Acrylamide-induced mitochondria collapse and apoptosis in human astrocytoma cells

Acrylamide (ACR) can be produced during food processing and has neurotoxic effects in humans. This study aims to determine ACR induced apoptotic responses in human astrocytoma U-1240 MG cells to realize the incurred toxic mechanisms. Under 1 and 2 mM ACR exposure, cell viability decreased as time increased. The increments in sub-G₁ phase were 87.5-fold, and pro-caspase 3 and PARP protein expressions decreased 35% and 54.5% respectively relative to the control after 2 mM ACR treatment. Molecular evidence of Bax/bcl-2 ratio and cytochrome c expression increased 8.86-fold and 6.81-fold as well as pro-caspase 9 decreased 67.8% relative to the control respectively under 2 mM ACR exposure. Trolox, an ROS scavenging agent, attenuated cell death and induced ROS production by 2 mM ACR. The ultrastructure alterations of mitochondria showed marked vesicular matrix compartmentalization and cytoplasmic vacuole formation after 2 mM ACR was treated for 48 h, whereas those treated for 72 h showed chromatin condensation, pyknosis, and swelling. These results indicate long-term exposure to ACR induced mitochondria collapse and finally led to apoptosis. Although 2 mM ACR is higher than average daily intake dosage, workers in chemical industries may be exposed to sufficient doses to entail health risks.     

Acrylamide-induced astrogliotic and apoptotic responses in human astrocytoma cells

This study was to clarify whether acrylamide (ACR) will induce apoptosis and astrogliosis in an astrocytic cell line in vitro. Different time- and dose-dependent cytotoxic studies were conducted upon neuronal (SH-SY5Y) and glial cell lines (U-1240 MG) under exposure to ACR up to 72 h. We showed that SH-SY5Y cells were more sensitive in cytotoxic assays than U-1240 MG cells, and significantly decreased cell viability was observed at concentrations higher than 1 mM with increased lactate dehydrogenase leakage observed only at 5 and 10 mM in U-1240 MG cells. The ACR-induced apoptotic responses and phosphorylation of p53 protein at Ser15 for U-1240 MG cells were identified at 48 h. The increase of glial fibrillary acidic protein (GFAP) as a chemical-induced astrogliotic response was found to be associated with different ACR concentrations and exposure times, particularly at ≧48 h of ≧2 mM. In addition, immunocytochemical staining at 36 h of 5 and 10 mM treatments had significantly higher density of GFAP than the control. Thus, ACR-induced effects can be seen in neuronal and astrocytic cells. These results suggest that ACR exposure may lead to apoptotic and astrogliotic effects in human astrocytoma cells in vitro in a time- and dose-dependent manner.     

Dose dependent molecular effects of acrylamide and glycidamide in human cancer cell lines and human primary hepatocytes

Recently published studies suggest a weak positive correlation between increased dietary acrylamide intake and the increased risk of endometrial and ovarian cancer. However, risk assessment of acrylamide remains difficult because the carcinogenic mechanisms are still unknown and in particular the molecular effects of low level acrylamide exposure as seen by dietary intake are not well understood. Therefore, we analyzed in ovarian and endometrial cancer cell lines as well as in primary hepatocytes the expression of genes involved in cancer development and xenobiotic metabolism after high and low dose exposure (1–0.001 mM) of acrylamide and its metabolite glycidamide.     

Mitochondria are primary targets in apoptosis induced by the mixed phosphine gold species chlorotriphenylphosphine-1,3-bis(diphenylphosphino)propanegold(I) in melanoma cell lines

Based on previous evidence indicating a selective cytotoxic activity of the mixed phosphine gold complex chlorotriphenylphosphine-1,3-bis(diphenylphosphino)propanegold(I) for melanoma cells, we investigated the cellular bases of its antiproliferative effect in a panel of human melanoma cell lines (JR8, SK-Mel-5, Mel-501, 2/60, 2/21 and GRIG). The drug consistently induced a dose-dependent inhibition of cell growth, with IC50 values ranging from 0.8 to 2.3 microM and, when tested under the same experimental conditions, its cytotoxic activity was higher than (from 2- to 5-fold) or comparable to that of cisplatin as a function of cell lines. The ability of the gold complex to activate programmed cell death was assessed in JR8 and 2/60 cells, and a dose-dependent increase in cells with an apoptotic nuclear morphology was observed in both cell lines (up to 40 and 66% of the overall cell population, for JR8 and 2/60 cell lines, respectively). Such an apoptotic response was mediated by a dose-dependent loss of mitochondrial membrane potential, cytochrome c and Smac/DIABLO release from mitochondria into cytosol and enhanced caspase-9 and caspase-3 catalytic activity. A reduced or completely abrogated expression of the anti-apoptotic proteins c-IAP1, XIAP and survivin in drug-treated cells was also observed. Overall, results from the study indicate that chlorotriphenylphosphine-1,3-bis(diphenylphosphino)propanegold(I) markedly inhibits melanoma cell growth by inducing mitochondria-mediated apoptosis and suggest it as a good candidate for additional evaluation as an anticancer agent against melanoma.     

