Polychlorinated biphenyl mixtures (Aroclors) induce apoptosis via Bcl-2, Bax and caspase-3 proteins in neuronal cell cultures

Polychlorinated biphenyls (PCBs) are a group of persistent and widely dispersed environmental pollutants, some of which may be neurotoxic. In the present study, we have investigated the effect of PCB commercial mixtures (Aroclors) on neuronal cell cultures by assessing cell viability and apoptotic cell death. We have combined morphological and biochemical techniques to establish the relevance of apoptosis in neuronal cell death induced by Aroclors. Treatment with both Aroclor 1248 and Aroclor 1260 caused the loss of cell viability and accelerated apoptosis both in a concentration- and time-dependent manner. However, the extent of apoptosis resulted greater for Aroclor 1248 than for Aroclor 1260. This is correlated with the loss of cell viability since Aroclor 1248 is more cytotoxic. The apoptosis induced by Aroclors involves the increase of caspase-3 activity. To correlate the caspase-3 activity with respect to changes in protein processing, caspase-3 precursor protein (procaspase-3) was evaluated by Western blot analysis. Also, Bcl-2 and Bax protein were assessed in order to elucidate the cell death machinery induced in cortical neuronal cell cultures by Aroclor 1248. The results indicate that the increase in Aroclor-induced apoptosis correlates with a reduction in the expression of antiapoptotic Bcl-2 and an increase in the expression of proapoptotic Bax. These results suggest that, with our experimental conditions, Aroclors induce apoptosis in primary cultures of cortical neurons via proteins of the Bcl-2 and caspase families.     

Apoptosis-mediated neurotoxic potential of a planar (PCB 77) and a nonplanar (PCB 153) polychlorinated biphenyl congeners in neuronal cell cultures

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants, some of which may be neurotoxic depending on the chemical structure of the congeners. This study investigated the neurotoxic potential of 3,3',4,4'-tetrachlorobiphenyl (TCB) (PCB 77, a non-ortho-substituted planar congener) and 2,2',4,4',5,5'-hexachlorobiphenyl (HCB) (PCB 153, a di-ortho-substituted nonplanar congener) by assessing cell viability and apoptotic cell death in neuronal cell cultures. We have combined morphological and biochemical techniques to establish the relevance of apoptosis in neuronal cell death induced by the two selected PCB congeners. Treatment with both planar and nonplanar congeners caused the loss of cell viability and accelerated apoptosis in a time- and concentration-dependent manner. However, the extent of apoptosis generated was greater for the non-ortho-substituted planar congener (PCB 77) than for the di-ortho-substituted nonplanar congener (PCB 153). This was correlated with the loss of cell viability since the planar congener was more cytotoxic. Based on our findings, the apoptosis induced by PCBs involves the increase of caspase-3 activity in neuronal cell cultures. It is reasonable to assume that PCB-induced apoptosis may be linked to the neurotoxic effect of these toxicants and that different molecular mechanisms may operate in the induction of apoptosis depending on the planarity or nonplanarity of the PCB congeners.     

Role of nonsteroidal anti-inflammatory drug-activated gene-1 in docetaxel-induced cell death of human colorectal cancer cells with different p53 status

Nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1) expression is upregulated not only by NSAIDs such as sulindac sulfide, but also by several antitumorigenic dietary compounds, suggesting that NAG-1 is a specific target for the development of effective anticancer agents. Despite being a downstream target of p53, NAG-1 induction is both p53-dependent and p53-independent. It is not clear whether NAG-1 induction is the responsible factor in cancer cell apoptosis with mutated p53. In this study, we report that NAG-1 induction alone cannot determine apoptotic cell fate in colon cancer cells. Although docetaxel induced an increase in NAG-1 and apoptosis in both HCT-116 (wild-type p53) and HT-29 (mutant p53) colon cancer cells, NAG-1 knockdown with siRNA prevented docetaxel-induced cell death in only HCT-116 cells. Docetaxel decreased Bcl-2 in HCT-116 cells, which have functionally active p53, according to luciferase reporter gene analyses, and docetaxel-induced cell death and changes in Bcl-2 and NAG-1 expression were blocked by PFT-α, a p53 inhibitor. In HT-29 cells with functionally inactive p53, the docetaxel-induced Bcl-xL decrease, NAG-1 increase, and cell death were not blocked by PFT-α. On the other hand, sulindac sulfide at concentrations that significantly induced NAG-1 did not decrease cell viability comparable to docetaxel, and it did not affect the level of p53, Bax, Bcl-2, and Bcl-xL in either cell line. The present study demonstrates that p53-dependent NAG-1 induction is linked to cell death and that NAG-1 induction without accompanying alteration of antiapoptosis protein Bcl-2 family members may not lead to cancer cell death.     

