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Sample records for autophagic cell death

  1. Methods for assessing autophagy and autophagic cell death.

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    Tasdemir, Ezgi; Galluzzi, Lorenzo; Maiuri, M Chiara; Criollo, Alfredo; Vitale, Ilio; Hangen, Emilie; Modjtahedi, Nazanine; Kroemer, Guido

    2008-01-01

    Autophagic (or type 2) cell death is characterized by the massive accumulation of autophagic vacuoles (autophagosomes) in the cytoplasm of cells that lack signs of apoptosis (type 1 cell death). Here we detail and critically assess a series of methods to promote and inhibit autophagy via pharmacological and genetic manipulations. We also review the techniques currently available to detect autophagy, including transmission electron microscopy, half-life assessments of long-lived proteins, detection of LC3 maturation/aggregation, fluorescence microscopy, and colocalization of mitochondrion- or endoplasmic reticulum-specific markers with lysosomal proteins. Massive autophagic vacuolization may cause cellular stress and represent a frustrated attempt of adaptation. In this case, cell death occurs with (or in spite of) autophagy. When cell death occurs through autophagy, on the contrary, the inhibition of the autophagic process should prevent cellular demise. Accordingly, we describe a strategy for discriminating cell death with autophagy from cell death through autophagy.

  2. Bortezomib induces autophagic death in proliferating human endothelial cells

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    Belloni, Daniela; Veschini, Lorenzo [Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan (Italy); Foglieni, Chiara [Department of Cardiology, IRCCS H San Raffaele, Milan (Italy); Dell' Antonio, Giacomo [Department of Pathology, IRCCS H San Raffaele, Milan (Italy); Caligaris-Cappio, Federico [Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan (Italy); Universita Vita-Salute IRCCS H San Raffaele, Milan (Italy); Ferrarini, Marina [Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan (Italy); Ferrero, Elisabetta, E-mail: elisabetta.ferrero@hsr.it [Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan (Italy)

    2010-04-01

    The proteasome inhibitor Bortezomib has been approved for the treatment of relapsed/refractory multiple myeloma (MM), thanks to its ability to induce MM cell apoptosis. Moreover, Bortezomib has antiangiogenic properties. We report that endothelial cells (EC) exposed to Bortezomib undergo death to an extent that depends strictly on their activation state. Indeed, while quiescent EC are resistant to Bortezomib, the drug results maximally toxic in EC switched toward angiogenesis with FGF, and exerts a moderate effect on subconfluent HUVEC. Moreover, EC activation state deeply influences the death pathway elicited by Bortezomib: after treatment, angiogenesis-triggered EC display typical features of apoptosis. Conversely, death of subconfluent EC is preceded by ROS generation and signs typical of autophagy, including intense cytoplasmic vacuolization with evidence of autophagosomes at electron microscopy, and conversion of the cytosolic MAP LC3 I form toward the autophagosome-associated LC3 II form. Treatment with the specific autophagy inhibitor 3-MA prevents both LC3 I/LC3 II conversion and HUVEC cell death. Finally, early removal of Bortezomib is accompanied by the recovery of cell shape and viability. These findings strongly suggest that Bortezomib induces either apoptosis or autophagy in EC; interfering with the autophagic response may potentiate the antiangiogenic effect of the drug.

  3. Autophagy prevents autophagic cell death in Tetrahymena in response to oxidative stress.

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    Zhang, Si-Wei; Feng, Jiang-Nan; Cao, Yi; Meng, Li-Ping; Wang, Shu-Lin

    2015-05-18

    Autophagy is a major cellular pathway used to degrade long-lived proteins or organelles that may be damaged due to increased reactive oxygen species (ROS) generated by cellular stress. Autophagy typically enhances cell survival, but it may also act to promote cell death under certain conditions. The mechanism underlying this paradox, however, remains unclear. We showed that Tetrahymena cells exerted increased membrane-bound vacuoles characteristic of autophagy followed by autophagic cell death (referred to as cell death with autophagy) after exposure to hydrogen peroxide. Inhibition of autophagy by chloroquine or 3-methyladenine significantly augmented autophagic cell death induced by hydrogen peroxide. Blockage of the mitochondrial electron transport chain or starvation triggered activation of autophagy followed by cell death by inducing the production of ROS due to the loss of mitochondrial membrane potential. This indicated a regulatory role of mitochondrial ROS in programming autophagy and autophagic cell death in Tetrahymena. Importantly, suppression of autophagy enhanced autophagic cell death in Tetrahymena in response to elevated ROS production from starvation, and this was reversed by antioxidants. Therefore, our results suggest that autophagy was activated upon oxidative stress to prevent the initiation of autophagic cell death in Tetrahymena until the accumulation of ROS passed the point of no return, leading to delayed cell death in Tetrahymena.

  4. The natural product peiminine represses colorectal carcinoma tumor growth by inducing autophagic cell death

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    Lyu, Qing [School of Life Sciences, Tsinghua University, Beijing, 100084 (China); Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055 (China); Tou, Fangfang [Jiangxi Provincial Key Lab of Oncology Translation Medicine, Jiangxi Cancer Hospital, Nanchang, 330029 (China); Su, Hong; Wu, Xiaoyong [First Affiliated Hospital, Guiyang College of Traditional Chinese Medicine, Guiyang, 550002 (China); Chen, Xinyi [Department of Hematology and Oncology, Beijing University of Chinese Medicine, Beijing, 100029 (China); Zheng, Zhi, E-mail: zheng_sheva@hotmail.com [Jiangxi Provincial Key Lab of Oncology Translation Medicine, Jiangxi Cancer Hospital, Nanchang, 330029 (China)

    2015-06-19

    Autophagy is evolutionarily conservative in eukaryotic cells that engulf cellular long-lived proteins and organelles, and it degrades the contents through fusion with lysosomes, via which the cell acquires recycled building blocks for the synthesis of new molecules. In this study, we revealed that peiminine induces cell death and enhances autophagic flux in colorectal carcinoma HCT-116 cells. We determined that peiminine enhances the autophagic flux by repressing the phosphorylation of mTOR through inhibiting upstream signals. Knocking down ATG5 greatly reduced the peiminine-induced cell death in wild-type HCT-116 cells, while treating Bax/Bak-deficient cells with peiminine resulted in significant cell death. In summary, our discoveries demonstrated that peiminine represses colorectal carcinoma cell proliferation and cell growth by inducing autophagic cell death. - Highlights: • Peiminine induces autophagy and upregulates autophagic flux. • Peiminine represses colorectal carcinoma tumor growth. • Peiminine induces autophagic cell death. • Peiminine represses mTOR phosphorylation by influencing PI3K/Akt and AMPK pathway.

  5. Apigenin induces autophagic cell death in human papillary thyroid carcinoma BCPAP cells.

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    Zhang, Li; Cheng, Xian; Gao, Yanyan; Zheng, Jie; Xu, Qiang; Sun, Yang; Guan, Haixia; Yu, Huixin; Sun, Zhen

    2015-11-01

    Apigenin, abundantly present in fruits and vegetables, is recognized as a flavonoid with anti-inflammatory, antioxidant and anticancer properties. In this study, we first investigated the anti-neoplastic effects of apigenin on papillary thyroid carcinoma (PTC) cell line BCPAP cells. Our results show that apigenin inhibited the viability of BCPAP cells in a dose-dependent manner. A large body of evidence demonstrates that autophagy contributes to cell death in certain contexts. In the present study, autophagy was induced by apigenin treatment in BCPAP cells, as evidenced by Beclin-1 accumulation, conversion of LC3 protein, p62 degradation as well as the significantly increased formation of acidic vesicular organelles (AVOs) compared to the control group. 3-MA, an autophagy inhibitor, rescued the cells from apigenin-induced cell death. Notably, apigenin enhanced production of reactive oxygen species (ROS), and subsequent induction of significant DNA damage as monitored by the TUNEL assay. In addition, apigenin treatment caused a significant accumulation of cells in the G2/M phase via down-regulation of Cdc25C expression. Our findings reveal that apigenin inhibits papillary thyroid cancer cell viability by the stimulation of reactive oxygen species (ROS) production, induction of DNA damage, leading to G2/M cell cycle arrest followed by autophagic cell death. Thus, our results provide new insights into the molecular mechanisms underlying apigenin-mediated autophagic cell death and suggest apigenin as a potential chemotherapeutic agent which is able to fight against papillary thyroid cancer.

  6. Autophagic components contribute to hypersensitive cell death in Arabidopsis

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    Hofius, Daniel; Schultz-Larsen, Torsten; Joensen, Jan;

    2009-01-01

    Autophagy has been implicated as a prosurvival mechanism to restrict programmed cell death (PCD) associated with the pathogen-triggered hypersensitive response (HR) during plant innate immunity. This model is based on the observation that HR lesions spread in plants with reduced autophagy gene ex...... contributes to HR PCD and can function in parallel with other prodeath pathways....

  7. Isogambogenic acid induces apoptosis-independent autophagic cell death in human non-small-cell lung carcinoma cells.

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    Yang, Jianhong; Zhou, Yongzhao; Cheng, Xia; Fan, Yi; He, Shichao; Li, Shucai; Ye, Haoyu; Xie, Caifeng; Wu, Wenshuang; Li, Chunyan; Pei, Heying; Li, Luyuan; Wei, Zhe; Peng, Aihua; Wei, Yuquan; Li, Weimin; Chen, Lijuan

    2015-01-09

    To overcome drug resistance caused by apoptosis deficiency in patients with non-small cell lung carcinoma (NSCLC), there is a need to identify other means of triggering apoptosis-independent cancer cell death. We are the first to report that isogambogenic acid (iso-GNA) can induce apoptosis-independent autophagic cell death in human NSCLC cells. Several features of the iso-GNA-treated NSCLC cells indicated that iso-GNA induced autophagic cell death. First, there was no evidence of apoptosis or cleaved caspase 3 accumulation and activation. Second, iso-GNA treatment induced the formation of autophagic vacuoles, increased LC3 conversion, caused the appearance of autophagosomes and increased the expression of autophagy-related proteins. These findings provide evidence that iso-GNA induces autophagy in NSCLC cells. Third, iso-GNA-induced cell death was inhibited by autophagic inhibitors or by selective ablation of Atg7 and Beclin 1 genes. Furthermore, the mTOR inhibitor rapamycin increased iso-GNA-induced cell death by enhancing autophagy. Finally, a xenograft model provided additional evidence that iso-GNA exhibited anticancer effect through inducing autophagy-dependent cell death in NSCLC cells. Taken together, our results demonstrated that iso-GNA exhibited an anticancer effect by inducing autophagy-dependent cell death in NSCLC cells, which may be an effective chemotherapeutic agent that can be used against NSCLC in a clinical setting.

  8. The tricyclic antidepressant imipramine induces autophagic cell death in U-87MG glioma cells.

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    Jeon, Seung-Hyun; Kim, Se Hyun; Kim, Yeni; Kim, Yong Sik; Lim, Yoongho; Lee, Young Han; Shin, Soon Young

    2011-09-23

    In this study, we investigated the antitumor effects of the tricyclic antidepressant 3-(10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)-N,N-dimethylpropan-1-amine (imipramine) on glioma cells. We found that exposure of U-87MG cells to imipramine resulted in the inhibition of PI3K/Akt/mTOR signaling, reduction of clonogenicity, and induction of cell death. Imipramine stimulated the formation of acidic vesicular organelles, the conversion of LC3-I to LC3-II, and the redistribution of LC3 to autophagosomes, suggesting that it stimulates the progression of autophagy. It did not, however, induce apoptosis. We further showed that knockdown of Beclin-1 using siRNA abrogated imipramine-induced cell death. These results suggest that imipramine exerts antitumor effects on PTEN-null U-87MG human glioma cells by inhibiting PI3K/Akt/mTOR signaling and by inducing autophagic cell death.

  9. Conessine Interferes with Oxidative Stress-Induced C2C12 Myoblast Cell Death through Inhibition of Autophagic Flux.

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    Hyunju Kim

    Full Text Available Conessine, a steroidal alkaloid isolated from Holarrhena floribunda, has anti-malarial activity and interacts with the histamine H3 receptor. However, the cellular effects of conessine are poorly understood. Accordingly, we evaluated the involvement of conessine in the regulation of autophagy. We searched natural compounds that modulate autophagy, and conessine was identified as an inhibitor of autophagic flux. Conessine treatment induced the formation of autophagosomes, and p62, an autophagic adapter, accumulated in the autophagosomes. Reactive oxygen species such as hydrogen peroxide (H2O2 result in muscle cell death by inducing excessive autophagic flux. Treatment with conessine inhibited H2O2-induced autophagic flux in C2C12 myoblast cells and also interfered with cell death. Our results indicate that conessine has the potential effect to inhibit muscle cell death by interfering with autophagic flux.

  10. Conessine Interferes with Oxidative Stress-Induced C2C12 Myoblast Cell Death through Inhibition of Autophagic Flux

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    Kim, Hyunju; Lee, Kang Il; Jang, Minsu; Namkoong, Sim; Park, Rackhyun; Ju, Hyunwoo; Choi, Inho; Oh, Won Keun

    2016-01-01

    Conessine, a steroidal alkaloid isolated from Holarrhena floribunda, has anti-malarial activity and interacts with the histamine H3 receptor. However, the cellular effects of conessine are poorly understood. Accordingly, we evaluated the involvement of conessine in the regulation of autophagy. We searched natural compounds that modulate autophagy, and conessine was identified as an inhibitor of autophagic flux. Conessine treatment induced the formation of autophagosomes, and p62, an autophagic adapter, accumulated in the autophagosomes. Reactive oxygen species such as hydrogen peroxide (H2O2) result in muscle cell death by inducing excessive autophagic flux. Treatment with conessine inhibited H2O2-induced autophagic flux in C2C12 myoblast cells and also interfered with cell death. Our results indicate that conessine has the potential effect to inhibit muscle cell death by interfering with autophagic flux. PMID:27257813

  11. Cyclic Mechanical Stretching Induces Autophagic Cell Death in Tenofibroblasts Through Activation of Prostaglandin E2 Production

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    Hua Chen

    2015-04-01

    Full Text Available Background/Aims: Autophagic cell death has recently been implicated in the pathophysiology of tendinopathy. Prostaglandin E2 (PGE2, a known inflammatory mediator of tendinitis, inhibits tenofibroblast proliferation in vitro; however, the underlying mechanism is unclear. The present study investigated the relationship between PGE2 production and autophagic cell death in mechanically loaded human patellar tendon fibroblasts (HPTFs in vitro. Methods: Cultured HPTFs were subjected to exogenous PGE2 treatment or repetitive cyclic mechanical stretching. Cell death was determined by flow cytometry with acridine orange/ethidium bromide staining. Induction of autophagy was assessed by autophagy markers including the formation of autophagosomes and autolysosomes (by electron microscopy, AO staining, and formation of GPF-LC3-labeled vacuoles and the expression of LC3-II and BECN1 (by western blot. Stretching-induced PGE2 release was determined by ELISA. Results: Exogenous PGE2 significantly induced cell death and autophagy in HPTFs in a dose-dependent manner. Blocking autophagy using inhibitors 3-methyladenine and chloroquine, or small interfering RNAs against autophagy genes Becn-1 and Atg-5 prevented PGE2-induced cell death. Cyclic mechanical stretching at 8% and 12% magnitudes for 24 h significantly stimulated PGE2 release by HPTFs in a magnitude-dependent manner. In addition, mechanical stretching induced autophagy and cell death. Blocking PGE2 production using COX inhibitors indomethacin and celecoxib significantly reduced stretching-induced autophagy and cell death. Conclusion: Taken together, cyclic mechanical stretching induces autophagic cell death in tenofibroblasts through activation of PGE2 production.

  12. Features of autophagic cell death in Plasmodium liver-stage parasites.

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    Eickel, Nina; Kaiser, Gesine; Prado, Monica; Burda, Paul-Christian; Roelli, Matthias; Stanway, Rebecca R; Heussler, Volker T

    2013-04-01

    Analyzing molecular determinants of Plasmodium parasite cell death is a promising approach for exploring new avenues in the fight against malaria. Three major forms of cell death (apoptosis, necrosis and autophagic cell death) have been described in multicellular organisms but which cell death processes exist in protozoa is still a matter of debate. Here we suggest that all three types of cell death occur in Plasmodium liver-stage parasites. Whereas typical molecular markers for apoptosis and necrosis have not been found in the genome of Plasmodium parasites, we identified genes coding for putative autophagy-marker proteins and thus concentrated on autophagic cell death. We characterized the Plasmodium berghei homolog of the prominent autophagy marker protein Atg8/LC3 and found that it localized to the apicoplast. A relocalization of PbAtg8 to autophagosome-like vesicles or vacuoles that appear in dying parasites was not, however, observed. This strongly suggests that the function of this protein in liver-stage parasites is restricted to apicoplast biology.

  13. 5-ALA mediated photodynamic therapy induces autophagic cell death via AMP-activated protein kinase

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    Lin Yu-Hsin

    2010-04-01

    Full Text Available Abstract Photodynamic therapy (PDT has been developed as an anticancer treatment, which is based on the tumor-specific accumulation of a photosensitizer that induces cell death after irradiation of light with a specific wavelength. Depending on the subcellular localization of the photosensitizer, PDT could trigger various signal transduction cascades and induce cell death such as apoptosis, autophagy, and necrosis. In this study, we report that both AMP-activated protein kinase (AMPK and mitogen-activated protein kinase (MAPK signaling cascades are activated following 5-aminolevulinic acid (ALA-mediated PDT in both PC12 and CL1-0 cells. Although the activities of caspase-9 and -3 are elevated, the caspase inhibitor zVAD-fmk did not protect cells against ALA-PDT-induced cell death. Instead, autophagic cell death was found in PC12 and CL1-0 cells treated with ALA-PDT. Most importantly, we report here for the first time that it is the activation of AMPK, but not MAPKs that plays a crucial role in mediating autophagic cell death induced by ALA-PDT. This novel observation indicates that the AMPK pathway play an important role in ALA-PDT-induced autophagy.

  14. MP Resulting in Autophagic Cell Death of Microglia through Zinc Changes against Spinal Cord Injury

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    Dingding Li

    2016-01-01

    Full Text Available Methylprednisolone pulse therapy (MPPT, as a public recognized therapy of spinal cord injury (SCI, is doubted recently, and the exact mechanism of MP on SCI is unclear. This study sought to investigate the exact effect of MP on SCI. We examined the effect of MP in a model of SCI in vivo and an LPS induced model in vitro. We found that administration of MP produced an increase in the Basso, Beattie, and Bresnahan scores and motor neurons counts of injured rats. Besides the number of activated microglia was apparently reduced by MP in vivo, and Beclin-1 dependent autophagic cell death of microglia was induced by MP in LPS induced model. At the same time, MP increases cellular zinc concentration and level of ZIP8, and TPEN could revert effect of MP on autophagic cell death of microglia. Finally, we have found that MP could inhibit NF-κβ in LPS induced model. These results show that the MP could result in autophagic cell death of microglia, which mainly depends on increasing cellular labile zinc, and may be associated with inhibition of NF-κβ, and that MP can produce neuroprotective effect in SCI.

  15. Clozapine Induces Autophagic Cell Death in Non-Small Cell Lung Cancer Cells

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    Yu-Chun Yin

    2015-02-01

    Full Text Available Background/Aims: Previous studies have shown that patients with schizophrenia have a lower incidence of cancer than the general population, and several antipsychotics have been demonstrated to have cytotoxic effects on cancer cells. However, the mechanisms underlying these results remain unclear. The present study aimed to investigate the effect of clozapine, which is often used to treat patients with refractory schizophrenia, on the growth of non-small cell lung carcinoma cell lines and to examine whether autophagy contributes to its effects. Methods: A549 and H1299 cells were treated with clozapine, and cell cytotoxicity, cell cycle and autophagy were then assessed. The autophagy inhibitor bafilomycin A1 and siRNA-targeted Atg7 were used to determine the role of autophagy in the effect of clozapine. Results: Clozapine inhibited A549 and H1299 proliferation and increased p21 and p27 expression levels, leading to cell cycle arrest. Clozapine also induced a high level of autophagy, but not apoptosis, in both cell lines, and the growth inhibitory effect of clozapine was blunted by treatment with the autophagy inhibitor bafilomycin A1 or with an siRNA targeting atg7. Conclusions: Clozapine inhibits cell proliferation by inducing autophagic cell death in two non-small cell lung carcinoma cell lines. These findings may provide insights into the relationship between clozapine use and the lower incidence of lung cancer among patients with schizophrenia.

  16. HAMLET (human alpha-lactalbumin made lethal to tumor cells) triggers autophagic tumor cell death.

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    Aits, Sonja; Gustafsson, Lotta; Hallgren, Oskar; Brest, Patrick; Gustafsson, Mattias; Trulsson, Maria; Mossberg, Ann-Kristin; Simon, Hans-Uwe; Mograbi, Baharia; Svanborg, Catharina

    2009-03-01

    HAMLET, a complex of partially unfolded alpha-lactalbumin and oleic acid, kills a wide range of tumor cells. Here we propose that HAMLET causes macroautophagy in tumor cells and that this contributes to their death. Cell death was accompanied by mitochondrial damage and a reduction in the level of active mTOR and HAMLET triggered extensive cytoplasmic vacuolization and the formation of double-membrane-enclosed vesicles typical of macroautophagy. In addition, HAMLET caused a change from uniform (LC3-I) to granular (LC3-II) staining in LC3-GFP-transfected cells reflecting LC3 translocation during macroautophagy, and this was blocked by the macroautophagy inhibitor 3-methyladenine. HAMLET also caused accumulation of LC3-II detected by Western blot when lysosomal degradation was inhibited suggesting that HAMLET caused an increase in autophagic flux. To determine if macroautophagy contributed to cell death, we used RNA interference against Beclin-1 and Atg5. Suppression of Beclin-1 and Atg5 improved the survival of HAMLET-treated tumor cells and inhibited the increase in granular LC3-GFP staining. The results show that HAMLET triggers macroautophagy in tumor cells and suggest that macroautophagy contributes to HAMLET-induced tumor cell death.

  17. BH3 Mimetics Reactivate Autophagic Cell Death in Anoxia-Resistant Malignant Glioma Cells

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    Holger Hetschko

    2008-08-01

    Full Text Available Here, we investigated the specific roles of Bcl-2 family members in anoxia tolerance of malignant glioma. Flow cytometry analysis of cell death in 17 glioma cell lines revealed drastic differences in their sensitivity to oxygen withdrawal (<0.1% O2. Cell death correlated with mitochondrial depolarization, cytochrome C release, and translocation of green fluorescent protein (GFP-tagged light chain 3 to autophagosomes but occurred in the absence of caspase activation or phosphatidylserine exposure. In both sensitive and tolerant glioma cell lines, anoxia caused a significant up-regulation of BH3-only genes previously implicated in mediating anoxic cell death in other cell types (BNIP3, NIX, PUMA, and Noxa. In contrast, we detected a strong correlation between anoxia resistance and high expression levels of antiapoptotic Bcl-2 family proteins Bcl-xL, Bcl-2, and Mcl-1 that function to neutralize the proapoptotic activity of BH3-only proteins. Importantly, inhibition of both Bcl-2 and Bcl-xL with the small-molecule BH3 mimetics HA14-1 and BH3I-2′ and by RNA interference reactivated anoxia-induced autophagic cell death in previously resistant glioma cells. Our data suggest that endogenous BH3-only protein induction may not be able to compensate for the high expression of antiapoptotic Bcl-2 family proteins in anoxia-resistant astrocytomas. They also support the conjecture that BH3 mimetics may represent an exciting new approach for the treatment of malignant glioma.

  18. Dealcoholated red wine induces autophagic and apoptotic cell death in an osteosarcoma cell line.

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    Tedesco, I; Russo, M; Bilotto, S; Spagnuolo, C; Scognamiglio, A; Palumbo, R; Nappo, A; Iacomino, G; Moio, L; Russo, G L

    2013-10-01

    Until recently, the supposed preventive effects of red wine against cardiovascular diseases, the so-called "French Paradox", has been associated to its antioxidant properties. The interest in the anticancer capacity of polyphenols present in red wine strongly increased consequently to the enormous number of studies on resveratrol. In this study, using lyophilized red wine, we present evidence that its anticancer effect in a cellular model is mediated by apoptotic and autophagic cell death. Using a human osteosarcoma cell line, U2Os, we found that the lyophilized red wine was cytotoxic in a dose-dependent manner with a maximum effect in the range of 100-200 μg/ml equivalents of gallic acid. A mixed phenotype of types I/II cell death was evidenced by means of specific assays following treatment of U2Os with lyophilized red wine, e.g., autophagy and apoptosis. We found that cell death induced by lyophilized red wine proceeded through a mechanism independent from its anti-oxidant activity and involving the inhibition of PI3K/Akt kinase signaling. Considering the relative low concentration of each single bioactive compound in lyophilized red wine, our study suggests the activation of synergistic mechanism able to inhibit growth in malignant cells.

  19. Mediation of autophagic cell death by type 3 ryanodine receptor (RyR3 in adult hippocampal neural stem cells

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    Kyung Min eChung

    2016-05-01

    Full Text Available Cytoplasmic Ca2+ actively engages in diverse intracellular processes from protein synthesis, folding and trafficking to cell survival and death. Dysregulation of intracellular Ca2+ levels is observed in various neuropathological states including Alzheimer’s and Parkinson’s diseases. Ryanodine receptors (RyRs and IP3 receptors (IP3Rs, the main Ca2+ release channels located in endoplasmic reticulum (ER membranes, are known to direct various cellular events such as autophagy and apoptosis. Here we investigated the intracellular Ca2+-mediated regulation of survival and death of adult hippocampal neural stem (HCN cells utilizing an insulin withdrawal model of autophagic cell death. Despite comparable expression levels of RyR and IP3R transcripts in HCN cells at normal state, the expression levels of RyRs — especially RyR3 — were markedly upregulated upon insulin withdrawal. While treatment with the RyR agonist caffeine significantly promoted the autophagic death of insulin-deficient HCN cells, treatment with its inhibitor dantrolene prevented the induction of autophagy following insulin withdrawal. Furthermore, CRISPR/Cas9-mediated knockout of the RyR3 gene abolished autophagic cell death of HCN cells. This study delineates a distinct, RyR3-mediated ER Ca2+ regulation of autophagy and programmed cell death in neural stem cells. Our findings provide novel insights into the critical, yet understudied mechanisms underlying the regulatory function of ER Ca2+ in neural stem cell biology.

  20. Autophagic Cell Death and Apoptosis Jointly Mediate Cisatracurium Besylate-Induced Cell Injury

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    Haixia Zhuang

    2016-04-01

    Full Text Available Cisatracurium besylate is an ideal non-depolarizing muscle relaxant which is widely used in clinical application. However, some studies have suggested that cisatracurium besylate can affect cell proliferation. Moreover, its specific mechanism of action remains unclear. Here, we found that the number of GFP-LC3 (green fluoresent protein-light chain 3 positive autophagosomes and the rate of mitochondria fracture both increased significantly in drug-treated GFP-LC3 and MitoDsRed stable HeLa cells. Moreover, cisatracurium promoted the co-localization of LC3 and mitochondria and induced formation of autolysosomes. Levels of mitochondrial proteins decreased, which were reversed by the lysosome inhibitor Bafinomycin A1. Similar results with evidence of dose-dependent effects were found in both HeLa and Human Umbilical Vein Endothelial Cells (HUVECs. Cisatracurium lowered HUVEC viability to 0.16 (OD490 at 100 µM and to 0.05 (OD490 after 48 h in vitro; it increased the cell death rate to 56% at 100 µM and to 60% after 24 h in a concentration- and time-dependent manner (p < 0.01. Cell proliferation decreased significantly by four fold in Atg5 WT (wildtype MEF (mouse embryonic fibroblast (p < 0.01 but was unaffected in Atg5 KO (Knockout MEF, even upon treatment with a high dose of cisatracurium. Cisatracurium induced significant increase in cell death of wild-type MEFs even in the presence of the apoptosis inhibitor zVAD. Thus, we conclude that activation of both the autophagic cell death and cell apoptosis pathways contributes to cisatracurium-mediated cell injury.

  1. Lapatinib induces autophagic cell death and differentiation in acute myeloblastic leukemia

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    Chen YJ

    2016-07-01

    Full Text Available Yu-Jen Chen,1–4 Li-Wen Fang,5 Wen-Chi Su,6,7 Wen-Yi Hsu,1 Kai-Chien Yang,1 Huey-Lan Huang8 1Department of Medical Research, 2Department of Radiation Oncology, Mackay Memorial Hospital, 3Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, 4Institute of Pharmacology, Taipei Medical University, Taipei, 5Department of Nutrition, I-Shou University, Kaohsiung, 6Research Center for Emerging Viruses, China Medical University Hospital, 7Graduate Institute of Clinical Medical Science, China Medical University, Taichung, 8Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Republic of China Abstract: Lapatinib is an oral-form dual tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR or ErbB/Her superfamily members with anticancer activity. In this study, we examined the effects and mechanism of action of lapatinib on several human leukemia cells lines, including acute myeloid leukemia (AML, chronic myeloid leukemia (CML, and acute lymphoblastic leukemia (ALL cells. We found that lapatinib inhibited the growth of human AML U937, HL-60, NB4, CML KU812, MEG-01, and ALL Jurkat T cells. Among these leukemia cell lines, lapatinib induced apoptosis in HL-60, NB4, and Jurkat cells, but induced nonapoptotic cell death in U937, K562, and MEG-01 cells. Moreover, lapatinib treatment caused autophagic cell death as shown by positive acridine orange staining, the massive formation of vacuoles as seen by electronic microscopy, and the upregulation of LC3-II, ATG5, and ATG7 in AML U937 cells. Furthermore, autophagy inhibitor 3-methyladenine and knockdown of ATG5, ATG7, and Beclin-1 using short hairpin RNA (shRNA partially rescued lapatinib-induced cell death. In addition, the induction of phagocytosis and ROS production as well as the upregulation of surface markers CD14 and CD68 was detected in lapatinib-treated U937 cells, suggesting the induction of

  2. Precise temporal regulation of roughest is required for correct salivary gland autophagic cell death in Drosophila.

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    Simon, Claudio R; Moda, Livia M R; Octacilio-Silva, Shirlei; Anhezini, Lucas; Machado-Gitai, Luciana C H; Ramos, Ricardo Guelerman P

    2009-07-01

    The Drosophila roughest (rst) locus encodes an immunoglobulin superfamily transmembrane glycoprotein implicated in a variety of embryonic and postembryonic developmental processes. Here we demonstrate a previously unnoticed role for this gene in the autophagic elimination of larval salivary glands during early pupal stages by showing that overexpression of the Rst protein ectodomain in early pupa leads to persistence of salivary glands up to at least 12 hours after head eversion, although with variable penetrance. The same phenotype is observed in individuals carrying the dominant regulatory allele rst(D), but not in loss of function alleles. Analysis of persistent glands at the ultrastructural level showed that programmed cell death starts at the right time but is arrested at an early stage of the process. Finally we describe the expression pattern and intracellular distribution of Rst in wild type and rst(D) mutants, showing that its downregulation in salivary glands at the beginning of pupal stage is an important factor in the correct implementation of the autophagic program of this tissue in space and time.

  3. Glucagon-like Peptide-1 Protects Pancreatic Beta-cells from Death by Increasing Autophagic Flux and Restoring Lysosomal Function.

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    Zummo, Francesco P; Cullen, Kirsty S; Honkanen-Scott, Minna; Shaw, James Am; Lovat, Penny E; Arden, Catherine

    2017-02-23

    Studies in animal models of type 2 diabetes have shown that glucagon-like peptide-1 (GLP-1) receptor agonists prevent β-cell loss. Whether GLP-1 mediates β-cell survival via the key lysosomal-mediated process of autophagy is unknown.Here we report that treatment of INS-1E β-cells and primary islets with glucolipotoxicity (0.5mmol/l palmitate, 25mmol/l glucose) increases LC3 II, a marker of autophagy. Further analysis indicates a blockage in autophagic flux associated with lysosomal dysfunction. Accumulation of defective lysosomes leads to lysosomal membrane permeabilisation (LMP) and release of Cathepsin D, which contributes to cell death. Our data further demonstrated defects in autophagic flux and lysosomal staining in human samples of type 2 diabetes. Co-treatment with the GLP-1 receptor agonist exendin-4 reversed the lysosomal dysfunction, relieving the impairment in autophagic flux and further stimulated autophagy. siRNA knockdown showed the restoration of autophagic flux is also essential for the protective effects of exendin-4.Collectively, our data highlights lysosomal dysfunction as a critical mediator of β-cell loss and shows that exendin-4 improves cell survival via restoration of lysosomal function and autophagic flux. Modulation of autophagy / lysosomal homeostasis may thus define a novel therapeutic strategy for type 2 diabetes, with the GLP-1 signalling pathway as a potential focus.

  4. HDAC1 inactivation induces mitotic defect and caspase-independent autophagic cell death in liver cancer.

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    Hong Jian Xie

    Full Text Available Histone deacetylases (HDACs are known to play a central role in the regulation of several cellular properties interlinked with the development and progression of cancer. Recently, HDAC1 has been reported to be overexpressed in hepatocellular carcinoma (HCC, but its biological roles in hepatocarcinogenesis remain to be elucidated. In this study, we demonstrated overexpression of HDAC1 in a subset of human HCCs and liver cancer cell lines. HDAC1 inactivation resulted in regression of tumor cell growth and activation of caspase-independent autophagic cell death, via LC3B-II activation pathway in Hep3B cells. In cell cycle regulation, HDAC1 inactivation selectively induced both p21(WAF1/Cip1 and p27(Kip1 expressions, and simultaneously suppressed the expression of cyclin D1 and CDK2. Consequently, HDAC1 inactivation led to the hypophosphorylation of pRb in G1/S transition, and thereby inactivated E2F/DP1 transcription activity. In addition, we demonstrated that HDAC1 suppresses p21(WAF1/Cip1 transcriptional activity through Sp1-binding sites in the p21(WAF1/Cip1 promoter. Furthermore, sustained suppression of HDAC1 attenuated in vitro colony formation and in vivo tumor growth in a mouse xenograft model. Taken together, we suggest the aberrant regulation of HDAC1 in HCC and its epigenetic regulation of gene transcription of autophagy and cell cycle components. Overexpression of HDAC1 may play a pivotal role through the systemic regulation of mitotic effectors in the development of HCC, providing a particularly relevant potential target in cancer therapy.