Oridonin induces human epidermoid carcinoma A431 cell apoptosis through tyrosine kinase and mitochondrial pathway

Oridonin, a diterpenoid isolated from the plant Rabdosia rubescens, induces human epidermoid carcinoma A431 cell death through apoptosis and tyrosine kinase pathway. To examine the pathway of oridonin-induced A431 cell death, morphologic observation, lactate dehydrogenase activity-based assay, DNA agarose gel electrophoresis and Western blot analysis were carried out. When A431 cells, which overexpress epidermal growth factor receptor (EGFR), were treated with oridonin, caspase-3 was activated followed by the degradation of caspase-3 substrates, inhibitor of caspase-activated DNase (ICAD) and poly(ADP-ribose) polymerase (PARP) in a time-dependent manner. Oridonin promoted the release of cytochrome c and the down-regulation of mitochondrial transmembrane potential (ΔΨm). Oridonin up-regulated the expression ratio of mitochondrial proteins, Bax/Bcl-2. In addition, the total tyrosine kinase activity of A431 cellular proteins and the expression of EGFR were markedly reduced after oridonin treatment. Taken together, oridonin induced apoptosis in A431 cells via mitochondrial pathway, activation of caspase-3 and inhibition of tyrosine kinase activities.     

Methamphetamine induces apoptosis in an immortalized rat striatal cell line by activating the mitochondrial cell death pathway

Methamphetamine is a neurotoxic drug of abuse known to cause cell death both in vitro and in vivo. Nevertheless, the molecular and cellular mechanisms involved in this process remain to be clarified. Herein, we show that methamphetamine-induced apoptosis is associated with early (2 h) overexpression of bax, decreases of mitochondrial membrane potential and oxygen consumption as well as release of cytochrome c from mitochondria. In addition, activated caspase-9 was detected at 4 h post-METH exposure. Cell death was detectable by annexin V and propidium iodide staining after 8 h of methamphetamine exposure. At that time, the majority of the cells were stained by annexin V alone, with some cells being stained for both annexin V and propidium iodide. Moreover, cleavage of caspase-3, poly (ADP-ribose) polymerase and DNA fragmentation-related factor 45 was detected at 8 h post drug treatment. These results indicate that methamphetamine-induced apoptotic cell death results from early overexpression of bax, reduction of mitochondrial respiration and membrane potential and release of mitochondrial cytochrome c with subsequent activation of the caspase cascade.     

Suppression of acrylamide toxicity by carboxyfullerene in human neuroblastoma cells in vitro

In our previous study, we found that caspase-dependent apoptosis played a role in the genesis of toxicity of acrylamide in human neuroblastoma (SH-SY5Y) cells (Sumizawa and Igisu in Arch Toxicol 81:279–282, 2007). In the present experiment, we examined whether carboxyfullerene may suppress the cytotoxicity of acrylamide because carboxyfullerene has been reported to protect nerve cells from various pathologic processes including apoptosis. Carboxyfullerene lowered lactate dehydrogense leakage and elevated cell viability in SH-SY5Y cells exposed to acrylamide. It also lowered caspase-3 activities and cell population in the sub-G₁ phase induced by acrylamide. Nevertheless, carboxyfullerene enhanced cellular uptake of [¹⁴C]acrylamide. On the other hand, acrylamide markedly decreased glutathione (GSH)-content in cells and carboxyfullerene blocked the decrease. The toxicity of acrylamide was suppressed by adding GSH or GSH monoethyl ester, whereas it was not lowered by carboxyfullerene when GSH synthesis was inhibited by l-buthionine-(S,R)-sulfoximine. Thus, the cytotoxicity of acrylamide including apoptotic processes is closely related to GSH level in SH-SY5Y cells and carboxyfullerene suppresses the toxicity by maintaining GSH content. Neither tricarboxylic acids without fullerene moiety nor hydroxylated fullerene showed comparable effects of carboxyfullerene (60 μM) against 1–5 mM acrylamide, suggesting the importance of the three malonic acid groups at specific positions in a fullerene molecule for the effects.     

