氧化苦参碱诱导人结肠癌SW480细胞凋亡的机制

目的探讨氧化苦参碱诱导人结肠癌SW480细胞凋亡的作用及机制。方法以不同剂量的氧化苦参碱作用于人结肠癌细胞株SW480,四甲基偶氮唑蓝法(MTT)检测细胞的增殖能力,Hoechst 33258染色法观测细胞凋亡。免疫印迹法测定B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)的表达,荧光法测定半胱氨酸蛋白酶(caspase)-3的活性。结果氧化苦参碱可剂量依赖性地抑制细胞的增殖,促进细胞凋亡。Western印迹方法显示氧化苦参碱可抑制抗凋亡蛋白Bcl-2的表达,提高促凋亡蛋白Bax的表达,同时激活凋亡效应分子caspase-3。结论氧化苦参碱能够抑制结肠癌SW480细胞的增殖,通过提高Bax的表达、抑制Bcl-2的表达、激活caspase-3发挥其诱导细胞凋亡的作用。     

苦参碱诱导人结肠癌SW1116细胞凋亡及机制探讨

目的观察苦参碱（Ma）诱导结肠癌SW1116细胞凋亡的作用，并探讨其机制。方法采用不同浓度的Ma处理SW1116细胞48h，并设正常对照组，MTT法检测细胞增殖抑制率，流式细胞仪检测细胞凋亡率，半定量RT-PCR检测Fas和Bax mRNA表达水平。结果与正常对照组相比，不同浓度Ma处理的SW1116细胞抑制率、胞凋亡率显著升高（P均〈0.01），Fas和Bax mRNA表达上调（P〈0.05，P〈0.01）。结论Ma可诱导SW1116细胞凋亡，其作用机制可能与上调Fas和Bax mRNA表达有关。     

乙醇诱导肝癌细胞凋亡的实验研究

目的 研究低浓度乙醇对肝癌细胞增殖的影响及作用机理。方法 采用MTT比色法观察乙醇对细胞增殖的影响；采用流式细胞仪法观察乙醇对肝癌细胞内活性氧的影响；采用琼脂凝胶电泳法观察DNA片段的梯形条带。结果 低浓度乙醇抑制了细胞的增殖；乙醇作用于细胞后，在2h内引起活性氧的产生；24h后细胞出现典型的凋亡表现。结论 乙醇能通过诱导细胞内活性氧的产生而引起细胞凋亡，呈明显的剂量依赖性。     

相关基因在苦参碱诱导人肺腺癌细胞凋亡中的表达

目的 探讨苦参碱对肺腺癌细胞凋亡和Bcl-2、Bax蛋白表达的影响.方法 肺腺癌A549细胞进行传代培养后,分别加入30、60、120、240 mg/L的苦参碱,MTT法检测其对A549细胞生长的抑制作用,流式细胞仪检测细胞凋亡及Bcl-2、Bax蛋白的表达.结果 不同浓度的苦参碱对肺腺癌细胞生长均有抑制作用,抑制率与浓度呈正相关.苦参碱可诱导A549细胞凋亡,与作用时间呈正相关.苦参碱能显著降低Bcl-2蛋白表达(P＜0.01),而显著升高Bax蛋白表达水平.结论 Bcl-2基因表达降低、Bax基因表达增高可能在苦参碱诱导肺腺癌A549细胞凋亡中起重要作用.     

苦参碱诱导人前列腺癌pc-3m细胞凋亡及对骨桥蛋白表达的影响

目的 探讨苦参碱治疗前列腺癌的可行性及机制.方法 将一定浓度梯度的苦参碱与人前列腺癌细胞株pc-3m孵育后,采用MTT法及流式细胞仪检测细胞增殖与凋亡变化,逆转录聚合酶链反应(RT-PCR)检测pc-3m中骨桥蛋白基因(OPN mRNA)表达水平.结果 苦参碱作用后pc-3m生长明显受抑,且呈时间-浓度依赖性;在流式细胞仪上可见凋亡率增加;pc-3m细胞中OPN mRNA表达阳性,OPN mRNA表达水平明显下调.结论 苦参碱体外能有效抑制pc-3m生长,其机制可能与诱导细胞凋亡、下调OPN mRNA表达有关.     