Enantioselective cytotoxicity of isocarbophos is mediated by oxidative stress-induced JNK activation in human hepatocytes

Recent studies have shown the enantioselectivity of chiral pesticides in environmental fate, aquatic toxicity, endocrine disruption and cytotoxicity. Thus it is of significance to investigate the molecular mechanisms of chiral pesticides enantioselectivity in cytotoxicity. In the present study, we used Hep G2 cells as in vitro model to assay cytotoxicity of enantiomers of isocarbophos (ICP), a widely used chiral organophosphorus pesticide. The results of cell viability assay and cytoflow assay indicated an obvious enantioselective hepatocyte toxicity of ICP: (−)-ICP was about two times more toxic than (+)-ICP in Hep G2 cells. We found that (−)-ICP, but not (+)-ICP, up-regulated Bax protein expression and down-regulated Bcl-2 expression levels, which resulted in an increase in Bax/Bcl-2 ratio with the apoptosis co-ordination. Although (−)-ICP enantioselectively activated both ERK and JNK, only the specific inhibitor for JNK could completely reverse (−)-ICP-induced apoptosis of Hep G2 cells. It suggests that (−)-ICP-induced hepatocyte toxicity was more dominantly through the sustained activation of JNK pathway, but only partially via ERK cascade. Furthermore, (−)-ICP induced ROS production, while (+)-ICP had no effect on ROS generation. The antioxidant MnTBAP attenuated (–)-ICP-induced activation of JNK and ERK, indicating that the outcome from challenge with (−)-ICP enantiomer depends on the oxidative stress-induced activation of a series of signaling cascades that promote hepatocyte apoptosis. In conclusion, (−)-ICP enantioselectively causes the change of Bax/Bcl-2 ratio, triggers the generation of intracellular ROS and sequentially induces sustainable activation of JNK, which in turn, results in a decrease in cell viability and an increase in cell apoptosis. Our observations provide further insight into enantiomers toxicity pathway which is able to differentiate between enantiomer activities at molecular level.     

珠子参总皂苷对H2O2诱导新生大鼠心肌细胞凋亡的抑制作用

目的:观察珠子参总皂苷对H2O2诱导新生大鼠心肌细胞凋亡的抑制作用,并探讨其作用机制.方法:Wistar乳鼠心肌细胞原代培养,用H2O2建立氧化应激损伤模型,然后用珠子参总皂苷(100,200 μg/mL)孵育24 h后,MTT法检测珠子参总皂苷对细胞活力的影响,流式细胞仪和Hoechst33258染色检测珠子参总皂苷对氧化应激诱导细胞凋亡及胞内ROS含量的影响,比色法测定心肌细胞Caspase-3、Caspase-9的活性,荧光定量PCR测定心肌细胞Bcl-2和Bax mRNA表达,并计算Bcl-2与Bax的比值.结果:珠子参总皂苷(100,200 μg/mL)能显著改善心肌细胞活性,有效保护线粒体膜电位的稳定,抑制心肌细胞凋亡和改善细胞形态,降低细胞内活性氧(ROS)含量;下调Bax mRNA表达,上调Bcl-2mRNA表达及Bcl-2与Bax的比值;降低H2O2所致新生大鼠心肌细胞中Caspase-3、Caspase-9的活性.结论:珠子参总皂苷对H2O2诱导心肌细胞凋亡有显著的抑制作用,其机制可能与其稳定心肌细胞膜、清除ROS及调节心肌细胞Bcl-2、Bax和Caspase-3、Caspase 9表达有关.     