Effect of miR-132 on bupivacaine-induced neurotoxicity in human neuroblastoma cell line

Background

Local anesthetics (LAs) may generate neurotoxicity in neurons. In the current study, we explored the mechanisms by which microRNA-132 (miR-132) regulated the neurotoxicity of human neuroblastoma cells (SH-SY5Y) induced by bupivacaine (BUP).

Toxic effects induced by curcumin in human astrocytoma cell lines

Abstract

Objective: The objective of this study was to describe the toxicity induced by curcumin in human astrocytoma cell lines.

Methods: The effects induced by curcumin, at 100?µM for 24?h, were evaluated in four astrocytoma cell lines using crystal violet assay and through the evaluation of morphological and ultrastructural changes by electron microscopy. Also, the results of vital staining with acridine orange and propidium iodide for acidic vesicles and apoptotic bodies were analyzed and the expression of the Beclin1 gene was assessed by RT-PCR.

Results: The cells treated with curcumin at 100?µM induced an inhibitory concentration₅₀ of viability with morphological changes characterized by a progressive increase in large, non-acidic vesicles devoid of cytoplasmic components and organelles, but that conserved the cell nuclei. No DNA breakage was observed. The astrocytoma cells showed no apoptosis, necrosis or autophagy. Expression of BECLIN1 was not induced (p?<?0.05) by curcumin in the astrocytoma cells.

Conclusions: Curcumin at 100?µm induced a new type of death cell in astrocytoma cell lines.     

顺铂诱导人宫颈鳞癌细胞Caski细胞凋亡的分子机制

目的研究顺铂对人宫颈癌Caski细胞体外增殖抑制作用及凋亡的影响,探究顺铂诱导宫颈鳞癌细胞凋亡的分子机制。方法运用体外细胞培养,顺铂以不同浓度（20、10、5、2、1μg/ml）作用于人宫颈癌Caski细胞。采用噻唑蓝（MTT）法测定顺铂对细胞杀伤率;用流式细胞检测法测定细胞周期时相改变及细胞凋亡率;琼脂糖电泳法观察凋亡细胞DNALadder现象;Western blot检测凋亡相关基因Bcl-2等表达;荧光染色观察细胞线粒体膜电位的改变。结果顺铂对人宫颈癌Caski细胞有较强的抑制作用,有明显的时间和剂量依赖性;可使Caski细胞G2/M期比例明显下降（P〈0.01）,S期比例升高（P〈0.01）;诱导细胞凋亡发生;顺铂作用Caski细胞后,Bcl-2表达量减少,Bax表达增加,Caspase3活化,线粒体膜电位改变。结论顺铂在体外可有效抑制人宫颈癌Caski细胞增殖,可能通过影响肿瘤细胞DNA合成,改变细胞周期时相分布、诱导凋亡发挥抑制细胞增殖作用,其凋亡分子机制与Bcl-2家族表达调控,线粒体膜跨膜电位下降的线粒体参与凋亡途径相关。     

青蒿琥酯对人肝癌HEPG-2细胞株凋亡、周期的体外作用

目的研究青蒿琥酯(Art)对肿瘤细胞凋亡、周期的影响。方法采用MTT法测定Art与5-FU联用对人肝癌细胞系HEPG-2的增殖抑制作用,流式细胞术检测细胞凋亡率和细胞周期分布。结果Art能明显抑制HEPG-2细胞的生长,并呈明显的时间-剂量效应。24、48、72 h的IC50分别为103.1±8.6、75.3±4.1、65.7±6.0μg.ml-1。当10、20μg.ml-1Art与2.5、5.0μg.ml-15-Fu联合使用时,表现出明显的协同作用,并可诱导细胞凋亡,影响细胞周期的分布。结论Art对人肝癌细胞系HEPG-2的增殖有显著抑制作用。与5-FU联合使用有协同作用,其机制可能是诱导细胞凋亡,阻滞细胞周期。     

Enhancement of cisplatin induced apoptosis by suberoylanilide hydroxamic acid in human oral squamous cell carcinoma cell lines

Both the resistance of tumor cells to cisplatin and dose-related toxicity remain two of the most important problems in the chemotherapy of clinical oral squamous cell carcinoma (OSCC). Researchers have been seeking a combinative treatment regimen to improve the effect of chemotherapy. As potent new anti-cancer drugs, histone deacetylase inhibitors (HDACI(S)) have been reported to be associated with chromatin modification and display synergistic activities with some traditional chemotherapeutic agents. In this study, we evaluated the potential combinative effect of low dose cisplatin and suberoylanilide hydroxamic acid (SAHA, one of the most potent HDACI(S)) in OSCC cell lines. Cell viability and apoptotic assay were examined. Compared with either cisplatin (4 microg/ml) or SAHA (2 microM) treated alone, co-administration of both drugs synergistically induces cytotoxicity and apoptosis in both Tca8113 and KB cell lines. Furthermore, diverse apoptosis-associated proteins, including p53, BID, cytochrome C and caspase-3 were involved in the induction of apoptosis. Our results suggest that concurrent treatment with SAHA enhances tumor cell sensitivity to subtoxic doses of cisplatin. This may be regarded as a novel strategy for treatment of OSCC.     