  5. Benzyl isothiocyanate causes FoxO1-mediated autophagic death in human breast cancer cells.

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    Dong Xiao

    Full Text Available Benzyl isothiocyanate (BITC, a constituent of edible cruciferous vegetables, inhibits growth of breast cancer cells but the mechanisms underlying growth inhibitory effect of BITC are not fully understood. Here, we demonstrate that BITC treatment causes FoxO1-mediated autophagic death in cultured human breast cancer cells. The BITC-treated breast cancer cells (MDA-MB-231, MCF-7, MDA-MB-468, BT-474, and BRI-JM04 and MDA-MB-231 xenografts from BITC-treated mice exhibited several features characteristic of autophagy, including appearance of double-membrane vacuoles (transmission electron microscopy and acidic vesicular organelles (acridine orange staining, cleavage of microtubule-associated protein 1 light chain 3 (LC3, and/or suppression of p62 (p62/SQSTM1 or sequestosome 1 expression. On the other hand, a normal human mammary epithelial cell line (MCF-10A was resistant to BITC-induced autophagy. BITC-mediated inhibition of MDA-MB-231 and MCF-7 cell viability was partially but statistically significantly attenuated in the presence of autophagy inhibitors 3-methyl adenine and bafilomycin A1. Stable overexpression of Mn-superoxide dismutase, which was fully protective against apoptosis, conferred only partial protection against BITC-induced autophagy. BITC treatment decreased phosphorylation of mTOR and its downstream targets (P70s6k and 4E-BP1 in cultured MDA-MB-231 and MCF-7 cells and MDA-MB-231 xenografts, but activation of mTOR by transient overexpression of its positive regulator Rheb failed to confer protection against BITC-induced autophagy. Autophagy induction by BITC was associated with increased expression and acetylation of FoxO1. Furthermore, autophagy induction and cell growth inhibition resulting from BITC exposure were significantly attenuated by small interfering RNA knockdown of FoxO1. In conclusion, the present study provides novel insights into the molecular circuitry of BITC-induced cell death involving FoxO1-mediated autophagy.

  6. UCP2 inhibition triggers ROS-dependent nuclear translocation of GAPDH and autophagic cell death in pancreatic adenocarcinoma cells.

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    Dando, Ilaria; Fiorini, Claudia; Pozza, Elisa Dalla; Padroni, Chiara; Costanzo, Chiara; Palmieri, Marta; Donadelli, Massimo

    2013-03-01

    Mitochondrial uncoupling protein 2 (UCP2) can moderate oxidative stress by favoring the influx of protons into the mitochondrial matrix, thus reducing electron leakage from respiratory chain and mitochondrial superoxide production. Here, we demonstrate that UCP2 inhibition by genipin or UCP2 siRNA strongly increases reactive oxygen species (ROS) production inhibiting pancreatic adenocarcinoma cell growth. We also show that UCP2 inhibition triggers ROS-dependent nuclear translocation of the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH), formation of autophagosomes, and the expression of the autophagy marker LC3-II. Consistently, UCP2 over-expression significantly reduces basal autophagy confirming the anti-autophagic role of UCP2. Furthermore, we demonstrate that autophagy induced by UCP2 inhibition determines a ROS-dependent cell death, as indicated by the apoptosis decrease in the presence of the autophagy inhibitors chloroquine (CQ) or 3-methyladenine (3-MA), or the radical scavenger NAC. Intriguingly, the autophagy induced by genipin is able to potentiate the autophagic cell death triggered by gemcitabine, the standard chemotherapeutic drug for pancreatic adenocarcinoma, supporting the development of an anti-cancer therapy based on UCP2 inhibition associated to standard chemotherapy. Our results demonstrate for the first time that UCP2 plays a role in autophagy regulation bringing new insights into mitochondrial uncoupling protein field.

  7. Thymoquinone induces caspase-independent, autophagic cell death in CPT-11-resistant lovo colon cancer via mitochondrial dysfunction and activation of JNK and p38.

    Science.gov (United States)

    Chen, Ming-Cheng; Lee, Nien-Hung; Hsu, Hsi-Hsien; Ho, Tsung-Jung; Tu, Chuan-Chou; Hsieh, Dennis Jine-Yuan; Lin, Yueh-Min; Chen, Li-Mien; Kuo, Wei-Wen; Huang, Chih-Yang

    2015-02-11

    Chemotherapy causes unwanted side effects and chemoresistance, limiting its effectiveness. Therefore, phytochemicals are now used as alternative treatments. Thymoquinone (TQ) is used to treat different cancers, including colon cancer. The irinotecan-resistant (CPT-11-R) LoVo colon cancer cell line was previously constructed by stepwise CPT-11 challenges to untreated parental LoVo cells. TQ dose-dependently increased the total cell death index and activated apoptosis at 2 μM, which then diminished at increasing doses. The possibility of autophagic cell death was then investigated. TQ caused mitochondrial outer membrane permeability (MOMP) and activated autophagic cell death. JNK and p38 inhibitors (SP600125 and SB203580, respectively) reversed TQ autophagic cell death. TQ was also found to activate apoptosis before autophagy, and the direction of cell death was switched toward autophagic cell death at initiation of autophagosome formation. Therefore, TQ resulted in caspase-independent, autophagic cell death via MOMP and activation of JNK and p38 in CPT-11-R LoVo colon cancer cells.

  8. Staurosporine-induced cell death in Tetrahymena thermophila has mixed characteristics of both apoptotic and autophagic degeneration

    DEFF Research Database (Denmark)

    Christensen, S T; Chemnitz, J; Straarup, E M;

    1998-01-01

    phosphorylation of the PKC-specific substrate, myelin basic protein fragment 4-14. Our results show that cell death in the presence of staurosporine is associated with morphological and ultrastructural changes similar to both apoptosis and autophagic degeneration, but these in turn can be postponed or prevented......Staurosporine blocks signal transduction associated with cell survival, proliferation and chemosensory behaviour in the ciliated protozoan, Tetrahymena thermophila. Staurosporine inhibits cell proliferation and in vivo protein phosphorylation induced by phorbol ester. It also reduces the in vitro...... by 8-bromo-cyclic GMP, protoporphyrin IX, hemin or actinomycin D, although phorbol ester and insulin were ineffective. The results support the notion that staurosporine-induced cell death is an active process, associated with and/or requiring de novo RNA synthesis....

  9. Novel monofunctional platinum (II) complex Mono-Pt induces apoptosis-independent autophagic cell death in human ovarian carcinoma cells, distinct from cisplatin.

    Science.gov (United States)

    Guo, Wen-Jie; Zhang, Yang-Miao; Zhang, Li; Huang, Bin; Tao, Fei-Fei; Chen, Wei; Guo, Zi-Jian; Xu, Qiang; Sun, Yang

    2013-07-01

    Failure to engage apoptosis appears to be a leading mechanism of resistance to traditional platinum drugs in patients with ovarian cancer. Therefore, an alternative strategy to induce cell death is needed for the chemotherapy of this apoptosis-resistant cancer. Here we report that autophagic cell death, distinct from cisplatin-induced apoptosis, is triggered by a novel monofunctional platinum (II) complex named Mono-Pt in human ovarian carcinoma cells. Mono-Pt-induced cell death has the following features: cytoplasmic vacuolation, caspase-independent, no nuclear fragmentation or chromatin condensation, and no apoptotic bodies. These characteristics integrally indicated that Mono-Pt, rather than cisplatin, initiated a nonapoptotic cell death in Caov-3 ovarian carcinoma cells. Furthermore, incubation of the cells with Mono-Pt but not with cisplatin produced an increasing punctate distribution of microtubule-associated protein 1 light chain 3 (LC3), and an increasing ratio of LC3-II to LC3-I. Mono-Pt also caused the formation of autophagic vacuoles as revealed by monodansylcadaverine staining and transmission electron microscopy. In addition, Mono-Pt-induced cell death was significantly inhibited by the knockdown of either BECN1 or ATG7 gene expression, or by autophagy inhibitors 3-methyladenine, chloroquine and bafilomycin A 1. Moreover, the effect of Mono-Pt involved the AKT1-MTOR-RPS6KB1 pathway and MAPK1 (ERK2)/MAPK3 (ERK1) signaling, since the MTOR inhibitor rapamycin increased, while the MAPK1/3 inhibitor U0126 decreased Mono-Pt-induced autophagic cell death. Taken together, our results suggest that Mono-Pt exerts anticancer effect via autophagic cell death in apoptosis-resistant ovarian cancer. These findings lead to increased options for anticancer platinum drugs to induce cell death in cancer.

  10. Sulindac sulfide induces autophagic death in gastric epithelial cells via survivin down-regulation: a mechanism of NSAIDs-induced gastric injury.

    Science.gov (United States)

    Chiou, Shiun-Kwei; Hoa, Neil; Hodges, Amy

    2011-06-01

    Sulindac sulfide, a nonsteroidal anti-inflammatory drug (NSAID), has anti-tumorigenic and anti-inflammatory activities, but causes gastric mucosal damage. NSAIDs cause gastric injury in part by down-regulation of Survivin, an apoptosis inhibitor, resulting in apoptosis induction. Autophagy is a process that promotes cellular health by destroying unwanted cellular materials. Excessive autophagy induction could lead to a non-apoptotic cell death (autophagic cell death). The present study showed that sulindac sulfide at a physiological concentration also induces autophagic death in human gastric epithelial AGS and rat gastric epithelial RGM-1 cells, and that Survivin down-regulation is a mechanism involved: Sulindac sulfide treatment increased LC3b-II and APG7 levels and cytosolic vacuole formation, indications of autophagy induction, in AGS and RGM-1 cells. Sulindac sulfide treatment induced AGS and RGM-1 cell death, which was significantly reduced by pretreatment with the autophagy inhibitors 3-methyladenine and chloroquine, indicating that sulindac sulfide induced autophagic cell death. Stable overexpression of Survivin in RGM-1 cells did not inhibit the induction of LC3b-II levels or vacuole formation by sulindac sulfide, but significantly reduced the resulting cell death, suggesting that Survivin may inhibit autophagic cell death downstream of LC3b-II induction and vacuole formation. Indeed, siRNA depletion of LC3b in AGS cells inhibited the down-regulation of Survivin levels and the induction of cell death by sulindac sulfide, confirming that down-regulation of Survivin occurs in the autophagy pathway downstream of LC3b-II induction by sulindac sulfide. Induction of Survivin-dependent autophagic cell death is a novel mechanism by which sulindac sulfide induces gastric mucosal injury.

  11. Protective effect of N-acetylcysteine against nicardipine hydrochloride-induced autophagic cell death of human vascular endothelial cells.

    Science.gov (United States)

    Ochi, Masanori; Tanaka, Yoshiyuki; Toyoda, Hiromu

    2015-01-01

    Nicardipine hydrochloride (NIC) injection has been widely used for emergency treatment of abnormally high blood pressure. However, NIC injection often causes severe peripheral vascular injury. The purpose of the present study was to reduce the NIC-induced cell injury in human vascular endothelial cells by use of clinical agents. The mechanism of NIC-induced cell injury was evaluated by time-lapse microscopic imaging, autophagosome staining with monodansylcadaverine, immunostaining of light chain 3 isoform B (LC-3B) and assessment of cell viability after exposure to NIC with or without an inhibitor of autophagosome formation (3-methyladenine, 3-MA). Results from autophagosome labeling and immunostaining of LC-3B revealed an increase of autophagosomes and LC-3B in NIC-treated cells. NIC-mediated reduction of cell viability was inhibited by 3-methyladenine. Moreover, we found that N-acetylcysteine (NAC) reduced NIC-induced cell injury in human vascular endothelial cells. These findings suggest that NIC causes severe peripheral venous irritation via induction of autophagic cell death and that inhibition of autophagy with NAC could contribute to the reduction of NIC-induced vascular injury.

  12. The antimalarial amodiaquine causes autophagic-lysosomal and proliferative blockade sensitizing human melanoma cells to starvation- and chemotherapy-induced cell death.

    Science.gov (United States)

    Qiao, Shuxi; Tao, Shasha; Rojo de la Vega, Montserrat; Park, Sophia L; Vonderfecht, Amanda A; Jacobs, Suesan L; Zhang, Donna D; Wondrak, Georg T

    2013-12-01

    Pharmacological inhibition of autophagic-lysosomal function has recently emerged as a promising strategy for chemotherapeutic intervention targeting cancer cells. Repurposing approved and abandoned non-oncological drugs is an alternative approach to the identification and development of anticancer therapeutics, and antimalarials that target autophagic-lysosomal functions have recently attracted considerable attention as candidates for oncological repurposing. Since cumulative research suggests that dependence on autophagy represents a specific vulnerability of malignant melanoma cells, we screened a focused compound library of antimalarials for antimelanoma activity. Here we report for the first time that amodiaquine (AQ), a clinical 4-aminoquinoline antimalarial with unexplored cancer-directed chemotherapeutic potential, causes autophagic-lysosomal and proliferative blockade in melanoma cells that surpasses that of its parent compound chloroquine. Monitoring an established set of protein markers (LAMP1, LC3-II, SQSTM1) and cell ultrastructural changes detected by electron microscopy, we observed that AQ treatment caused autophagic-lysosomal blockade in malignant A375 melanoma cells, a finding substantiated by detection of rapid inactivation of lysosomal cathepsins (CTSB, CTSL, CTSD). AQ-treatment was associated with early induction of energy crisis (ATP depletion) and sensitized melanoma cells to either starvation- or chemotherapeutic agent-induced cell death. AQ displayed potent antiproliferative effects, and gene expression array analysis revealed changes at the mRNA (CDKN1A, E2F1) and protein level (TP53, CDKN1A, CCND1, phospho-RB1 [Ser 780]/[Ser 807/811], E2F1) consistent with the observed proliferative blockade in S-phase. Taken together, our data suggest that the clinical antimalarial AQ is a promising candidate for repurposing efforts that aim at targeting autophagic-lysosomal function and proliferative control in malignant melanoma cells.

  13. Propofol prevents autophagic cell death following oxygen and glucose deprivation in PC12 cells and cerebral ischemia-reperfusion injury in rats.

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    Derong Cui

    Full Text Available BACKGROUND: Propofol exerts protective effects on neuronal cells, in part through the inhibition of programmed cell death. Autophagic cell death is a type of programmed cell death that plays elusive roles in controlling neuronal damage and metabolic homeostasis. We therefore studied whether propofol could attenuate the formation of autophagosomes, and if so, whether the inhibition of autophagic cell death mediates the neuroprotective effects observed with propofol. METHODOLOGY/PRINCIPAL FINDINGS: The cell model was established by depriving the cells of oxygen and glucose (OGD for 6 hours, and the rat model of ischemia was introduced by a transient two-vessel occlusion for 10 minutes. Transmission electron microscopy (TEM revealed that the formation of autophagosomes and autolysosomes in both neuronal PC12 cells and pyramidal rat hippocampal neurons after respective OGD and ischemia/reperfusion (I/R insults. A western blot analysis revealed that the autophagy-related proteins, such as microtubule-associated protein 1 light chain 3 (LC3-II, Beclin-1 and class III PI3K, were also increased accordingly, but cytoprotective Bcl-2 protein was decreased. The negative effects of OGD and I/R, including the formation of autophagosomes and autolysosomes, the increase in LC3-II, Beclin-1 and class III PI3K expression and the decline in Bcl-2 production were all inhibited by propofol and specific inhibitors of autophagy, such as 3-methyladenine (3-MA, LY294002 and Bafilomycin A1 (Baf,. Furthermore, in vitro OGD cultures and in vivo I/R rats showed an increase in cell survival following the administration of propofol, as assessed by an MTT assay or histochemical analyses. CONCLUSIONS/SIGNIFICANCE: Our data suggest that propofol can markedly attenuate autophagic processes via the decreased expression of autophagy-related proteins in vitro and in vivo. This inhibition improves cell survival, which provides a novel explanation for the pleiotropic effects of

  14. Aqueous Extract of Solanum nigrum Leaf Activates Autophagic Cell Death and Enhances Docetaxel-Induced Cytotoxicity in Human Endometrial Carcinoma Cells

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    Cheng-Jeng Tai

    2012-01-01

    Full Text Available Chemotherapy is the main approach in dealing with advanced and recurrent endometrial cancer. An effective complementary ingredient can be helpful in improving the clinical outcome. Aqueous extract of Solanum nigrum leaf (AE-SN is a principal ingredient for treating cancer patients in traditional Chinese medicinal practice but lacks sufficient evidence to verify its tumor suppression efficacy. This study evaluated the antitumor effects of AE-SN and also assessed the synergistic effects of AE-SN with docetaxel On the human endometrial cancer cell lines, HEC1A, HEC1B, and KLE. The activation of apoptotic markers, caspase-3 and poly-ADP-ribose polymerase, and autophagic marker, microtubule-associated protein 1 light chain 3 A/B, wAS determined to clarify the cell death pathways responsible for AE-SN induced tumor cell death. Results indicated that AE-SN-treatment has significant cytotoxicity on the tested endometrial cancer cells with accumulation of LC3 A/B II and demonstrated a synergistic effect of AE-SN and docetaxel in HEC1A and HEC1B cells, but not KLE cells. In conclusion, AE-SN treatment was effective in suppressing endometrial cancer cells via the autophagic pathway and was also capable of enhancing the cytotoxicity of docetaxel in human endometrial cancer cells. Our results provide meaningful evidence for integrative cancer therapy in the future.

  15. Studying p53 family proteins in yeast: Induction of autophagic cell death and modulation by interactors and small molecules

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    Leão, Mariana; Gomes, Sara; Bessa, Cláudia; Soares, Joana; Raimundo, Liliana [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal); Monti, Paola; Fronza, Gilberto [Mutagenesis Unit, Istituto di Ricerca e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST-Istituto Nazionale per la Ricerca sul Cancro, 16132 Genoa (Italy); Pereira, Clara [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal); Saraiva, Lucília, E-mail: lucilia.saraiva@ff.up.pt [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal)

    2015-01-01

    In this work, the yeast Saccharomyces cerevisiae was used to individually study human p53, p63 (full length and truncated forms) and p73. Using this cell system, the effect of these proteins on cell proliferation and death, and the influence of MDM2 and MDMX on their activities were analyzed. When expressed in yeast, wild-type p53, TAp63, ΔNp63 and TAp73 induced growth inhibition associated with S-phase cell cycle arrest. This growth inhibition was accompanied by reactive oxygen species production and autophagic cell death. Furthermore, they stimulated rapamycin-induced autophagy. On the contrary, none of the tested p53 family members induced apoptosis either per se or after apoptotic stimuli. As previously reported for p53, also TAp63, ΔNp63 and TAp73 increased actin expression levels and its depolarization, suggesting that ACT1 is also a p63 and p73 putative yeast target gene. Additionally, MDM2 and MDMX inhibited the activity of all tested p53 family members in yeast, although the effect was weaker on TAp63. Moreover, Nutlin-3a and SJ-172550 were identified as potential inhibitors of the p73 interaction with MDM2 and MDMX, respectively. Altogether, the yeast-based assays herein developed can be envisaged as a simplified cell system to study the involvement of p53 family members in autophagy, the modulation of their activities by specific interactors (MDM2 and MDMX), and the potential of new small molecules to modulate these interactions. - Highlights: • p53, p63 and p73 are individually studied in the yeast S. cerevisiae. • p53 family members induce ROS production, cell cycle arrest and autophagy in yeast. • p53 family members increase actin depolarization and expression levels in yeast. • MDM2 and MDMX inhibit the activity of p53 family members in yeast. • Yeast can be a useful tool to study the biology and drugability of p53, p63 and p73.

  16. 6-Shogaol Inhibits Breast Cancer Cells and Stem Cell-Like Spheroids by Modulation of Notch Signaling Pathway and Induction of Autophagic Cell Death.

    Science.gov (United States)

    Ray, Anasuya; Vasudevan, Smreti; Sengupta, Suparna

    2015-01-01

    Cancer stem cells (CSCs) pose a serious obstacle to cancer therapy as they can be responsible for poor prognosis and tumour relapse. In this study, we have investigated inhibitory activity of the ginger-derived compound 6-shogaol against breast cancer cells both in monolayer and in cancer-stem cell-like spheroid culture. The spheroids were generated from adherent breast cancer cells. 6-shogaol was effective in killing both breast cancer monolayer cells and spheroids at doses that were not toxic to noncancerous cells. The percentages of CD44+CD24-/low cells and the secondary sphere content were reduced drastically upon treatment with 6-shogaol confirming its action on CSCs. Treatment with 6-shogaol caused cytoplasmic vacuole formation and cleavage of microtubule associated protein Light Chain3 (LC3) in both monolayer and spheroid culture indicating that it induced autophagy. Kinetic analysis of the LC3 expression and a combination treatment with chloroquine revealed that the autophagic flux instigated cell death in 6-shogaol treated breast cancer cells in contrast to the autophagy inhibitor chloroquine. Furthermore, 6-shogaol-induced cell death got suppressed in the presence of chloroquine and a very low level of apoptosis was exhibited even after prolonged treatment of the compound, suggesting that autophagy is the major mode of cell death induced by 6-shogaol in breast cancer cells. 6-shogaol reduced the expression levels of Cleaved Notch1 and its target proteins Hes1 and Cyclin D1 in spheroids, and the reduction was further pronounced in the presence of a γ-secretase inhibitor. Secondary sphere formation in the presence of the inhibitor was also further reduced by 6-shogaol. Together, these results indicate that the inhibitory action of 6-shogaol on spheroid growth and sustainability is conferred through γ-secretase mediated down-regulation of Notch signaling. The efficacy of 6-shogaol in monolayer and cancer stem cell-like spheroids raise hope for its

  17. Acute NMDA toxicity in cultured rat cerebellar granule neurons is accompanied by autophagy induction and late onset autophagic cell death phenotype

    Directory of Open Access Journals (Sweden)

    Kobeissy Firas H

    2010-02-01

    Full Text Available Abstract Background Autophagy, an intracellular response to stress, is characterized by double membrane cytosolic vesicles called autophagosomes. Prolonged autophagy is known to result in autophagic (Type II cell death. This study examined the potential role of an autophagic response in cultured cerebellar granule neurons challenged with excitotoxin N-methyl-D-aspartate (NMDA. Results NMDA exposure induced light chain-3 (LC-3-immunopositive and monodansylcadaverine (MDC fluorescent dye-labeled autophagosome formation in both cell bodies and neurites as early as 3 hours post-treatment. Elevated levels of Beclin-1 and the autophagosome-targeting LC3-II were also observed following NMDA exposure. Prolonged exposure of the cultures to NMDA (8-24 h generated MDC-, LC3-positive autophagosomal bodies, concomitant with the neurodegenerative phase of NMDA challenge. Lysosomal inhibition studies also suggest that NMDA-treatment diverted the autophagosome-associated LC3-II from the normal lysosomal degradation pathway. Autophagy inhibitor 3-methyladenine significantly reduced NMDA-induced LC3-II/LC3-I ratio increase, accumulation of autophagosomes, and suppressed NMDA-mediated neuronal death. ATG7 siRNA studies also showed neuroprotective effects following NMDA treatment. Conclusions Collectively, this study shows that autophagy machinery is robustly induced in cultured neurons subjected to prolonged exposure to excitotoxin, while autophagosome clearance by lysosomal pathway might be impaired. Our data further show that prolonged autophagy contributes to cell death in NMDA-mediated excitotoxicity.

  18. The novel pterostilbene derivative ANK-199 induces autophagic cell death through regulating PI3 kinase class III/beclin 1/Atg‑related proteins in cisplatin‑resistant CAR human oral cancer cells.

    Science.gov (United States)

    Hsieh, Min-Tsang; Chen, Hao-Ping; Lu, Chi-Cheng; Chiang, Jo-Hua; Wu, Tian-Shung; Kuo, Daih-Huang; Huang, Li-Jiau; Kuo, Sheng-Chu; Yang, Jai-Sing

    2014-08-01

    Pterostilbene is an effective chemopreventive agent against multiple types of cancer cells. A novel pterostilbene derivative, ANK-199, was designed and synthesized by our group. Its antitumor activity and mechanism in cisplatin-resistant CAR human oral cancer cells were investigated in this study. Our results show that ANK-199 has an extremely low toxicity in normal oral cell lines. The formation of autophagic vacuoles and acidic vesicular organelles (AVOs) was observed in the ANK-199-treated CAR cells by monodansylcadaverine (MDC) and acridine orange (AO) staining, suggesting that ANK-199 is able to induce autophagic cell death in CAR cells. Neither DNA fragmentation nor DNA condensation was observed, which means that ANK-199-induced cell death is not triggered by apoptosis. In accordance with morphological observation, 3-MA, a specific inhibitor of PI3K kinase class III, can inhibit the autophagic vesicle formation induced by ANK-199. In addition, ANK-199 is also able to enhance the protein levels of autophagic proteins, Atg complex, beclin 1, PI3K class III and LC3-II, and mRNA expression of autophagic genes Atg7, Atg12, beclin 1 and LC3-II in the ANK-199-treated CAR cells. A molecular signaling pathway induced by ANK-199 was therefore summarized. Results presented in this study show that ANK-199 may become a novel therapeutic reagent for the treatment of oral cancer in the near future (patent pending).

  19. 6-Shogaol Inhibits Breast Cancer Cells and Stem Cell-Like Spheroids by Modulation of Notch Signaling Pathway and Induction of Autophagic Cell Death.

    Directory of Open Access Journals (Sweden)

    Anasuya Ray

    Full Text Available Cancer stem cells (CSCs pose a serious obstacle to cancer therapy as they can be responsible for poor prognosis and tumour relapse. In this study, we have investigated inhibitory activity of the ginger-derived compound 6-shogaol against breast cancer cells both in monolayer and in cancer-stem cell-like spheroid culture. The spheroids were generated from adherent breast cancer cells. 6-shogaol was effective in killing both breast cancer monolayer cells and spheroids at doses that were not toxic to noncancerous cells. The percentages of CD44+CD24-/low cells and the secondary sphere content were reduced drastically upon treatment with 6-shogaol confirming its action on CSCs. Treatment with 6-shogaol caused cytoplasmic vacuole formation and cleavage of microtubule associated protein Light Chain3 (LC3 in both monolayer and spheroid culture indicating that it induced autophagy. Kinetic analysis of the LC3 expression and a combination treatment with chloroquine revealed that the autophagic flux instigated cell death in 6-shogaol treated breast cancer cells in contrast to the autophagy inhibitor chloroquine. Furthermore, 6-shogaol-induced cell death got suppressed in the presence of chloroquine and a very low level of apoptosis was exhibited even after prolonged treatment of the compound, suggesting that autophagy is the major mode of cell death induced by 6-shogaol in breast cancer cells. 6-shogaol reduced the expression levels of Cleaved Notch1 and its target proteins Hes1 and Cyclin D1 in spheroids, and the reduction was further pronounced in the presence of a γ-secretase inhibitor. Secondary sphere formation in the presence of the inhibitor was also further reduced by 6-shogaol. Together, these results indicate that the inhibitory action of 6-shogaol on spheroid growth and sustainability is conferred through γ-secretase mediated down-regulation of Notch signaling. The efficacy of 6-shogaol in monolayer and cancer stem cell-like spheroids raise

  20. PAMAM Nanoparticles Promote Acute Lung Injury by Inducing Autophagic Cell Death through the Akt-TSC2-mTOR Signaling Pathway

    Institute of Scientific and Technical Information of China (English)

    Chenggang Li; Haolin Liu; Yang Sun; Hongliang Wang; Feng Guo; Shuan Rao; Jiejie Deng; Yanli Zhang; Yufa Miao; Chenying Guo; Jie Meng; Xiping Chen; Limin Li; Dangsheng Li; Haiyan Xu; Heng Wang; Bo Li; Chengyu Jiang

    2009-01-01

    Nanotechnology is an important and emerging industry with a projected annual market of around one trillion US dollars by 2011–2015. Concerns about the toxicity of nanomaterials in humans, however, have recently been raised. Although studies of nanoparticle toxicity have focused on lung disease the molecular link between nanoparticle exposure and lung injury remained unclear. In this report, we show that cationic Starburst polyamidoamine dendrimer (PAMAM), a class of nanomaterials that are being widely developed for clinical applications can induce acute lung injury in vivo. PAMAM triggers autophagic cell death by deregulating the Akt-TSC2-mTOR signaling pathway. The autophagy inhibitor 3-methyladenine rescued PAMAM dendrimer-induced cell death and ameliorated acute lung injury caused by PAMAM in mice. Our data provide a molecular explanation for nanoparticle-induced lung injury, and suggest potential remedies to address the growing concerns of nanotechnology safety.

  1. A novel herbal medicine, KIOM-C, induces autophagic and apoptotic cell death mediated by activation of JNK and reactive oxygen species in HT1080 human fibrosarcoma cells.

    Directory of Open Access Journals (Sweden)

    Aeyung Kim

    Full Text Available KIOM-C was recently demonstrated to have anti-metastatic activity in highly malignant cancer cells via suppression of NF-κB-mediated MMP-9 activity. In addition, it was reported to be effective for clearance of the influenza virus by increasing production of anti-viral cytokines, such as TNF-α and IFN-γ, and efficacious in the treatment of pigs suffering from porcine circovirus-associated disease (PCVAD. In this study, we investigated whether KIOM-C induces cancer cell death and elucidated the underlying anti-cancer mechanisms. In addition, we examined whether KIOM-C oral administration suppresses in vivo tumor growth of HT1080 cells in athymic nude mice. We initially found that KIOM-C at concentrations of 500 and 1000 µg/ml caused dose- and time-dependent cell death in cancer cells, but not normal hepatocytes, to approximately 50% of control levels. At the early stage of KIOM-C treatment (12 h, cells were arrested in G1 phase, which was accompanied by up-regulation of p21 and p27, down-regulation of cyclin D1, and subsequent increases in apoptotic and autophagic cells. Following KIOM-C treatment, the extent of caspase-3 activation, PARP cleavage, Beclin-1 expression, and LC3-II conversion was remarkably up-regulated, but p62 expression was down-regulated. Phosphorylation of AMPK, ULK, JNK, c-jun, and p53 was increased significantly in response to KIOM-C treatment. The levels of intracellular ROS and CHOP expression were also increased. In particular, the JNK-specific inhibitor SP600125 blocked KIOM-C-induced ROS generation and CHOP expression almost completely, which consequently almost completely rescued cell death, indicating that JNK activation plays a critical role in KIOM-C-induced cell death. Furthermore, daily oral administration of 85 and 170 mg/kg KIOM-C efficiently suppressed the tumorigenic growth of HT1080 cells, without systemic toxicity. These results collectively suggest that KIOM-C efficiently induces cancer cell death by

  2. Silencing of MicroRNA-21 confers the sensitivity to tamoxifen and fulvestrant by enhancing autophagic cell death through inhibition of the PI3K-AKT-mTOR pathway in breast cancer cells.

    Science.gov (United States)

    Yu, Xinfeng; Li, Ruilian; Shi, Wenna; Jiang, Tao; Wang, Yufei; Li, Cong; Qu, Xianjun

    2016-02-01

    Tamoxifen (TAM) and fulvestrant (FUL) represent the major adjuvant therapy to estrogen receptor-alpha positive (ER(+)) breast cancer patients. However, endocrine resistance to TAM and FUL is a great impediment for successful treatment. We hypothesized that miR-21 might alter the sensitivity of breast cancer cells to TAM or FUL by regulating cell autophagy. Using the ER(+) breast cancer cells, we knockdown miR-21.by transfection with miR-21 inhibitor, then the cells were exposed to TAM or FUL and the percentages of apoptosis and autophagy were determined. Knockdown of miR-21 significantly increased the TAM or FUL-induced apoptosis in ER(+) breast cancer cells. Further, silencing of miR-21 in MCF-7 cells enhanced cell autophagy at both basal and TAM or FUL-induced level. The increase of autophagy in miR-21-knockdown MCF-7 cells was also indicated by increase of beclin-1, LC3-II and increased GFP-LC3 dots. Importantly, knockdown of miR-21 contributed to autophagic cell death, which is responsible for part of TAM induced cell death in miR-21 inhibitor-transfected cells. Further analysis suggested that miR-21 inhibitor enhance autophagic cell death through inhibition of PI3K-AKT-mTOR pathway. MiR-21 coordinated the function of autophagy and apoptosis by targeting Phosphatase and tensin homolog (PTEN) through inhibition of PI3K-AKT-mTOR pathway. In conclusion, silencing of miR-21 increased the sensitivity of ER(+) breast cancer cells to TAM or FUL by increasing autophagic cell death. Targeting autophagy-related miRNAs is a potential strategy for overcoming endocrine resistance to TAM and FUL.

  3. Autophagic Cell Death by Poncirus trifoliata Rafin., a Traditional Oriental Medicine, in Human Oral Cancer HSC-4 Cells

    Directory of Open Access Journals (Sweden)

    Hye-Yeon Han

    2015-01-01

    Full Text Available Poncirus trifoliata Rafin. has long been used as anti-inflammatory and antiallergic agent to treat gastrointestinal disorders and pulmonary diseases such as indigestion, constipation, chest fullness, chest pain, bronchitis, and sputum in Korea. P. trifoliata extract has recently been reported to possess anticancer properties; however, its mechanisms of action remain unclear. In this study, its antiproliferative effects and possible mechanisms were investigated in HSC-4 cells. The methanol extract of P. trifoliata (MEPT significantly decreased the proliferation of HSC-4 cells (inhibitory concentration (IC50 = 142.7 μg/mL in a dose-dependent manner. While there were no significant changes observed upon cell cycle analysis and ANNEXIN V and 7-AAD double staining in the MEPT-treated groups, the intensity of acidic vesicular organelle (AVO staining and microtubule-associated protein 1 light chain (LC 3-II protein expression increased in response to MEPT treatment. Furthermore, 3-methyladenine (3-MA, autophagy inhibitor effectively blocked the MEPT-induced cytotoxicity of HSC-4 cells and triggered the activation of p38 and extracellular signal-regulated kinases (ERK proteins. Taken together, our results indicate that MEPT is a potent autophagy agonist in oral cancer cells with antitumor therapeutic potential that acts through the mitogen-activated protein kinase (MAPK pathway.

  4. Nucleolin antagonist triggers autophagic cell death in human glioblastoma primary cells and decreased in vivo tumor growth in orthotopic brain tumor model.

    Science.gov (United States)

    Benedetti, Elisabetta; Antonosante, Andrea; d'Angelo, Michele; Cristiano, Loredana; Galzio, Renato; Destouches, Damien; Florio, Tiziana Marilena; Dhez, Anne Chloé; Astarita, Carlo; Cinque, Benedetta; Fidoamore, Alessia; Rosati, Floriana; Cifone, Maria Grazia; Ippoliti, Rodolfo; Giordano, Antonio; Courty, José; Cimini, Annamaria

    2015-12-01

    Nucleolin (NCL) is highly expressed in several types of cancer and represents an interesting therapeutic target. It is expressed at the plasma membrane of tumor cells, a property which is being used as a marker for several human cancer including glioblastoma. In this study we investigated targeting NCL as a new therapeutic strategy for the treatment of this pathology. To explore this possibility, we studied the effect of an antagonist of NCL, the multivalent pseudopeptide N6L using primary culture of human glioblastoma cells. In this system, N6L inhibits cell growth with different sensitivity depending to NCL localization. Cell cycle analysis indicated that N6L-induced growth reduction was due to a block of the G1/S transition with down-regulation of the expression of cyclin D1 and B2. By monitoring autophagy markers such as p62 and LC3II, we demonstrate that autophagy is enhanced after N6L treatment. In addition, N6L-treatment of mice bearing tumor decreased in vivo tumor growth in orthotopic brain tumor model and increase mice survival. The results obtained indicated an anti-proliferative and pro-autophagic effect of N6L and point towards its possible use as adjuvant agent to the standard therapeutic protocols presently utilized for glioblastoma.