Studying the effect of LPS on cytotoxicity and apoptosis in PC12 neuronal cells: Role of Bax,Bcl-2, and Caspase-3 protein expression

Gram-negative bacteria and their endotoxins may be a causal or complicating factor in many serious diseases. Bacterial lipopolysaccharides (LPS) could potentially be human pathogens. Among the many disorders induced by LPS, neurodegenerative diseases such as Parkinson’s are reported and are of great interest. Despite the evidence on LPS-induced neurodegeneration, the exact mechanism is unknown. The purpose of this study was to investigate the cytotoxic effect of LPS and also to examine the involvement of Bax, pro-apoptotic, Bcl-2, anti-apoptotic, and caspase-3, the executioner of apoptosis, protein expression, during LPS-induced apoptosis in neuronal PC12 cells. The cell viability was evaluated by MTT assy. The expression of pro-apoptotic Bax and anti-apoptotic Bcl2 and caspase -3 protein expressions were measured by immunoblotting. The results showed that LPS could reduce cell viability after 72?h in a dose-dependent manner which was statistically significant in concentration of 200 µg/ml. In western blotting analysis, LPS (200 µg/ml) also enhanced expression of pro-apoptotic Bax and pro-caspase-3 proteins compared to controls, while the expression of Bcl-2 protein was not changed significantly. The Bax/Bcl-2 ratio was significantly increased in LPS-treated cells compared to controls. From the present results, it might be concluded that LPS can cause PC12 cell death, in which apoptosis plays an important role, possibly by the mitochondrial pathway through higher expression of the Bax as well as caspase 3 protein.     

SOD类似物阻断百草枯诱导的N27细胞凋亡的作用

目的探讨在离体培养的细胞中,SOD类似物[manganese(Ⅲ)meso-tetrakis(N,N′-diethylimidazolium-2-yl)porphyrin,MnTDM]阻断百草枯诱导的N27细胞凋亡的作用。方法以N27细胞为多巴胺能神经元的细胞模型,检测不同浓度的MnTDM对百草枯诱导的N27细胞凋亡的保护作用,四甲基偶氮唑盐(MTT)法检测细胞活性及代谢状态;电镜观察凋亡形态;免疫细胞化学染色法观察凋亡相关蛋白Bax、Bcl-2蛋白的表达。结果经百草枯作用后N27细胞活性下降,且其下降程度与百草枯浓度的升高呈线性关系,MnTDM明显阻断百草枯诱导的细胞活性下降(P<0.05),且该阻断作用与MnTDM的浓度成正相关;MnTDM预处理后,电镜观察到细胞凋亡形态好转,凋亡相关蛋白Bcl-2表达升高,Bax表达降低,Bcl-2/Bax值升高。结论MnTDM对百草枯介导的凋亡有一定的保护作用,提示其可能对帕金森病患者的临床防治有一定作用。     

薏苡仁脂调控凋亡相关蛋白Bax、Bcl-2及Survivin增强胰腺癌细胞对吉西他滨敏感性的研究

目的研究薏苡仁脂增强胰腺癌细胞系BXPC3对吉西他滨化疗敏感性的分子作用机制。方法 MTT法检测不同浓度薏苡仁脂与吉西他滨对BXPC3细胞系增殖活性的影响;Annexin V-FITC/PI双染料标记-流式细胞技术检测不同药物对BXPC3细胞系凋亡率;Western bolt技术检测不同药物处理对BXPC3细胞系Caspase-3、Bax、Bcl-2及Survivin蛋白表达影响。结果薏苡仁脂可明显降低吉西他滨杀伤BXPC3细胞的IC50,增强吉西他滨诱导细胞凋亡作用,逆转吉西他滨诱导的Bcl-2、Survivin蛋白表达上调,提高Bax/Bcl-2比值。结论薏苡仁脂可通过抑制抗凋亡蛋白Bcl-2、Survivin表达,增强促凋亡蛋白Bax表达,增强胰腺癌细胞BXPC3对吉西他滨的化疗敏感性。     

Solamargine induces apoptosis and sensitizes breast cancer cells to cisplatin.