Adenosine and purine nucleosides prevent the disruption of mitochondrial transmembrane potential by peroxynitrite in rat primary astrocytes

Previously, we have shown that astrocytes deprived of glucose became highly vulnerable to peroxynitrite, and adenosine and its metabolites attenuated the gliotoxicity via the preservation of cellular ATP level. Here, we found that adenosine and related metabolites prevented the disruption of mitochondrial transmembrane potential (MTP) in glucose-deprived rat primary astrocytes exposed to 3-morpholinosydnonimine (SIN-1), a peroxynitrite releasing agent. Exposure to glucose deprivation and SIN-1 (2 h) significantly disrupted MTP in astrocytes, and adenosine prevented it in dose-dependent manner with an EC50 of 5.08 microM. Adenosine also partially prevented the cell death by myxothiazol, a well-known inhibitor of mitochondrial respiration. Blockade of adenosine deamination or intracellular transport with erythro-9-(-hydroxy-3-nonyl)adenosine (EHNA) or S-(4-nitrobenzyl)-6-thioinosine (NBTI), respectively, completely reversed the protective effect of adenosine. Other purine nucleos(t)ides including inosine, guanosine, ATP, ADP, AMP, ITP, and GTP also showed similar protective effects. This study indicates that adenosine and related purine nucleos(t)ides may protect astrocytes from peroxynitrite-induced mitochondrial dysfunction.     

Cadmium-induced apoptosis of hepatocytes is not associated with death receptor-related caspase-dependent pathways in the rat

Cadmium (Cd) is a heavy metal of considerable environmental and occupational concern. The liver is the major target organ of Cd toxicity that follows from repeated exposure to Cd. The aim of this study was to investigate the mechanism of cell death of Cd-induced hepatotoxicity in a rat model. Eighteen adult male Sprague–Dawley (SD) rats were injected daily with a dose of Cd acetate (30 μM/kg body weight, subcutaneously). After 1, 2 and 7 days rats were euthanized and blood and liver tissues were sampled for analysis. Biochemical analyses of the level of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were undertaken. Histopathological and Western blot analyses for liver cellular damage and cell death were also performed. The results for the Cd-treated group of animals were compared to those from 12 control rats. The serum AST/ALT levels increased significantly 24 h after CD exposure. From the Western blot analyses, activation of Bid, independent of caspase-8 was seen and Bax induced the release of cytochrome c into the cytosol from mitochondria in a dose-dependent manner. The level of Bcl-2 was decreased. Eventually, caspase-9 and caspase-3 were activated, and poly(ADP-ribose) polymerase (PARP) was cleaved in a dose-dependent manner. A histopathological analysis and DNA fragmentation test showed apoptotic cell death of the hepatocytes increased over time. These results suggest that Cd-induced liver cell apoptosis in the rat, over a period of 7 days, may not be related to the death-receptor pathway. Moreover, apoptosis is dose-dependent and associated with the decrement of Bcl-2.     

Reactive oxygen species accumulation contributes to gambogic acid-induced apoptosis in human hepatoma SMMC-7721 cells

It is reported that gambogic acid (GA), the main active compound of gamboge which is a dry resin extracted from Garcinia hanburyi tree, has potent antitumor activity both in vivo and in vitro. Activation of mitochondrial apoptotic pathway in cancer cells is one effective therapy for cancer treatment. In the present study, we focus on the effect of GA on induction of reactive oxygen species (ROS) accumulation and triggering the mitochondrial signaling pathway in human hepatoma SMMC-7721 cells. The results indicated that GA induced ROS accumulation and collapse of mitochondrial membrane potential in SMMC-7721 cells in a concentration-dependent manner and subsequently induced that release of Cytochrome c and apoptosis-inducing factor from mitochondria to cytosol, which inhibited ATP generation and induced apoptosis in the cells. Moreover, GA elevated the phosphorylation of c-Jun-N-terminal protein kinase (JNK) and p38, which was the downstream effect of ROS accumulation. Furthermore, N-acetylcysteine, a ROS production inhibitor, partly reversed the activation of JNK and p38 and the induction of apoptosis in GA-treated cells. Collectively, our study demonstrated that accumulation of ROS played an important role in GA-induced mitochondrial signaling pathway, which provided further theoretical support for the application of GA as a promising anticancer agent.     