  5. Autophagic regulation of smooth muscle cell biology

    Science.gov (United States)

    Salabei, Joshua K.; Hill, Bradford G.

    2014-01-01

    Autophagy regulates the metabolism, survival, and function of numerous cell types, including those comprising the cardiovascular system. In the vasculature, changes in autophagy have been documented in atherosclerotic and restenotic lesions and in hypertensive vessels. The biology of vascular smooth muscle cells appears particularly sensitive to changes in the autophagic program. Recent evidence indicates that stimuli or stressors evoked during the course of vascular disease can regulate autophagic activity, resulting in modulation of VSMC phenotype and viability. In particular, certain growth factors and cytokines, oxygen tension, and pharmacological drugs have been shown to trigger autophagy in smooth muscle cells. Importantly, each of these stimuli has a redox component, typically associated with changes in the abundance of reactive oxygen, nitrogen, or lipid species. Collective findings support the hypothesis that autophagy plays a critical role in vascular remodeling by regulating smooth muscle cell phenotype transitions and by influencing the cellular response to stress. In this graphical review, we summarize current knowledge on the role of autophagy in the biology of the smooth muscle cell in (patho)physiology. PMID:25544597

  6. Autophagic regulation of smooth muscle cell biology

    Directory of Open Access Journals (Sweden)

    Joshua K. Salabei

    2015-04-01

    Full Text Available Autophagy regulates the metabolism, survival, and function of numerous cell types, including those comprising the cardiovascular system. In the vasculature, changes in autophagy have been documented in atherosclerotic and restenotic lesions and in hypertensive vessels. The biology of vascular smooth muscle cells appears particularly sensitive to changes in the autophagic program. Recent evidence indicates that stimuli or stressors evoked during the course of vascular disease can regulate autophagic activity, resulting in modulation of VSMC phenotype and viability. In particular, certain growth factors and cytokines, oxygen tension, and pharmacological drugs have been shown to trigger autophagy in smooth muscle cells. Importantly, each of these stimuli has a redox component, typically associated with changes in the abundance of reactive oxygen, nitrogen, or lipid species. Collective findings support the hypothesis that autophagy plays a critical role in vascular remodeling by regulating smooth muscle cell phenotype transitions and by influencing the cellular response to stress. In this graphical review, we summarize current knowledge on the role of autophagy in the biology of the smooth muscle cell in (pathophysiology.

  7. Attenuation of Aβ{sub 25–35}-induced parallel autophagic and apoptotic cell death by gypenoside XVII through the estrogen receptor-dependent activation of Nrf2/ARE pathways

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiangbao; Wang, Min [Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193 (China); Sun, Guibo, E-mail: sunguibo@126.com [Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193 (China); Ye, Jingxue [Jilin Agricultural University, Changchun, Jilin 130021 (China); Zhou, Yanhui [Center of Cardiology, People' s Hospital of Jilin Province, Changchun, 130021, Jilin (China); Dong, Xi [Wenzhou Medical University, Wenzhou, Zhejiang 325035 (China); Wang, Tingting; Lu, Shan [Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193 (China); Sun, Xiaobo, E-mail: sun_xiaobo163@163.com [Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193 (China)

    2014-08-15

    Amyloid-beta (Aβ) has a pivotal function in the pathogenesis of Alzheimer's disease. To investigate Aβ neurotoxicity, we used an in vitro model that involves Aβ{sub 25–35}-induced cell death in the nerve growth factor-induced differentiation of PC12 cells. Aβ{sub 25–35} (20 μM) treatment for 24 h caused apoptotic cell death, as evidenced by significant cell viability reduction, LDH release, phosphatidylserine externalization, mitochondrial membrane potential disruption, cytochrome c release, caspase-3 activation, PARP cleavage, and DNA fragmentation in PC12 cells. Aβ{sub 25–35} treatment led to autophagic cell death, as evidenced by augmented GFP-LC3 puncta, conversion of LC3-I to LC3-II, and increased LC3-II/LC3-I ratio. Aβ{sub 25–35} treatment induced oxidative stress, as evidenced by intracellular ROS accumulation and increased production of mitochondrial superoxide, malondialdehyde, protein carbonyl, and 8-OHdG. Phytoestrogens have been proved to be protective against Aβ-induced neurotoxicity and regarded as relatively safe targets for AD drug development. Gypenoside XVII (GP-17) is a novel phytoestrogen isolated from Gynostemma pentaphyllum or Panax notoginseng. Pretreatment with GP-17 (10 μM) for 12 h increased estrogen response element reporter activity, activated PI3K/Akt pathways, inhibited GSK-3β, induced Nrf2 nuclear translocation, augmented antioxidant responsive element enhancer activity, upregulated heme oxygenase 1 (HO-1) expression and activity, and provided protective effects against Aβ{sub 25–35}-induced neurotoxicity, including oxidative stress, apoptosis, and autophagic cell death. In conclusion, GP-17 conferred protection against Aβ{sub 25–35}-induced neurotoxicity through estrogen receptor-dependent activation of PI3K/Akt pathways, inactivation of GSK-3β and activation of Nrf2/ARE/HO-1 pathways. This finding might provide novel insights into understanding the mechanism for neuroprotective effects of phytoestrogens

  8. Rapid screening of potential autophagic inductor agents using mammalian cell lines.

    Science.gov (United States)

    Martins, Waleska K; Severino, Divinomar; Souza, Cleidiane; Stolf, Beatriz S; Baptista, Maurício S

    2013-06-01

    Recent progress in understanding the molecular basis of autophagy has demonstrated its importance in several areas of human health. Affordable screening techniques with higher sensitivity and specificity to identify autophagy are, however, needed to move the field forward. In fact, only laborious and/or expensive methodologies such as electron microscopy, dye-staining of autophagic vesicles, and LC3-II immunoblotting or immunoassaying are available for autophagy identification. Aiming to fulfill this technical gap, we describe here the association of three widely used assays to determine cell viability - Crystal Violet staining (CVS), 3-[4, 5-dimethylthiaolyl]-2, 5-diphenyl-tetrazolium bromide (MTT) reduction, and neutral red uptake (NRU) - to predict autophagic cell death in vitro. The conceptual framework of the method is the superior uptake of NR in cells engaging in autophagy. NRU was then weighted by the average of MTT reduction and CVS allowing the calculation of autophagic arbitrary units (AAU), a numeric variable that correlated specifically with the autophagic cell death. The proposed strategy is very useful for drug discovery, allowing the investigation of potential autophagic inductor agents through a rapid screening using mammalian cell lines B16-F10, HaCaT, HeLa, MES-SA, and MES-SA/Dx5 in a unique single microplate.

  9. The autophagic- lysosomal pathway determines the fate of glial cells under manganese- induced oxidative stress conditions.

    Science.gov (United States)

    Gorojod, R M; Alaimo, A; Porte Alcon, S; Pomilio, C; Saravia, F; Kotler, M L

    2015-10-01

    Manganese (Mn) overexposure is frequently associated with the development of a neurodegenerative disorder known as Manganism. The Mn-mediated generation of reactive oxygen species (ROS) promotes cellular damage, finally leading to apoptotic cell death in rat astrocytoma C6 cells. In this scenario, the autophagic pathway could play an important role in preventing cytotoxicity. In the present study, we found that Mn induced an increase in the amount and total volume of acidic vesicular organelles (AVOs), a process usually related to the activation of the autophagic pathway. Particularly, the generation of enlarged AVOs was a ROS- dependent event. In this report we demonstrated for the first time that Mn induces autophagy in glial cells. This conclusion emerged from the results obtained employing a battery of autophagy markers: a) the increase in LC3-II expression levels, b) the formation of autophagic vesicles labeled with monodansylcadaverine (MDC) or LC3 and, c) the increase in Beclin 1/ Bcl-2 and Beclin 1/ Bcl-X(L) ratio. Autophagy inhibition employing 3-MA and mAtg5(K130R) resulted in decreased cell viability indicating that this event plays a protective role in Mn- induced cell death. In addition, mitophagy was demonstrated by an increase in LC3 and TOM-20 colocalization. On the other hand, we proposed the occurrence of lysosomal membrane permeabilization (LMP) based in the fact that cathepsins B and D activities are essential for cell death. Both cathepsin B inhibitor (Ca-074 Me) or cathepsin D inhibitor (Pepstatin A) completely prevented Mn- induced cytotoxicity. In addition, low dose of Bafilomycin A1 showed a similar effect, a finding that adds evidence about the lysosomal role in Mn cytotoxicity. Finally, in vivo experiments demonstrated that Mn induces injury and alters LC3 expression levels in rat striatal astrocytes. In summary, our results demonstrated that autophagy is activated to counteract the harmful effect caused by Mn. These data is valuable to

  10. Hydrogen peroxide impairs autophagic flux in a cell model of nonalcoholic fatty liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Pengtao [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China); University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan District, Beijing 100049 (China); Huang, Zhen [Department of Abdominal Surgical Oncology, Cancer Hospital, Chinese Academy of Medical Sciences, 17 Panjiayuan Nanli, Chaoyang District, Beijing 100021 (China); Zhao, Hong, E-mail: zhaohong9@sina.com [Department of Abdominal Surgical Oncology, Cancer Hospital, Chinese Academy of Medical Sciences, 17 Panjiayuan Nanli, Chaoyang District, Beijing 100021 (China); Wei, Taotao, E-mail: weitt@moon.ibp.ac.cn [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)

    2013-04-19

    Highlights: •Free fatty acids exposure induces elevated autophagy. •H{sub 2}O{sub 2} inhibits autophagic flux through impairing the fusion between autophagosomes and lysosomes. •Inhibition of autophagy potentiates H{sub 2}O{sub 2}-induced cell death. -- Abstract: Nonalcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver disease, but the pathogenesis of NAFLD is not fully clear. The aim of this study was to determine whether autophagy plays a role in the pathogenesis of NAFLD. We found that the levels of autophagy were elevated in hepatoma cells upon exposure to free fatty acids, as confirmed by the increase in the number of autophagosomes. However, exposure of hepatoma cells to H{sub 2}O{sub 2} and TNF-α, two typical “second hit” factors, increased the initiation of autophagy but inhibited the autophagic flux. The inhibition of autophagy sensitized cells to pro-apoptotic stimuli. Taken together, our results suggest that autophagy acts as a protective mechanism in the pathogenesis of NAFLD and that impairment of autophagy might induce more severe lesions of the liver. These findings will be a benefit to the understanding of the pathogenesis of NAFLD and might suggest a strategy for the prevention and cure of NAFLD.

  11. Endothelial cells are damaged by autophagic induction before hepatocytes in Con A-induced acute hepatitis.

    Science.gov (United States)

    Yang, Ming-Chen; Chang, Chih-Peng; Lei, Huan-Yao

    2010-08-01

    We have reported both T-cell-dependent and -independent hepatitis in immunocompetent and immunodeficiency mice, respectively, after intravenous injection of Con A in mice. The mode of hepatocyte cell death is different: autophagy for T-cell-independent hepatitis in contrast to apoptosis for T-cell-dependent one. In this study, we further demonstrate that liver blood vessels are the first target in both modes. The infused Con A bond to the hepatic vascular endothelial cells and cause its damage with autophagy. Before the elevation of the serum alanine aminotransferase at 6 h post-injection, the plasma leakage and hemorrhage occur at 1-3 h without inflammation. Con A induces autophagy of endothelial cells and hemorrhage that is enhanced by IFN-gamma. Using the endothelial cell line HMEC-1, a dose- and time-dependent cell death with autophagic LC3-II (microtubule-associated protein light chain 3) conversion was induced by Con A and was enhanced by IFN-gamma. In conclusion, Con A induced autophagy on hepatic endothelial cells; the damage of liver blood vessel occurs before the induction of T-cell-dependent hepatitis via apoptosis or T-cell-independent hepatitis via autophagy.

  12. Autophagic flux is highly active in early mitosis and differentially regulated throughout the cell cycle

    OpenAIRE

    Li, Zhiyuan; Ji, Xinmiao; Wang, Dongmei; Liu, Juanjuan; Zhang, Xin

    2016-01-01

    Mitosis is a fast process that involves dramatic cellular remodeling and has a high energy demand. Whether autophagy is active or inactive during the early stages of mitosis in a naturally dividing cell is still debated. Here we aimed to use multiple assays to resolve this apparent discrepancy. Although the LC3 puncta number was reduced in mitosis, the four different cell lines we tested all have active autophagic flux in both interphase and mitosis. In addition, the autophagic flux was highl...

  13. Autophagic vesicles on mature human reticulocytes explain phosphatidylserine-positive red cells in sickle cell disease.

    Science.gov (United States)

    Mankelow, Tosti J; Griffiths, Rebecca E; Trompeter, Sara; Flatt, Joanna F; Cogan, Nicola M; Massey, Edwin J; Anstee, David J

    2015-10-08

    During maturation to an erythrocyte, a reticulocyte must eliminate any residual organelles and reduce its surface area and volume. Here we show this involves a novel process whereby large, intact, inside-out phosphatidylserine (PS)-exposed autophagic vesicles are extruded. Cell surface PS is a well-characterized apoptotic signal initiating phagocytosis. In peripheral blood from patients after splenectomy or in patients with sickle cell disease (SCD), the number of circulating red cells exposing PS on their surface is elevated. We show that in these patients PS is present on the cell surface of red cells in large (∼1.4 µm) discrete areas corresponding to autophagic vesicles. The autophagic vesicles found on reticulocytes are identical to those observed on red cells from splenectomized individuals and patients with SCD. Our data suggest the increased thrombotic risk associated with splenectomy, and patients with hemoglobinopathies is a possible consequence of increased levels of circulating mature reticulocytes expressing inside-out PS-exposed autophagic vesicles because of asplenia.

  14. Graveoline isolated from ethanolic extract of Ruta graveolens triggers apoptosis and autophagy in skin melanoma cells: a novel apoptosis-independent autophagic signaling pathway.

    Science.gov (United States)

    Ghosh, Samrat; Bishayee, Kausik; Khuda-Bukhsh, Anisur Rahman

    2014-08-01

    Anti-cancer drugs generally kill cancer cells by apoptosis but fail to do so when they become resistant and escape apoptosis signals. But these resistant cells can still be killed by autophagy. Therefore, drugs having both apoptotic and autophagic abilities are solicited in effective cancer management. In search of such a drug, we examined the efficacy of graveoline, a bioactive compound isolated from Ruta graveolens on skin melanoma A375 cells through the use of specific signaling cascades and their inhibitors. Cytotoxicity of graveoline was tested by conducting MTT assay. Induction of autophagy and apoptosis was checked. Expression of related proteins and their localization were studied by conducting immunoblot assay and through confocal microscopy, respectively. We found graveoline-induced Beclin-1 associated autophagy in A375 cells and 3-methyladenine, an inhibitor of autophagy did not affect apoptosis. Conversely, caspase inhibitor that blocked apoptosis did not affect autophagic cell death, suggesting thereby that these two were independent events. Use of reactive oxygen species (ROS) scavengers inhibited cell death, but blocking autophagy did not affect graveoline-induced ROS generation, suggesting that ROS generation ensued autophagy. Thus, graveoline-induced both apoptotic and autophagic cell death in skin melanoma cells, a desirable quality in effective anti-cancer drug design.

  15. The Ketone Body, β-Hydroxybutyrate Stimulates the Autophagic Flux and Prevents Neuronal Death Induced by Glucose Deprivation in Cortical Cultured Neurons.

    Science.gov (United States)

    Camberos-Luna, Lucy; Gerónimo-Olvera, Cristian; Montiel, Teresa; Rincon-Heredia, Ruth; Massieu, Lourdes

    2016-03-01

    Glucose is the major energy substrate in brain, however, during ketogenesis induced by starvation or prolonged hypoglycemia, the ketone bodies (KB), acetoacetate and β-hydroxybutyrate (BHB) can substitute for glucose. KB improve neuronal survival in diverse injury models, but the mechanisms by which KB prevent neuronal damage are still not well understood. In the present study we have investigated whether protection by the D isomer of BHB (D-BHB) against neuronal death induced by glucose deprivation (GD), is related to autophagy. Autophagy is a lysosomal-dependent degradation process activated during nutritional stress, which leads to the digestion of damaged proteins and organelles providing energy for cell survival. Results show that autophagy is activated in cortical cultured neurons during GD, as indicated by the increase in the levels of the lipidated form of the microtubule associated protein light chain 3 (LC3-II), and the number of autophagic vesicles. At early phases of glucose reintroduction (GR), the levels of p62 declined suggesting that the degradation of the autophagolysosomal content takes place at this time. In cultures exposed to GD and GR in the presence of D-BHB, the levels of LC3-II and p62 rapidly declined and remained low during GR, suggesting that the KB stimulates the autophagic flux preventing autophagosome accumulation and improving neuronal survival.

  16. Graphene Oxide Nanoribbons Induce Autophagic Vacuoles in Neuroblastoma Cell Lines

    Directory of Open Access Journals (Sweden)

    Emanuela Mari

    2016-11-01

    Full Text Available Since graphene nanoparticles are attracting increasing interest in relation to medical applications, it is important to understand their potential effects on humans. In the present study, we prepared graphene oxide (GO nanoribbons by oxidative unzipping of single-wall carbon nanotubes (SWCNTs and analyzed their toxicity in two human neuroblastoma cell lines. Neuroblastoma is the most common solid neoplasia in children. The hallmark of these tumors is the high number of different clinical variables, ranging from highly metastatic, rapid progression and resistance to therapy to spontaneous regression or change into benign ganglioneuromas. Patients with neuroblastoma are grouped into different risk groups that are characterized by different prognosis and different clinical behavior. Relapse and mortality in high risk patients is very high in spite of new advances in chemotherapy. Cell lines, obtained from neuroblastomas have different genotypic and phenotypic features. The cell lines SK-N-BE(2 and SH-SY5Y have different genetic mutations and tumorigenicity. Cells were exposed to low doses of GO for different times in order to investigate whether GO was a good vehicle for biological molecules delivering individualized therapy. Cytotoxicity in both cell lines was studied by measuring cellular oxidative stress (ROS, mitochondria membrane potential, expression of lysosomial proteins and cell growth. GO uptake and cytoplasmic distribution of particles were studied by Transmission Electron Microscopy (TEM for up to 72 h. The results show that GO at low concentrations increased ROS production and induced autophagy in both neuroblastoma cell lines within a few hours of exposure, events that, however, are not followed by growth arrest or death. For this reason, we suggest that the GO nanoparticle can be used for therapeutic delivery to the brain tissue with minimal effects on healthy cells.

  17. SET overexpression in HEK293 cells regulates mitochondrial uncoupling proteins levels within a mitochondrial fission/reduced autophagic flux scenario.

    Science.gov (United States)

    Almeida, Luciana O; Goto, Renata N; Neto, Marinaldo P C; Sousa, Lucas O; Curti, Carlos; Leopoldino, Andréia M

    2015-03-01

    We hypothesized that SET, a protein accumulated in some cancer types and Alzheimer disease, is involved in cell death through mitochondrial mechanisms. We addressed the mRNA and protein levels of the mitochondrial uncoupling proteins UCP1, UCP2 and UCP3 (S and L isoforms) by quantitative real-time PCR and immunofluorescence as well as other mitochondrial involvements, in HEK293 cells overexpressing the SET protein (HEK293/SET), either in the presence or absence of oxidative stress induced by the pro-oxidant t-butyl hydroperoxide (t-BHP). SET overexpression in HEK293 cells decreased UCP1 and increased UCP2 and UCP3 (S/L) mRNA and protein levels, whilst also preventing lipid peroxidation and decreasing the content of cellular ATP. SET overexpression also (i) decreased the area of mitochondria and increased the number of organelles and lysosomes, (ii) increased mitochondrial fission, as demonstrated by increased FIS1 mRNA and FIS-1 protein levels, an apparent accumulation of DRP-1 protein, and an increase in the VDAC protein level, and (iii) reduced autophagic flux, as demonstrated by a decrease in LC3B lipidation (LC3B-II) in the presence of chloroquine. Therefore, SET overexpression in HEK293 cells promotes mitochondrial fission and reduces autophagic flux in apparent association with up-regulation of UCP2 and UCP3; this implies a potential involvement in cellular processes that are deregulated such as in Alzheimer's disease and cancer.

  18. Autophagic deficiency is related to steroidogenic decline in aged rat Leydig cells

    Institute of Scientific and Technical Information of China (English)

    Wei-Ren Li; Zhe-Zhu Gao; Zhong-Cheng Xin; Liang Chen; Zhi-Jie Chang; Hua Xin; Tao Liu; Yan-Quan Zhang; Guang-Yong Li; Feng Zhou; Yan-Qing Gong

    2011-01-01

    Late-onset hypogonadism (LOH) is closely related to secondary androgen deficiency in aged males,but the mechanism remains unclear.In this study,we found that reduced testosterone production in aged rat Leydig cells is associated with decreased autophagic activity.Primary rat Leydig cells and the TM3 mouse Leydig cell line were used to study the effect of autophagic deficiency on Leydig cell testosterone production.In Leydig cells from young and aged rats,treatment with wortmannin,an autophagy inhibitor,inhibited luteinising hormone (LH)-stimulated steroidogenic acute regulatory (StAR) protein expression and decreased testosterone production.In contrast,treatment with rapamycin,an autophagy activator,enhanced LH-stimulated steroidogenesis in Leydig cells from aged,but not young,rats.Intracellular reactive oxygen species (ROS) levels were increased in both young and aged Leydig cells treated with wortmannin but decreased only in aged Leydig cells treated with rapamycin.Furthermore,an increased level of ROS,induced by H2O2,resulted in LH-stimulated steroidogenic inhibition.Finally,knockdown of Beclin 1 decreased LH-stimulated StAR expression and testosterone production in TM3 mouse Leydig cells,which were associated with increased intracellular ROS level.These results suggested that autophagic deficiency is related to steroidogenic decline in aged rat Leydig cells,which might be influenced by intracellular ROS levels.

  19. Autophagic flux promotes cisplatin resistance in human ovarian carcinoma cells through ATP-mediated lysosomal function.

    Science.gov (United States)

    Ma, Liwei; Xu, Ye; Su, Jing; Yu, Huimei; Kang, Jinsong; Li, Hongyan; Li, Xiaoning; Xie, Qi; Yu, Chunyan; Sun, Liankun; Li, Yang

    2015-11-01

    Lysosomes are involved in promoting resistance of cancer cells to chemotherapeutic agents. However, the mechanisms underlying lysosomal influence of cisplatin resistance in ovarian cancer remain incompletely understood. We report that, compared with cisplatin-sensitive SKOV3 cells, autophagy increases in cisplatin-resistant SKOV3/DDP cells treated with cisplatin. Inhibition of early-stage autophagy enhanced cisplatin-mediated cytotoxicity in SKOV3/DDP cells, but autophagy inhibition at a later stage by disturbing autophagosome-lysosome fusion is more effective. Notably, SKOV3/DDP cells contained more lysosomes than cisplatin-sensitive SKOV3 cells. Abundant lysosomes and lysosomal cathepsin D activity were required for continued autolysosomal degradation and maintenance of autophagic flux in SKOV3/DDP cells. Furthermore, SKOV3/DDP cells contain abundant lysosomal ATP required for lysosomal function, and inhibition of lysosomal ATP accumulation impaired lysosomal function and blocked autophagic flux. Therefore, our findings suggest that lysosomes at least partially contribute to cisplatin resistance in ovarian cancer cells through their role in cisplatin-induced autophagic processes, and provide insight into the mechanism of cisplatin resistance in tumors.

  20. Lysosomal cell death mechanisms in aging.

    Science.gov (United States)

    Gómez-Sintes, Raquel; Ledesma, María Dolores; Boya, Patricia

    2016-12-01

    Lysosomes are degradative organelles essential for cell homeostasis that regulate a variety of processes, from calcium signaling and nutrient responses to autophagic degradation of intracellular components. Lysosomal cell death is mediated by the lethal effects of cathepsins, which are released into the cytoplasm following lysosomal damage. This process of lysosomal membrane permeabilization and cathepsin release is observed in several physiopathological conditions and plays a role in tissue remodeling, the immune response to intracellular pathogens and neurodegenerative diseases. Many evidences indicate that aging strongly influences lysosomal activity by altering the physical and chemical properties of these organelles, rendering them more sensitive to stress. In this review we focus on how aging alters lysosomal function and increases cell sensitivity to lysosomal membrane permeabilization and lysosomal cell death, both in physiological conditions and age-related pathologies.

  1. Molecular Basis of Autophagic Cell Death in Prostate Cancer

    Science.gov (United States)

    2009-03-01

    putative BH3 domain with a number of known BH3-only pro- teins (PUMA, BAD, NOXA , and apoL6) and apoL4, further showed that the 9-aa BH3 domain of apoL1...showed that the 9-aa BH3 domain of apoL1 pos- sessed amphipathic -helical struc- ture, similar to other BH3-only pro- teins of PUMA, BAD, NOXA , and...containing putative BH3 domain in known BH3-only proteins (PUMA, BAD, NOXA , and apoL6) and apoL1 and apoL4. The 9-aa BH3 domain are in boldface and the two

  2. SET overexpression in HEK293 cells regulates mitochondrial uncoupling proteins levels within a mitochondrial fission/reduced autophagic flux scenario

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Luciana O.; Goto, Renata N. [Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Neto, Marinaldo P.C. [Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Sousa, Lucas O. [Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Curti, Carlos [Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Leopoldino, Andréia M., E-mail: andreiaml@usp.br [Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil)

    2015-03-06

    We hypothesized that SET, a protein accumulated in some cancer types and Alzheimer disease, is involved in cell death through mitochondrial mechanisms. We addressed the mRNA and protein levels of the mitochondrial uncoupling proteins UCP1, UCP2 and UCP3 (S and L isoforms) by quantitative real-time PCR and immunofluorescence as well as other mitochondrial involvements, in HEK293 cells overexpressing the SET protein (HEK293/SET), either in the presence or absence of oxidative stress induced by the pro-oxidant t-butyl hydroperoxide (t-BHP). SET overexpression in HEK293 cells decreased UCP1 and increased UCP2 and UCP3 (S/L) mRNA and protein levels, whilst also preventing lipid peroxidation and decreasing the content of cellular ATP. SET overexpression also (i) decreased the area of mitochondria and increased the number of organelles and lysosomes, (ii) increased mitochondrial fission, as demonstrated by increased FIS1 mRNA and FIS-1 protein levels, an apparent accumulation of DRP-1 protein, and an increase in the VDAC protein level, and (iii) reduced autophagic flux, as demonstrated by a decrease in LC3B lipidation (LC3B-II) in the presence of chloroquine. Therefore, SET overexpression in HEK293 cells promotes mitochondrial fission and reduces autophagic flux in apparent association with up-regulation of UCP2 and UCP3; this implies a potential involvement in cellular processes that are deregulated such as in Alzheimer's disease and cancer. - Highlights: • SET, UCPs and autophagy prevention are correlated. • SET action has mitochondrial involvement. • UCP2/3 may reduce ROS and prevent autophagy. • SET protects cell from ROS via UCP2/3.

  3. Cell death and autophagy: cytokines, drugs, and nutritional factors.

    Science.gov (United States)

    Bursch, Wilfried; Karwan, Anneliese; Mayer, Miriam; Dornetshuber, Julia; Fröhwein, Ulrike; Schulte-Hermann, Rolf; Fazi, Barbara; Di Sano, Federica; Piredda, Lucia; Piacentini, Mauro; Petrovski, Goran; Fésüs, László; Gerner, Christopher

    2008-12-30

    Cells may use multiple pathways to commit suicide. In certain contexts, dying cells generate large amounts of autophagic vacuoles and clear large proportions of their cytoplasm, before they finally die, as exemplified by the treatment of human mammary carcinoma cells with the anti-estrogen tamoxifen (TAM, < or = 1 microM). Protein analysis during autophagic cell death revealed distinct proteins of the nuclear fraction including GST-pi and some proteasomal subunit constituents to be affected during autophagic cell death. Depending on the functional status of caspase-3, MCF-7 cells may switch between autophagic and apoptotic features of cell death [Fazi, B., Bursch, W., Fimia, G.M., Nardacci R., Piacentini, M., Di Sano, F., Piredda, L., 2008. Fenretinide induces autophagic cell death in caspase-defective breast cancer cells. Autophagy 4(4), 435-441]. Furthermore, the self-destruction of MCF-7 cells was found to be completed by phagocytosis of cell residues [Petrovski, G., Zahuczky, G., Katona, K., Vereb, G., Martinet, W., Nemes, Z., Bursch, W., Fésüs, L., 2007. Clearance of dying autophagic cells of different origin by professional and non-professional phagocytes. Cell Death Diff. 14 (6), 1117-1128]. Autophagy also constitutes a cell's strategy of defense upon cell damage by eliminating damaged bulk proteins/organelles. This biological condition may be exemplified by the treatment of MCF-7 cells with a necrogenic TAM-dose (10 microM), resulting in the lysis of almost all cells within 24h. However, a transient (1h) challenge of MCF-7 cells with the same dose allowed the recovery of cells involving autophagy. Enrichment of chaperones in the insoluble cytoplasmic protein fraction indicated the formation of aggresomes, a potential trigger for autophagy. In a further experimental model HL60 cells were treated with TAM, causing dose-dependent distinct responses: 1-5 microM TAM, autophagy predominant; 7-9 microM, apoptosis predominant; 15 microM, necrosis. These phenomena

  4. Programmed cell death

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The purpose of this conference to provide a multidisciplinary forum for exchange of state-of-the-art information on the role programmed cell death plays in normal development and homeostasis of many organisms. This volume contains abstracts of papers in the following areas: invertebrate development; immunology/neurology; bcl-2 family; biochemistry; programmed cell death in viruses; oncogenesis; vertebrate development; and diseases.

  5. Interactions between autophagic and endo-lysosomal markers in endothelial cells.

    Science.gov (United States)

    Oeste, Clara L; Seco, Esther; Patton, Wayne F; Boya, Patricia; Pérez-Sala, Dolores

    2013-05-01

    Autophagic and endo-lysosomal degradative pathways are essential for cell homeostasis. Availability of reliable tools to interrogate these pathways is critical to unveil their involvement in physiology and pathophysiology. Although several probes have been recently developed to monitor autophagic or lysosomal compartments, their specificity has not been validated through co-localization studies with well-known markers. Here, we evaluate the selectivity and interactions between one lysosomal (Lyso-ID) and one autophagosomal (Cyto-ID) probe under conditions modulating autophagy and/or endo-lysosomal function in live cells. The probe for acidic compartments Lyso-ID was fully localized inside vesicles positive for markers of late endosome-lysosomes, including Lamp1-GFP and GFP-CINCCKVL. Induction of autophagy by amino acid deprivation in bovine aortic endothelial cells caused an early and potent increase in the fluorescence of the proposed autophagy dye Cyto-ID. Cyto-ID-positive compartments extensively co-localized with the autophagosomal fluorescent reporter RFP-LC3, although the time and/or threshold for organelle detection was different for each probe. Interestingly, use of Cyto-ID in combination with Lysotracker Red or Lyso-ID allowed the observation of structures labeled with either one or both probes, the extent of co-localization increasing upon treatment with protease inhibitors. Inhibition of the endo-lysosomal pathway with chloroquine or U18666A resulted in the formation of large Cyto-ID and Lyso-ID-positive compartments. These results constitute the first assessment of the selectivity of Cyto-ID and Lyso-ID as probes for the autophagic and lysosomal pathways, respectively. Our observations show that these probes can be used in combination with protein-based markers for monitoring the interactions of both pathways in live cells.

  6. Blocking autophagic flux enhances matrine-induced apoptosis in human hepatoma cells.

    Science.gov (United States)

    Wang, Li; Gao, Chun; Yao, Shukun; Xie, Bushan

    2013-11-25

    Autophagy, a self-defense mechanism, has been found to be associated with drug resistance in hepatocellular carcinoma (HCC). Our study was designed to investigate the role and related mechanisms of autophagy in matrine-induced apoptosis in hepatoma cells of HepG2 and Bel7402. Cell apoptosis was detected by flow cytometry analysis (Annexin V-FITC/PI double-staining assay), the activity and activating cleavages of caspase-3, -8, and -9. MTT assay and colony forming assay were used to assess the effect of matrine on growth and proliferation of HCC cells. Autophagic flux in HCC cells was analyzed using the expression of LC3BI/II and p62/SQSTM1, GFP-LC3 transfection, and transmission electron microscopy. Moreover, regarding to the associated mechanisms, the effects of matrine on the phosphoinositide 3-kinase/AKT/mTOR pathway and beclin-1 were studied. Our results showed that: (1) both autophagy and apoptosis could be induced by treatment with matrine; (2) using the autophagic inhibitor chloroquine and beclin-1 small-interfering RNA, cell apoptosis induced by matrine could be enhanced in a caspase-dependent manner; and (3) autophagy was induced via inhibition of PI3K/AKT/mTOR pathway and up-regulation of beclin-1. In conclusion, inhibition of autophagy could enhance matrine-induced apoptosis in human hepatoma cells.

  7. Blocking Autophagic Flux Enhances Matrine-Induced Apoptosis in Human Hepatoma Cells

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    Li Wang

    2013-11-01

    Full Text Available Autophagy, a self-defense mechanism, has been found to be associated with drug resistance in hepatocellular carcinoma (HCC. Our study was designed to investigate the role and related mechanisms of autophagy in matrine-induced apoptosis in hepatoma cells of HepG2 and Bel7402. Cell apoptosis was detected by flow cytometry analysis (Annexin V–FITC/PI double-staining assay, the activity and activating cleavages of caspase-3, -8, and -9. MTT assay and colony forming assay were used to assess the effect of matrine on growth and proliferation of HCC cells. Autophagic flux in HCC cells was analyzed using the expression of LC3BI/II and p62/SQSTM1, GFP-LC3 transfection, and transmission electron microscopy. Moreover, regarding to the associated mechanisms, the effects of matrine on the phosphoinositide 3-kinase/AKT/mTOR pathway and beclin-1 were studied. Our results showed that: (1 both autophagy and apoptosis could be induced by treatment with matrine; (2 using the autophagic inhibitor chloroquine and beclin-1 small-interfering RNA, cell apoptosis induced by matrine could be enhanced in a caspase-dependent manner; and (3 autophagy was induced via inhibition of PI3K/AKT/mTOR pathway and up-regulation of beclin-1. In conclusion, inhibition of autophagy could enhance matrine-induced apoptosis in human hepatoma cells.