氧化砷诱导胃癌细胞凋亡的实验研究

目的 研究三氧二化砷（氧化砷）对胃癌细胞的诱导凋亡作用。方法 应用ＴＵＮＥＬ染色、流式细胞仪技术研究氧化砷对胃癌细胞ＭＫＮ－４５、ＭＫＮ－２８的诱导凋亡作用。结果 氧化砷作用于不同分化程度的胃癌细胞后,可看到较为典型的细胞凋亡的形态学变化：细胞核固缩,染色质凝集,呈新月型紧贴于核膜周边,核碎裂,染色质片断化,凋 亡小体形成等。流式细胞仪ＤＮＡ直方图上出现典型的亚二倍体的“凋亡峰”。ＴＵＮＥＬ染色法     

苦参碱诱导乳腺癌MCF-7细胞凋亡及其对Bax表达的影响

目的 探讨苦参碱在体外诱导乳腺癌MCF-7细胞的凋亡作用及其机制.方法 用MTT方法检测乳腺癌MCF-7细胞生长抑制率,用流式细胞仪(FCM)分别检测MCF-7细胞凋亡情况,MCF-7细胞线粒体跨膜电位及MCF-7细胞Bax蛋白表达情况.结果 苦参碱对乳腺癌MCF-7细胞生长抑制率测定结果显示,不同浓度的苦参碱对MCF-7细胞生长抑制率与对照组相比存在明显差异(P＜0.05),呈剂量-效应正相关及时间-效应正相关,流式细胞仪检测MCF-7细胞凋亡,与对照组相比均有显著差异(P＜0.05),随着苦参碱浓度的增高,凋亡的发生率也相应提高,呈正相关.线粒体跨膜电位检测,苦参碱处理组MCF-7细胞罗丹明染色阳性数明显低于对照组,存在显著差异(P＜0.05),并随苦参碱浓度的增高而减少,呈负相关.流式细胞仪检测Bax蛋白表达显示,Bax蛋白表达上调,与对照组相比,存在显著差异(P＜0.05),且随作用浓度增高表达增强,呈正相关.结论 中药苦参碱在体外能抑制乳腺癌MCF-7细胞之生长抑制,并能诱导该细胞凋亡.     

二硫代氨基甲酸吡咯烷对苦参碱诱导肝癌细胞凋亡的影响

目的 观察二硫代氨基甲酸吡咯烷(PDTC)抑制核因子-κB(NF-κB)活化后对苦参碱诱导肝癌细胞HepG2凋亡的影响.方法 MTT法观察苦参碱(分0.8、1.0、1.5、2.0、2.5 g/L组)及PDTC联合苦参碱对HepG2细胞增殖的抑制作用.将HepG2细胞随机分为细胞对照组、PDTC组(20μmol/L)、苦参碱组(1.5 g/L)和PDTC+苦参碱联合组,流式细胞仪和末端脱氧核苷酸转移酶介导的脱氧三磷酸尿苷缺口末端标记法检测细胞凋亡;电泳迁移率改变实验检测细胞核内NF-κB的活化水平.结果 PDTC增强了苦参碱对细胞增殖的抑制作用(F=183.92,P＜0.01).苦参碱同时具有诱导HepG2细胞凋亡和NF-κ B活化的作用;PDTC能显著增加苦参碱诱导的HepG2细胞凋亡和抑制苦参碱诱导的HepG2的NF-κB活化,细胞凋亡率由6.11%±0.81%增加至12.95%±0.02%(χ2=9.67,P＜0.05),NF-κB活化的灰度值由38.82±0.17降至32.01±0.69(χ2=10.38,P＜0.05).结论 苦参碱诱导HepG2细胞凋亡的同时激活NF-κB;PDTC可通过抑制NF-κB活化,增强苦参碱诱导HepG2细胞凋亡的作用.     