Solamargine (SM), a major steroidal alkaloid glycoside, was purified from Solanum incanum plant. SM exhibited the most cytotoxic effect comparing with that of cisplatin (cDDP), methotrexate (MTX), 5-fluorouracil (5-FU), epirubicin (EPI) and cyclophosphamide (CP) against human breast cancer cells. In this study, SM induces apoptosis of the breast cancer cells and the mechanism was characterized. SM up-regulated the expressions of external death receptors, such as tumor necrosis factor receptor I (TNFR-I), Fas receptor (Fas), TNFR-I-associated death domain (TRADD), and Fas-associated death domain (FADD). SM also enhanced the intrinsic ratio of Bax to Bcl-2 by up-regulating Bax and down-regulating Bcl-2 and Bcl-xL expressions. These effects resulted in the release of mitochondrial cytochrome c and activation of caspase-8, -9 and -3 in the cells, indicating that SM triggered extrinsic and intrinsic apoptotic pathways of breast cancer cells. Similar to function way of SM, cDDP causes cancer cell apoptosis though caspase-8/caspase-3 and Bax/cytochrome c pathways, but the resistance to cDDP is correlated with Bcl-2 and Bcl-xL overexpression. However, the overexpression of Bcl-2 and Bcl-xL can be broken through by SM. The combined treatment of SM and cDDP significantly reduced Bcl-2 and Bcl-xL expressions, and enhanced Bax, cytochrome c, caspase-9 and -3 expressions in breast cancer cells. Thus, the combined use of SM and cDDP may be effective in cDDP-resistant breast cancer.     

右美托咪定通过lncRNA H19介导香烟提取物诱导的肺泡巨噬细胞效应研究

目的探索右美托咪定(Dexmedetomidine,DEX)通过长链非编码RNA(long noncoding RNA,lncRNA)H19对香烟烟雾提取物(cigarette smoke extract,CSE)诱导的RAW264.7巨噬细胞活力、凋亡和自噬的影响。方法制备CSE及CSE干预巨噬细胞模型,运用体外细胞培养,DEX以不同浓度(2、4和8μmol/L)作用于CSE诱导的巨噬细胞,采用MTT法检测细胞存活率,流式细胞术检测模型细胞的凋亡率,采用蛋白质印迹法(Western blot)检测细胞中凋亡相关蛋白Bax和Bcl-2及自噬相关蛋白LC3Ⅱ和ATG7表达情况,实时荧光定量PCR(qRT-PCR)检测H19表达水平;为了进一步验证DEX对CSE诱导的巨噬细胞增殖、凋亡和自噬影响,运用双酶切法构建pcDNA3.1-H19表达载体。结果一定剂量的DEX可明显拮抗CSE诱导的巨噬细胞活力下降作用(P<0.05),具有浓度依赖性;DEX抑制CSE诱导的巨噬细胞凋亡,且细胞中凋亡蛋白Bax明显下调(P<0.05),抗凋亡蛋白Bcl-2上调(P<0.05),自噬相关蛋白LC3Ⅱ和ATG7表达上调(P<0.05),H19表达下调(P<0.05);成功构建pcDNA3.1-H19表达载体,DEX作用于CSE诱导的巨噬细胞,细胞活力明显降低(P<0.05),且细胞中凋亡蛋白Bax上调(P<0.05),抗凋亡蛋白Bcl-2下调(P<0.05),自噬相关蛋白LC3Ⅱ和ATG7表达下调(P<0.05)。结论DEX抑制H19表达,增强CSE诱导的巨噬细胞活力,抑制细胞凋亡和自噬。     

美洲大蠊多肽提取物对SMMC-7721细胞凋亡及Bcl-2和Bax蛋白表达的影响

目的：研究美洲大蠊多肽提取物诱导人肝癌细胞SMMC-7721凋亡及其分子机制。方法：采用不同质量浓度的美洲大蠊多肽提取物作用于SMMC-7721,以Cell Counting Kit-8（CCK-8）法检测细胞抑制率;Hoechst33342/PI与Annexin V-FITC/PI双染法相结合检测SMMC-7721细胞的凋亡;蛋白免疫印迹（Western blotting）法检测细胞凋亡相关因子Bcl-2和Bax蛋白表达。结果：不同质量浓度的美洲大蠊多肽提取物可抑制SMMC-7721细胞的增殖,诱导其凋亡,呈一定的量效关系;Western Blot法显示Bax表达增多,Bcl-2蛋白表达减少,Bcl-2/Bax比值降低。结论：美洲大蠊多肽提取物可明显诱导SMMC-7721细胞凋亡,抑制其增殖,其机制可能与下调Bcl-2蛋白表达,上调Bax蛋白表达,降低Bcl-2/Bax比值有关。     