  8. YAP enhances autophagic flux to promote breast cancer cell survival in response to nutrient deprivation.

    Directory of Open Access Journals (Sweden)

    Qinghe Song

    Full Text Available The Yes-associated protein (YAP, a transcriptional coactivator inactivated by the Hippo tumor suppressor pathway, functions as an oncoprotein in a variety of cancers. However, its contribution to breast cancer remains controversial. This study investigated the role of YAP in breast cancer cells under nutrient deprivation (ND. Here, we show that YAP knockdown sensitized MCF7 breast cancer cells to nutrient deprivation-induced apoptosis. Furthermore, in response to ND, YAP increased the autolysosome degradation, thereby enhancing the cellular autophagic flux in breast cancer cells. Of note, autophagy is crucial for YAP to protect MCF7 cells from apoptosis under ND conditions. In addition, the TEA domain (TEAD family of growth-promoting transcription factors was indispensable for YAP-mediated regulation of autophagy. Collectively, our data reveal a role for YAP in promoting breast cancer cell survival upon ND stress and uncover an unappreciated function of YAP/TEAD in the regulation of autophagy.

  9. Staphylococcal lipoteichoic acid promotes osteogenic differentiation of mouse mesenchymal stem cells by increasing autophagic activity.

    Science.gov (United States)

    Liu, Xin; Wang, Yuan; Cao, Zhen; Dou, Ce; Bai, Yun; Liu, Chuan; Dong, Shiwu; Fei, Jun

    2017-02-16

    This study sought to explore the effect of staphylococcal lipoteichoic acid (LTA) on autophagy in mouse mesenchymal stem cells (MSCs), and then influence osteogenesis through the change of autophagy. C3H10T1/2 cells were induced by osteogenic medium with the treatment of LTA at different concentrations (1, 5, 10 μg/mL); 3-methyladenine (3-MA) were used as the autophagy inhibitor, and rapamycin (rapamycin, Rap) were used to activate autophagy; the effects on osteogenesis were detected by alkaline phosphatase staining, alizarin red staining, real-time quantitative PCR, and western blotting; autophagic activity was investigated by the expression of LC3-Ⅱand p62 proteins. Compared with control group, the expression of osteogenesis markers was significantly up-regulated with the LTA treatment on the mRNA and protein level; the positive rate of alkaline phosphatase was enhanced in the LTA groups; and the formation of calcium nodules was increased simultaneously. The expression of LC3-Ⅱ protein was increased in LTA groups, while the expression of p62 protein was decreased. Inhibition of autophagy significantly reduced the effect of LTA on osteogenesis of MSCs; the promotion of LTA on osteogenic differentiation was further enhanced when adding rapamycin to activate autophagic activity. It provides new insight of prevention and treatment for bone infection.

  10. Inhibition of autophagic flux by salinomycin results in anti-cancer effect in hepatocellular carcinoma cells.

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    Johannes Klose

    Full Text Available Salinomycin raised hope to be effective in anti-cancer therapies due to its capability to overcome apoptosis-resistance in several types of cancer cells. Recently, its effectiveness against human hepatocellular carcinoma (HCC cells both in vitro and in vivo was demonstrated. However, the mechanism of action remained unclear. Latest studies implicated interference with the degradation pathway of autophagy. This study aimed to determine the impact of Salinomycin on HCC-autophagy and whether primary human hepatocytes (PHH likewise are affected. Following exposure of HCC cell lines HepG2 and Huh7 to varying concentrations of Salinomycin (0-10 µM, comprehensive analysis of autophagic activity using western-blotting and flow-cytometry was performed. Drug effects were analyzed in the settings of autophagy stimulation by starvation or PP242-treatment and correlated with cell viability, proliferation, apoptosis induction, mitochondrial mass accumulation and reactive oxygen species (ROS formation. Impact on apoptosis induction and cell function of PHH was analyzed. Constitutive and stimulated autophagic activities both were effectively suppressed in HCC by Salinomycin. This inhibition was associated with dysfunctional mitochondria accumulation, increased apoptosis and decreased proliferation and cell viability. Effects of Salinomycin were dose and time dependent and could readily be replicated by pharmacological and genetic inhibition of HCC-autophagy alone. Salinomycin exposure to PHH resulted in transient impairment of synthesis function and cell viability without apoptosis induction. In conclusion, our data suggest that Salinomycin suppresses late stages of HCC-autophagy, leading to impaired recycling and accumulation of dysfunctional mitochondria with increased ROS-production all of which are associated with induction of apoptosis.

  11. Inhibition of autophagic flux by salinomycin results in anti-cancer effect in hepatocellular carcinoma cells.

    Science.gov (United States)

    Klose, Johannes; Stankov, Metodi V; Kleine, Moritz; Ramackers, Wolf; Panayotova-Dimitrova, Diana; Jäger, Mark D; Klempnauer, Jürgen; Winkler, Michael; Bektas, Hüseyin; Behrens, Georg M N; Vondran, Florian W R

    2014-01-01

    Salinomycin raised hope to be effective in anti-cancer therapies due to its capability to overcome apoptosis-resistance in several types of cancer cells. Recently, its effectiveness against human hepatocellular carcinoma (HCC) cells both in vitro and in vivo was demonstrated. However, the mechanism of action remained unclear. Latest studies implicated interference with the degradation pathway of autophagy. This study aimed to determine the impact of Salinomycin on HCC-autophagy and whether primary human hepatocytes (PHH) likewise are affected. Following exposure of HCC cell lines HepG2 and Huh7 to varying concentrations of Salinomycin (0-10 µM), comprehensive analysis of autophagic activity using western-blotting and flow-cytometry was performed. Drug effects were analyzed in the settings of autophagy stimulation by starvation or PP242-treatment and correlated with cell viability, proliferation, apoptosis induction, mitochondrial mass accumulation and reactive oxygen species (ROS) formation. Impact on apoptosis induction and cell function of PHH was analyzed. Constitutive and stimulated autophagic activities both were effectively suppressed in HCC by Salinomycin. This inhibition was associated with dysfunctional mitochondria accumulation, increased apoptosis and decreased proliferation and cell viability. Effects of Salinomycin were dose and time dependent and could readily be replicated by pharmacological and genetic inhibition of HCC-autophagy alone. Salinomycin exposure to PHH resulted in transient impairment of synthesis function and cell viability without apoptosis induction. In conclusion, our data suggest that Salinomycin suppresses late stages of HCC-autophagy, leading to impaired recycling and accumulation of dysfunctional mitochondria with increased ROS-production all of which are associated with induction of apoptosis.

  12. The convergent point of the endocytic and autophagic pathways in leydig cells

    Institute of Scientific and Technical Information of China (English)

    YIJING; XUEMINGTANG

    1999-01-01

    Endocytic tracers and marker enzyme of lysosomes were used in the present study to analyze the processes of autophagocytosis and endocytosis,and the convergent point of these two pathways in Leydig cells.The endocytic and autophagic compartments can be easily identified in Leydig cells,which makes easier to difine the stages of two pathways than was possible before.The evidences indicated that late endosomes (dense MVBs) deliver their endocytosed gold tracers together with lysosomal enzymes to the early autophagosomes and they are the convergent point of the two pathways.During this convergent process,the early autophadosomes transform into late autophagosomes and the late endosomes transform into mature lysosomes.

  13. Programmed cell death: Superman meets Dr Death.

    Science.gov (United States)

    Meier, Pascal; Silke, John

    2003-12-01

    This year's Cold Spring Harbor meeting on programmed cell death (September 17-21, 2003), organised by Craig Thompson and Junying Yuan, was proof that the 'golden age' of research in this field is far from over. There was a flurry of fascinating insights into the regulation of diverse apoptotic pathways and unexpected non-apoptotic roles for some of the key apoptotic regulators and effectors. In addition to their role in cell death, components of the apoptotic molecular machinery are now known to also function in a variety of essential cellular processes, such as regulating glucose homeostasis, lipid metabolism, cell proliferation and differentiation.

  14. Targeting autophagic pathways for cancer drug discovery

    Institute of Scientific and Technical Information of China (English)

    Bo Liu; Jin-Ku Bao; Jin-Ming Yang; Yan Cheng

    2013-01-01

    Autophagy,an evolutionarily conserved lysosomal degradation process,has drawn an increasing amount of attention in recent years for its role in a variety of human diseases,such as cancer.Notably,autophagy plays an important role in regulating several survival and death signaling pathways that determine cell fate in cancer.To date,substantial evidence has demonstrated that some key autophagic mediators,such as autophagy-related genes (ATGs),PI3K,mTOR,p53,and Beclin-1,may play crucial roles in modulating autophagic activity in cancer initiation and progression.Because autophagy-modulating agents such as rapamycin and chloroquine have already been used clinically to treat cancer,it is conceivable that targeting autophagic pathways may provide a new opportunity for discovery and development of more novel cancer therapeutics.With a deeper understanding of the regulatory mechanisms governing autophagy,we will have a better opportunity to facilitate the exploitation of autophagy as a target for therapeutic intervention in cancer.This review discusses the current status of targeting autophagic pathways as a potential cancer therapy.

  15. Carbazole alkaloids from Murraya koenigii trigger apoptosis and autophagic flux inhibition in human oral squamous cell carcinoma cells.

    Science.gov (United States)

    Utaipan, Tanyarath; Athipornchai, Anan; Suksamrarn, Apichart; Jirachotikoon, Canussanun; Yuan, Xiaohong; Lertcanawanichakul, Monthon; Chunglok, Warangkana

    2017-01-01

    Carbazole alkaloids, a major constituent of Murraya koenigii (L.) Sprengel (Rutaceae), exhibit biological effects such as anticancer activity via the induction of apoptosis, and they represent candidate chemotherapeutic agents. Oral squamous cell carcinoma (OSCC) is the most prevalent cancer of the oral cavity and a growing and serious health problem worldwide. In this study, we investigated the anticancer properties and mechanisms of action of two carbazole alkaloids derived from M. koenigii leaves, mahanine and isomahanine, in the OSCC cell line CLS-354. At 15 μM, mahanine and isomahanine were cytotoxic to CLS-354 cells, triggering apoptosis via caspase-dependent and -independent mechanisms. Autophagosomes, visualised using monodansylcadaverine (MDC) labelling, were numerous in carbazole alkaloid-treated cells. Mahanine and isomahanine markedly induced the expression of the autophagosome marker microtubule-associated protein 1 light chain 3, type II (LC3B-II). Genetic and chemical inhibition of autophagy via silencing of the Autophagy protein 5 gene and exposure to bafilomycin A1 (BafA1), respectively, did not arrest carbazole alkaloid-induced apoptosis, indicating that it occurs independently of autophagic activation. Surprisingly, both carbazole alkaloids caused increased accumulation of p62/sequestosome1 (p62/SQSTM1), with coordinated expression of LC3B-II and cleaved caspase-3, suggesting inhibition of autophagic flux. Our results suggest that inhibition of autophagic flux is associated with carbazole alkaloid-induced apoptosis. Our findings provide evidence of a novel cytotoxic action of natural carbazole alkaloids and support their use as candidate chemotherapeutic agents for the treatment of OSCC.

  16. Immunohistochemistry of Programmed Cell Death in Archival Human Pathology Specimens

    Directory of Open Access Journals (Sweden)

    Takami Matsuyama

    2012-05-01

    Full Text Available Immunohistochemistry (IHC for detecting key signal molecules involved in programmed cell death (PCD in archival human pathology specimens is fairly well established. Detection of cleaved caspase-3 in lymphocytes in rheumatoid arthritis (RA and gastric surface foveolar glandular epithelia but not in synoviocytes in RA, gastric fundic glandular epithelia, or nasal NK/T-cell lymphoma (NKTCL cells suggests anti-apoptotic mechanisms in cell differentiation and in oncogenesis such as the induction of survivin. Enzymatically pretreated and ultra-super sensitive detection of beclin-1 in synoviocytes in RA and gastric fundic glandular epithelia suggests enhanced autophagy. The deposition of beclin-1 in fibrinoid necrosis in RA and expression of beclin-1 in detached gastric fundic glandular cells suggest that enhanced autophagy undergoes autophagic cell death (ACD. NKTCL exhibited enhanced autophagy through LC3 labeling and showed densely LC3 labeled cell-debris in regions of peculiar necrosis without deposition of beclin-1, indicating massive ACD in NKTCL and the alternative pathway enhancing autophagy following autophagic vesicle nucleation. Autophagy progression was monitored by labeling aggregated mitochondria and cathepsin D. The cell-debris in massive ACD in NKTCL were positive for 8-hydroxydeoxyguanosine, suggesting DNA oxidation occurred in ACD. Immunohistochemical autophagy and PCD analysis in archival human pathology specimens may offer new insights into autophagy in humans.

  17. Cell Death Pathways and Phthalocyanine as an Efficient Agent for Photodynamic Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Ivan Mfouo-Tynga

    2015-05-01

    Full Text Available The mechanisms of cell death can be predetermined (programmed or not and categorized into apoptotic, autophagic and necrotic pathways. The process of Hayflick limits completes the execution of death-related mechanisms. Reactive oxygen species (ROS are associated with oxidative stress and subsequent cytodamage by oxidizing and degrading cell components. ROS are also involved in immune responses, where they stabilize and activate both hypoxia-inducible factors and phagocytic effectors. ROS production and presence enhance cytodamage and photodynamic-induced cell death. Photodynamic cancer therapy (PDT uses non-toxic chemotherapeutic agents, photosensitizer (PS, to initiate a light-dependent and ROS-related cell death. Phthalocyanines (PCs are third generation and stable PSs with improved photochemical abilities. They are effective inducers of cell death in various neoplastic models. The metallated PCs localize in critical cellular organelles and are better inducers of cell death than other previous generation PSs as they favor mainly apoptotic cell death events.

  18. The Impact of Autophagy on Cell Death Modalities

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    Stefan W. Ryter

    2014-01-01

    Full Text Available Autophagy represents a homeostatic cellular mechanism for the turnover of organelles and proteins, through a lysosome-dependent degradation pathway. During starvation, autophagy facilitates cell survival through the recycling of metabolic precursors. Additionally, autophagy can modulate other vital processes such as programmed cell death (e.g., apoptosis, inflammation, and adaptive immune mechanisms and thereby influence disease pathogenesis. Selective pathways can target distinct cargoes (e.g., mitochondria and proteins for autophagic degradation. At present, the causal relationship between autophagy and various forms of regulated or nonregulated cell death remains unclear. Autophagy can occur in association with necrosis-like cell death triggered by caspase inhibition. Autophagy and apoptosis have been shown to be coincident or antagonistic, depending on experimental context, and share cross-talk between signal transduction elements. Autophagy may modulate the outcome of other regulated forms of cell death such as necroptosis. Recent advances suggest that autophagy can dampen inflammatory responses, including inflammasome-dependent caspase-1 activation and maturation of proinflammatory cytokines. Autophagy may also act as regulator of caspase-1 dependent cell death (pyroptosis. Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases in which apoptosis or other forms of regulated cell death may play a cardinal role.

  19. Atg3 Overexpression Enhances Bortezomib-Induced Cell Death in SKM-1 Cell.

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    Lin Zhuang

    Full Text Available Myelodysplastic syndrome (MDS is a group of heterogeneous hematopoietic stem cell malignancies with a high risk of transformation into acute myeloid leukemia (AML. Clonal evolutions are significantly associated with transformation to AML. According to a gene expression microarray, atg3 is downregulated in MDS patients progressing to leukemia, but less is known about the function of Atg3 in the survival and death of MSD/AML cells. Moreover, the role of autophagy as a result of bortezomib treatment is controversial. The current study was designed to investigate the function of Atg3 in SKM-1 cells and to study the effect of Atg3 on cell viability and cell death following bortezomib treatment.Four leukemia cell lines (SKM-1, THP-1, NB4 and K562 and two healthy patients' bone marrow cells were analyzed for Atg3 expression via qRT-PCR and Western blotting analysis. The role of Atg3 in SKM-1 cell survival and cell death was analyzed by CCK-8 assay, trypan blue exclusion assay, DAPI staining and Annexin V/PI dual staining with or without bortezomib treatment. Western blotting analysis was used to detect proteins in autophagic and caspase signaling pathways. Electron microscopy was used to observe ultrastructural changes after Atg3 overexpression.Downregulation of Atg3 expression was detected in four leukemia cell lines compared with healthy bone marrow cells. Atg3 mRNA was significantly decreased in MDS patients' bone marrow cells. Overexpression of Atg3 in SKM-1 cells resulted in AKT-mTOR-dependent autophagy, a significant reduction in cell proliferation and increased cell death, which could be overcome by the autophagy inhibitor 3-MA. SKM-1 cells overexpressing Atg3 were hypersensitive to bortezomib treatment at different concentrations via autophagic cell death and enhanced sensitivity to apoptosis in the SKM-1 cell line. Following treatment with 3-MA, the sensitivity of Atg3-overexpressing cells to bortezomib treatment was reduced. Atg3 knockdown

  20. NF-κB p65 repression by the sesquiterpene lactone, Helenalin, contributes to the induction of autophagy cell death

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    Lim Chuan

    2012-07-01

    Full Text Available Abstract Background Numerous studies have demonstrated that autophagy plays a vital role in maintaining cellular homeostasis. Interestingly, several anticancer agents were found to exert their anticancer effects by triggering autophagy. Emerging data suggest that autophagy represents a novel mechanism that can be exploited for therapeutic benefit. Pharmacologically active natural compounds such as those from marine, terrestrial plants and animals represent a promising resource for novel anticancer drugs. There are several prominent examples from the past proving the success of natural products and derivatives exhibiting anticancer activity. Helenalin, a sesquiterpene lactone has been demonstrated to have potent anti-inflammatory and antitumor activity. Albeit previous studies demonstrating helenalin’s multi modal action on cellular proliferative and apoptosis, the mechanisms underlying its action are largely unexplained. Methods To deduce the mechanistic action of helenalin, cancer cells were treated with the drug at various concentrations and time intervals. Using western blot, FACS analysis, overexpression and knockdown studies, cellular signaling pathways were interrogated focusing on apoptosis and autophagy markers. Results We show here that helenalin induces sub-G1 arrest, apoptosis, caspase cleavage and increases the levels of the autophagic markers. Suppression of caspase cleavage by the pan caspase inhibitor, Z-VAD-fmk, suppressed induction of LC3-B and Atg12 and reduced autophagic cell death, indicating caspase activity was essential for autophagic cell death induced by helenalin. Additionally, helenalin suppressed NF-κB p65 expression in a dose and time dependent manner. Exogenous overexpression of p65 was accompanied by reduced levels of cell death whereas siRNA mediated suppression led to augmented levels of caspase cleavage, autophagic cell death markers and increased cell death. Conclusions Taken together, these results show

  1. Cotyledon cells of Vigna mungo seedlings use at least two distinct autophagic machineries for degradation of starch granules and cellular components.

    Science.gov (United States)

    Toyooka, K; Okamoto, T; Minamikawa, T

    2001-09-01

    alpha-Amylase is expressed in cotyledons of germinated Vigna mungo seeds and is responsible for the degradation of starch that is stored in the starch granule (SG). Immunocytochemical analysis of the cotyledon cells with anti-alpha-amylase antibody showed that alpha-amylase is transported to protein storage vacuole (PSV) and lytic vacuole (LV), which is converted from PSV by hydrolysis of storage proteins. To observe the insertion/degradation processes of SG into/in the inside of vacuoles, ultrastructural analyses of the cotyledon cells were conducted. The results revealed that SG is inserted into LV through autophagic function of LV and subsequently degraded by vacuolar alpha-amylase. The autophagy for SG was structurally similar to micropexophagy detected in yeast cells. In addition to the autophagic process for SG, autophagosome-mediated autophagy for cytoplasm and mitochondria was detected in the cotyledon cells. When the embryo axes were removed from seeds and the detached cotyledons were incubated, the autophagosome-mediated autophagy was observed, but the autophagic process for the degradation of SG was not detected, suggesting that these two autophagic processes were mediated by different cellular mechanisms. The two distinct autophagic processes were thought to be involved in the breakdown of SG and cell components in the cells of germinated cotyledon.

  2. A systems level strategy for analyzing the cell death network: implication in exploring the apoptosis/autophagy connection.

    Science.gov (United States)

    Zalckvar, E; Yosef, N; Reef, S; Ber, Y; Rubinstein, A D; Mor, I; Sharan, R; Ruppin, E; Kimchi, A

    2010-08-01

    The mammalian cell death network comprises three distinct functional modules: apoptosis, autophagy and programmed necrosis. Currently, the field lacks systems level approaches to assess the extent to which the intermodular connectivity affects cell death performance. Here, we developed a platform that is based on single and double sets of RNAi-mediated perturbations targeting combinations of apoptotic and autophagic genes. The outcome of perturbations is measured both at the level of the overall cell death responses, using an unbiased quantitative reporter, and by assessing the molecular responses within the different functional modules. Epistatic analyses determine whether seemingly unrelated pairs of proteins are genetically linked. The initial running of this platform in etoposide-treated cells, using a few single and double perturbations, identified several levels of connectivity between apoptosis and autophagy. The knock down of caspase3 turned on a switch toward autophagic cell death, which requires Atg5 or Beclin-1. In addition, a reciprocal connection between these two autophagic genes and apoptosis was identified. By applying computational tools that are based on mining the protein-protein interaction database, a novel biochemical pathway connecting between Atg5 and caspase3 is suggested. Scaling up this platform into hundreds of perturbations potentially has a wide, general scope of applicability, and will provide the basis for future modeling of the cell death network.

  3. Interplay between autophagy and programmed cell death in mammalian neural stem cells

    Directory of Open Access Journals (Sweden)

    Kyung Min Chung

    2013-08-01

    Full Text Available Mammalian neural stem cells (NSCs are of particular interestbecause of their role in brain development and function. Recentfindings suggest the intimate involvement of programmed celldeath (PCD in the turnover of NSCs. However, the underlyingmechanisms of PCD are largely unknown. Although apoptosis isthe best-defined form of PCD, accumulating evidence hasrevealed a wide spectrum of PCD encompassing apoptosis,autophagic cell death (ACD and necrosis. This mini-reviewaims to illustrate a unique regulation of PCD in NSCs. Theresults of our recent studies on autophagic death of adulthippocampal neural stem (HCN cells are also discussed. HCNcell death following insulin withdrawal clearly provides areliable model that can be used to analyze the molecularmechanisms of ACD in the larger context of PCD. Moreresearch efforts are needed to increase our understanding of themolecular basis of NSC turnover under degenerating conditions,such as aging, stress and neurological diseases. Efforts aimed atprotecting and harnessing endogenous NSCs will offer novelopportunities for the development of new therapeutic strategiesfor neuropathologies. [BMB Reports 2013; 46(8: 383-390

  4. Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial Endosymbiont.

    Directory of Open Access Journals (Sweden)

    Weiwen Zheng

    Full Text Available Programmed cell death (PCD is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20% of the total cell population, depending on the cell type and host developmental stage. Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays, together with visualization of cytoskeleton alterations (FITC-phalloidin staining, showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20 further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom.

  5. Glutathione in Cancer Cell Death

    Directory of Open Access Journals (Sweden)

    Jose M. Estrela

    2011-03-01

    Full Text Available Glutathione (L-γ-glutamyl-L-cysteinyl-glycine; GSH in cancer cells is particularly relevant in the regulation of carcinogenic mechanisms; sensitivity against cytotoxic drugs, ionizing radiations, and some cytokines; DNA synthesis; and cell proliferation and death. The intracellular thiol redox state (controlled by GSH is one of the endogenous effectors involved in regulating the mitochondrial permeability transition pore complex and, in consequence, thiol oxidation can be a causal factor in the mitochondrion-based mechanism that leads to cell death. Nevertheless GSH depletion is a common feature not only of apoptosis but also of other types of cell death. Indeed rates of GSH synthesis and fluxes regulate its levels in cellular compartments, and potentially influence switches among different mechanisms of death. How changes in gene expression, post-translational modifications of proteins, and signaling cascades are implicated will be discussed. Furthermore, this review will finally analyze whether GSH depletion may facilitate cancer cell death under in vivo conditions, and how this can be applied to cancer therapy.

  6. Glutathione in Cancer Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Angel L. [Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 17 Av. Blasco Ibanez, 46010 Valencia (Spain); Mena, Salvador [Green Molecular SL, Pol. Ind. La Coma-Parc Cientific, 46190 Paterna, Valencia (Spain); Estrela, Jose M., E-mail: jose.m.estrela@uv.es [Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 17 Av. Blasco Ibanez, 46010 Valencia (Spain)

    2011-03-11

    Glutathione (L-γ-glutamyl-L-cysteinyl-glycine; GSH) in cancer cells is particularly relevant in the regulation of carcinogenic mechanisms; sensitivity against cytotoxic drugs, ionizing radiations, and some cytokines; DNA synthesis; and cell proliferation and death. The intracellular thiol redox state (controlled by GSH) is one of the endogenous effectors involved in regulating the mitochondrial permeability transition pore complex and, in consequence, thiol oxidation can be a causal factor in the mitochondrion-based mechanism that leads to cell death. Nevertheless GSH depletion is a common feature not only of apoptosis but also of other types of cell death. Indeed rates of GSH synthesis and fluxes regulate its levels in cellular compartments, and potentially influence switches among different mechanisms of death. How changes in gene expression, post-translational modifications of proteins, and signaling cascades are implicated will be discussed. Furthermore, this review will finally analyze whether GSH depletion may facilitate cancer cell death under in vivo conditions, and how this can be applied to cancer therapy.

  7. Cell death in genome evolution.

    Science.gov (United States)

    Teng, Xinchen; Hardwick, J Marie

    2015-03-01

    Inappropriate survival of abnormal cells underlies tumorigenesis. Most discoveries about programmed cell death have come from studying model organisms. Revisiting the experimental contexts that inspired these discoveries helps explain confounding biases that inevitably accompany such discoveries. Amending early biases has added a newcomer to the collection of cell death models. Analysis of gene-dependent death in yeast revealed the surprising influence of single gene mutations on subsequent eukaryotic genome evolution. Similar events may influence the selection for mutations during early tumorigenesis. The possibility that any early random mutation might drive the selection for a cancer driver mutation is conceivable but difficult to demonstrate. This was tested in yeast, revealing that mutation of almost any gene appears to specify the selection for a new second mutation. Some human tumors contain pairs of mutant genes homologous to co-occurring mutant genes in yeast. Here we consider how yeast again provide novel insights into tumorigenesis.

  8. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Webb, J.S.; Thompson, L.S.; James, S.

    2003-01-01

    . However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death....... We propose that prophage-mediated cell death is an important mechanism of differentiation inside microcolonies that facilitates dispersal of a subpopulation of surviving cells....

  9. Avian influenza A virus H5N1 causes autophagy-mediated cell death through suppression of mTOR signaling

    Institute of Scientific and Technical Information of China (English)

    Jianhui Ma; Qian Sun; Ruifang Mi; Hongbing Zhang

    2011-01-01

    Of the few avian influenza viruses that have crossed the species barrier to infect humans,the highly pathogenic influenza A (H5N1) strain has claimed the lives of more than half of the infected patients.With largely unknown mechanism of lung injury by H5N1 infection,acute respiratory distress syndrome (ARDS) is the major cause of death among the victims.Here we present the fact that H5N1 caused autophagic cell death through suppression of mTOR signaling.Inhibition of autophagy,either by depletion of autophagy gene Beclinl or by autophagy inhibitor 3-methyladenine (3-MA),significantly reduced H5N1 mediated cell death.We suggest that autophagic cell death may contribute to the development of ARDS in H5N1 influenza patients and inhibition of autophagy could therefore become a novel strategy for the treatment of H5N1 infection.

  10. New steroidal aromatase inhibitors: Suppression of estrogen-dependent breast cancer cell proliferation and induction of cell death

    Directory of Open Access Journals (Sweden)

    Roleira Fernanda MF

    2008-07-01

    Full Text Available Abstract Background Aromatase, the cytochrome P-450 enzyme (CYP19 responsible for estrogen biosynthesis, is an important target for the treatment of estrogen-dependent breast cancer. In fact, the use of synthetic aromatase inhibitors (AI, which induce suppression of estrogen synthesis, has shown to be an effective alternative to the classical tamoxifen for the treatment of postmenopausal patients with ER-positive breast cancer. New AIs obtained, in our laboratory, by modification of the A and D-rings of the natural substrate of aromatase, compounds 3a and 4a, showed previously to efficiently suppress aromatase activity in placental microsomes. In the present study we have investigated the effects of these compounds on cell proliferation, cell cycle progression and induction of cell death using the estrogen-dependent human breast cancer cell line stably transfected with the aromatase gene, MCF-7 aro cells. Results The new steroids inhibit hormone-dependent proliferation of MCF-7aro cells in a time and dose-dependent manner, causing cell cycle arrest in G0/G1 phase and inducing cell death with features of apoptosis and autophagic cell death. Conclusion Our in vitro studies showed that the two steroidal AIs, 3a and 4a, are potent inhibitors of breast cancer cell proliferation. Moreover, it was also shown that the antiproliferative effects of these two steroids on MCF-7aro cells are mediated by disrupting cell cycle progression, through cell cycle arrest in G0/G1 phase and induction of cell death, being the dominant mechanism autophagic cell death. Our results are important for the elucidation of the cellular effects of steroidal AIs on breast cancer.

  11. Polycation-mediated integrated cell death processes

    DEFF Research Database (Denmark)

    Parhamifar, Ladan; Andersen, Helene; Wu, Linping

    2014-01-01

    standard. PEIs are highly efficient transfectants, but depending on their architecture and size they induce cytotoxicity through different modes of cell death pathways. Here, we briefly review dynamic and integrated cell death processes and pathways, and discuss considerations in cell death assay design...

  12. Programmed cell death in Giardia.

    Science.gov (United States)

    Bagchi, Susmita; Oniku, Abraham E; Topping, Kate; Mamhoud, Zahra N; Paget, Timothy A

    2012-06-01

    Programmed cell death (PCD) has been observed in many unicellular eukaryotes; however, in very few cases have the pathways been described. Recently the early divergent amitochondrial eukaryote Giardia has been included in this group. In this paper we investigate the processes of PCD in Giardia. We performed a bioinformatics survey of Giardia genomes to identify genes associated with PCD alongside traditional methods for studying apoptosis and autophagy. Analysis of Giardia genomes failed to highlight any genes involved in apoptotic-like PCD; however, we were able to induce apoptotic-like morphological changes in response to oxidative stress (H2O2) and drugs (metronidazole). In addition we did not detect caspase activity in induced cells. Interestingly, we did observe changes resembling autophagy when cells were starved (staining with MDC) and genome analysis revealed some key genes associated with autophagy such as TOR, ATG1 and ATG 16. In organisms such as Trichomonas vaginalis, Entamoeba histolytica and Blastocystis similar observations have been made but no genes have been identified. We propose that Giardia possess a pathway of autophagy and a form of apoptosis very different from the classical known mechanism; this may represent an early form of programmed cell death.

  13. Simultaneous activation of mitophagy and autophagy by staurosporine protects against dopaminergic neuronal cell death.

    Science.gov (United States)

    Ha, Ji-Young; Kim, Ji-Soo; Kim, Seo-Eun; Son, Jin H

    2014-02-21

    Abnormal autophagy is frequently observed during dopaminergic neurodegeneration in Parkinson's disease (PD). However, it is not yet firmly established whether active autophagy is beneficial or pathogenic with respect to dopaminergic cell loss. Staurosporine, a common inducer of apoptosis, is often used in mechanistic studies of dopaminergic cell death. Here we report that staurosporine activates both autophagy and mitophagy simultaneously during dopaminergic neuronal cell death, and evaluate the physiological significance of these processes during cell death. First, staurosporine treatment resulted in induction of autophagy in more than 75% of apoptotic cells. Pharmacological inhibition of autophagy by bafilomycin A1 decreased significantly cell viability. In addition, staurosporine treatment resulted in activation of the PINK1-Parkin mitophagy pathway, of which deficit underlies some familial cases of PD, in the dopaminergic neuronal cell line, SN4741. The genetic blockade of this pathway by PINK1 null mutation also dramatically increased staurosporine-induced cell death. Taken together, our data suggest that staurosporine induces both mitophagy and autophagy, and that these pathways exert a significant neuroprotective effect, rather than a contribution to autophagic cell death. This model system may therefore be useful for elucidating the mechanisms underlying crosstalk between autophagy, mitophagy, and cell death in dopaminergic neurons.

  14. Investigating the cell death mechanisms in primary prostate cancer cells using low-temperature plasma treatment

    Science.gov (United States)

    O'Connell, Deborah; Hirst, A. M.; Packer, J. R.; Simms, M. S.; Mann, V. M.; Frame, F. M.; Maitland, N. J.

    2016-09-01

    Atmospheric pressure plasmas have shown considerable promise as a potential cancer therapy. An atmospheric pressure plasma driven with kHz kV excitation, operated with helium and oxygen admixtures is used to investigate the interaction with prostate cancer cells. The cytopathic effect was verified first in two commonly used prostate cancer cell lines (BPH-1 and PC-3 cells) and further extended to examine the effects in paired normal and tumour prostate epithelial cells cultured directly from patient tissues. Through the formation of reactive species in cell culture media, and potentially other plasma components, we observed high levels of DNA damage, together with reduced cell viability and colony-forming ability. We observed differences in response between the prostate cell lines and primary cells, particularly in terms of the mechanism of cell death. The primary cells ultimately undergo necrotic cell death in both the normal and tumour samples, in the complete absence of apoptosis. In addition, we provide the first evidence of an autophagic response in primary cells. This work highlights the importance of studying primary cultures in order to gain a more realistic insight into patient efficacy. EPSRC EP/H003797/1 & EP/K018388/1, Yorkshire Cancer Research: YCR Y257PA.

  15. Programmed Cell Death in Neurospora crassa

    Directory of Open Access Journals (Sweden)

    A. Pedro Gonçalves

    2014-01-01

    Full Text Available Programmed cell death has been studied for decades in mammalian cells, but simpler organisms, including prokaryotes, plants, and fungi, also undergo regulated forms of cell death. We highlight the usefulness of the filamentous fungus Neurospora crassa as a model organism for the study of programmed cell death. In N. crassa, cell death can be triggered genetically due to hyphal fusion between individuals with different allelic specificities at het loci, in a process called “heterokaryon incompatibility.” Chemical induction of cell death can also be achieved upon exposure to death-inducing agents like staurosporine, phytosphingosine, or hydrogen peroxide. A summary of the recent advances made by our and other groups on the discovery of the mechanisms and mediators underlying the process of cell death in N. crassa is presented.