生存素反义寡核苷酸诱导肝癌细胞凋亡的实验研究

目的　生存素 (survivin)是近年来发现的凋亡抑制蛋白家族新成员 ,在多数恶性肿瘤组织中丰富表达。因此 ,观察生存素反义寡核苷酸转染对肝癌细胞凋亡、增殖、细胞对化疗药物敏感性的影响。方法　设计合成特异性靶向生存素的反义寡核苷酸 (ASODN)。肝癌细胞株hepG2 分为 6组 :空白对照组、脂质体转染对照组、正义链转染对照组、2 0 0、40 0和 6 0 0nmol/LASODN转染组。作用 2 0h后收获各组细胞。倒置显微镜观察细胞形态变化 ,Westernblot法检测各组细胞生存素表达情况 ,流式细胞术检测各组细胞增殖和凋亡指数 ,MTT法检测 5 氟尿嘧啶 (5 FU)和顺铂 (DDP)对各组细胞的生长抑制率。结果　各ASODN转染组细胞生存素表达有不同程度减弱 ,细胞变圆、折光增强、漂浮、细胞碎片形成等 ,而各对照组细胞生长良好 ;各ASODN转染组细胞凋亡指数明显高于各对照组 (P <0 .0 5 ) ,以 6 0 0nmol/L转染组最为明显 (P <0 .0 5 ) ,而各对照组间差异无显著性 (P >0 .0 5 ) ;各ASODN转染组细胞增殖指数明显低于各对照组 (P <0 .0 5 ) ,以 6 0 0nmol/L转染组最为明显 (P <0 .0 5 ) ,而各对照组间差异无显著性 (P >0 .0 5 ) ;等浓度化疗药物 5 FU和DDP对各ASODN转染组细胞的抑制率明显高于各对照组(P <0 .0 5 ) ,以 6 0 0nmol/L     

Helicobacter pylori infection induces apoptosis in gastric cancer cells through the mitochondrial pathway

BACKGROUND AND AIMS: To clarify the role of the mitochondrial pathway in apoptosis induced by H. pylori infection in gastric epithelial cells. METHODS: Cells of a gastric adenocarcinoma cell line SGC-7,901 were co-cultured with H. pylori NCTC 11,637, with or without preincubation with the inhibitors of caspases -3, -8, and -9. Apoptosis was determined by flow cytometry. RT-PCR was used to determine the expression of Bid, Bax, and Bcl-2 mRNA, and Western blotting was used to determine the expression of Bid, Bax, and Bcl-2 proteins, and the activation of caspases -3 and -9. RESULTS: H. pylori directly induced apoptosis in SGC-7,901 cells. Apoptotic indices (AIs) were 6.30 +/- 0.40%, 11.57 +/- 0.78%, 8.63 +/- 0.67%, and 7.22 +/- 0.97%, respectively, at 6, 12, 24, and 48 h after SGC-7,901 cells were co-cultured with H. pylori. H. pylori up-regulated the expression of Bid and Bax at both protein and mRNA levels, and induced a time-dependent activation of caspases -3 and -9. Apoptosis was inhibited significantly by the preincubation of SGC-7,901 cells with the inhibitors of caspase-3 (AIs were 1.72 +/- 0.59%, 2.97 +/- 0.55%, 4.38 +/- 1.56%, and 3.29 +/- 0.83%, respectively, at 6, 12, 24, and 48 h), and caspase -9 (AIs were 2.47 +/- 0.53%, 6.68 +/- 0.47%, 5.97 +/- 0.46%, and 5.43 +/- 0.15%, respectively, at 6, 12, 24, and 48 h). The caspase-8 inhibitor also reduced H. pylori-induced apoptosis by 20%. CONCLUSIONS: H. pylori infection induces apoptosis and the activation of caspases -3 and -9 in gastric cancer cells. Moreover, the caspase inhibitors significantly suppress H. pylori-induced apoptosis. These findings suggest that the mitochondrial pathway may be the major pathway in H. pylori-induced apoptosis in gastric epithelial cells.     

