induced by SPR was associated with the activation of initiator caspases-8 and -9, as well as the effector caspase-3. SPR stimulated Bid cleavage, indicating that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. SPR increased the expression of the pro-apoptotic protein, Bax, and decreased the expression of the anti-apoptotic protein, Bcl-2. SPR also increased the expression of the caspase-independent mitochondrial apoptosis factor, AIF, in HT-29 cells. These results indicate that SPR inhibits HT-29 cell proliferation by inducing apoptosis, which may be mediated via both caspase-dependent and -independent pathways.     

Anti-proliferative effects of Lethariella zahlbruckneri extracts in human HT-29 human colon cancer cells

This study was performed to elucidate the anti-proliferative effects and the apoptotic mechanisms of extracts from Lethariella zahlbruckneri in HT-29 human colon cancer cells. Both the acetone extract (AEL) and methanolic extract (MEL) of L. zahlbruckneri decreased viable cell numbers in a dose- and time-dependent manner in HT-29 cells. The AEL showed stronger cytotoxicity than MEL. Cell death induced by AEL increased cell populations in the sub-G1 phase, as well as the formation of apoptotic bodies and nuclear condensation, whereas MEL did not. Therefore, the potential of AEL to induce apoptosis was examined. Apoptosis induced by AEL was associated with the activation of initiator caspases-8 and -9, as well as the effector caspase-3. AEL stimulated Bid cleavage. This indicated that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. AEL increased the expression of the pro-apoptotic protein, Bax, and decreased the expression of the anti-apoptotic protein, Bcl-2. AEL also increased the expression of the caspase-independent mitochondrial apoptosis factor, AIF, in HT-29 cells. These results indicate that AEL inhibited HT-29 cell proliferation by inducing apoptosis, which might be mediated via both caspase-dependent and -independent pathways.