  16. Detection of Cell Death in Drosophila Tissues

    Science.gov (United States)

    Vasudevan, Deepika; Ryoo, Hyung Don

    2016-01-01

    Drosophila has served as a particularly attractive model to study cell death due to the vast array of tools for genetic manipulation under defined spatial and temporal conditions in vivo as well as in cultured cells. These genetic methods have been well supplemented by enzymatic assays and a panel of antibodies recognizing cell death markers. This chapter discusses reporters, mutants and assays used by various laboratories to study cell death in the context of development and in response to external insults. PMID:27108437

  17. Catalase and NO CATALASE ACTIVITY1 promote autophagy-dependent cell death in Arabidopsis

    DEFF Research Database (Denmark)

    Hackenberg, Thomas; Andersen, Trine Juul; Auzina, Aija

    2013-01-01

    Programmed cell death often depends on generation of reactive oxygen species, which can be detoxified by antioxidative enzymes, including catalases. We previously isolated catalase-deficient mutants (cat2) in a screen for resistance to hydroxyurea-induced cell death. Here, we identify an Arabidop......Programmed cell death often depends on generation of reactive oxygen species, which can be detoxified by antioxidative enzymes, including catalases. We previously isolated catalase-deficient mutants (cat2) in a screen for resistance to hydroxyurea-induced cell death. Here, we identify......-induced autophagy appeared normal in the nca1 and cat2 mutants. By contrast, autophagic degradation induced by avrRpm1 challenge was compromised, indicating that catalase acted upstream of immunity-triggered autophagy. The direct interaction of catalase with reactive oxygen species could allow catalase to act...

  18. Mild MPP(+) exposure impairs autophagic degradation through a novel lysosomal acidity-independent mechanism.

    Science.gov (United States)

    Miyara, Masatsugu; Kotake, Yaichiro; Tokunaga, Wataru; Sanoh, Seigo; Ohta, Shigeru

    2016-10-01

    Parkinson's disease (PD) is the second most common neurodegenerative disorder, but its underlying cause remains unknown. Although recent studies using PD-related neurotoxin MPP(+) suggest autophagy involvement in the pathogenesis of PD, the effect of MPP(+) on autophagic processes under mild exposure, which mimics the slow progressive nature of PD, remains largely unclear. We examined the effect of mild MPP(+) exposure (10 and 200 μM for 48 h), which induces a more slowly developing cell death, on autophagic processes and the mechanistic differences with acute MPP(+) toxicity (2.5 and 5 mM for 24 h). In SH-SY5Y cells, mild MPP(+) exposure predominantly inhibited autophagosome degradation, whereas acute MPP(+) exposure inhibited both autophagosome degradation and basal autophagy. Mild MPP(+) exposure reduced lysosomal hydrolase cathepsin D activity without changing lysosomal acidity, whereas acute exposure decreased lysosomal density. Lysosome biogenesis enhancers trehalose and rapamycin partially alleviated mild MPP(+) exposure induced impaired autophagosome degradation and cell death, but did not prevent the pathogenic response to acute MPP(+) exposure, suggesting irreversible lysosomal damage. We demonstrated impaired autophagic degradation by MPP(+) exposure and mechanistic differences between mild and acute MPP(+) toxicities. Mild MPP(+) toxicity impaired autophagosome degradation through novel lysosomal acidity-independent mechanisms. Sustained mild lysosomal damage may contribute to PD. We examined the effects of MPP(+) on autophagic processes under mild exposure, which mimics the slow progressive nature of Parkinson's disease, in SH-SY5Y cells. This study demonstrated impaired autophagic degradation through a reduction in lysosomal cathepsin D activity without altering lysosomal acidity by mild MPP(+) exposure. Mechanistic differences between acute and mild MPP(+) toxicity were also observed. Sustained mild damage of lysosome may be an underlying cause

  19. Cell biology. Metabolic control of cell death.

    Science.gov (United States)

    Green, Douglas R; Galluzzi, Lorenzo; Kroemer, Guido

    2014-09-19

    Beyond their contribution to basic metabolism, the major cellular organelles, in particular mitochondria, can determine whether cells respond to stress in an adaptive or suicidal manner. Thus, mitochondria can continuously adapt their shape to changing bioenergetic demands as they are subjected to quality control by autophagy, or they can undergo a lethal permeabilization process that initiates apoptosis. Along similar lines, multiple proteins involved in metabolic circuitries, including oxidative phosphorylation and transport of metabolites across membranes, may participate in the regulated or catastrophic dismantling of organelles. Many factors that were initially characterized as cell death regulators are now known to physically or functionally interact with metabolic enzymes. Thus, several metabolic cues regulate the propensity of cells to activate self-destructive programs, in part by acting on nutrient sensors. This suggests the existence of "metabolic checkpoints" that dictate cell fate in response to metabolic fluctuations. Here, we discuss recent insights into the intersection between metabolism and cell death regulation that have major implications for the comprehension and manipulation of unwarranted cell loss.

  20. Autophagy and apoptosis act as partners to induce germ cell death after heat stress in mice.

    Directory of Open Access Journals (Sweden)

    Mianqiu Zhang

    Full Text Available Testicular heating suppresses spermatogenesis which is marked by germ cell loss via apoptotic pathways. Recently, it is reported that autophagy also can be induced by heat treatment in somatic cells. In this study, the status of autophagy in germ cells after heat treatment, as well as the partnership between autophagy and apoptosis in these cells was investigated. The results demonstrated that besides initiating apoptotic pathways, heat also induced autophagic pathways in germ cells. Exposure of germ cells to hyperthermia resulted in several specific features of the autophagic process, including autophagosome formation and the conversion of LC3-I to LC3-II. Furthermore, the ubiquitin-like protein conjugation system was implicated as being likely responsible for heat-induced autophagy in germ cells since all genes involving this system were found to be expressed in the testes. In addition, the upstream protein in this system, Atg7 (Autophagy-related gene 7, was found to be expressed in all types of spermatogenic cells, and its expression level was positively correlated with the level of autophagy in germ cells. As a result, Atg7 was selected as the investigative target to further analyze the role of autophagy in heat-induced germ cell death. It was shown that down expression of Atg7 protein resulted in the notable decrease in the level of autophagy in heat-treated germ cells, and this down-regulation of autophagy caused by Atg7 knockdown further reduced the apoptotic rate of germ cells. These results suggest that autophagy plays a positive role in the process of germ cell apoptosis after heat treatment. In conclusion, this study demonstrates that heat triggers autophagy and apoptosis in germ cells. These two mechanisms might act as partners, not antagonist, to induce cell death and lead to eventual destruction of spermatogenesis.

  1. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms.

    Science.gov (United States)

    Pareja, Maria Eugenia Mansilla; Colombo, Maria I

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance.

  2. Dynamic effects of autophagy on arsenic trioxide-induced death of human leukemia cell line HL60 cells

    Institute of Scientific and Technical Information of China (English)

    Ya-ping YANG; Zhong-qin LIANG; Bo GAO; Yan-li JIA; Zheng-hong QIN

    2008-01-01

    Aim: To evaluate the contribution of an autophagic mechanism to the As2O3-induced death of human acute myeloid leukaemia cell line HL60 cells. Methods: The growth inhibition of HL60 cells induced by As2O3 was assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazohum bromide colorimetric assay. The ac-tivation of autophagy was determined with monodansylcadaverine labeling and transmission electron microscope. The role of autophagy in the As2O3-induced death of HL60 cells was assessed using autophagic and lysosomal inhibitors. Immunofluorescence, flow cytometry, and Western blot analysis were used to study the apoptotic and autophagic mechanisms. Results: After treatment with As2O3, the proliferation of HL60 cells was significantly inhibited and the formation of autophagosomes increased. The blockade of autophagy maturation with the autophagy-specific inhibitor 3-methyladenine (3-MA) or the lysosome-neutraliz-ing agent NH4C11 h before As2O3 potentiated the As2O3-induced death of HL60 cells. In contrast, 3-MA attenuated As2O3-induced death when administered 30 min after As2O3. 3-MA and NH4Cl also inhibited As2O3-induced upregulation of microtubule-associated protein 1 light chain 3, the protein required for autophagy in mammalian cells. Following As2O3, lysosomes were activated as indicated by increased levels of cathepsins B and L. The apoptotic response of HL60 cells to As2O3 was suggested by the collapse of mitochondrial membrane potential, re-lease of cytochrome c from mitochondria, and the activation of caspase-3. Pre-treatment with 3-MA prior to As2O3 amplified these apoptotic signals, while post-treatment with 3-MA 30 min after As2O3 attenuated the apoptotic pathways. Conclusion: Autophagy plays complex roles in the As2O3-induced death of HL60 cells; it inhibits As2O3-induced apoptosis in the initiation stage, but amplifies the AS2O3-mediated apoptotic program if it is persistently activated.

  3. Morphological classification of plant cell deaths

    DEFF Research Database (Denmark)

    van Doorn, W.G.; Beers, E.P.; Dangl, J.L.;

    2011-01-01

    the classification of PCD in plants. Here we suggest a classification based on morphological criteria. According to this classification, the use of the term 'apoptosis' is not justified in plants, but at least two classes of PCD can be distinguished: vacuolar cell death and necrosis. During vacuolar cell death......Programmed cell death (PCD) is an integral part of plant development and of responses to abiotic stress or pathogens. Although the morphology of plant PCD is, in some cases, well characterised and molecular mechanisms controlling plant PCD are beginning to emerge, there is still confusion about......, the cell contents are removed by a combination of autophagy-like process and release of hydrolases from collapsed lytic vacuoles. Necrosis is characterised by early rupture of the plasma membrane, shrinkage of the protoplast and absence of vacuolar cell death features. Vacuolar cell death is common during...

  4. Targeting Protective Autophagy Exacerbates UV-Triggered Apoptotic Cell Death

    Directory of Open Access Journals (Sweden)

    Shih-Hwa Chiou

    2012-01-01

    Full Text Available Autophagy is activated by various stresses, including DNA damage, and previous studies of DNA damage-induced autophagy have focused on the response to chemotherapeutic drugs, ionizing radiation, and reactive oxygen species. In this study, we investigated the biological significance of autophagic response to ultraviolet (UV irradiation in A549 and H1299 cells. Our results indicated that UV induces on-rate autophagic flux in these cells. Autophagy inhibition resulting from the knockdown of beclin-1 and Atg5 reduced cell viability and enhanced apoptosis. Moreover, we found that ATR phosphorylation was accompanied by microtubule-associated protein 1 light chain 3B II (LC3B-II expression during the early phases following UV irradiation, which is a well-established inducer of ATR. Knocking down ATR further attenuated the reduction in LC3B-II at early stages in response to UV treatment. Despite the potential role of ATR in autophagic response, reduced ATR expression does not affect autophagy induction during late phases (24 and 48 h after UV treatment. The result is consistent with the reduced ATR phosphorylation at the same time points and suggests that autophagic response at this stage is activated via a distinct pathway. In conclusion, this study demonstrated that autophagy acts as a cytoprotective mechanism against UV-induced apoptosis and that autophagy induction accompanied with apoptosis at late stages is independent of ATR activation.

  5. ASSAYING OF AUTOPHAGIC PROTEIN DEGRADATION

    NARCIS (Netherlands)

    C. Bauvy; A.J. Meijer; P. Codogno

    2009-01-01

    Macroautophagy is a three-step process: (1) autophagosomes form and mature, (2) the autophagosomes fuse with lysosomes, and (3) the autophagic cargo is degraded in the lysosomes. It is this lysosomal degradation of the autophagic cargo that constitutes the autophagic flux. As in the case of metaboli

  6. CERT depletion predicts chemotherapy benefit and mediates cytotoxic and polyploid‐specific cancer cell death through autophagy induction

    DEFF Research Database (Denmark)

    Lee, Alvin J. X.; Roylance, Rebecca; Sander, Jil

    2012-01-01

    and predictor of outcome in adjuvant chemotherapy‐treated patients with primary breast cancer. These data suggest that the induction of LAMP2‐dependent autophagic flux through CERT targeting may provide a rational approach to enhance multidrug sensitization and potentiate the death of polyploid cells following...... to the death of CIN cancer cells. Using an integrative functional genomics approach, we find that CERT‐specific multidrug sensitization is associated with enhanced autophagosome–lysosome flux, resulting from the expression of LAMP2 following CERT silencing in colorectal and HER2+ breast cancer cell lines. Live...... cell microscopy analysis revealed that CERT depletion induces LAMP2‐dependent death of polyploid cells following exit from mitosis in the presence of paclitaxel. We find that CERT is relatively over‐expressed in HER2+ breast cancer and CERT protein expression acts as an independent prognostic variable...

  7. Autophagy inhibitor chloroquine enhanced the cell death inducing effect of the flavonoid luteolin in metastatic squamous cell carcinoma cells.

    Directory of Open Access Journals (Sweden)

    Lien Verschooten

    Full Text Available BACKGROUND: Flavonoids are widely proposed as very interesting compounds with possible chemopreventive and therapeutic capacities. METHODS & RESULTS: In this study, we showed that in vitro treatment with the flavonoid Luteolin induced caspase-dependent cell death in a model of human cutaneous squamous cell carcinoma (SCC derived cells, representing a matched pair of primary tumor and its metastasis. Notably, no cytotoxic effects were observed in normal human keratinocytes when treated with similar doses of Luteolin. Luteolin-induced apoptosis was accompanied by inhibition of AKT signaling, and sensitivity decreased with tumor progression, as the primary MET1 SCC cells were considerably more sensitive to Luteolin than the isogenic metastatic MET4 cells. Extensive intracellular vacuolization was observed in Luteolin-treated MET4 cells, which were characterized as acidic lysosomal vacuoles, suggesting the involvement of autophagy. Transmission electron microscopy, mRFP-GFP-LC3 assay and p62 protein degradation, confirmed that Luteolin stimulated the autophagic process in the metastatic MET4 cells. Blocking autophagy using chloroquine magnified Luteolin-induced apoptosis in the metastatic SCC cells. CONCLUSION: Together, these results suggest that Luteolin has the capacity to induce selectively apoptotic cell death both in primary cutaneous SCC cells and in metastatic SCC cells in combination with chloroquine, an inhibitor of autophagosomal degradation. Hence, Luteolin might be a promising agent for the treatment of cutaneous SCC.

  8. Autophagic induction of amyotrophic lateral sclerosis-linked Cu/Zn superoxide dismutase 1 G93A mutant in NSC34 cells

    Institute of Scientific and Technical Information of China (English)

    Yanming Wei

    2014-01-01

    Previous studies have conifrmed that the beclin 1 complex plays a key role in the initial stage of autophagy and deregulated autophagy might involve in amyotrophic lateral sclerosis. However, the mechanism underlying altered autophagy associated with the beclin 1 complex remains un-clear. In this study, we transfected the Cu/Zn superoxide dismutase 1 G93A mutant protein into the motor neuron-like cell line NSC34 cultured in vitro. Western blotting and co-immunopre-cipitation showed that the Cu/Zn superoxide dismutase 1 G93A mutant enhanced the turnover of autophagic marker microtubule-associated protein light chain 3II (LC3II) and stimulated the conversion of EGFP-LC3I to EGFP-LC3II, but had little inlfuence on the binding capacity of the autophagy modulators ATG14L, rubicon, UVRAG, and hVps34 to beclin 1 during auto-phagosome formation. These results suggest that the amyotrophic lateral sclerosis-linked Cu/Zn superoxide dismutase 1 G93A mutant can upregulate autophagic activity in NSC34 cells, but that this does not markedly affect beclin 1 complex components.

  9. Deoxycholate, an Endogenous Cytotoxin/Genotoxin, Induces the Autophagic Stress-Survival Pathway: Implications for Colon Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Claire M. Payne

    2009-01-01

    Full Text Available We report that deoxycholate (DOC, a hydrophobic bile acid associated with a high-fat diet, activates the autophagic pathway in non-cancer colon epithelial cells (NCM-460, and that this activation contributes to cell survival. The DOC-induced increase in autophagy was documented by an increase in autophagic vacuoles (detected using transmission electron microscopy, increased levels of LC3-I and LC3-II (western blotting, an increase in acidic vesicles (fluorescence spectroscopy of monodansycadaverine and lysotracker red probes, and increased expression of the autophagic protein, beclin-1 (immunohistochemistry/western blotting. The DOC-induced increase in beclin-1 expression was ROS-dependent. Rapamycin (activator of autophagy pre-treatment of NCM-460 cells significantly (P<.05 decreased, and 3-MA (inhibitor of autophagy significantly (P<.05 increased the cell loss caused by DOC treatment, alone. Rapamycin pre-treatment of the apoptosis-resistant colon cancer cell line, HCT-116RC (developed in our laboratory, resulted in a significant decrease in DOC-induced cell death. Bafilomycin A1 and hydroxychloroquine (inhibitors of the autophagic process increased the DOC-induced percentage of apoptotic cells in HCT-116RC cells. It was concluded that the activation of autophagy by DOC has important implications for colon carcinogenesis and for the treatment of colon cancer in conjunction with commonly used chemotherapeutic agents.

  10. Control of adult neurogenesis by programmed cell death in the mammalian brain.

    Science.gov (United States)

    Ryu, Jae Ryun; Hong, Caroline Jeeyeon; Kim, Joo Yeon; Kim, Eun-Kyoung; Sun, Woong; Yu, Seong-Woon

    2016-04-21

    The presence of neural stem cells (NSCs) and the production of new neurons in the adult brain have received great attention from scientists and the public because of implications to brain plasticity and their potential use for treating currently incurable brain diseases. Adult neurogenesis is controlled at multiple levels, including proliferation, differentiation, migration, and programmed cell death (PCD). Among these, PCD is the last and most prominent process for regulating the final number of mature neurons integrated into neural circuits. PCD can be classified into apoptosis, necrosis, and autophagic cell death and emerging evidence suggests that all three may be important modes of cell death in neural stem/progenitor cells. However, the molecular mechanisms that regulate PCD and thereby impact the intricate balance between self-renewal, proliferation, and differentiation during adult neurogenesis are not well understood. In this comprehensive review, we focus on the extent, mechanism, and biological significance of PCD for the control of adult neurogenesis in the mammalian brain. The role of intrinsic and extrinsic factors in the regulation of PCD at the molecular and systems levels is also discussed. Adult neurogenesis is a dynamic process, and the signals for differentiation, proliferation, and death of neural progenitor/stem cells are closely interrelated. A better understanding of how adult neurogenesis is influenced by PCD will help lead to important insights relevant to brain health and diseases.

  11. Pollen tube reuses intracellular components of nucellar cells undergoing programmed cell death in Pinus densiflora.

    Science.gov (United States)

    Hiratsuka, Rie; Terasaka, Osamu

    2011-04-01

    Through the process known as programmed cell death (PCD), nucelli of Pinus densiflora serve as the transmitting tissue for growth of the pollen tube. We sought to clarify the processes of degradation of nucellar cell components and their transport to the pollen tube during PCD in response to pollen tube penetration of such nucelli. Stimulated by pollination, synthesis of large amounts of starch grains occurred in cells in a wide region of the nucellus, but as the pollen tube penetrated the nucellus, starch grains were degraded in amyloplasts of nucellar cells. In cells undergoing PCD, electron-dense vacuoles with high membrane contrast appeared, assumed a variety of autophagic structures, expanded, and ultimately collapsed and disappeared. Vesicles and electron-dense amorphous materials were released inside the thickened walls of cells undergoing PCD, and those vesicles and materials reaching the pollen tube after passing through the extracellular matrix were taken into the tube by endocytosis. These results show that in PCD of nucellar cells, intracellular materials are degraded in amyloplasts and vacuoles, and some of the degraded material is supplied to the pollen tube by vesicular transport to support tube growth.

  12. Mimulone-Induced Autophagy through p53-Mediated AMPK/mTOR Pathway Increases Caspase-Mediated Apoptotic Cell Death in A549 Human Lung Cancer Cells

    Science.gov (United States)

    Lee, Ji-Won; Park, Mi-Hyun; Moon, Hyung-In; Park, Shin-Ji; Baik, Ji-Sue; Kim, Cheorl-Ho; Lee, Young-Choon

    2014-01-01

    Anticancer properties and mechanisms of mimulone (MML), C-geranylflavonoid isolated from the Paulownia tomentosa fruits, were firstly elucidated in this study. MML prevented cell proliferation in a dose- and time-dependent way and triggered apoptosis through the extrinsic pathway in A549 human lung adenocarcinoma cells. Furthermore, MML-treated cells displayed autophagic features, such as the formation of autophagic vacuoles, a primary morphological feature of autophagy, and the accumulation of microtubule-associated protein 1 light chain 3 (LC3) puncta, another typical maker of autophagy, as determined by FITC-conjugated immunostaining and monodansylcadaverine (MDC) staining, respectively. The expression levels of LC3-I and LC3-II, specific markers of autophagy, were also augmented by MML treatment. Autophagy inhibition by 3-methyladenine (3-MA), pharmacological autophagy inhibitor, and shRNA knockdown of Beclin-1 reduced apoptotic cell death induced by MML. Autophagic flux was not significantly affected by MML treatment and lysosomal inhibitor, chloroquine (CQ) suppressed MML-induced autophagy and apoptosis. MML-induced autophagy was promoted by decreases in p53 and p-mTOR levels and increase of p-AMPK. Moreover, inhibition of p53 transactivation by pifithrin-α (PFT-α) and knockdown of p53 enhanced induction of autophagy and finally promoted apoptotic cell death. Overall, the results demonstrate that autophagy contributes to the cytotoxicity of MML in cancer cells harboring wild-type p53. This study strongly suggests that MML is a potential candidate for an anticancer agent targeting both autophagy and apoptotic cell death in human lung cancer. Moreover, co-treatment of MML and p53 inhibitor would be more effective in human lung cancer therapy. PMID:25490748

  13. Mimulone-induced autophagy through p53-mediated AMPK/mTOR pathway increases caspase-mediated apoptotic cell death in A549 human lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Hyun-Kyu An

    Full Text Available Anticancer properties and mechanisms of mimulone (MML, C-geranylflavonoid isolated from the Paulownia tomentosa fruits, were firstly elucidated in this study. MML prevented cell proliferation in a dose- and time-dependent way and triggered apoptosis through the extrinsic pathway in A549 human lung adenocarcinoma cells. Furthermore, MML-treated cells displayed autophagic features, such as the formation of autophagic vacuoles, a primary morphological feature of autophagy, and the accumulation of microtubule-associated protein 1 light chain 3 (LC3 puncta, another typical maker of autophagy, as determined by FITC-conjugated immunostaining and monodansylcadaverine (MDC staining, respectively. The expression levels of LC3-I and LC3-II, specific markers of autophagy, were also augmented by MML treatment. Autophagy inhibition by 3-methyladenine (3-MA, pharmacological autophagy inhibitor, and shRNA knockdown of Beclin-1 reduced apoptotic cell death induced by MML. Autophagic flux was not significantly affected by MML treatment and lysosomal inhibitor, chloroquine (CQ suppressed MML-induced autophagy and apoptosis. MML-induced autophagy was promoted by decreases in p53 and p-mTOR levels and increase of p-AMPK. Moreover, inhibition of p53 transactivation by pifithrin-α (PFT-α and knockdown of p53 enhanced induction of autophagy and finally promoted apoptotic cell death. Overall, the results demonstrate that autophagy contributes to the cytotoxicity of MML in cancer cells harboring wild-type p53. This study strongly suggests that MML is a potential candidate for an anticancer agent targeting both autophagy and apoptotic cell death in human lung cancer. Moreover, co-treatment of MML and p53 inhibitor would be more effective in human lung cancer therapy.

  14. Cellular metabolic and autophagic pathways: traffic control by redox signaling.

    Science.gov (United States)

    Dodson, Matthew; Darley-Usmar, Victor; Zhang, Jianhua

    2013-10-01

    It has been established that the key metabolic pathways of glycolysis and oxidative phosphorylation are intimately related to redox biology through control of cell signaling. Under physiological conditions glucose metabolism is linked to control of the NADH/NAD redox couple, as well as providing the major reductant, NADPH, for thiol-dependent antioxidant defenses. Retrograde signaling from the mitochondrion to the nucleus or cytosol controls cell growth and differentiation. Under pathological conditions mitochondria are targets for reactive oxygen and nitrogen species and are critical in controlling apoptotic cell death. At the interface of these metabolic pathways, the autophagy-lysosomal pathway functions to maintain mitochondrial quality and generally serves an important cytoprotective function. In this review we will discuss the autophagic response to reactive oxygen and nitrogen species that are generated from perturbations of cellular glucose metabolism and bioenergetic function.

  15. Programmed cell death in cereal aleurone.

    Science.gov (United States)

    Fath, A; Bethke, P; Lonsdale, J; Meza-Romero, R; Jones, R

    2000-10-01

    Progress in understanding programmed cell death (PCD) in the cereal aleurone is described. Cereal aleurone cells are specialized endosperm cells that function to synthesize and secrete hydrolytic enzymes that break down reserves in the starchy endosperm. Unlike the cells of the starchy endosperm, aleurone cells are viable in mature grain but undergo PCD when germination is triggered or when isolated aleurone layers or protoplasts are incubated in gibberellic acid (GA). Abscisic acid (ABA) slows down the process of aleurone cell death and isolated aleurone protoplasts can be kept alive in media containing ABA for up to 6 months. Cell death in barley aleurone occurs only after cells become highly vacuolated and is manifested in an abrupt loss of plasma membrane integrity. Aleurone cell death does not follow the apoptotic pathway found in many animal cells. The hallmarks of apoptosis, including internucleosomal DNA cleavage, plasma membrane and nuclear blebbing and formation of apoptotic bodies, are not observed in dying aleurone cells. PCD in barley aleurone cells is accompanied by the accumulation of a spectrum of nuclease and protease activities and the loss of organelles as a result of cellular autolysis.

  16. Epidermal cell death in frogs with chytridiomycosis

    Science.gov (United States)

    Roberts, Alexandra A.; Skerratt, Lee F.; Berger, Lee

    2017-01-01

    Background Amphibians are declining at an alarming rate, and one of the major causes of decline is the infectious disease chytridiomycosis. Parasitic fungal sporangia occur within epidermal cells causing epidermal disruption, but these changes have not been well characterised. Apoptosis (planned cell death) can be a damaging response to the host but may alternatively be a mechanism of pathogen removal for some intracellular infections. Methods In this study we experimentally infected two endangered amphibian species Pseudophryne corroboree and Litoria verreauxii alpina with the causal agent of chytridiomycosis. We quantified cell death in the epidermis through two assays: terminal transferase-mediated dUTP nick end-labelling (TUNEL) and caspase 3/7. Results Cell death was positively associated with infection load and morbidity of clinically infected animals. In infected amphibians, TUNEL positive cells were concentrated in epidermal layers, correlating to the localisation of infection within the skin. Caspase activity was stable and low in early infection, where pathogen loads were light but increasing. In animals that recovered from infection, caspase activity gradually returned to normal as the infection cleared. Whereas, in amphibians that did not recover, caspase activity increased dramatically when infection loads peaked. Discussion Increased cell death may be a pathology of the fungal parasite, likely contributing to loss of skin homeostatic functions, but it is also possible that apoptosis suppression may be used initially by the pathogen to help establish infection. Further research should explore the specific mechanisms of cell death and more specifically apoptosis regulation during fungal infection. PMID:28168107

  17. Dismantling the autophagic arsenal when it is time to die: concerted AMBRA1 degradation by caspases and calpains.

    Science.gov (United States)

    Corazzari, Marco; Fimia, Gian Maria; Piacentini, Mauro

    2012-08-01

    Under stress conditions cells activate different response pathways which result in cell survival or apoptosis depending on: (1) the nature of the insults, (2) the type, if acute or chronic stress, and (3) how long the stress persists. Generally, autophagy is induced early to sustain cell survival and inhibit cell death. However, adverse conditions are able to overcome autophagy to promote cell death. Increasing evidence suggests that the inhibition of autophagy by the apoptotic machinery has been proposed as one of the crucial events responsible for the irreversible switch from survival to death. The mechanism seems to be related to the selective apoptotic protease-mediated degradation of key autophagic proteins. We recently found that AMBRA1, an important regulator of the autophagic process mediating the initial steps of autophagosome formation, is also irreversibly degraded by the combined activity of caspases and calpains. This phenomenon is not merely a consequence of apoptosis execution but represents a key step required to efficiently promote the autophagic vs apoptosis switch.

  18. Programmed cell death and hybrid incompatibility.

    Science.gov (United States)

    Frank, S A; Barr, C M

    2003-01-01

    We propose a new theory to explain developmental aberrations in plant hybrids. In our theory, hybrid incompatibilities arise from imbalances in the mechanisms that cause male sterility in hermaphroditic plants. Mitochondria often cause male sterility by killing the tapetal tissue that nurtures pollen mother cells. Recent evidence suggests that mitochondria destroy the tapetum by triggering standard pathways of programmed cell death. Some nuclear genotypes repress mitochondrial male sterility and restore pollen fertility. Normal regulation of tapetal development therefore arises from a delicate balance between the disruptive effects of mitochondria and the defensive countermeasures of the nuclear genes. In hybrids, incompatibilities between male-sterile mitochondria and nuclear restorers may frequently upset the regulatory control of programmed cell death, causing tapetal abnormalities and male sterility. We propose that hybrid misregulation of programmed cell death may also spill over into other tissues, explaining various developmental aberrations observed in hybrids.

  19. STAT3 Decoy Oligodeoxynucleotides-Loaded Solid Lipid Nanoparticles Induce Cell Death and Inhibit Invasion in Ovarian Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Yanhui Ma

    Full Text Available Recent advances in the synthesis of multi-functional nanoparticles have opened up tremendous opportunities for the targeted delivery of genes of interest. Cationic solid lipid nanoparticles (SLN can efficiently bind nucleic acid molecules and transfect genes in vitro. Few reports have combined SLN with therapy using decoy oligodeoxynucleotides (ODN. In the present study, we prepared SLN to encapsulate STAT3 decoy ODN; then, the properties and in vitro behavior of SLN-STAT3 decoy ODN complexes were investigated. SLN-STAT3 decoy ODN complexes were efficiently taken up by human ovarian cancer cells and significantly suppressed cell growth. Blockage of the STAT3 pathway by SLN-STAT3 decoy ODN complexes resulted in an evident induction of cell death, including apoptotic and autophagic death. The mechanism involved the increased expression of cleaved caspase 3, Bax, Beclin-1 and LC3-II and reduced expression of Bcl-2, pro-caspase 3, Survivin, p-Akt and p-mTOR. In addition, SLN-STAT3 decoy ODN complexes inhibited cell invasion by up-regulating E-cadherin expression and down-regulating Snail and MMP-9 expression. These findings confirmed that SLN as STAT3 decoy ODN carriers can induce cell death and inhibit invasion of ovarian cancer cells. We propose that SLN represent a potential approach for targeted gene delivery in cancer therapy.

  20. Autophagy-related cell death by pan-histone deacetylase inhibition in liver cancer

    Science.gov (United States)

    Di Fazio, Pietro; Waldegger, Petra; Jabari, Samir; Lingelbach, Susanne; Montalbano, Roberta; Ocker, Matthias; Slater, Emily P.; Bartsch, Detlef K.; Illig, Romana; Neureiter, Daniel; Wissniowski, Thaddeus T.

    2016-01-01

    Autophagy is a homeostatic, catabolic degradation process and cell fate essential regulatory mechanism. Protracted autophagy triggers cell death; its aberrant function is responsible for several malignancies. Panobinostat, a potent pan-deacetylase inhibitor, causes endoplasmic reticulum stress-induced cell death. The aim of this study was to investigate the role of autophagy in deacetylase inhibitor-triggered liver cancer cell death. HepG2 (p53wt) and Hep3B (p53 null) liver cancer cell lines were exposed to panobinostat. RT-qPCR and western blot confirmed autophagic factor modulation. Immuno-fluorescence, -precipitation and -histochemistry as well as transmission electron microscopy verified autophagosome formation. The cytotoxicity of panobinostat and autophagy modulators was detected using a real time cell viability assay. Panobinostat induced autophagy-related factor expression and aggregation. Map1LC3B and Beclin1 were significantly over-expressed in HepG2 xenografts in nude mice treated with panobinostat for 4 weeks. Subcellular distribution of Beclin1 increased with the appearance of autophagosomes-like aggregates. Cytosolic loss of p53, in HepG2, and p73, in Hep3B cells, and a corresponding gain of their nuclear level, together with modulation of DRAM1, were observed. Autophagosome aggregation was visible after 6 h of treatment. Treatment of cells stably expressing GFP-RFPtag Map1LC3B resulted in aggregation and a fluorescence switch, thus confirming autophagosome formation and maturation. Tamoxifen, an inducer of autophagy, caused only a block in cell proliferation; but in combination with panobinostat it resulted in cell death. Autophagy triggers cell demise in liver cancer. Its modulation by the combination of tamoxifen and panobinostat could be a new option for palliative treatment of hepatocellular carcinoma. PMID:27058414

  1. The regulation of apoptotic cell death

    Directory of Open Access Journals (Sweden)

    G.P. Amarante-Mendes

    1999-09-01

    Full Text Available Apoptosis is a fundamental biological phenomenon in which the death of a cell is genetically and biochemically regulated. Different molecules are involved in the regulation of the apoptotic process. Death receptors, coupled to distinct members of the caspases as well as other adapter molecules, are involved in the initiation of the stress signals (The Indictment. Members of the Bcl-2 family control at the mitochondrial level the decision between life and death (The Judgement. The effector caspases are responsible for all morphological and biochemical changes related to apoptosis including the "eat-me" signals perceived by phagocytes and neighboring cells (The Execution. Finally, apoptosis would have little biological significance without the recognition and removal of the dying cells (The Burial.

  2. The regulation of apoptotic cell death

    Directory of Open Access Journals (Sweden)

    Amarante-Mendes G.P.

    1999-01-01

    Full Text Available Apoptosis is a fundamental biological phenomenon in which the death of a cell is genetically and biochemically regulated. Different molecules are involved in the regulation of the apoptotic process. Death receptors, coupled to distinct members of the caspases as well as other adapter molecules, are involved in the initiation of the stress signals (The Indictment. Members of the Bcl-2 family control at the mitochondrial level the decision between life and death (The Judgement. The effector caspases are responsible for all morphological and biochemical changes related to apoptosis including the "eat-me" signals perceived by phagocytes and neighboring cells (The Execution. Finally, apoptosis would have little biological significance without the recognition and removal of the dying cells (The Burial.

  3. ETosis: A Microbicidal Mechanism beyond Cell Death

    Directory of Open Access Journals (Sweden)

    Anderson B. Guimarães-Costa

    2012-01-01

    Full Text Available Netosis is a recently described type of neutrophil death occurring with the release to the extracellular milieu of a lattice composed of DNA associated with histones and granular and cytoplasmic proteins. These webs, initially named neutrophil extracellular traps (NETs, ensnare and kill microorganisms. Similarly, other cell types, such as eosinophils, mast cells, and macrophages, can also dye by this mechanism; thus, it was renamed as ETosis, meaning death with release of extracellular traps (ETs. Here, we review the mechanism of NETosis/etosis, emphasizing its role in diseases caused by protozoan parasites, fungi, and viruses.