Guggulsterone induces apoptosis of human hepatocellular carcinoma cells through intrinsic mitochondrial pathway

AIM: To investigate the effects of guggulsterone on the proliferation and apoptosis of human hepatoma Hep G2 cells in vitro and relevant mechanisms.METHODS: Human hepatocellular carcinoma Hep G2 cells and normal human liver L-02 cells were treated with different concentrations of guggulsterone(5-100 μmol/L) for 24-72 h. Cell proliferation was tested by MTT assay. Cell cycle and apoptosis were investigated using flow cytometry(FACS). Bcl-2 and Bax m RNA and protein expression was detected by real-time PCR and Western blot, respectively. TGF-β1, TNF-α, and VEGF contents were determined by ELISA.RESULTS: Guggulsterone significantly inhibited Hep G2 cell proliferation in a dose- and time-dependent manner. FACS showed that guggulsterone arrested Hep G2 cell cycle at G0/G1 phase. Guggulsterone induced apoptosis was also observed in Hep G2 cells, with 24.91% ± 2.41% and 53.03% ± 2.28% of apoptotic cells in response to the treatment with 50 μmol/L and 75 μmol/L guggulsterone, respectively. Bax m RNA and protein expression was significantly increased and Bcl-2 m RNA and protein expression was decreased. ELISA analysis showed that the concentrations of TGF-β1 and VEGF were significantly decreased and TNF-α concentration was increased.CONCLUSION: Guggulsterone exerts its anticancer effects by inhibiting cell proliferation and inducing apoptosis in Hep G2 cells. Guggulsterone induces apoptosis by activation of the intrinsic mitochondrial pathway.     

A specifically radiolabeled somatostatin analog with strong antitumor activity induces apoptosis and accumulates in the cytosol and the nucleus of HT29 human colon carcinoma cells

The new heptapeptide somatostatin analog TT-232 decreases proliferation of HT-29 human colon carcinoma cells in vitro by reducing mitotic and increasing apoptotic activity. We have synthesized and characterized a specifically tritium labeled ³H-Tyr3-TT-232 (30 Ci/mmol) to investigate the effect and the fate of this antitumor peptide on human colon tumor cells. ³H-labeled TT-232 could be detected on the cell surface, on cytoplasmic membranes and also in the nucleus of HT-29 cells, 1–6 h after the administration of 0.5 and 50 μg/mL [³H]TT-232. Binding and internalization of TT-232 to human colon tumor cells at a relatively high dose provide further evidence for the existence of low-affinity somatostatin receptors in such cells, which might mediate the apoptosis-inducing effect. Our data suggest the possible use of TT-232 in the treatment of human colon tumors.     

Harmine induces apoptosis in HepG2 cells via mitochondrial signaling pathway

BACKGROUND:Harmine has antitumor and antinociceptive effects,and inhibits human DNA topoisomerase.However no detailed data are available on the mechanisms of action of harmine in hepatocellular carcinoma.This study aimed to investigate the effects of harmine on proliferation and apoptosis and the underlying mechanisms in the human hepatocellular carcinoma cell line HepG2.METHODS:The proliferation of HepG2 cells was determined by the cell counting kit-8 (CCK-8) assay and the clone formation test.The morpholo...     