羟基红花黄素A拮抗IL-1β诱导软骨终板细胞凋亡的作用机制

目的探讨羟基红花黄素A(hydroxy safflower yellowA,HSYA)对IL-1β诱导小鼠软骨终板细胞凋亡的拮抗作用。方法用10μg.L-1的IL-1β诱导正常软骨终板细胞退变,分别制备不同浓度的HSYA培养基作为干预措施,采用流式细胞仪检测细胞凋亡,RT-PCR检测凋亡相关基因的表达水平。采用Western blot检测细胞内Bax、Bcl-2蛋白表达量,细胞免疫荧光分析各组Bax、Bcl-2细胞内定位。结果不同浓度的HSYA培养基均能拮抗IL-1β诱导的软骨细胞凋亡。流式细胞分析结果显示各浓度HSYA可以降低IL-1β诱导的小鼠椎间盘软骨终板细胞的凋亡比例;RT-PCR结果显示各浓度HSYA可拮抗IL-1β诱导细胞上调Bax基因表达,下调Bcl-2基因表达作用;细胞免疫荧光结果显示HSYA 10-5 mol.L-1给药组可下调Bax表达,上调Bcl-2表达;Western blot结果显示HSYA 10-5 mol.L-1和HSYA10-6 mol.L-1均可以拮抗IL-1β诱导细胞上调Bax蛋白表达,下调Bcl-2蛋白表达作用。结论羟基红花黄素A具有拮抗IL-1β诱导小鼠椎间盘软骨终板细胞凋亡的作用。     

儿茶素对人肝癌细胞HepG2的影响

目的研究儿茶素[(+)-catechin,Cat]不同时间、不同浓度对人肝癌细胞(HepG2)的增殖、迁移能力的抑制及诱导凋亡作用。方法 HepG2细胞分别与不同浓度Cat作用,MTT法检测细胞增殖率的变化,显微镜观察细胞形态学变化,划痕法检测细胞的迁移能力,流式细胞术检测细胞凋亡率,免疫组织化学染色法检测HepG2的Bcl-2、Bax和Caspase-3蛋白表达。结果 Cat(4~100mg·mL-1)能明显抑制人肝癌细胞HepG2的增殖和迁移能力,并呈浓度依赖性。流式细胞术检测结果显示Cat(4mg.L-1)作用于HepG2细胞24h即可诱导细胞凋亡。免疫组织化学结果显示Cat(4~20mg·mL-1)的Bax和Caspase-3的表达呈浓度依赖性升高,而Bcl-2的表达呈浓度依赖性降低。结论 Cat可以一定程度的抑制HepG2细胞的增殖和迁移能力并诱导其凋亡,其诱导凋亡机制可能与其下调HepG2细胞内Bcl-2蛋白的表达,上调Bax蛋白的表达,从而促进Caspase-3活化有关。     

Emodin induces apoptosis in human lung adenocarcinoma cells through a reactive oxygen species-dependent mitochondrial signaling pathway