  4. Viral subversion of immunogenic cell death.

    Science.gov (United States)

    Kepp, Oliver; Senovilla, Laura; Galluzzi, Lorenzo; Panaretakis, Theocharis; Tesniere, Antoine; Schlemmer, Frederic; Madeo, Frank; Zitvogel, Laurence; Kroemer, Guido

    2009-03-15

    While physiological cell death is non-immunogenic, pathogen induced cell death can be immunogenic and hence stimulate an immune response against antigens that derive from dying cells and are presented by dendritic cells (DCs). The obligate immunogenic "eat-me" signal generated by dying cells consists in the exposure of calreticulin (CRT) at the cell surface. This particular "eat-me" signal, which facilitates engulfment by DCs, can only be found on cells that succumb to immunogenic apoptosis, while it is not present on cells dying in an immunologically silent fashion. CRT normally resides in the lumen of the endoplasmic reticulum (ER), yet can translocate to the plasma membrane surface through a complex pathway that involves elements of the ER stress response (e.g., the eIF2alpha-phosphorylating kinase PERK), the apoptotic machinery (e.g., caspase-8 and its substrate BAP31, Bax, Bak), the anterograde transport from the ER to the Golgi apparatus, and SNARE-dependent exocytosis. A large panoply of viruses encodes proteins that inhibit eIF2alpha kinases, catalyze the dephosphorylation of eIF2alpha, bind to caspase-8, Bap31, Bax or Bak, or perturb exocytosis. We therefore postulate that obligate intracellular pathogens have developed a variety of strategies to subvert CRT exposure, thereby avoiding immunogenic cell death.

  5. Alternative messenger RNA splicing of autophagic gene Beclin 1 in human B-cell acute lymphoblastic leukemia cells.

    Science.gov (United States)

    Niu, Yu-Na; Liu, Qing-Qing; Zhang, Su-Ping; Yuan, Na; Cao, Yan; Cai, Jin-Yang; Lin, Wei-Wei; Xu, Fei; Wang, Zhi-Jian; Chen, Bo; Wang, Jian-Rong

    2014-01-01

    Beclin 1 is a key factor for initiation and regulation of autophagy, which is a cellular catabolic process involved in tumorigenesis. To investigate the role of alternative splicing of Beclin1 in the regulation of autophagy in leukemia cells, Beclin1 mRNA from 6 different types of cell lines and peripheral blood mononuclear cells from 2 healthy volunteers was reversely transcribed, subcloned, and screened for alternative splicing. New transcript variants were analyzed by DNA sequencing. A transcript variant of Beclin 1 gene carrying a deletion of exon 11, which encoded a C-terminal truncation of Beclin 1 isoform, was found. The alternative isoform was assessed by bioinformatics, immunoblotting and subcellular localization. The results showed that this variable transcript is generated by alternative 3' splicing, and its translational product displayed a reduced activity in induction of autophagy by starvation, indicating that the spliced isoform might function as a dominant negative modulator of autophagy. Our findings suggest that the alternative splicing of Beclin 1 might play important roles in leukemogenesis regulated by autophagy.

  6. The deaths of a cell: how language and metaphor influence the science of cell death.

    Science.gov (United States)

    Reynolds, Andrew S

    2014-12-01

    Multicellular development and tissue maintenance involve the regular elimination of damaged and healthy cells. The science of this genetically regulated cell death is particularly rich in metaphors: 'programmed cell death' or 'cell suicide' is considered an 'altruistic' act on the part of a cell for the benefit of the organism as a whole. It is also considered a form of 'social control' exerted by the body/organism over its component cells. This paper analyzes the various functions of these metaphors and critical discussion about them within the scientific community. Bodies such as the Nomenclature Committee on Cell Death (NCCD) have been charged with bringing order to the language of cell death to facilitate scientific progress. While the NCCD recommends adopting more objective biochemical terminology to describe the mechanisms of cell death, the metaphors in question retain an important function by highlighting the broader context within which cell death occurs. Scientific metaphors act as conceptual 'tools' which fulfill various roles, from highlighting a phenomenon as of particular interest, situating it in a particular context, or suggesting explanatory causal mechanisms.

  7. Inducible cell death in plant immunity

    DEFF Research Database (Denmark)

    Hofius, Daniel; Tsitsigiannis, Dimitrios I; Jones, Jonathan D G;

    2006-01-01

    Programmed cell death (PCD) occurs during vegetative and reproductive plant growth, as typified by autumnal leaf senescence and the terminal differentiation of the endosperm of cereals which provide our major source of food. PCD also occurs in response to environmental stress and pathogen attack,...

  8. Hemoglobins, programmed cell death and somatic embryogenesis.

    Science.gov (United States)

    Hill, Robert D; Huang, Shuanglong; Stasolla, Claudio

    2013-10-01

    Programmed cell death (PCD) is a universal process in all multicellular organisms. It is a critical component in a diverse number of processes ranging from growth and differentiation to response to stress. Somatic embryogenesis is one such process where PCD is significantly involved. Nitric oxide is increasingly being recognized as playing a significant role in regulating PCD in both mammalian and plant systems. Plant hemoglobins scavenge NO, and evidence is accumulating that events that modify NO levels in plants also affect hemoglobin expression. Here, we review the process of PCD, describing the involvement of NO and plant hemoglobins in the process. NO is an effector of cell death in both plants and vertebrates, triggering the cascade of events leading to targeted cell death that is a part of an organism's response to stress or to tissue differentiation and development. Expression of specific hemoglobins can alter this response in plants by scavenging the NO, thus, interrupting the death process. Somatic embryogenesis is used as a model system to demonstrate how cell-specific expression of different classes of hemoglobins can alter the embryogenic process, affecting hormone synthesis, cell metabolite levels and genes associated with PCD and embryogenic competence. We propose that plant hemoglobins influence somatic embryogenesis and PCD through cell-specific expression of a distinct plant hemoglobin. It is based on the premise that both embryogenic competence and PCD are strongly influenced by cellular NO levels. Increases in cellular NO levels result in elevated Zn(2+) and reactive-oxygen species associated with PCD, but they also result in decreased expression of MYC2, a transcription factor that is a negative effector of indoleacetic acid synthesis, a hormone that positively influences embryogenic competence. Cell-specific hemoglobin expression reduces NO levels as a result of NO scavenging, resulting in cell survival.

  9. Fucosylation of LAMP-1 and LAMP-2 by FUT1 correlates with lysosomal positioning and autophagic flux of breast cancer cells.

    Science.gov (United States)

    Tan, Keng-Poo; Ho, Ming-Yi; Cho, Huan-Chieh; Yu, John; Hung, Jung-Tung; Yu, Alice Lin-Tsing

    2016-08-25

    Alpha1,2-fucosyltransferases, FUT1 and FUT2, which transfer fucoses onto the terminal galactose of N-acetyl-lactosamine via α1,2-linkage have been shown to be highly expressed in various types of cancers. A few studies have shown the involvement of FUT1 substrates in tumor cell proliferation and migration. Lysosome-associated membrane protein 1, LAMP-1, has been reported to carry alpha1,2-fucosylated Lewis Y (LeY) antigens in breast cancer cells, however, the biological functions of LeY on LAMP-1 remain largely unknown. Whether or not its family member, LAMP-2, displays similar modifications and functions as LAMP-1 has not yet been addressed. In this study, we have presented evidence supporting that both LAMP-1 and 2 are substrates for FUT1, but not FUT2. We have also demonstrated the presence of H2 and LeY antigens on LAMP-1 by a targeted nanoLC-MS(3) and the decreased levels of fucosylation on LAMP-2 by MALDI-TOF analysis upon FUT1 knockdown. In addition, we found that the expression of LeY was substantial in less invasive ER+/PR+/HER- breast cancer cells (MCF-7 and T47D) but negligible in highly invasive triple-negative MDA-MB-231 cells, of which LeY levels were correlated with the levels of LeY carried by LAMP-1 and 2. Intriguingly, we also observed a striking change in the subcellular localization of lysosomes upon FUT1 knockdown from peripheral distribution of LAMP-1 and 2 to a preferential perinuclear accumulation. Besides that, knockdown of FUT1 led to an increased rate of autophagic flux along with diminished activity of mammalian target of rapamycin complex 1 (mTORC1) and enhanced autophagosome-lysosome fusion. This may be associated with the predominantly perinuclear distribution of lysosomes mediated by FUT1 knockdown as lysosomal positioning has been reported to regulate mTOR activity and autophagy. Taken together, our results suggest that downregulation of FUT1, which leads to the perinuclear localization of LAMP-1 and 2, is correlated with increased

  10. Autophagic effect on tumor and its potential applicationsin non-small cell lung cancer molecular targeted therapy%肿瘤自噬效应及其在非小细胞肺癌分子靶向治疗中的潜在应用

    Institute of Scientific and Technical Information of China (English)

    陈美娟; 詹瑧; 张旭

    2012-01-01

    目前针对非小细胞肺癌(NSCLC)的手术、放化疗等治疗手段临床疗效仍很不足,相应的分子靶向治疗药物随着临床抗药性的产生疗效也明显下降.自噬对肿瘤进展具有双重影响作用.在NSCLC临床治疗的各个阶段都应充分考虑自噬效应所起的作用,对其进行合理调节和利用,从而提高各种治疗手段的临床疗效.%Now clinical treatments for non-small cell lung cancer ( NSCLC ) such as surgery, radiotherapy, and chemotherapy are still insufficient, and the efficacy of some molecular targeted therapy is also limited because of natural and acquired resistance in clinics. Autophagy exhibited the effects of a double-blade sword on tumor progression. On the one hand, autophagic can induce the death of tumor cells, and on the other hand, it alsoprotects the tumor in stress such as nutritional deficiency. Clinical treatment of NSCLC at various stages should take full account of autophagic effect on its progression, which can improve the clinical efficacy of various treatments by reasonable combination.

  11. Fenugreek extract as an inducer of cellular death via autophagy in human T lymphoma Jurkat cells

    Directory of Open Access Journals (Sweden)

    Al-Daghri Nasser M

    2012-10-01

    Full Text Available Abstract Background Drugs used both in classical chemotherapy and the more recent targeted therapy do not have cancer cell specificity and, hence, cause severe systemic side effects. Tumors also develop resistance to such drugs due to heterogeneity of cell types and clonal selection. Several traditional dietary ingredients from plants, on the other hand, have been shown to act on multiple targets/pathways, and may overcome drug resistance. The dietary agents are safe and readily available. However, application of plant components for cancer treatment/prevention requires better understanding of anticancer functions and elucidation of their mechanisms of action. The current study focuses on the anticancer properties of fenugreek, a herb with proven anti-diabetic, antitumor and immune-stimulating functions. Method Jurkat cells were incubated with 30 to 1500 μg/mL concentrations of 50% ethanolic extract of dry fenugreek seeds and were followed for changes in viability (trypan blue assay, morphology (microscopic examination and autophagic marker LC3 transcript level (RT-PCR. Results Incubation of Jurkat cells with fenugreek extract at concentrations ranging from 30 to 1500 μg/mL for up to 3 days resulted in cell death in a dose- and time-dependent manner. Jurkat cell death was preceded by the appearance of multiple large vacuoles, which coincided with transcriptional up-regulation of LC3. GC-MS analysis of fenugreek extract indicated the presence of several compounds with anticancer properties, including gingerol (4.82%, cedrene (2.91%, zingerone (16.5%, vanillin (1.52% and eugenol (1.25%. Conclusions Distinct morphological changes involving appearance of large vacuoles, membrane disintegration and increased expression of LC3 transcripts indicated that fenugreek extract induced autophagy and autophagy-associated death of Jurkat cells. In addition to the already known apoptotic activation, induction of autophagy may be an additional mechanism

  12. Mycobacterium tuberculosis eis regulates autophagy, inflammation, and cell death through redox-dependent signaling.

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    Dong-Min Shin

    Full Text Available The "enhanced intracellular survival" (eis gene of Mycobacterium tuberculosis (Mtb is involved in the intracellular survival of M. smegmatis. However, its exact effects on host cell function remain elusive. We herein report that Mtb Eis plays essential roles in modulating macrophage autophagy, inflammatory responses, and cell death via a reactive oxygen species (ROS-dependent pathway. Macrophages infected with an Mtb eis-deletion mutant H37Rv (Mtb-Δeis displayed markedly increased accumulation of massive autophagic vacuoles and formation of autophagosomes in vitro and in vivo. Infection of macrophages with Mtb-Δeis increased the production of tumor necrosis factor-α and interleukin-6 over the levels produced by infection with wild-type or complemented strains. Elevated ROS generation in macrophages infected with Mtb-Δeis (for which NADPH oxidase and mitochondria were largely responsible rendered the cells highly sensitive to autophagy activation and cytokine production. Despite considerable activation of autophagy and proinflammatory responses, macrophages infected with Mtb-Δeis underwent caspase-independent cell death. This cell death was significantly inhibited by blockade of autophagy and c-Jun N-terminal kinase-ROS signaling, suggesting that excessive autophagy and oxidative stress are detrimental to cell survival. Finally, artificial over-expression of Eis or pretreatment with recombinant Eis abrogated production of both ROS and proinflammatory cytokines, which depends on the N-acetyltransferase domain of the Eis protein. Collectively, these data indicate that Mtb Eis suppresses host innate immune defenses by modulating autophagy, inflammation, and cell death in a redox-dependent manner.

  13. Programmed cell death in the plant immune system.

    Science.gov (United States)

    Coll, N S; Epple, P; Dangl, J L

    2011-08-01

    Cell death has a central role in innate immune responses in both plants and animals. Besides sharing striking convergences and similarities in the overall evolutionary organization of their innate immune systems, both plants and animals can respond to infection and pathogen recognition with programmed cell death. The fact that plant and animal pathogens have evolved strategies to subvert specific cell death modalities emphasizes the essential role of cell death during immune responses. The hypersensitive response (HR) cell death in plants displays morphological features, molecular architectures and mechanisms reminiscent of different inflammatory cell death types in animals (pyroptosis and necroptosis). In this review, we describe the molecular pathways leading to cell death during innate immune responses. Additionally, we present recently discovered caspase and caspase-like networks regulating cell death that have revealed fascinating analogies between cell death control across both kingdoms.

  14. Tumor cell "dead or alive": caspase and survivin regulate cell death, cell cycle and cell survival.

    Science.gov (United States)

    Suzuki, A; Shiraki, K

    2001-04-01

    Cell death and cell cycle progression are two sides of the same coin, and these two different phenomenons are regulated moderately to maintain the cellular homeostasis. Tumor is one of the disease states produced as a result of the disintegrated regulation and is characterized as cells showing an irreversible progression of cell cycle and a resistance to cell death signaling. Several investigations have been performed for the understanding of cell death or cell cycle, and cell death research has remarkably progressed in these 10 years. Caspase is a nomenclature referring to ICE/CED-3 cysteine proteinase family and plays a central role during cell death. Recently, several investigations raised some possible hypotheses that caspase is also involved in cell cycle regulation. In this issue, therefore, we review the molecular basis of cell death and cell cycle regulated by caspase in tumor, especially hepatocellular carcinoma cells.

  15. Enhancing lysosomal biogenesis and autophagic flux by activating the transcription factor EB protects against cadmium-induced neurotoxicity

    Science.gov (United States)

    Pi, Huifeng; Li, Min; Tian, Li; Yang, Zhiqi; Yu, Zhengping; Zhou, Zhou

    2017-01-01

    Cadmium (Cd), a highly ubiquitous heavy metal, is a well-known inducer of neurotoxicity. However, the mechanism underlying cadmium-induced neurotoxicity remains unclear. In this study, we found that Cd inhibits autophagosome-lysosome fusion and impairs lysosomal function by reducing the levels of lysosomal-associated membrane proteins, inhibiting lysosomal proteolysis and altering lysosomal pH, contributing to defects in autophagic clearance and subsequently leading to nerve cell death. In addition, Cd decreases transcription factor EB (TFEB) expression at both the mRNA and protein levels. Furthermore, Cd induces the nuclear translocation of TFEB and TFEB target-gene expression, associated with compromised lysosomal function or a compensatory effect after the impairment of the autophagic flux. Notably, restoration of the levels of lysosomal-associated membrane protein, lysosomal proteolysis, lysosomal pH and autophagic flux through Tfeb overexpression protects against Cd-induced neurotoxicity, and this protective effect is incompletely dependent on TFEB nuclear translocation. Moreover, gene transfer of the master autophagy regulator TFEB results in the clearance of toxic proteins and the correction of Cd-induced neurotoxicity in vivo. Our study is the first to demonstrate that Cd disrupts lysosomal function and autophagic flux and manipulation of TFEB signalling may be a therapeutic approach for antagonizing Cd-induced neurotoxicity. PMID:28240313

  16. Programmed cell death during quinoa perisperm development.

    Science.gov (United States)

    López-Fernández, María Paula; Maldonado, Sara

    2013-08-01

    At seed maturity, quinoa (Chenopodium quinoa Willd.) perisperm consists of uniform, non-living, thin-walled cells full of starch grains. The objective of the present study was to study quinoa perisperm development and describe the programme of cell death that affects the entire tissue. A number of parameters typically measured during programmed cell death (PCD), such as cellular morphological changes in nuclei and cytoplasm, endoreduplication, DNA fragmentation, and the participation of nucleases and caspase-like proteases in nucleus dismantling, were evaluated; morphological changes in cytoplasm included subcellular aspects related to starch accumulation. This study proved that, following fertilization, the perisperm of quinoa simultaneously accumulates storage reserves and degenerates, both processes mediated by a programme of developmentally controlled cell death. The novel findings regarding perisperm development provide a starting point for further research in the Amaranthaceae genera, such as comparing seeds with and without perisperm, and specifying phylogeny and evolution within this taxon. Wherever possible and appropriate, differences between quinoa perisperm and grass starchy endosperm--a morphologically and functionally similar, although genetically different tissue--were highlighted and discussed.

  17. UV-Induced Cell Death in Plants

    Directory of Open Access Journals (Sweden)

    Chang Ho Kang

    2013-01-01

    Full Text Available Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400–700 nm, plants are exposed to UV light, which is comprised of UV-C (below 280 nm, UV-B (280–320 nm and UV-A (320–390 nm. The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS. Arabidopsis metacaspase-8 (AtMC8 is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1 gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD.

  18. The Autophagic Machinery in Enterovirus Infection

    Directory of Open Access Journals (Sweden)

    Jeffrey K. F. Lai

    2016-01-01

    Full Text Available The Enterovirus genus of the Picornaviridae family comprises many important human pathogens, including polioviruses, rhinovirus, enterovirus A71, and enterovirus D68. They cause a wide variety of diseases, ranging from mild to severe life-threatening diseases. Currently, no effective vaccine is available against enteroviruses except for poliovirus. Enteroviruses subvert the autophagic machinery to benefit their assembly, maturation, and exit from host. Some enteroviruses spread between cells via a process described as autophagosome-mediated exit without lysis (AWOL. The early and late phases of autophagy are regulated through various lipids and their metabolizing enzymes. Some of these lipids and enzymes are specifically regulated by enteroviruses. In the present review, we summarize the current understanding of the regulation of autophagic machinery by enteroviruses, and provide updates on recent developments in this field.

  19. JS-K, a nitric oxide-releasing prodrug, induces breast cancer cell death while sparing normal mammary epithelial cells.

    Science.gov (United States)

    McMurtry, Vanity; Saavedra, Joseph E; Nieves-Alicea, René; Simeone, Ann-Marie; Keefer, Larry K; Tari, Ana M

    2011-04-01

    Targeted therapy with reduced side effects is a major goal in cancer research. We investigated the effects of JS-K, a nitric oxide (NO) prodrug designed to release high levels of NO when suitably activated, on human breast cancer cell lines, on non-transformed human MCF-10A mammary cells, and on normal human mammary epithelial cells (HMECs). Cell viability assay, flow cytometry, electron microscopy, and Western blot analysis were used to study the effects of JS-K on breast cancer and on mammary epithelial cells. After a 3-day incubation, the IC50s of JS-K against the breast cancer cells ranged from 0.8 to 3 µM. However, JS-K decreased the viability of the MCF-10A cells by only 20% at 10-µM concentration, and HMECs were unaffected by 10 µM JS-K. Flow cytometry indicated that JS-K increased the percentages of breast cancer cells under-going apoptosis. Interestingly, flow cytometry indicated that JS-K increased acidic vesicle organelle formation in breast cancer cells, suggesting that JS-K induced autophagy in breast cancer cells. Electron microscopy confirmed that JS-K-treated breast cancer cells underwent autophagic cell death. Western blot analysis showed that JS-K induced the expression of microtubule light chain 3-II, another autophagy marker, in breast cancer cells. However, JS-K did not induce apoptosis or autophagy in normal human mammary epithelial cells. These data indicate that JS-K selectively induces programmed cell death in breast cancer cells while sparing normal mammary epithelial cells under the same conditions. The selective anti-tumor activity of JS-K warrants its further investigation in breast tumors.

  20. Heme oxygenase-1, a critical arbitrator of cell death pathways in lung injury and disease.

    Science.gov (United States)

    Morse, Danielle; Lin, Ling; Choi, Augustine M K; Ryter, Stefan W

    2009-07-01

    Increases in cell death by programmed (i.e., apoptosis, autophagy) or nonprogrammed mechanisms (i.e., necrosis) occur during tissue injury and may contribute to the etiology of several pulmonary or vascular disease states. The low-molecular-weight stress protein heme oxygenase-1 (HO-1) confers cytoprotection against cell death in various models of lung and vascular injury by inhibiting apoptosis, inflammation, and cell proliferation. HO-1 serves a vital metabolic function as the rate-limiting step in the heme degradation pathway and in the maintenance of iron homeostasis. The transcriptional induction of HO-1 occurs in response to multiple forms of chemical and physical cellular stress. The cytoprotective functions of HO-1 may be attributed to heme turnover, as well as to beneficial properties of its enzymatic reaction products: biliverdin-IXalpha, iron, and carbon monoxide (CO). Recent studies have demonstrated that HO-1 or CO inhibits stress-induced extrinsic and intrinsic apoptotic pathways in vitro. A variety of signaling molecules have been implicated in the cytoprotection conferred by HO-1/CO, including autophagic proteins, p38 mitogen-activated protein kinase, signal transducer and activator of transcription proteins, nuclear factor-kappaB, phosphatidylinositol 3-kinase/Akt, and others. Enhanced HO-1 expression or the pharmacological application of HO end-products affords protection in preclinical models of tissue injury, including experimental and transplant-associated ischemia/reperfusion injury, promising potential future therapeutic applications.

  1. TNF α and reactive oxygen species in necrotic cell death

    Institute of Scientific and Technical Information of China (English)

    Michael J Morgan; You-Sun Kim; Zheng-gang Liu

    2008-01-01

    Death receptors, including the TNF receptor-1 (TNF-RI), have been shown to be able to initiate caspase-independent cell death. This form of "necrotic cell death" appears to be dependent on the generation of reactive oxygen species. Recent data have indicated that superoxide generation is dependent on the activation of NADPH oxidases, which form a complex with the adaptor molecules RIP1 and TRADD. The mechanism of superoxide generation further establishes RIP1 as the central molecule in ROS production and cell death initiated by TNFa and other death receptors. A role for the sustained JNK activation in necrotic cell death is also suggested. The sensitization of virus-infected cells to TNFa indicates that necrotic cell death may represent an alternative cell death pathway for clearance of infected cells.

  2. Molecular cell death platforms and assemblies.

    Science.gov (United States)

    Mace, Peter D; Riedl, Stefan J

    2010-12-01

    Multi-cellular animals have evolved a variety of mechanisms to respond to diverse apoptotic stimuli. In general these proceed through activation of apical caspases and culminate in executioner caspase activation and cell death. Because of the breadth of possible initiators, various molecular platforms are used to trigger different apical caspases. Although some common protein domains are used to assemble the apoptosome, the PIDDosome and death receptor complexes, an array of checks-and-balances are employed to ensure appropriate activation. Notwithstanding, these pathways share the underlying principle of proximity-dependent activation and post-translational modification. Here we will describe our current structural understanding of assembly and regulation of these signaling platforms.

  3. Programmed cell death and its role in inflammation

    Institute of Scientific and Technical Information of China (English)

    Yong Yang; Ge-Ning Jiang; Peng Zhang; Jie Fan

    2015-01-01

    Cell death plays an important role in the regulation of inflammation and may be the result of inflammation. The maintenance of tissue homeostasis necessitates both the recognition and removal of invading microbial pathogens as well as the clearance of dying cells. In the past few decades, emerging knowledge on cell death and inflammation has enriched our molecular understanding of the signaling pathways that mediate various programs of cell death and multiple types of inflammatory responses. This review provides an overview of the major types of cell death related to inflammation. Modification of cell death pathways is likely to be a logical therapeutic target for inflammatory diseases.

  4. Programmed cell death in plants and caspase-like activities

    NARCIS (Netherlands)

    Gaussand, Gwénael Martial Daniel Jean-Marie

    2007-01-01

    The development of multicellular organisms involves an important balance between cell growth, cell division and cell death. In animals, programmed cell death (PCD) plays a key role by forming and deleting structures, controlling cell numbers and eliminating abnormal damaged cells. Caspases were foun

  5. Induction of apoptotic cell death by putrescine

    DEFF Research Database (Denmark)

    Takao, Koichi; Rickhag, Karl Mattias; Hegardt, Cecilia

    2006-01-01

    The polyamines are essential for cellular growth and differentiation. Ornithine decarboxylase (ODC), which catalyses the first step in the biosynthesis of the polyamines, has a very fast turnover and is subject to a strong feedback control by the polyamines. In the present study, we show that ove......The polyamines are essential for cellular growth and differentiation. Ornithine decarboxylase (ODC), which catalyses the first step in the biosynthesis of the polyamines, has a very fast turnover and is subject to a strong feedback control by the polyamines. In the present study, we show...... for their growth. The induction of cell death was correlated with a dramatic increase in cellular putrescine levels. Analysis using flow cytometry revealed perturbed cell cycle kinetics, with a large accumulation of cells with sub-G1 amounts of DNA, which is a typical sign of apoptosis. Another strong indication...

  6. Molecular Theories of Cell Life and Death.

    Science.gov (United States)

    1987-07-27

    effects on human health . useful numbers - 1) h (Planck’s constant) = 6.626 x 10-27 erg-sec = 1.58 x 10- 3 4 cal-sec 2) 1 eV = 23 kcal/mole 3) N...Information based on Theoretical Notions from Spin-Glass Physics" Prebiotic polymers that contain internal conformational strains (analogous to...essentialA ife on another level, and vice versa. Possible roles of . such programmed cell deaths in health and diseases are reviewed. *’ 16. J. R

  7. Cell death in mammalian cell culture: molecular mechanisms and cell line engineering strategies.

    Science.gov (United States)

    Krampe, Britta; Al-Rubeai, Mohamed

    2010-07-01

    Cell death is a fundamentally important problem in cell lines used by the biopharmaceutical industry. Environmental stress, which can result from nutrient depletion, by-product accumulation and chemical agents, activates through signalling cascades regulators that promote death. The best known key regulators of death process are the Bcl-2 family proteins which constitute a critical intracellular checkpoint of apoptosis cell death within a common death pathway. Engineering of several members of the anti-apoptosis Bcl-2 family genes in several cell types has extended the knowledge of their molecular function and interaction with other proteins, and their regulation of cell death. In this review, we describe the various modes of cell death and their death pathways at molecular and organelle level and discuss the relevance of the growing knowledge of anti-apoptotic engineering strategies to inhibit cell death and increase productivity in mammalian cell culture.

  8. Heat shock transcription factors regulate heat induced cell death in a rat histiocytoma

    Indian Academy of Sciences (India)

    Kolla V, P Rasad; Aftab Taiyab; D Jyothi; Usha K Srinivas; Amere S Sreedhar

    2007-04-01

    Heat shock response is associated with the synthesis of heat shock proteins (Hsps) which is strictly regulated by different members of heat shock transcription factors (HSFs). We previously reported that a rat histiocytoma, BC-8 failed to synthesize Hsps when subjected to typical heat shock conditions (42°C, 60 min). The lack of Hsp synthesis in these cells was due to a failure in HSF1 DNA binding activity. In the present study we report that BC-8 tumor cells when subjected to heat shock at higher temperature (43°C, 60 min) or incubation for longer time at 42°C, exhibited necrosis characteristics; however, under mild heat shock (42°C, 30 min) conditions cells showed activation of autophagy. Mild heat shock treatment induced proteolysis of HSF1, and under similar conditions we observed an increase in HSF2 expression followed by its enhanced DNA binding activity. Inhibiting HSF1 proteolysis by reversible proteasome inhibition failed to inhibit heat shock induced autophagy. Compromising HSF2 expression but not HSF1 resulted in the inhibition of autophagy, suggesting HSF2 dependent activation of autophagy. We are reporting for the first time that HSF2 is heat inducible and functions in heat shock induced autophagic cell death in BC-8 tumor cells.

  9. Colorectal Cancer Stem Cells and Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Catalano, Veronica [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Gaggianesi, Miriam [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Department of Cellular and Molecular Oncology, IRCCS Fondazione Salvatore Maugeri, Via Salvatore Maugeri, 27100 Pavia, PV (Italy); Spina, Valentina; Iovino, Flora [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Dieli, Francesco [Departement of Biopathology and Medicine Biotechnologies, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Stassi, Giorgio, E-mail: giorgio.stassi@unipa.it [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Department of Cellular and Molecular Oncology, IRCCS Fondazione Salvatore Maugeri, Via Salvatore Maugeri, 27100 Pavia, PV (Italy); Todaro, Matilde [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy)

    2011-04-11

    Nowadays it is reported that, similarly to other solid tumors, colorectal cancer is sustained by a rare subset of cancer stem–like cells (CSCs), which survive conventional anticancer treatments, thanks to efficient mechanisms allowing escape from apoptosis, triggering tumor recurrence. To improve patient outcomes, conventional anticancer therapies have to be replaced with specific approaches targeting CSCs. In this review we provide strong support that BMP4 is an innovative therapeutic approach to prevent colon cancer growth increasing differentiation markers expression and apoptosis. Recent data suggest that in colorectal CSCs, protection from apoptosis is achieved by interleukin-4 (IL-4) autocrine production through upregulation of antiapoptotic mediators, including survivin. Consequently, IL-4 neutralization could deregulate survivin expression and localization inducing chemosensitivity of the colon CSCs pool.

  10. Cell death in mammalian cell culture: molecular mechanisms and cell line engineering strategies

    OpenAIRE

    Krampe, Britta; Al-Rubeai, Mohamed

    2010-01-01

    Cell death is a fundamentally important problem in cell lines used by the biopharmaceutical industry. Environmental stress, which can result from nutrient depletion, by-product accumulation and chemical agents, activates through signalling cascades regulators that promote death. The best known key regulators of death process are the Bcl-2 family proteins which constitute a critical intracellular checkpoint of apoptosis cell death within a common death pathway. Engineering of several members o...

  11. Rpr- and hid-driven cell death in Drosophila photoreceptors.

    Science.gov (United States)

    Hsu, Cheng Da; Adams, Sheila M; O'Tousa, Joseph E

    2002-02-01

    The reaper (rpr) and head involution defective (hid) genes mediate programmed cell death (PCD) during Drosophila development. We show that expression of either rpr or hid under control of a rhodopsin promoter induces rapid cell death of adult photoreceptor cells. Ultrastructural analysis revealed that the dying photoreceptor cells share morphological features with other cells undergoing PCD. The anti-apoptotic baculoviral P35 protein acts downstream of hid activity to suppress the photoreceptor cell death driven by rpr and hid. These results establish that the Drosophila photoreceptors are sensitive to the rpr- and hid-driven cell death pathways.

  12. Active oxygen and cell death in cereal aleurone cells.

    Science.gov (United States)

    Fath, Angelika; Bethke, Paul; Beligni, Veronica; Jones, Russell

    2002-05-01

    The cereal aleurone layer is a secretory tissue whose function is regulated by gibberellic acid (GA) and abscisic acid (ABA). Aleurone cells lack functional chloroplasts, thus excluding photosynthesis as a source of active oxygen species (AOS) in cell death. Incubation of barley aleurone layers or protoplasts in GA initiated the cell death programme, but incubation in ABA delays programmed cell death (PCD). Light, especially blue and UV-A light, and H(2)O(2) accelerate PCD of GA-treated aleurone cells, but ABA-treated aleurone cells are refractory to light and H(2)O(2) and are not killed. It was shown that light elevated intracellular H(2)O(2), and that the rise in H(2)O(2) was greater in GA-treated cells compared to cells in ABA. Experiments with antioxidants show that PCD in aleurone is probably regulated by AOS. The sensitivity of GA-treated aleurone to light and H(2)O(2) is a result of lowered amounts of enzymes that metabolize AOS. mRNAs encoding catalase, ascorbate peroxidase and superoxide dismutase are all reduced during 6-18 h of incubation in GA, but these mRNAs were present in higher amounts in cells incubated in ABA. The amounts of protein and enzyme activities encoded by these mRNAs were also dramatically reduced in GA-treated cells. Aleurone cells store and metabolize neutral lipids via the glyoxylate cycle in response to GA, and glyoxysomes are one potential source of AOS in the GA-treated cells. Mitochondria are another potential source of AOS in GA-treated cells. AOS generated by these organelles bring about membrane rupture and cell death.

  13. Conventional calpains and programmed cell death.

    Science.gov (United States)

    Łopatniuk, Paulina; Witkowski, Jacek M

    2011-01-01

    The evidence on the crucial role of a family of calcium-dependent cysteine proteases called calpains in programmed cell death is rich and still growing. However, understanding of the mechanisms of their functions in apoptosis is not full yet. Calpains have been implicated in both physiological and pathological cell death control, especially in various malignancies, but also in the immune system development and function. There is also growing evidence on calpain involvement in apoptosis execution in certain pathological conditions of the central nervous system, in cardiovascular diseases, etc. Understanding of the clinical significance of calpain activation pathways, after intense studies of the influence of calpain activity on drug-induced apoptosis, seems especially important lately, as calpains have become noticed as potential therapeutic targets. To allow pharmacological targeting of these enzymes, thorough knowledge of their patterns of activation and further interactions with already known apoptotic pathways is necessary. A comprehensive summary of both well established and recently obtained information in the field is an important step that may lead to future advances in the use of calpain-targeted agents in the clinic.

  14. Impairment of Atg5-dependent autophagic flux promotes paraquat- and MPP⁺-induced apoptosis but not rotenone or 6-hydroxydopamine toxicity.