Melatonin induces apoptosis in human neuroblastoma cancer cells

Low concentrations (nanomolar) of melatonin had been previously shown to inhibit cell proliferation in several cancer cell lines as well as in experimental animal models. Additionally, cell growth inhibition and differentiation of prostate cancer cell lines by high concentrations (micromolar to millimolar) of melatonin have been recently reported. In the present paper, we show the induction of apoptosis by high doses of melatonin in the human neuroblastoma cell line SK-N-MC. We found accumulation of cells in the G2/M cell cycle phase and induction of cellular death, measured as lactate dehydrogenase (LDH) released into the culture medium, under millimolar concentration of melatonin. Apoptosis was evaluated using 4,6-diamidino-2-phenylindole staining, DNA gel electrophoresis, electron microscopy, and annexin V binding. Apoptosis progressed through the classical pathway, which involves caspase-3 activation. Cell death was dose and time-dependent; the lowest effective concentration of melatonin was 100 microm. Treatment with 1 mm melatonin for 6 days induced cell death in 75% of the cells. This novel finding shows that a nontoxic natural indoleamine may be potential therapy for some types of human neuroblastomas.     

Nitric oxide-donating aspirin induces apoptosis in human colon cancer cells through induction of oxidative stress

Nitric oxide-donating aspirin (NO-ASA) is a promising chemoprevention agent against colon cancer and other cancers. It consists of traditional ASA to which a NO-releasing moiety is bound through a spacer. NO-ASA inhibits colon cancer cell growth several hundred times more potently than does ASA. In Min mice, NO-ASA inhibited intestinal carcinogenesis without affecting cell proliferation. Thus, we examined whether NO-ASA's most important cell kinetic effect is the induction of apoptosis. After confirming induction of apoptosis in Min mice, we studied the underlying mechanism in human colon adenocarcinoma cells. NO-ASA's spacer formed a conjugate with glutathione, depleting glutathione stores. This induced oxidative stress (increased intracellular levels of peroxides and O(2)(.-)) leads to apoptosis by activating the intrinsic apoptosis pathway. NO-ASA disrupted adherens junctions by inducing cleavage of beta- and gamma-catenin, resulting in cell detachment. NO-ASA inhibited Wnt signaling by a dual mechanism: at low concentrations it blocked the formation of beta-catenin/Tcf complexes (dominant mechanism), and at higher concentrations it also cleaved beta-catenin. These findings provide a mechanism of action by a potent chemopreventive agent, underscore the significance of these pathways in regulating cell death in the context of cancer chemoprevention, and present a paradigm for developing agents with enhanced cancer cell growth inhibitory properties.     

Melittin induces human gastric cancer cell apoptosis via activation of mitochondrial pathway

AIM: To investigate the apoptotic effects of melittin on SGC-7901 cells via activation of the mitochondrial signaling pathway in vitro.METHODS: SGC-7901 cells were stimulated by melittin, and its effect on proliferation and apoptosis of was investigated by methyl thiazolyl tetrazolium assay, morphologic structure with transmission electron microscopy, annexin-V/propidium iodide double-staining assay, measuring mitochondrial membrane potential(MMP) levels, and analyzing reactive oxygen species(ROS) concentrations were analyzed by flow cytometry. Cytochrome C(Cyt C), apoptosis-inducing factor(AIF), endonuclease G(Endo G), second mitochondria-derived activator of caspases(Smac)/direct IAP binding protein with low isoelectric point(Diablo), and FAS were analyzed by western blot. The expression of caspase-3 and caspase-8 was measured using activity assay kits.RESULTS: Melittin was incubated at 1.0, 2.0, 4.0, or 6.0 μg/m L for 1, 2, 4, 6, or 8 h and showed a timeand concentration-dependent inhibition of SGC-7901 cell growth. Melittin induced SGC-7901 cell apoptosis, which was confirmed by typical morphological changes. Treatment with 4 μg/m L melittin induced early apoptosis of SGC-7901 cells, and the early apoptosis rates were 39.97% ± 3.19%, 59.27% ± 3.94%, and 71.50% ± 2.87% vs 32.63% ± 2.75% for 1, 2, and 4 h vs 0 h(n = 3, P 0.05); the ROS levels were 616.53% ± 79.78%, 974.81% ± 102.40%, and 1330.94% ± 93.09% vs 603.74% ± 71.99%(n = 3, P 0.05); the MMP values were 2.07 ± 0.05, 1.78 ± 0.29, and 1.16 ± 0.25 vs 2.55 ± 0.42(n = 3, P 0.05); caspase-3 activity was significantly higher compared to the control(5492.3 ± 321.1, 6562.0 ± 381.3, and 8695.7 ± 449.1 vs 2330.0 ± 121.9), but the caspase activity of the non-tumor cell line L-O2 was not different from that of the control. With the addition of the caspase-3 inhibitor(Ac-DEVD-CHO), caspase-3 activity was significantly decreased compared to the control group(1067.0 ± 132.5 U/g vs 8695.7 ± 449.1 U/g). The expression of the Cyt C, Endo G, and AIF proteins in SGC-7901 cells was significantly higher than those in the control(P 0.05), while the expression of the Smac/Diablo protein was significantly lower than the control group after melittin exposure(P 0.01). Ac-DEVD-CHO did not, however, have any effect on the expression of caspase-8 and FAS in the SGC-7901 cells.CONCLUSION: Melittin can induce apoptosis of human gastric cancer(GC) cells through the mitochondria pathways, and it may be a potent agent in the treatment of human GC.     