Emodin, a natural anthraquinone derivative isolated from Rheum palmatum L., has been reported to exhibit anti-cancer effect on several human cancers such as liver cancers and lung cancers. However, the molecular mechanisms of emodin-mediated tumor regression have not been fully defined. In this study, we show that treatment with 50 μM emodin resulted in a pronounced release of cytochrome c, activation of caspase-2, -3, and -9, and apoptosis in human lung adenocarcinoma A549 cells. These events were accompanied by the inactivation of ERK and AKT, generation of reactive oxygen species (ROS), disruption of mitochondrial membrane potential (Δψ_m), decrease of mitochondrial Bcl-2, and increase of mitochondrial Bax content. Ectopic expression of Bcl-2, or treatment with aurintricarboxylic acid, furosemide or caspase inhibitors markedly blocked emodin-induced apoptosis. Conversely, pharmacologic ERK and AKT inhibition promoted emodin-induced apoptosis. Furthermore, the free radical scavenger ascorbic acid and N-acetylcysteine attenuated emodin-mediated ROS production, ERK and AKT inactivation, mitochondrial dysfunction, Bcl-2/Bax modulation, and apoptosis. Take together, these findings suggest that in A549 cells, emodin-mediated oxidative injury acts as an early and upstream change in the cell death cascade to antagonize cytoprotective ERK and AKT signaling, triggers mitochondrial dysfunction, Bcl-2 and Bax modulation, mitochondrial cytochrome c release, caspase activation, and consequent leading to apoptosis.     

迷迭香酸抗过氧化氢诱导血管平滑肌细胞凋亡作用的研究

目的探讨迷迭香酸对过氧化氢(H2O2)诱导血管平滑肌细胞凋亡的保护作用及其机制。方法流式细胞术检测细胞凋亡率;吖啶橙(acridine orange,AO)染色观察细胞形态学变化;MTT法检测细胞活性;Western blot检测细胞中Bcl-2、Bax、Fas和FasL蛋白的表达。结果经500μmol·L-1H2O2处理24h后,细胞凋亡率为34.9%±2.55%,出现核固缩、核碎裂等典型的凋亡形态学改变,所以随后实验选择500μmol·L-1H2O2为诱导血管平滑肌细胞凋亡的最佳浓度。①500μmol·L-1的H2O2处理血管平滑肌细胞24h能引起细胞活性明显降低;细胞凋亡率明显增加,达35.7%±1.33%;细胞中Bcl-2蛋白表达降低,Bax蛋白表达升高,Bcl-2/Bax蛋白比值减少,Fas和FasL蛋白表达升高。②用迷迭香酸(10、20、40μmol·L-1)预处理细胞30min,可以增加细胞活性;降低细胞凋亡率,呈浓度依赖性;细胞中Bcl-2/Bax蛋白比值升高,Fas和FasL蛋白表达降低。结论迷迭香酸能拮抗H2O2诱导血管平滑肌细胞凋亡;其作用机制可能与升高细胞中Bcl-2/Bax蛋白比值,减少Fas、FasL蛋白表达有关。     

Altered expression of p53, Bcl-2 and Bax induced by microcystin-LR in vivo and in vitro.

It has been reported that MC-LR could induce apoptosis in a variety of cell types. Although the induction of oxidative stress and mitochondrial alteration played critical role in MC-LR induced apoptosis, but the exact mechanisms of MC-LR induced apoptosis are still unknown. In spite of extensive studies on MC-LR mediated cell damages, there is little information on the protein expression of p53 and Bcl-2, Bax in vivo and in vitro, which are vital regulator of apoptosis in response to a variety of stimuli. The present study was undertaken to determine the expression level of p53 and Bcl-2, Bax in cultured hepatocytes and rat liver tissues. The results show that MC-LR can increase the expression of p53 and Bax significantly both in vivo and in vitro, however, MC-LR can only decrease the expression of Bcl-2 significantly in vitro and there is no difference observed in vivo. It can be concluded that the expression of p53, Bcl-2 and Bax are involved in the regulation of MC-LR induced apoptosis.     

Protective role of estrogen receptor-alpha on lower chlorinated PCB congener-induced DNA damage and repair in human tumoral breast cells