    Science.gov (United States)

    Garcia-Garcia, Aracely; Anandhan, Annandurai; Burns, Michaela; Chen, Han; Zhou, You; Franco, Rodrigo

    2013-11-01

    Controversial reports on the role of autophagy as a survival or cell death mechanism in dopaminergic cell death induced by parkinsonian toxins exist. We investigated the alterations in autophagic flux and the role of autophagy protein 5 (Atg5)-dependent autophagy in dopaminergic cell death induced by parkinsonian toxins. Dopaminergic cell death induced by the mitochondrial complex I inhibitors 1-methyl-4-phenylpyridinium (MPP⁺) and rotenone, the pesticide paraquat, and the dopamine analog 6-hydroxydopamine (6-OHDA) was paralleled by increased autophagosome accumulation. However, when compared with basal autophagy levels using chloroquine, autophagosome accumulation was a result of impaired autophagic flux. Only 6-OHDA induced an increase in autophagosome formation. Overexpression of a dominant negative form of Atg5 increased paraquat- and MPP⁺-induced cell death. Stimulation of mammalian target of rapamycin (mTOR)-dependent signaling protected against cell death induced by paraquat, whereas MPP⁺-induced toxicity was enhanced by wortmannin, a phosphoinositide 3-kinase class III inhibitor, rapamycin, and trehalose, an mTOR-independent autophagy activator. Modulation of autophagy by either pharmacological or genetic approaches had no effect on rotenone or 6-OHDA toxicity. Cell death induced by parkinsonian neurotoxins was inhibited by the pan caspase inhibitor (Z-VAD), but only caspase-3 inhibition was able to decrease MPP⁺-induced cell death. Finally, inhibition of the lysosomal hydrolases, cathepsins, increased the toxicity by paraquat and MPP⁺, supporting a protective role of Atg5-dependent autophagy and lysosomes degradation pathways on dopaminegic cell death. These results demonstrate that in dopaminergic cells, Atg5-dependent autophagy acts as a protective mechanism during apoptotic cell death induced by paraquat and MPP⁺ but not during rotenone or 6-OHDA toxicity.

  15. Genetic regulation of programmed cell death in Drosophila

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Programmed cell death plays an important role in maintaining homeostasis during animal development, and has been conserved in animals as different as nematodes and humans. Recent studies of Drosophila have provided valuable information toward our understanding of genetic regulation of death. Different signals trigger the novel death regulators rpr, hid, and grim, that utilize the evolutionarily conserved iap and ark genes to modulate caspase function. Subsequent removal of dying cells also appears to be accomplished by conserved mechanisms. The similarity between Drosophila and human in cell death signaling pathways illustrate the promise of fruit flies as a model system to elucidate the mechanisms underlying regulation of programmed cell death.

  16. Cell death signaling and anticancer therapy

    Directory of Open Access Journals (Sweden)

    Lorenzo eGalluzzi

    2011-05-01

    Full Text Available For a long time, it was commonly believed that efficient anticancer regimens would either trigger the apoptotic demise of tumor cells or induce a permanent arrest in the G1 phase of the cell cycle, i.e., senescence. The recent discovery that necrosis can occur in a regulated fashion and the increasingly more precise characterization of the underlying molecular mechanisms have raised great interest, as non-apoptotic pathways might be instrumental to circumvent the resistance of cancer cells to conventional, pro-apoptotic therapeutic regimens. Moreover, it has been shown that some anticancer regimens engage lethal signaling cascades that can ignite multiple oncosuppressive mechanisms, including apoptosis, necrosis and senescence. Among these signaling pathways is mitotic catastrophe, whose role as a bona fide cell death mechanism has recently been reconsidered. Thus, anticancer regimens get ever more sophisticated, and often distinct strategies are combined to maximize efficacy and minimize side effects. In this review, we will discuss the importance of apoptosis, necrosis and mitotic catastrophe in the response of tumor cells to the most common clinically employed and experimental anticancer agents.

  17. Apelin-13 impedes foam cell formation by activating Class III PI3K/Beclin-1-mediated autophagic pathway.

    Science.gov (United States)

    Yao, Feng; Lv, Yun-Cheng; Zhang, Min; Xie, Wei; Tan, Yu-Lin; Gong, Duo; Cheng, Hai-Peng; Liu, Dan; Li, Liang; Liu, Xiao-Yan; Zheng, Xi-Long; Tang, Chao-Ke

    2015-10-30

    Apelin-13, an adipokine, promotes cholesterol efflux in macrophages with antiatherosclerotic effect. Autophagy, an evolutionarily ancient response to cellular stress, has been involved in atherosclerosis. Therefore, the purpose of this study was to investigate whether apelin-13 regulates macrophage foam cell cholesterol metabolism through autophagy, and also explore the underlying mechanisms. Here, we revealed that apelin-13 decreased lipid accumulation in THP-1 derived macrophages through markedly enhancing cholesterol efflux. Our study further demonstrated that apelin-13 induced autophagy via activation of Class III phosphoinositide 3-kinase (PI3K) and Beclin-1. Inhibition of Class III PI3K and Beclin-1 suppressed the stimulatory effects of apelin-13 on autophagy activity. The present study concluded that apelin-13 reduces lipid accumulation of foam cells by activating autophagy via Class III PI3K/Beclin-1 pathway. Therefore, our results provide brand new insight about apelin-13 inhibiting foam cell formation and highlight autophagy as a promising therapeutic target in atherosclerosis.

  18. Plant programmed cell death, ethylene and flower senescence

    NARCIS (Netherlands)

    Woltering, E.J.; Jong, de A.; Hoeberichts, F.A.; Iakimova, E.T.; Kapchina, V.

    2005-01-01

    Programmed cell death (PCD) applies to cell death that is part of the normal life of multicellular organisms. PCD is found throughout the animal and plant kingdoms; it is an active process in which a cell suicide pathway is activated resulting in controlled disassembly of the cell. Most cases of PCD

  19. Concanavalin A/IFN-gamma triggers autophagy-related necrotic hepatocyte death through IRGM1-mediated lysosomal membrane disruption.

    Directory of Open Access Journals (Sweden)

    Chih-Peng Chang

    Full Text Available Interferon-gamma (IFN-γ, a potent Th1 cytokine with multiple biological functions, can induce autophagy to enhance the clearance of the invading microorganism or cause cell death. We have reported that Concanavalin A (Con A can cause autophagic cell death in hepatocytes and induce both T cell-dependent and -independent acute hepatitis in immunocompetent and immunodeficient mice, respectively. Although IFN-γ is known to enhance liver injury in Con A-induced hepatitis, its role in autophagy-related hepatocyte death is not clear. In this study we report that IFN-γ can enhance Con A-induced autophagic flux and cell death in hepatoma cell lines. A necrotic cell death with increased lysosomal membrane permeabilization (LMP is observed in Con A-treated hepatoma cells in the presence of IFN-γ. Cathepsin B and L were released from lysosomes to cause cell death. Furthermore, IFN-γ induces immunity related GTPase family M member 1(IRGM1 translocation to lysosomes and prolongs its activity in Con A-treated hepatoma cells. Knockdown of IRGM1 inhibits the IFN-γ/Con A-induced LMP change and cell death. Furthermore, IFN-γ(-/- mice are resistant to Con A-induced autophagy-associated necrotic hepatocyte death. We conclude that IFN-γ enhances Con A-induced autophagic flux and causes an IRGM1-dependent lysosome-mediated necrotic cell death in hepatocytes.

  20. Cabazitaxel-induced autophagy via the PI3K/Akt/mTOR pathway contributes to A549 cell death

    Science.gov (United States)

    Huo, Ruichao; Wang, Lili; Liu, Peijuan; Zhao, Yong; Zhang, Caiqin; Bai, Bing; Liu, Xueying; Shi, Changhong; Wei, Sanhua; Zhang, Hai

    2016-01-01

    Cabazitaxel has been used to treat castration-resistant prostate cancer since its approval by the US Food and Drug Administration in 2010. However, whether cabazitaxel may inhibit the proliferation of other tissue-derived cancer cells, and its underlying mechanism, remains unknown. In the present study, the A549 lung adenocarcinoma cancer cell line was exposed to cabazitaxel, in order to investigate its cytotoxic effect and determine the underlying mechanism. The results demonstrated that cabazitaxel was able to induce autophagy in A549 cells, as evidenced by the formation of autophagosomes, upregulated LC3-II expression and increased LC3 puncta. Cabazitaxel-induced autophagy had a cytotoxic effect on A549 cells, as evidenced by the induction of cell death and cell cycle arrest at G2/M phase, which was independent of the apoptotic pathway. Furthermore, transfection with Beclin1 small interfering RNA and treatment with the autophagy inhibitor 3-methyladenine protected cells from cabazitaxel-induced cell death, thus confirming that cabazitaxel-induced autophagy contributed to A549 cell death. In addition, cabazitaxel targeted the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway to induce autophagy, as indicated by reduced phosphorylation of Akt and mTOR. In conclusion, the present study demonstrated that cabazitaxel exerts a cytotoxic effect on A549 cells by acting on the PI3K/Akt/mTOR pathway to promote autophagic cell death. This result supports the potential use of cabazitaxel as a chemotherapeutic agent for the treatment of lung cancer. PMID:27572899

  1. Cabazitaxel-induced autophagy via the PI3K/Akt/mTOR pathway contributes to A549 cell death.

    Science.gov (United States)

    Huo, Ruichao; Wang, Lili; Liu, Peijuan; Zhao, Yong; Zhang, Caiqin; Bai, Bing; Liu, Xueying; Shi, Changhong; Wei, Sanhua; Zhang, Hai

    2016-10-01

    Cabazitaxel has been used to treat castration-resistant prostate cancer since its approval by the US Food and Drug Administration in 2010. However, whether cabazitaxel may inhibit the proliferation of other tissue‑derived cancer cells, and its underlying mechanism, remains unknown. In the present study, the A549 lung adenocarcinoma cancer cell line was exposed to cabazitaxel, in order to investigate its cytotoxic effect and determine the underlying mechanism. The results demonstrated that cabazitaxel was able to induce autophagy in A549 cells, as evidenced by the formation of autophagosomes, upregulated LC3‑II expression and increased LC3 puncta. Cabazitaxel‑induced autophagy had a cytotoxic effect on A549 cells, as evidenced by the induction of cell death and cell cycle arrest at G2/M phase, which was independent of the apoptotic pathway. Furthermore, transfection with Beclin1 small interfering RNA and treatment with the autophagy inhibitor 3‑methyladenine protected cells from cabazitaxel‑induced cell death, thus confirming that cabazitaxel‑induced autophagy contributed to A549 cell death. In addition, cabazitaxel targeted the phosphoinositide 3‑kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway to induce autophagy, as indicated by reduced phosphorylation of Akt and mTOR. In conclusion, the present study demonstrated that cabazitaxel exerts a cytotoxic effect on A549 cells by acting on the PI3K/Akt/mTOR pathway to promote autophagic cell death. This result supports the potential use of cabazitaxel as a chemotherapeutic agent for the treatment of lung cancer.

  2. NAC1 modulates sensitivity of ovarian cancer cells to cisplatin by altering the HMGB1-mediated autophagic response.

    Science.gov (United States)

    Zhang, Y; Cheng, Y; Ren, X; Zhang, L; Yap, K L; Wu, H; Patel, R; Liu, D; Qin, Z-H; Shih, I-M; Yang, J-M

    2012-02-23

    Nucleus accumbens-1 (NAC1), a nuclear factor belonging to the BTB/POZ gene family, is known to have important roles in proliferation and growth of tumor cells and in chemotherapy resistance. Yet, the mechanisms underlying how NAC1 contributes to drug resistance remain largely unclear. We report here that autophagy was involved in NAC1-mediated resistance to cisplatin, a commonly used chemotherapeutic drug in the treatment of ovarian cancer. We found that treatment with cisplatin caused an activation of autophagy in ovarian cancer cell lines, A2780, OVCAR3 and SKOV3. We further demonstrated that knockdown of NAC1 by RNA interference or inactivation of NAC1 by inducing the expression of a NAC1 deletion mutant that contains only the BTB/POZ domain significantly inhibited the cisplatin-induced autophagy, resulting in increased cisplatin cytotoxicity. Moreover, inhibition of autophagy and sensitization to cisplatin by NAC1 knockdown or inactivation were accompanied by induction of apoptosis. To confirm that the sensitizing effect of NAC1 inhibition on the cytotoxicity of cisplatin was attributed to suppression of autophagy, we assessed the effects of the autophagy inhibitors 3-methyladenosine and chloroquine, and small interfering RNAs (siRNAs) targeting beclin 1 or Atg5 on the cytotoxicity of cisplatin. Treatment with 3-methyladenosine, chloroquine or beclin 1 and Atg5-targeted siRNA also enhanced the sensitivity of SKOV3, A2780 and OVCAR3 cells to cisplatin, indicating that suppression of autophagy indeed renders tumor cells more sensitive to cisplatin. Regulation of autophagy by NAC1 was mediated by the high-mobility group box 1 (HMGB1), as the functional status of NAC1 was associated with the expression, translocation and release of HMGB1. The results of our study not only revealed a new mechanism determining cisplatin sensitivity but also identified NAC1 as a novel regulator of autophagy. Thus, the NAC1-mediated autophagy may be exploited as a new target for

  3. Stroke and cardiac cell death: Two peas in a pod.

    Science.gov (United States)

    Gonzales-Portillo, Chiara; Ishikawa, Hiroto; Shinozuka, Kazutaka; Tajiri, Naoki; Kaneko, Yuji; Borlongan, Cesar V

    2016-03-01

    A close pathological link between stroke brain and heart failure may exist. Here, we discuss relevant laboratory and clinical reports demonstrating neural and cardiac myocyte cell death following ischemic stroke. Although various overlapping risk factors exist between cerebrovascular incidents and cardiac incidents, stroke therapy has largely neglected the cardiac pathological consequences. Recent preclinical stroke studies have implicated an indirect cell death pathway, involving toxic molecules, that originates from the stroke brain and produces cardiac cell death. In concert, previous laboratory reports have revealed a reverse cell death cascade, in that cardiac arrest leads to ischemic cell death in the brain. A deeper understanding of the crosstalk of cell death pathways between stroke and cardiac failure will facilitate the development of novel treatments designed to arrest the global pathology of both diseases thereby improving the clinical outcomes of patients diagnosed with stroke and heart failure.

  4. Cell death sensitization of leukemia cells by opioid receptor activation

    Science.gov (United States)

    Friesen, Claudia; Roscher, Mareike; Hormann, Inis; Fichtner, Iduna; Alt, Andreas; Hilger, Ralf A.; Debatin, Klaus-Michael; Miltner, Erich

    2013-01-01

    Cyclic AMP (cAMP) regulates a number of cellular processes and modulates cell death induction. cAMP levels are altered upon stimulation of specific G-protein-coupled receptors inhibiting or activating adenylyl cyclases. Opioid receptor stimulation can activate inhibitory Gi-proteins which in turn block adenylyl cyclase activity reducing cAMP. Opioids such as D,L-methadone induce cell death in leukemia cells. However, the mechanism how opioids trigger apoptosis and activate caspases in leukemia cells is not understood. In this study, we demonstrate that downregulation of cAMP induced by opioid receptor activation using the opioid D,L-methadone kills and sensitizes leukemia cells for doxorubicin treatment. Enhancing cAMP levels by blocking opioid-receptor signaling strongly reduced D,L-methadone-induced apoptosis, caspase activation and doxorubicin-sensitivity. Induction of cell death in leukemia cells by activation of opioid receptors using the opioid D,L-methadone depends on critical levels of opioid receptor expression on the cell surface. Doxorubicin increased opioid receptor expression in leukemia cells. In addition, the opioid D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux in leukemia cells, suggesting that the opioid D,L-methadone as well as doxorubicin mutually increase their cytotoxic potential. Furthermore, we found that opioid receptor activation using D,L-methadone alone or in addition to doxorubicin inhibits tumor growth significantly in vivo. These results demonstrate that opioid receptor activation via triggering the downregulation of cAMP induces apoptosis, activates caspases and sensitizes leukemia cells for doxorubicin treatment. Hence, opioid receptor activation seems to be a promising strategy to improve anticancer therapies. PMID:23633472

  5. Death of mitochondria during programmed cell death of leaf mesophyll cells.

    Science.gov (United States)

    Selga, Tūrs; Selga, Maija; Pāvila, Vineta

    2005-12-01

    The role of plant mitochondria in the programmed cell death (PCD) is widely discussed. However, spectrum and sequence of mitochondrial structural changes during different types of PCD in leaves are poorly described. Pea, cucumber and rye plants were grown under controlled growing conditions. A part of them were sprinkled with ethylene releaser to accelerate cell death. During yellowing the palisade parenchyma mitochondria were attracted to nuclear envelope. Mitochondrial matrix became electron translucent. Mitochondria entered vacuole by invagination of tonoplast and formed multivesicular bodies. Ethephon treatment increased the frequency of sticking of mitochondria to the nuclear envelope or chloroplasts and peroxisomes. Mitochondria divided by different mechanisms and became enclosed in Golgi and ER derived authopagic vacuoles or in the central vacuole. Several fold increase of the diameter of cristae became typical. In all cases mitochondria were attached to nuclear envelope. It can be considered as structural mechanism of promoting of PCD.

  6. Cellular and molecular mechanisms activating the cell death processes by chalcones: Critical structural effects.

    Science.gov (United States)

    Champelovier, Pierre; Chauchet, Xavier; Hazane-Puch, Florence; Vergnaud, Sabrina; Garrel, Catherine; Laporte, François; Boutonnat, Jean; Boumendjel, Ahcène

    2013-12-01

    Chalcones are naturally occurring compounds with diverse pharmacological activities. Chalcones derive from the common structure: 1,3-diphenylpropenone. The present study aims to better understand the mechanistic pathways triggering chalcones anticancer effects and providing evidences that minor structural difference could lead to important difference in mechanistic effect. We selected two recently investigated chalcones (A and B) and investigated them on glioblastoma cell lines. It was found that chalcone A induced an apoptotic process (type I PCD), via the activation of caspase-3, -8 and -9. Chalcone A also increased CDK1/cyclin B ratios and decreased the mitochondrial transmembrane potential (ΔΨm). Chalcone B induced an autophagic cell death process (type II PCD), ROS-related but independent of both caspases and protein synthesis. Both chalcones increased Bax/Bcl2 ratios and decreased Ki67 and CD71 antigen expressions. The present investigation reveals that despite the close structure of chalcones A and B, significant differences in mechanism of effect were found.

  7. Sensitization of radiation-induced cell death by genistein

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Rim; Kim, In Gyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-03-15

    A number of epidemiological studies as well as biological experiments, showed that genistein, one of the isoflavone, prevents prostate cancer occurrence. In this study, we showed that genistein inhibited the cell proliferation of human promyeoltic leukemia HL-60 cells and induced G2/M phase arrest. In addition, combination of genistein treatment and {gamma}-irradiation displayed synergistic effect in apoptotic cell death of HL-60 cells. This means that the repair of genistein-induced DNA damage was hindered by {gamma}-irradiation and thus cell death was increased. In conclusion, genistein is one of the important chemicals that sensitize radiation-induced cell death.

  8. Interleukin-8 enhances the effect of colchicine on cell death.

    Science.gov (United States)

    Yokoyama, Chikako; Yajima, Chika; Machida, Tetsuro; Kawahito, Yuji; Uchida, Marie; Hisatomi, Hisashi

    2017-02-09

    Pro-inflammatory cytokines are known to be generated in tumors and play important roles in angiogenesis, mitosis, and tumor progression. However, few studies have investigated the synergistic effects of pro-inflammatory cytokines and anticancer drugs on cell death. In the present study, we examined the combined effects of pro-inflammatory cytokines and colchicine on cell death of cancer cells. Colchicine induces G2/M arrest in the cell cycle by binding to tubulin, one of the main constituents of microtubules. SUIT-2 human pancreatic cancer cell line cells overexpressing pro-inflammatory cytokines, including interleukin (IL)-1β, IL-8, and tumor necrosis factor (TNF)-α, were treated with colchicine. The effect of colchicine on cell death was enhanced in cells overexpressing IL-8. Moreover, the effect of colchicine on cell death was enhanced in cells overexpressing two IL-8 up-regulators, NF-κB and IL-6, but not in cells overexpressing an IL-8 down-regulator, splicing factor proline/glutamine-rich (SFPQ). Synergistic effects of IL-8 and colchicine were also observed in cells overexpressing IL-8 isoforms lacking the signal peptide. Therefore, IL-8 appeared to function as an enhancer of cell death in cancer cells treated with colchicine. The present results suggest a new role for IL-8 related to cell death of cancer cells.

  9. Vibrio vulnificus VvhA induces autophagy-related cell death through the lipid raft-dependent c-Src/NOX signaling pathway.

    Science.gov (United States)

    Song, Eun Ju; Lee, Sei-Jung; Lim, Hyeon Su; Kim, Jun Sung; Jang, Kyung Ku; Choi, Sang Ho; Han, Ho Jae

    2016-06-02

    VvhA, a virulent factor of Vibrio (V.) vulnificus, induces acute cell death in a destructive manner. Autophagy plays an important role in cell death, but the functional role of VvhA in autophagy-related cell death has not been elucidated yet. We found that rVvhA significantly increased LC3 puncta formation and autophagic flux in promoting the cell death of human intestinal epithelial Caco-2 cells. The cell death induced by rVvhA was independent of lysosomal permeabilizaton and caspase activation. rVvhA induced rapid phosphorylation of c-Src in the membrane lipid raft, which resulted in an increased interaction between lipid raft molecule caveolin-1 and NADPH oxidase (NOX) complex Rac1 for ROS production. NOX-mediated ROS signaling induced by rVvhA increased the phosphorylation of extracellular signal-regulated kinase (ERK) and eukaryotic translation initiation factor 2α (eIF2α) which are required for mRNA expression of Atg5 and Atg16L1 involved in autophagosome formation. In an in vivo model, VvhA increased autophagy activation and paracellular permeabilization in intestinal epithelium. Collectively, the results here show that VvhA plays a pivotal role in the pathogenesis and dissemination of V. vulnificus by autophagy upregulation, through the lipid raft-mediated c-Src/NOX signaling pathway and ERK/eIF2α activation.

  10. Programmed cell death and cell extrusion in rat duodenum

    DEFF Research Database (Denmark)

    Schauser, Kirsten; Larsson, Lars-Inge

    2005-01-01

    The small intestinal epithelium is continously renewed through a balance between cell division and cell loss. How this balance is achieved is uncertain. Thus, it is unknown to what extent programmed cell death (PCD) contributes to intestinal epithelial cell loss. We have used a battery...... of techniques detecting the events associated with PCD in order to better understand its role in the turnover of the intestinal epithelium, including modified double- and triple-staining techniques for simultaneously detecting multiple markers of PCD in individual cells. Only a partial correlation between TUNEL...... positivity for DNA fragmentation, c-jun phosphorylation on serine-63, positivity for activated caspase-3 and apoptotic morphology was observed. Our results show that DNA fragmentation does not invariable correlate to activation of caspase-3. Moreover, many cells were found to activate caspase-3 early...

  11. Visualization of co-localization in Aβ42-administered neuroblastoma cells reveals lysosome damage and autophagosome accumulation related to cell death.

    Science.gov (United States)

    Soura, Violetta; Stewart-Parker, Maris; Williams, Thomas L; Ratnayaka, Arjuna; Atherton, Joe; Gorringe, Kirsti; Tuffin, Jack; Darwent, Elisabeth; Rambaran, Roma; Klein, William; Lacor, Pascale; Staras, Kevin; Thorpe, Julian; Serpell, Louise C

    2012-01-15

    Aβ42 [amyloid-β peptide-(1-42)] plays a central role in Alzheimer's disease and is known to have a detrimental effect on neuronal cell function and survival when assembled into an oligomeric form. In the present study we show that administration of freshly prepared Aβ42 oligomers to a neuroblastoma (SH-SY5Y) cell line results in a reduction in survival, and that Aβ42 enters the cells prior to cell death. Immunoconfocal and immunogold electron microscopy reveal the path of the Aβ42 with time through the endosomal system and shows that it accumulates in lysosomes. A 24 h incubation with Aβ results in cells that have damaged lysosomes showing signs of enzyme leakage, accumulate autophagic vacuoles and exhibit severely disrupted nuclei. Endogenous Aβ is evident in the cells and the results of the present study suggest that the addition of Aβ oligomers disrupts a crucial balance in Aβ conformation and concentration inside neuronal cells, resulting in catastrophic effects on cellular function and, ultimately, in cell death.

  12. Chemical- and pathogen-induced programmed cell death in plants

    NARCIS (Netherlands)

    Iakimova, E.T.; Atanassov, A.; Woltering, E.J.

    2005-01-01

    This review focuses on recent update in the understanding of programmed cell death regarding the differences and similarities between the diverse types of cell death in animal and plant systems and describes the morphological and some biochemical determinants. The role of PCD in plant development an

  13. Mangiferin induces cell death against rhabdomyosarcoma through sustained oxidative stress

    OpenAIRE

    Vishwanadha Vijaya Padma; Palanisamy Kalaiselvi; Rangasamy Yuvaraj; M. Rabeeth

    2015-01-01

    Background: Embryonic rhabdomyosarcoma (RD) is the most prevalent type of cancer among children. The present study aimed to investigate cell death induced by mangiferin in RD cells. Methods: The Inhibitory concentration (IC50) value of mangiferin was determined by an MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay. Cell death induced by mangiferin against RD cells was determined through lactate dehydrogenase and nitric oxide release, intracellular calcium levels, r...

  14. Activation-Induced Cell Death in T Cells and Autoimmunity

    Institute of Scientific and Technical Information of China (English)

    Jian Zhang; Xuemei Xu; Yong Liu

    2004-01-01

    Activation-induced cell death (AICD), which results from the interaction between Fas and Fas ligand, is responsible for maintaining tolerance to self-antigen. A defect in AICD may lead to development of autoimmunity. During the last several years, much progress has been made in understanding the mechanism(s) of AICD and its potential role in the pathogenesis of autoimmune diseases. In this review, we summarize the most recent progress on the regulation of the susceptibility of T cells to AICD and its possible involvement in autoimmune diseases.

  15. Chemical -induced apoptotic cell death in tomato cells : involvement of caspase-like proteases

    NARCIS (Netherlands)

    Jong, de A.J.; Hoeberichts, F.A.; Yakimova, E.T.; Maximova, E.; Woltering, E.J.

    2000-01-01

    A new system to study programmed cell death in plants is described. Tomato (Lycopersicon esculentum Mill.) suspension cells were induced to undergo programmed cell death by treatment with known inducers of apoptosis in mammalian cells. This chemical-induced cell death was accompanied by the characte

  16. Independent controls for neocortical neuron production and histogenetic cell death

    Science.gov (United States)

    Verney, C.; Takahashi, T.; Bhide, P. G.; Nowakowski, R. S.; Caviness, V. S. Jr

    2000-01-01

    We estimated the proportion of cells eliminated by histogenetic cell death during the first 2 postnatal weeks in areas 1, 3 and 40 of the mouse parietal neocortex. For each layer and for the subcortical white matter in each neocortical area, the number of dying cells per mm(2) was calculated and the proportionate cell death for each day of the 2-week interval was estimated. The data show that cell death proceeds essentially uniformly across the neocortical areas and layers and that it does not follow either the spatiotemporal gradient of cell cycle progression in the pseudostratified ventricular epithelium of the cerebral wall, the source of neocortical neurons, or the 'inside-out' neocortical neuronogenetic sequence. Therefore, we infer that the control mechanisms of neocortical histogenetic cell death are independent of mechanisms controlling neuronogenesis or neuronal migration but may be associated with the ingrowth, expansion and a system-wide matching of neuronal connectivity. Copyright 2000 S. Karger AG, Basel.

  17. Stem cell death and survival in heart regeneration and repair.

    Science.gov (United States)

    Abdelwahid, Eltyeb; Kalvelyte, Audrone; Stulpinas, Aurimas; de Carvalho, Katherine Athayde Teixeira; Guarita-Souza, Luiz Cesar; Foldes, Gabor

    2016-03-01

    Cardiovascular diseases are major causes of mortality and morbidity. Cardiomyocyte apoptosis disrupts cardiac function and leads to cardiac decompensation and terminal heart failure. Delineating the regulatory signaling pathways that orchestrate cell survival in the heart has significant therapeutic implications. Cardiac tissue has limited capacity to regenerate and repair. Stem cell therapy is a successful approach for repairing and regenerating ischemic cardiac tissue; however, transplanted cells display very high death percentage, a problem that affects success of tissue regeneration. Stem cells display multipotency or pluripotency and undergo self-renewal, however these events are negatively influenced by upregulation of cell death machinery that induces the significant decrease in survival and differentiation signals upon cardiovascular injury. While efforts to identify cell types and molecular pathways that promote cardiac tissue regeneration have been productive, studies that focus on blocking the extensive cell death after transplantation are limited. The control of cell death includes multiple networks rather than one crucial pathway, which underlies the challenge of identifying the interaction between various cellular and biochemical components. This review is aimed at exploiting the molecular mechanisms by which stem cells resist death signals to develop into mature and healthy cardiac cells. Specifically, we focus on a number of factors that control death and survival of stem cells upon transplantation and ultimately affect cardiac regeneration. We also discuss potential survival enhancing strategies and how they could be meaningful in the design of targeted therapies that improve cardiac function.

  18. ENERGY REQUIREMENT FOR THYMINELESS DEATH IN CELLS OF ESCHERICHIA COLI.

    Science.gov (United States)

    FREIFELDER, D; MAALOE, O

    1964-10-01

    Freifelder, David (University of California, Berkeley), and Ole Maaløe. Energy requirement for thymineless death in cells of Escherichia coli. J. Bacteriol. 88:987-990. 1964.-Thymineless death in thymine-requiring Escherichia coli is arrested immediately and reversibly by nitrogenation if the bacterial population is growing in a medium containing a carbon source that can only be metabolized aerobically. The mechanism of death, therefore, involves a metabolic process.

  19. Ceramide mediates caspase-independent programmed cell death.

    Science.gov (United States)

    Thon, Lutz; Möhlig, Heike; Mathieu, Sabine; Lange, Arne; Bulanova, Elena; Winoto-Morbach, Supandi; Schütze, Stefan; Bulfone-Paus, Silvia; Adam, Dieter

    2005-12-01

    Although numerous studies have implicated the sphingolipid ceramide in the induction of cell death, a causative function of ceramide in caspase-dependent apoptosis remains a highly debated issue. Here, we show that ceramide is a key mediator of a distinct route to programmed cell death (PCD), i.e., caspase-independent PCD. Under conditions where apoptosis is either not initiated or actively inhibited, TNF induces caspase-independent PCD in L929 fibrosarcoma cells, NIH3T3 fibroblasts, human leukemic Jurkat T cells, and lung fibroblasts by increasing intracellular ceramide levels prior to the onset of cell death. Survival is significantly enhanced when ceramide accumulation is prevented, as demonstrated in fibroblasts genetically deficient for acid sphingomyelinase, in L929 cells overexpressing acid ceramidase, by pharmacological intervention, or by RNA interference. Jurkat cells deficient for receptor-interacting protein 1 (RIP1) do not accumulate ceramide and therefore are fully resistant to caspase-independent PCD whereas Jurkat cells overexpressing the mitochondrial protein Bcl-2 are partially protected, implicating RIP1 and mitochondria as components of the ceramide death pathway. Our data point to a role of caspases (but not cathepsins) in suppressing the ceramide death pathway under physiological conditions. Moreover, clonogenic survival of tumor cells is clearly reduced by induction of the ceramide death pathway, promising additional options for the development of novel tumor therapies.

  20. Mechanical Stress Promotes Cisplatin-Induced Hepatocellular Carcinoma Cell Death

    Directory of Open Access Journals (Sweden)

    Laila Ziko

    2015-01-01

    Full Text Available Cisplatin (CisPt is a commonly used platinum-based chemotherapeutic agent. Its efficacy is limited due to drug resistance and multiple side effects, thereby warranting a new approach to improving the pharmacological effect of CisPt. A newly developed mathematical hypothesis suggested that mechanical loading, when coupled with a chemotherapeutic drug such as CisPt and immune cells, would boost tumor cell death. The current study investigated the aforementioned mathematical hypothesis by exposing human hepatocellular liver carcinoma (HepG2 cells to CisPt, peripheral blood mononuclear cells, and mechanical stress individually and in combination. HepG2 cells were also treated with a mixture of CisPt and carnosine with and without mechanical stress to examine one possible mechanism employed by mechanical stress to enhance CisPt effects. Carnosine is a dipeptide that reportedly sequesters platinum-based drugs away from their pharmacological target-site. Mechanical stress was achieved using an orbital shaker that produced 300 rpm with a horizontal circular motion. Our results demonstrated that mechanical stress promoted CisPt-induced death of HepG2 cells (~35% more cell death. Moreover, results showed that CisPt-induced death was compromised when CisPt was left to mix with carnosine 24 hours preceding treatment. Mechanical stress, however, ameliorated cell death (20% more cell death.

  1. Cell division and death inhibit glassy behaviour of confluent tissues

    CERN Document Server

    Matoz-Fernandez, D A; Sknepnek, Rastko; Barrat, J L; Henkes, S

    2016-01-01

    We investigate the effects of cell division and apopotosis on collective dynamics in two-dimensional epithelial tissues. Our model includes three key ingredients observed across many epithelia, namely cell-cell adhesion, cell death and a cell division process that depends on the surrounding environment. We show a rich non-equilibrium phase diagram depending on the ratio of cell death to cell division and on the adhesion strength. For large apopotosis rates, cells die out and the tissue disintegrates. As the death rate decreases, however, we show, consecutively, the existence of a gas-like phase, a gel-like phase, and a dense confluent (tissue) phase. Most striking is the observation that the tissue is self-melting through its own internal activity, ruling out the existence of any glassy phase.

  2. Heme oxygenase-1 accelerates erastin-induced ferroptotic cell death.

    Science.gov (United States)

    Kwon, Min-Young; Park, Eunhee; Lee, Seon-Jin; Chung, Su Wol

    2015-09-15

    The oncogenic RAS-selective lethal small molecule Erastin triggers a unique iron-dependent form of nonapoptotic cell death termed ferroptosis. Ferroptosis is dependent upon the production of intracellular iron-dependent reactive oxygen species (ROS), but not other metals. However, key regulators remain unknown. The heme oxygenase (HO) is a major intracellular source of iron. In this study, the role of heme oxygenase in Erastin-triggered ferroptotic cancer cell death has been investigated. Zinc protoporphyrin IX (ZnPP), a HO-1 inhibitor, prevented Erastin-triggered ferroptotic cancer cell death. Furthermore, Erastin induced the protein and mRNA levels of HO-1 in HT-1080 fibrosarcoma cells. HO-1+/+ and HO-1-/- fibroblast, HO-1 overexpression, and chycloheximide-treated experiments revealed that the expression of HO-1 has a decisive effects in Erastin-triggered cell death. Hemin and CO-releasing molecules (CORM) promote Erastin-induced ferroptotic cell death, not by biliverdin and bilirubin. In addition, hemin and CORM accelerate the HO-1 expression in the presence of Erastin and increase membranous lipid peroxidation. Thus, HO-1 is an essential enzyme for iron-dependent lipid peroxidation during ferroptotic cell death.