S1通过线粒体途径诱导人卵巢癌细胞凋亡

目的探讨小分子化合物S1对人卵巢癌(SKOV3)细胞线粒体凋亡的影响。方法通过倒置显微镜观察S1作用卵巢癌细胞的形态学改变;不同剂量S1作用8 h,JC-1染色检测线粒体膜电势变化;Western印迹检测线粒体凋亡相关蛋白细胞色素(Cyto)c、Bcl-2和Bax蛋白表达的变化。结果与对照组相比S1作用24 h能明显诱导SKOV3凋亡;流式细胞术结果显示,S1引起SKOV3细胞线粒体膜电势降低(P<0.05,n=3);蛋白水平检测S1作用8 h能明显抑制SKOV3细胞Bcl-2蛋白表达,胞浆Cyto c和Bax蛋白表达增高(P<0.05,n=3)。结论 S1可能通过抑制Bcl-2蛋白诱导人卵巢癌细胞线粒体凋亡。     

Anti-cancer effect of ethylacetate fraction from Orostachys japonicus on HT-29 human colon cancer cells by induction of apoptosis through caspase-dependent signaling pathway

Objective: To investigate the anti-colon cancer effects of ethylacetate fraction from Orostachys japonicus(0. japonicus) on HT-29 cancer cells. Methods: The viability of HT-29 cells was assayed by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium(MTS) method. Apoptosis induction and cell cycle inhibition were confirmed by fluorescein isothiocyanate and propidium iodide staining using flow cytometry.Morphological changes in the nucleus were observed, using a fluorescence microscope with4',6-diamidino-2-phenylindole(DAPI) nuclear staining. The expression levels of the upstream and downstream proteins involved in the anti-cancer mechanism were confirmed by Western blotting. Results: After treating HT-29 cells with different concentrations of ethylacetate fraction from O. japonicus, the viability of cells decreased in a concentration-dependent manner,while apoptosis induction and apoptotic body formation increased. Cell cycle analysis showed that the arrest occurred at the sub-G_1 and S phase. Among the upstream and downstream proteins involved in anti-cancer activity, the level of B cell lymphoma-2 decreased, and the bcl-2-associated x protein increased. The level of pro-caspase-3, pro-caspase-8, and pro-caspase-9 decreased, while the level of cleaved-caspase-3, cleaved-caspase-8, and cleaved-caspase-9 increased. Moreover, the phosphorylation, that is, activation of extracellular signal regulated kinase 1/2, Jun-N-terminal kinase, and p38 increased. Conclusions: Combining the above results, it is thought that the survival of HT-29 cells is suppressed by ethylacetate fraction from0. japonicus through mitochondrial regulation-induced caspase cascade activation, induction of apoptosis and cell cycle arrest.