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants. Much of the research has focused on the carcinogenic potential of higher chlorinated PCBs, but accumulative evidence has shown that lower chlorinated PCB congeners have initiating and promoting activities. The goal of this study was to examine the potential of lower chlorinated PCBs, including 2,2′,5,5′-tetrachlorobiphenyl (PCB52) and 3,3′,4,4′-tetrachlorobiphenyl (PCB77), to induce DNA damage and apoptosis in human MDA-MB-231 (MDA) and MCF-7 breast cancer cells. Results confirmed that treatment of cells with PCB52 and PCB77 resulted in oxidative stress and caspase-dependent apoptosis in both MDA and MCF-7 cells. We noticed that at non-cytotoxic concentrations PCB52 and PCB77-induced decreases in intracellular NAD(P)H in MDA cells but not in MCF-7 cells. Further investigation confirmed that decreases in intracellular NAD(P)H in PCB-treated MDA cells are primarily due to reduction in intracellular NAD⁺ pool mediated by poly(ADP-ribose)polymerase-1 activation through formation of DNA strand breaks. Antagonism was observed between PCB52 and PCB77 for the effect on induction of DNA strand breaks in MDA cells. Overall, this evidence demonstrates that at non-cytotoxic concentrations, lower chlorinated PCB congeners are capable of inducing oxidative DNA lesions in ERα(−)/MDA cells but not in ERα(+)/MCF-7 cells and that functional ERα plays a protective role in modulating the PCB-induced DNA damage in human breast cancer cells.     

DIDS对Bcl-2/Bax在staurosporine诱导心肌细胞凋亡中表达的影响

目的探讨氯离子通道阻断剂DIDS(4,4′-diisothiocy-ano-2,2′-stilbene-disulfonic acid)对staurosporine(STS)诱导心肌细胞凋亡的调节蛋白Bcl-2/Bax表达的影响。方法在STS诱导心肌细胞凋亡模型上,观察DIDS对心肌细胞存活率、caspase-3活性、Bcl-2/Bax蛋白表达水平及Bax细胞内分布的影响。实验分组:对照组、STS组、DIDS组。结果与STS组比较,DIDS能够明显抑制STS诱导的心肌细胞凋亡发生,心肌细胞存活率增加,caspase-3活性水平降低(P<0.01)。对照组、STS组和DIDS组在全细胞水平上Bcl-2、Bax表达差异无显著性(P>0.01),在亚细胞水平上发现STS组有明显的Bax蛋白从胞质向线粒体转位,DIDS可以抑制STS诱导的Bax线粒体转位。结论DIDS抑制心肌细胞凋亡可能与抑制促凋亡分子Bax由胞质向线粒体转位有关。     

Alisol A 24-acetate protects oxygen–glucose deprivation-induced brain microvascular endothelial cells against apoptosis through miR-92a-3p inhibition by targeting the B-cell lymphoma-2 gene

ContextAlisol A 24-acetate has been used to treat vascular diseases. However, the underlying mechanisms still remain unclear.ObjectiveThe present study evaluated the antiapoptotic effect of alisol A 24-acetate on brain microvascular endothelial cells (BMECs) and explored the underlying mechanisms.Materials and methodsBMECs were injured through oxygen -glucose deprivation (OGD) after alisol A 24-acetate treatment. Cell viability and half-maximal inhibitory concentration (IC₅₀) were measured using CCK-8, whereas inflammatory factors and oxidative stress indicators were measured using enzyme linked immunosorbent assay. Cell invasion and wound healing assays were detected. Cell apoptosis was assessed using flow cytometry. B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X (Bax) expression were analyzed using Western blotting. Dual-luciferase assay was applied to detect target genes of miR-92a-3p.ResultAlisol A 24-acetate had an IC₅₀ of 98.53 mg/L and inhibited cell viability at concentrations over 50mg/L. OGD induced apoptosis and promoted miR-92a-3p overexpression in BMECs. However, alisol A 24-acetate treatment suppressed inflammation, improved migration and invasion abilities, increased Bcl-2 expression, inhibited Bax expression, and repressed apoptosis and miR92a-3p overexpression in OGD-induced BMECs. MiR-92a-3p overexpression promoted cell apoptosis and suppressed Bcl-2 expression, whereas its inhibitor reversed the tendency. Alisol A 24-acetate treatment relieved the effects of miR-92a-3p overexpression. Dual-luciferase assay confirmed that miR-92a-3p negatively regulated the Bcl-2 expression.ConclusionsThese findings suggest that alisol A 24-acetate exerts antiapoptotic effects on OGD-induced BMECs through miR-92a-3p inhibition by targeting the Bcl-2 gene, indicating its potential for BMECs protection and as a novel therapeutic agent for the treatment of cerebrovascular disease.