奥沙利铂诱导人白血病细胞株凋亡的研究

目的：研究第三代铂类化合物奥沙利铂对人早幼粒细胞白血病细胞株(HL—60)的影响。方法：采用MTT法检测奥沙利铂对HL—60细胞作用的时间效应和剂量效应；流式细胞仪检测细胞的DNA含量，分析细胞周期的改变；光镜和电镜观察奥沙利铂作用后细胞形态变化。结果：随着作用时间及药物浓度的增加，奥沙利铂对HL-60细胞增殖的抑制作用就越明显。0．032mmol/L奥沙利铂作用72小时，细胞生长抑制率86．5％，流式细胞仪检测HL-60细胞Q／M期细胞增多，形态学显示细胞凋亡。结论：奥沙利铂有明显抑制恶性白血病细胞生长和促进细胞凋亡的作用。     

Doxorubicin can penetrate nitrile gloves and induces apoptosis in keratinocytes cell lines

Doxorubicin (DOXO) is an anthracycline antibiotic which is used in the treatment of human malignancies such as leukemia, lymphoma and a number of solid tumors, particularly breast cancer.     

大蒜油联合顺铂诱导人腺样囊性癌细胞株ACC-M凋亡

目的探讨大蒜油联合顺铂对人腺样囊性癌细胞株ACC—M细胞增殖、细胞周期及凋亡的影响。方法采用不同浓度大蒜油、顺铂、大蒜油联合顺铂分别处理人腺样囊性癌细胞株ACC—M细胞24、48、72h后,MTT法检测肿瘤细胞体外增殖抑制情况;选取2、8、32μg/mL的大蒜油、顺铂、大蒜油联合顺铂处理肿瘤细胞4、8h后,流式细胞术分析肿瘤细胞周期分布和凋亡率。结果8、16、32μg／mL大蒜油及2、4、8、16、32μg／mL顺铂、大蒜油联合顺铂作用24、韶、72h对ACC-M细胞均有明显抑制作用,随浓度及时间增加,抑制率呈上升趋势。联合组用药肿瘤细胞抑制率明显高于单一用药组。流式细胞术结果显示,不同浓度的大蒜油、顺铂、大蒜油联合顺铂作用能使ACC．M细胞发生G2/M期阻滞,诱导细胞凋亡,随浓度增高及作用时间延长,周期分布越明显,凋亡率增高,联合组用药细胞周期阻滞和促凋亡作用明显强于单一用药组,差异有统计学意义（P〈0．05）。结论不同浓度的大蒜油、顺铂、大蒜油联合顺铂均能有效抑制ACC-M细胞生长．阻滞细胞于G2／M期并诱导肿瘤细胞凋亡,大蒜油联合顺铂对ACC—M细胞生长抑制作用明显强于大蒜油、顺铂单独应用。     

Oxidative stress is involved in Dasatinib-induced apoptosis in rat primary hepatocytes

Dasatinib, a multitargeted inhibitor of BCR-ABL and SRC kinases, exhibits antitumor activity and extends the survival of patients with chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL). However, some patients suffer from hepatotoxicity, which occurs through an unknown mechanism. In the present study, we found that Dasatinib could induce hepatotoxicity both in vitro and in vivo. Dasatinib reduced the cell viability of rat primary hepatocytes, induced the release of alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) in vitro, and triggered the ballooning degeneration of hepatocytes in Sprague-Dawley rats in vivo. Apoptotic markers (chromatin condensation, cleaved caspase-3 and cleaved PARP) were detected to indicate that the injury induced by Dasatinib in hepatocytes in vitro was mediated by apoptosis. This result was further validated in vivo using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays. Here we found that Dasatinib dramatically increased the level of reactive oxygen species (ROS) in hepatocytes, reduced the intracellular glutathione (GSH) content, attenuated the activity of superoxide dismutase (SOD), generated malondialdehyde (MDA), a product of lipid peroxidation, decreased the mitochondrial membrane potential, and activated nuclear factor erythroid 2-related factor 2 (Nrf2) and mitogen-activated protein kinases (MAPK) related to oxidative stress and survival. These results confirm that oxidative stress plays a pivotal role in Dasatinib-mediated hepatotoxicity. N-acetylcysteine (NAC), a typical antioxidant, can scavenge free radicals, attenuate oxidative stress, and protect hepatocytes against Dasatinib-induced injury. Thus, relieving oxidative stress is a viable strategy for reducing Dasatinib-induced hepatotoxicity.