  3. Programmed cell death in the larval salivary glands of Apis mellifera (Hymenoptera, Apidae)

    Indian Academy of Sciences (India)

    E C M Silva-Zacarin; G A Tomaino; M R Brocheto-Braga; S R Taboga; R L M Silva De Moraes

    2007-03-01

    The morphological and histochemical features of degeneration in honeybee (Apis mellifera) salivary glands were investigated in 5th instar larvae and in the pre-pupal period. The distribution and activity patterns of acid phosphatase enzyme were also analysed. As a routine, the larval salivary glands were fixed and processed for light microscopy and transmission electron microscopy. Tissue sections were subsequently stained with haematoxylin–eosin, bromophenol blue, silver, or a variant of the critical electrolyte concentration (CEC) method. Ultrathin sections were contrasted with uranyl acetate and lead citrate. Glands were processed for the histochemical and cytochemical localization of acid phosphatase, as well as biochemical assay to detect its activity pattern. Acid phosphatase activity was histochemically detected in all the salivary glands analysed. The cytochemical results showed acid phosphatase in vesicles, Golgi apparatus and lysosomes during the secretory phase and, additionally, in autophagic structures and luminal secretion during the degenerative phase. These findings were in agreement with the biochemical assay. At the end of the 5th instar, the glandular cells had a vacuolated cytoplasm and pyknotic nuclei, and epithelial cells were shed into the glandular lumen. The transition phase from the 5th instar to the pre-pupal period was characterized by intense vacuolation of the basal cytoplasm and release of parts of the cytoplasm into the lumen by apical blebbing; these blebs contained cytoplasmic RNA, rough endoplasmic reticule and, occasionally, nuclear material. In the pre-pupal phase, the glandular epithelium showed progressive degeneration so that at the end of this phase only nuclei and remnants of the cytoplasm were observed. The nuclei were pyknotic, with peripheral chromatin and blebs. The gland remained in the haemolymph and was recycled during metamorphosis. The programmed cell death in this gland represented a morphological form

  4. Cell biology: Death drags down the neighbourhood

    Science.gov (United States)

    Vasquez, Claudia G.; Martin, Adam C.

    2015-02-01

    An analysis of dying cells reveals that they play an active part in modifying tissue shape by pulling on neighbouring cells. This induces neighbouring cells to contract at their apices, which results in tissue folding. See Letter p.245

  5. The control and execution of programmed cell death

    Energy Technology Data Exchange (ETDEWEB)

    Begum, R.; Pathak, N.; Hasnain, S.E.; Sah, N.K. [National Inst. of Immunology, New Delhi (India). Eukaryotic Gene Expression Lab.; Taneja, T.K.; Mohan, M. [National Inst. of Immunology, New Delhi (India). Eukaryotic Gene Expression Lab.]|[Dept. of Medical Elementology and Toxicology, New Delhi (India); Athar, M. [Dept. of Medical Elementology and Toxicology, New Delhi (India)

    1999-07-01

    Apoptosis or programmed cell death is a highly conserved genetically controlled response of metazoan cells to commit suicide. Non apoptotic programmed cell death seems to operate in single celled eukaryotes implying that evolution of PCD has preceded the evolution of multicellularity. PCD plays a crucial role in the regulation of cellular and tissue homeostasis and any aberrations in apoptosis leads to several diseases including cancer, neurodegenerative disorders and AIDS. The mechanisms by which apoptosis is controlled are varied. In some cells, members of bcl-2 family or p53 are crucial for regulating the apoptosis programme, whereas in other cells Fas ligand is more important. bcl-2 family members have a prime role in the regulation of cell death at all stages including development, whereas cell death during development is independent of p53. bcl-2 family members being localized on the outer mitochondrial membrane, control the mitochondrial homeostasis and cytochrome c redistribution and thereby regulate the cell death process. p53 promotes DNA damage mediated cell death after growth arrest and failed DNA repair. Caspases play a key role in the execution of cell death by mediating highly specific cleavages of crucial cellular proteins collectivley manifesting the apoptotic phenotype. Protein inhibitors like crm A, p35 and IAPs could prevent/control apoptosis induced by a broad array of cell death stimuli by several mechanisms specially interfering in caspase activation or caspase activity. Among endonucleases, caspase activated DNase (CAD) plays a crucial role in DNA fragmentation, a biochemical hallmark of apoptosis. As regulation of cell death seems to be as complex as regulation of cell proliferation, multiple kinase mediated regulatory mechanisms might control the apoptotic process. Thus, in spite of intensive research over the past few years, the field of apoptosis still remains fertile to unravel among others, the molecular mechanisms of cytochrome c

  6. The life and death of sponge cells

    NARCIS (Netherlands)

    Sipkema, D.; Snijders, A.P.L.; Schroën, C.G.P.H.; Osinga, R.; Wijffels, R.H.

    2004-01-01

    Cell viability is an essential touchstone in the study of the effect of medium components on cell physiology. We developed a flow-cytometric assay to determine sponge-cell viability, based on the combined use of fluorescein diacetate (FDA) and propidium iodide (PI). Cell fluorescence measurements ba

  7. Targeting Cell Death Pathways for Therapeutic Intervention in Kidney Diseases.

    Science.gov (United States)

    Garg, Jay P; Vucic, Domagoj

    2016-05-01

    Precise regulation of cell death and survival is essential for proper maintenance of organismal homeostasis, development, and the immune system. Deregulated cell death can lead to developmental defects, neuropathies, infections, and cancer. Kidney diseases, especially acute pathologies linked to ischemia-reperfusion injury, are among illnesses that profoundly are affected by improper regulation or execution of cell death pathways. Attempts to develop medicines for kidney diseases have been impacted by the complexity of these pathologies given the heterogeneous patient population and diverse etiologies. By analyzing cell death pathways activated in kidney diseases, we attempt to differentiate their importance for these pathologies with a goal of identifying those that have more profound impact and the best therapeutic potential. Although classic apoptosis still might be important, regulated necrosis pathways including necroptosis, ferroptosis, parthanatos, and mitochondrial permeability transition-associated cell death play a significantly role in kidney diseases, especially in acute kidney pathologies. Although targeting receptor-interacting protein 1 kinase appears to be the best therapeutic strategy, combination with inhibitors of other cell death pathways is likely to bring superior benefit and possible cure to patients suffering from kidney diseases.

  8. Acetylsalicylic acid induces programmed cell death in Arabidopsis cell cultures.

    Science.gov (United States)

    García-Heredia, José M; Hervás, Manuel; De la Rosa, Miguel A; Navarro, José A

    2008-06-01

    Acetylsalicylic acid (ASA), a derivative from the plant hormone salicylic acid (SA), is a commonly used drug that has a dual role in animal organisms as an anti-inflammatory and anticancer agent. It acts as an inhibitor of cyclooxygenases (COXs), which catalyze prostaglandins production. It is known that ASA serves as an apoptotic agent on cancer cells through the inhibition of the COX-2 enzyme. Here, we provide evidences that ASA also behaves as an agent inducing programmed cell death (PCD) in cell cultures of the model plant Arabidopsis thaliana, in a similar way than the well-established PCD-inducing agent H(2)O(2), although the induction of PCD by ASA requires much lower inducer concentrations. Moreover, ASA is herein shown to be a more efficient PCD-inducing agent than salicylic acid. ASA treatment of Arabidopsis cells induces typical PCD-linked morphological and biochemical changes, namely cell shrinkage, nuclear DNA degradation, loss of mitochondrial membrane potential, cytochrome c release from mitochondria and induction of caspase-like activity. However, the ASA effect can be partially reverted by jasmonic acid. Taking together, these results reveal the existence of common features in ASA-induced animal apoptosis and plant PCD, and also suggest that there are similarities between the pathways of synthesis and function of prostanoid-like lipid mediators in animal and plant organisms.

  9. IR-induced autophagy plays a role in survival of HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Mi Young; Jang, Eun Yeong; Ryu, Tae Ho; Chung, Dong Min; Kim, Jin Hong; Kim, Jin Kyu [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2014-04-15

    Cells respond to stress with repair, or are diverted into irreversible cell cycle exit (senescence) or are eliminated through programmed cell death. There are two major morphologically distinctive forms of programmed cell death, apoptosis and autophagic cell death. Apoptosis contribute to cell death, whereas autophagy can play a dual role in mediating either cell survival or death in response to various stress stimuli. Here we analysed cellular responses induced by IR. The understanding of an appropriate cellular stress response is of crucial importance in foreseeing the cell fate. Apoptotic feagures were not detected in HeLa under our experimental irradiation condition. Autophagic cell death in HeLa may play an important role in cell protection and can result in cell survival.

  10. Cbl negatively regulates JNK activation and cell death

    Institute of Scientific and Technical Information of China (English)

    Andrew A Sproul; Zhiheng Xu; Michael Wilhelm; Stephen Gire; Lloyd A Greene

    2009-01-01

    Here, we explore the role of Cbl proteins in regulation of neuronal apoptosis. In two paradigms of neuron apopto-sis--nerve growth factor (NGF) deprivation and DNA damage--cellular levels of c-Cbl and Cbl-b fell well before the onset of cell death. NGF deprivation also induced rapid loss of tyrosine phosphorylation (and most likely, activa-tion) of c-Cbl. Targeting e-Cbl and Cbl-b with siRNAs to mimic their loss/inactivation sensitized neuronal cells to death promoted by NGF deprivation or DNA damage. One potential mechanism by which Cbl proteins might affect neuronal death is by regulation of apoptotic c-Jun N-terminal kinase (JNK) signaling. We demonstrate that Cbl pro-teins interact with the JNK pathway components mixed lineage kinase (MLK) 3 and POSH and that knockdown of Cbl proteins is sufficient to increase JNK pathway activity. Furthermore, expression of c-Cbl blocks the ability of MLKs to signal to downstream components of the kinase cascade leading to JNK activation and protects neuronal cells from death induced by MLKs, but not from downstream JNK activators. On the basis of these findings, we propose that Cbls suppress cell death in healthy neurons at least in part by inhibiting the ability of MLKs to activate JNK signaling. Apoptotic stimuli lead to loss of Cbl protein/activity, thereby removing a critical brake on JNK acti-vation and on cell death.

  11. Acetaminophen induces human neuroblastoma cell death through NFKB activation.

    Directory of Open Access Journals (Sweden)

    Inmaculada Posadas

    Full Text Available Neuroblastoma resistance to apoptosis may contribute to the aggressive behavior of this tumor. Therefore, it would be relevant to activate endogenous cellular death mechanisms as a way to improve neuroblastoma therapy. We used the neuroblastoma SH-SY5Y cell line as a model to study the mechanisms involved in acetaminophen (AAP-mediated toxicity by measuring CYP2E1 enzymatic activity, NFkB p65 subunit activation and translocation to the nucleus, Bax accumulation into the mitochondria, cytochrome c release and caspase activation. AAP activates the intrinsic death pathway in the SH-SY5Y human neuroblastoma cell line. AAP metabolism is partially responsible for this activation, because blockade of the cytochrome CYP2E1 significantly reduced but did not totally prevent, AAP-induced SH-SY5Y cell death. AAP also induced NFkB p65 activation by phosphorylation and its translocation to the nucleus, where NFkB p65 increased IL-1β production. This increase contributed to neuroblastoma cell death through a mechanism involving Bax accumulation into the mitochondria, cytochrome c release and caspase3 activation. Blockade of NFkB translocation to the nucleus by the peptide SN50 prevented AAP-mediated cell death and IL-1β production. Moreover, overexpression of the antiapoptotic protein Bcl-x(L did not decrease AAP-mediated IL-1β production, but prevented both AAP and IL-1β-mediated cell death. We also confirmed the AAP toxic actions on SK-N-MC neuroepithelioma and U87MG glioblastoma cell lines. The results presented here suggest that AAP activates the intrinsic death pathway in neuroblastoma cells through a mechanism involving NFkB and IL-1β.

  12. Regulation of cell death receptor S-nitrosylation and apoptotic signaling by Sorafenib in hepatoblastoma cells.

    Science.gov (United States)

    Rodríguez-Hernández, A; Navarro-Villarán, E; González, R; Pereira, S; Soriano-De Castro, L B; Sarrias-Giménez, A; Barrera-Pulido, L; Álamo-Martínez, J M; Serrablo-Requejo, A; Blanco-Fernández, G; Nogales-Muñoz, A; Gila-Bohórquez, A; Pacheco, D; Torres-Nieto, M A; Serrano-Díaz-Canedo, J; Suárez-Artacho, G; Bernal-Bellido, C; Marín-Gómez, L M; Barcena, J A; Gómez-Bravo, M A; Padilla, C A; Padillo, F J; Muntané, J

    2015-12-01

    Nitric oxide (NO) plays a relevant role during cell death regulation in tumor cells. The overexpression of nitric oxide synthase type III (NOS-3) induces oxidative and nitrosative stress, p53 and cell death receptor expression and apoptosis in hepatoblastoma cells. S-nitrosylation of cell death receptor modulates apoptosis. Sorafenib is the unique recommended molecular-targeted drug for the treatment of patients with advanced hepatocellular carcinoma. The present study was addressed to elucidate the potential role of NO during Sorafenib-induced cell death in HepG2 cells. We determined the intra- and extracellular NO concentration, cell death receptor expression and their S-nitrosylation modifications, and apoptotic signaling in Sorafenib-treated HepG2 cells. The effect of NO donors on above parameters has also been determined. Sorafenib induced apoptosis in HepG2 cells. However, low concentration of the drug (10nM) increased cell death receptor expression, as well as caspase-8 and -9 activation, but without activation of downstream apoptotic markers. In contrast, Sorafenib (10 µM) reduced upstream apoptotic parameters but increased caspase-3 activation and DNA fragmentation in HepG2 cells. The shift of cell death signaling pathway was associated with a reduction of S-nitrosylation of cell death receptors in Sorafenib-treated cells. The administration of NO donors increased S-nitrosylation of cell death receptors and overall induction of cell death markers in control and Sorafenib-treated cells. In conclusion, Sorafenib induced alteration of cell death receptor S-nitrosylation status which may have a relevant repercussion on cell death signaling in hepatoblastoma cells.

  13. Cell Death Mechanisms Induced by Cytotoxic Lymphocytes

    Institute of Scientific and Technical Information of China (English)

    Ch(a)vez-Gal(a)n L; Arenas-Del Angel MC; Zenteno E; Ch(a)vez R; Lascurain R

    2009-01-01

    One of the functions of the immune system is to recognize and destroy abnormal or infected cells to maintain homeostasis. This is accomplished by cytotoxic lymphocytes. Cytotoxicity is a highly organized multifactor process. Here, we reviewed the apoptosis pathways induced by the two main cytotoxic lymphocyte subsets, natural killer (NK) cells and CD8+T cells. In base to recent experimental evidence, we reviewed NK receptors involved in recognition of target-cell, as well as lytic molecules such as perforin, granzymes-A and -B, and granulysin. In addition, we reviewed the Fas-FasL intercellular linkage mediated pathway, and briefly the cross-linking of tumor necrosis factor (TNF) and TNF receptor pathway. We discussed three models of possible molecular interaction between lyric molecules from effector cytotoxic cells and target-cell membrane to induction of apoptosis.

  14. The Apoptosome: Heart and Soul of the Cell Death Machine

    Directory of Open Access Journals (Sweden)

    Arul M. Chinnaiyan

    1999-04-01

    Full Text Available Apoptosis is a fundamental biologic process by which metazoan cells orchestrate their own self-demise. Genetic analyses of the nematode C elegans identified three core components of the suicide apparatus which include CED-3, CED-4, and CED-9. An analogous set of core constituents exists in mammalian cells and includes caspase-9, Apaf-1, and bcl-2/xL, respectively. CED-3 and CED-4, along with their mammalian counterparts, function to kill cells, whereas CED-9 and its mammalian equivalents protect cells from death. These central components biochemically intermingle in a ternary complex recently dubbed the “apoptosome.” The C elegans protein EGL-1 and its mammalian counterparts, pro-apoptotic members of the bcl-2 family, induce cell death by disrupting apoptosome interactions. Thus, EGL-1 may represent a primordial signal integrator for the apoptosome. Various biochemical processes including oligomerization, adenosine triphosphate ATP/dATP binding, and cytochrome c interaction play a role in regulating the ternary death complex. Recent studies suggest that cell death receptors, such as CD95, may amplify their suicide signal by activating the apoptosome. These mutual associations by core components of the suicide apparatus provide a molecular framework in which diverse death signals likely interface. Understanding the apoptosome and its cellular connections will facilitate the design of novel therapeutic strategies for cancer and other disease states in which apoptosis plays a pivotal role.

  15. Early cell death detection with digital holographic microscopy.

    Directory of Open Access Journals (Sweden)

    Nicolas Pavillon

    Full Text Available BACKGROUND: Digital holography provides a non-invasive measurement of the quantitative phase shifts induced by cells in culture, which can be related to cell volume changes. It has been shown previously that regulation of cell volume, in particular as it relates to ionic homeostasis, is crucially involved in the activation/inactivation of the cell death processes. We thus present here an application of digital holographic microscopy (DHM dedicated to early and label-free detection of cell death. METHODS AND FINDINGS: We provide quantitative measurements of phase signal obtained on mouse cortical neurons, and caused by early neuronal cell volume regulation triggered by excitotoxic concentrations of L-glutamate. We show that the efficiency of this early regulation of cell volume detected by DHM, is correlated with the occurrence of subsequent neuronal death assessed with the widely accepted trypan blue method for detection of cell viability. CONCLUSIONS: The determination of the phase signal by DHM provides a simple and rapid optical method for the early detection of cell death.

  16. The regulation of erythrocyte survival and suicidal cell death

    OpenAIRE

    Föller, Michael

    2008-01-01

    The life span of erythrocytes is tightly regulated. Therefore, a mechanism is required to remove senescent or damaged erythrocytes without rupture of the cell membrane resulting in the release of hemoglobin which may impair kidney function. The mechanism of suicidal erythrocyte death is called eryptosis and shares similarities with apoptosis of nucleated cells such as exposure of phosphatidylserine at the cell surface, increase in cytosolic Ca2+ concentration, blebbing of the membrane, cell s...

  17. Porcine circovirus-2 capsid protein induces cell death in PK15 cells

    Energy Technology Data Exchange (ETDEWEB)

    Walia, Rupali; Dardari, Rkia, E-mail: rdardari@ucalgary.ca; Chaiyakul, Mark; Czub, Markus

    2014-11-15

    Studies have shown that Porcine circovirus (PCV)-2 induces apoptosis in PK15 cells. Here we report that cell death is induced in PCV2b-infected PK15 cells that express Capsid (Cap) protein and this effect is enhanced in interferon gamma (IFN-γ)-treated cells. We further show that transient PCV2a and 2b-Cap protein expression induces cell death in PK15 cells at rate similar to PCV2 infection, regardless of Cap protein localization. These data suggest that Cap protein may have the capacity to trigger different signaling pathways involved in cell death. Although further investigation is needed to gain deeper insights into the nature of the pathways involved in Cap-induced cell death, this study provides evidence that PCV2-induced cell death in kidney epithelial PK15 cells can be mapped to the Cap protein and establishes the need for future research regarding the role of Cap-induced cell death in PCV2 pathogenesis. - Highlights: • IFN-γ enhances PCV2 replication that leads to cell death in PK15 cells. • IFN-γ enhances nuclear localization of the PCV2 Capsid protein. • Transient PCV2a and 2b-Capsid protein expression induces cell death. • Cell death is not dictated by specific Capsid protein sub-localization.

  18. Entamoeba histolytica induces cell death of HT29 colonic epithelial cells via NOX1-derived ROS.

    Science.gov (United States)

    Kim, Kyeong Ah; Kim, Ju Young; Lee, Young Ah; Min, Arim; Bahk, Young Yil; Shin, Myeong Heon

    2013-02-01

    Entamoeba histolytica, which causes amoebic colitis and occasionally liver abscess in humans, is able to induce host cell death. However, signaling mechanisms of colon cell death induced by E. histolytica are not fully elucidated. In this study, we investigated the signaling role of NOX in cell death of HT29 colonic epithelial cells induced by E. histolytica. Incubation of HT29 cells with amoebic trophozoites resulted in DNA fragmentation that is a hallmark of apoptotic cell death. In addition, E. histolytica generate intracellular reactive oxygen species (ROS) in a contact-dependent manner. Inhibition of intracellular ROS level with treatment with DPI, an inhibitor of NADPH oxidases (NOXs), decreased Entamoeba-induced ROS generation and cell death in HT29 cells. However, pan-caspase inhibitor did not affect E. histolytica-induced HT29 cell death. In HT29 cells, catalytic subunit NOX1 and regulatory subunit Rac1 for NOX1 activation were highly expressed. We next investigated whether NADPH oxidase 1 (NOX1)-derived ROS is closely associated with HT29 cell death induced by E. histolytica. Suppression of Rac1 by siRNA significantly inhibited Entamoeba-induced cell death. Moreover, knockdown of NOX1 by siRNA, effectively inhibited E. histolytica-triggered DNA fragmentation in HT29 cells. These results suggest that NOX1-derived ROS is required for apoptotic cell death in HT29 colon epithelial cells induced by E. histolytica.

  19. Chikungunya triggers an autophagic process which promotes viral replication

    Directory of Open Access Journals (Sweden)

    Briant Laurence

    2011-09-01

    Full Text Available Abstract Background Chikungunya Virus (ChikV surprised by a massive re-emerging outbreak in Indian Ocean in 2006, reaching Europe in 2007 and exhibited exceptional severe physiopathology in infants and elderly patients. In this context, it is important to analyze the innate immune host responses triggered against ChikV. Autophagy has been shown to be an important component of the innate immune response and is involved in host defense elimination of different pathogens. However, the autophagic process was recently observed to be hijacked by virus for their own replication. Here we provide the first evidence that hallmarks of autophagy are specifically found in HEK.293 infected cells and are involved in ChikV replication. Methods To test the capacity of ChikV to mobilize the autophagic machinery, we performed fluorescence microscopy experiments on HEK.GFP.LC3 stable cells, and followed the LC3 distribution during the time course of ChikV infection. To confirm this, we performed electron microscopy on HEK.293 infected cells. To test the effect of ChikV-induced-autophagy on viral replication, we blocked the autophagic process, either by pharmacological (3-MA or genetic inhibition (siRNA against the transcript of Beclin 1, an autophagic protein, and analyzed the percentage of infected cells and the viral RNA load released in the supernatant. Moreover, the effect of induction of autophagy by Rapamycin on viral replication was tested. Results The increasing number of GFP-LC3 positive cells with a punctate staining together with the enhanced number of GFP-LC3 dots per cell showed that ChikV triggered an autophagic process in HEK.293 infected cells. Those results were confirmed by electron microscopy analysis since numerous membrane-bound vacuoles characteristic of autophagosomes were observed in infected cells. Moreover, we found that inhibition of autophagy, either by biochemical reagent and RNA interference, dramatically decreases ChikV replication

  20. Cell death by mitotic catastrophe: a molecular definition

    NARCIS (Netherlands)

    Castedo, M.; Perfettini, J.-L.; Roumier, T.; Andreau, K.; Medema, R.H.; Kroemer, G.

    2004-01-01

    The current literature is devoid of a clearcut definition of mitotic catastrophe, a type of cell death that occurs during mitosis. Here, we propose that mitotic catastrophe results from a combination of deficient cell-cycle checkpoints (in particular the DNA structure checkpoints and the spindle ass

  1. Jasmonic acid signaling modulates ozone-induced hypersensitive cell death.

    Science.gov (United States)

    Rao, M V; Lee, H; Creelman, R A; Mullet, J E; Davis, K R

    2000-09-01

    Recent studies suggest that cross-talk between salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O(3)) exposure activates a hypersensitive response (HR)-like cell death pathway in the Arabidopsis ecotype Cvi-0. We now have confirmed the role of SA and JA signaling in influencing O(3)-induced cell death. Expression of salicylate hydroxylase (NahG) in Cvi-0 reduced O(3)-induced cell death. Methyl jasmonate (Me-JA) pretreatment of Cvi-0 decreased O(3)-induced H(2)O(2) content and SA concentrations and completely abolished O(3)-induced cell death. Cvi-0 synthesized as much JA as did Col-0 in response to O(3) exposure but exhibited much less sensitivity to exogenous Me-JA. Analyses of the responses to O(3) of the JA-signaling mutants jar1 and fad3/7/8 also demonstrated an antagonistic relationship between JA- and SA-signaling pathways in controlling the magnitude of O(3)-induced HR-like cell death.

  2. Ganglion cell death in glaucoma: from mice to men.

    Science.gov (United States)

    Nickells, Robert W

    2007-01-01

    Glaucoma results from the degeneration of retinal ganglion cells and their axons. Over the last 20 years several important advancements have been made in our understanding of the molecular pathology of this disease, particularly through the development of rat models of experimental glaucoma and the characterization of a spontaneous secondary form of glaucoma in DBA/2 substrains of inbred mice. One of these advances is the observation that ganglion cells die by apoptosis, an intrinsic molecular pathway of programmed cell death. An important aspect of this cell death process is the concept that these cells actually undergo compartmentalized self-destruction. Importantly, genetic evidence now suggests that axons die independently of the apoptotic program that executes the cell body or soma. This review briefly summarizes some of the most significant developments in glaucoma research, with respect to the process of ganglion cell degeneration.

  3. Ricinosomes: an organelle for developmentally regulated programmed cell death in senescing plant tissues

    Science.gov (United States)

    Gietl, C.; Schmid, M.

    2001-02-01

    This review describes aspects of programmed cell death (PCD). Present research maps the enzymes involved and explores the signal transduction pathways involved in their synthesis. A special organelle (the ricinosome) has been discovered in the senescing endosperm of germinating castor beans (Ricinus communis) that develops at the beginning of PCD and delivers large amounts of a papain-type cysteine endopeptidase (CysEP) in the final stages of cellular disintegration. Castor beans store oil and proteins in a living endosperm surrounding the cotyledons. These stores are mobilized during germination and transferred into the cotyledons. PCD is initiated after this transfer is complete. The CysEP is synthesized in the lumen of the endoplasmic reticulum (ER) where it is retained by its C-terminal KDEL peptide as a rather inactive pro-enzyme. Large number of ricinosomes bud from the ER at the same time as the nuclear DNA is characteristically fragmented during PCD. The mitochondria, glyoxysomes and ribosomes are degraded in autophagic vacuoles, while the endopeptidase is activated by removal of the propeptide and the KDEL tail and enters the cytosol. The endosperm dries and detaches from the cotyledons. A homologous KDEL-tailed cysteine endopeptidase has been found in several senescing tissues; it has been localized in ricinosomes of withering day-lily petals and dying seed coats. Three genes for a KDEL-tailed cysteine endopeptidase have been identified in Arabidopsis. One is expressed in senescing ovules, the second in the vascular vessels and the third in maturing siliques. These genes open the way to exploring PCD in plants.

  4. Isolation, characterisation and reconstitution of cell death signalling complexes.

    Science.gov (United States)

    Hughes, Michelle A; Langlais, Claudia; Cain, Kelvin; MacFarlane, Marion

    2013-06-01

    Apoptosis and necroptosis are dependent on the formation/activation of distinct multi-protein complexes; these include the Death-Inducing Signalling Complex (DISC), apoptosome, piddosome, necrosome and ripoptosome. Despite intense research, the mechanisms that regulate assembly/function of several of these cell death signalling platforms remain to be elucidated. It is now increasingly evident that the composition and stoichiometry of components within these key signalling platforms not only determines the final signalling outcome but also the mode of cell death. Characterising these complexes can therefore provide new insights into how cell death is regulated and also how these cell death signalling platforms could potentially be targeted in the context of disease. Large multi-protein complexes can initially be separated according to their size by gel filtration or sucrose density gradient centrifugation followed by subsequent affinity-purification or immunoprecipitation. The advantage of combining these techniques is that you can assess the assembly of individual components into a complex and then assess the size and stoichiometric composition of the native functional signalling complex within a particular cell type. This, alongside reconstitution of a complex from its individual core components can therefore provide new insight into the mechanisms that regulate assembly/function of key multi-protein signalling complexes. Here, we describe the successful application of a range of methodologies that can be used to characterise the assembly of large multi-protein complexes such as the apoptosome, DISC and ripoptosome. Together with their subsequent purification and/or reconstitution, these approaches can provide novel insights into how cell death signalling platforms are regulated in both normal cell physiology and disease.

  5. Signal transduction events in aluminum-induced cell death in tomato suspension cells

    NARCIS (Netherlands)

    Iakimova, E.T.; Kapchina-Toteva, V.M.; Woltering, E.J.

    2007-01-01

    In this study, some of the signal transduction events involved in AlCl3-induced cell death in tomato (Lycopersicon esculentum Mill.) suspension cells were elucidated. Cells treated with 100 ¿M AlCl3 showed typical features of programmed cell death (PCD) such as nuclear and cytoplasmic condensation.

  6. Augmented cell death with Bloom syndrome helicase deficiency.

    Science.gov (United States)

    Kaneko, Hideo; Fukao, Toshiyuki; Kasahara, Kimiko; Yamada, Taketo; Kondo, Naomi

    2011-01-01

    Bloom syndrome (BS) is a rare autosomal genetic disorder characterized by lupus-like erythematous telangi-ectasias of the face, sun sensitivity, infertility, stunted growth, upper respiratory infection, and gastrointestinal infections commonly associated with decreased immuno-globulin levels. The syndrome is associated with immuno-deficiency of a generalized type, ranging from mild and essentially asympto-matic to severe. Chromosomal abnormalities are hallmarks of the disorder, and high frequencies of sister chromatid exchanges and quadriradial configurations in lymphocytes and fibroblasts are diagnostic features. BS is caused by mutations in BLM, a member of the RecQ helicase family. We determined whether BLM deficiency has any effects on cell growth and death in BLM-deficient cells and mice. BLM-deficient EB-virus-transformed cell lines from BS patients and embryonic fibroblasts from BLM-/- mice showed slower growth than wild-type cells. BLM-deficient cells showed abnormal p53 protein expression after irradiation. In BLM-/- mice, small body size, reduced number of fetal liver cells and increased cell death were observed. BLM deficiency causes the up-regulation of p53, double-strand break and apoptosis, which are likely observed in irradiated control cells. Slow cell growth and increased cell death may be one of the causes of the small body size associated with BS patients.

  7. Methylglyoxal Induces Mitochondrial Dysfunction and Cell Death in Liver

    OpenAIRE

    Seo, Kyuhwa; Ki, Sung Hwan; Shin, Sang Mi

    2014-01-01

    Degradation of glucose is aberrantly increased in hyperglycemia, which causes various harmful effects on the liver. Methylglyoxal is produced during glucose degradation and the levels of methylglyoxal are increased in diabetes patients. In this study we investigated whether methylglyoxal induces mitochondrial impairment and apoptosis in HepG2 cells and induces liver toxicity in vivo. Methylglyoxal caused apoptotic cell death in HepG2 cells. Moreover, methylglyoxal significantly promoted the p...

  8. Sensory hair cell death and regeneration in fishes

    Directory of Open Access Journals (Sweden)

    Jerry D. Monroe

    2015-04-01

    Full Text Available Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation versus direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

  9. Activation of intracellular angiotensin AT2 receptors induces rapid cell death in human uterine leiomyosarcoma cells

    DEFF Research Database (Denmark)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen;

    2015-01-01

    densities in mitochondria. Activation of the cell membrane AT2 receptors by a concomitant treatment with angiotensin II and the AT1 receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT2 receptor...... of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT2 receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high...... agonist, Compound 21 (C21) penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT2 receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped from the cell death, displayed activation of the mitochondrial apoptotic pathway, i...

  10. Lipid raft involvement in yeast cell growth and death.

    Science.gov (United States)

    Mollinedo, Faustino

    2012-01-01

    The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na(+), K(+), and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  11. Lipid raft involvement in yeast cell growth and death

    Directory of Open Access Journals (Sweden)

    Faustino eMollinedo

    2012-10-01

    Full Text Available The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Crytococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na+, K+ and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  12. Real-time monitoring of cisplatin-induced cell death.

    Directory of Open Access Journals (Sweden)

    Hamed Alborzinia

    Full Text Available Since the discovery of cisplatin more than 40 years ago and its clinical introduction in the 1970s an enormous amount of research has gone into elucidating the mechanism of action of cisplatin on tumor cells. With a novel cell biosensor chip system allowing continuous monitoring of respiration, glycolysis, and impedance we followed cisplatin treatment of different cancer cell lines in real-time. Our measurements reveal a first effect on respiration, in all cisplatin treated cell lines, followed with a significant delay by interference with glycolysis in HT-29, HCT-116, HepG2, and MCF-7 cells but not in the cisplatin-resistant cell line MDA-MB-231. Most strikingly, cell death started in all cisplatin-sensitive cell lines within 8 to 11 h of treatment, indicating a clear time frame from exposure, first response to cisplatin lesions, to cell fate decision. The time points of most significant changes were selected for more detailed analysis of cisplatin response in the breast cancer cell line MCF-7. Phosphorylation of selected signal transduction mediators connected with cellular proliferation, as well as changes in gene expression, were analyzed in samples obtained directly from sensor chips at the time points when changes in glycolysis and impedance occurred. Our online cell biosensor measurements reveal for the first time the time scale of metabolic response until onset of cell death under cisplatin treatment, which is in good agreement with models of p53-mediated cell fate decision.

  13. Herceptin conjugates linked by EDC boost direct tumor cell death via programmed tumor cell necrosis.

    Directory of Open Access Journals (Sweden)

    Jiemiao Hu

    Full Text Available Tumor-targeted antibody therapy is one of the safest biological therapeutics for cancer patients, but it is often ineffective at inducing direct tumor cell death and is ineffective against resistant tumor cells. Currently, the antitumor efficacy of antibody therapy is primarily achieved by inducing indirect tumor cell death, such as antibody-dependent cell cytotoxicity. Our study reveals that Herceptin conjugates, if generated via the crosslinker EDC (1-ethyl-3-(3-dimethylaminopropyl carbodiimide hydrochloride, are capable of engendering human epidermal growth factor receptor 2 (Her2 positive tumor cells death. Using a high-performance liquid chromatography (HPLC system, three peaks with estimated molecular weights of antibody monomer, dimer, and trimer were isolated. Both Herceptin trimer and dimer separated by HPLC induced significant levels of necrotic tumor cell death, although the trimer was more effective than the dimer. Notably, the Herceptin trimer also induced Herceptin-resistant tumor cell death. Surprisingly different from the known cell death mechanism that often results from antibody treatment, the Herceptin trimer elicited effective and direct tumor cell death via a novel mechanism: programmed cell necrosis. In Her2-positive cells, inhibition of necrosis pathways significantly reversed Herceptin trimer-induced cell death. In summary, the Herceptin trimer reported herein harbors great potential for overcoming tumor cell resistance to Herceptin treatment.

  14. Hydrogen Peroxide-induced Cell Death in Arabidopsis : Transcriptional and Mutant Analysis Reveals a Role of an Oxoglutarate-dependent Dioxygenase Gene in the Cell Death Process

    NARCIS (Netherlands)

    Gechev, Tsanko S.; Minkov, Ivan N.; Hille, Jacques

    2005-01-01

    Hydrogen peroxide is a major regulator of plant programmed cell death (PCD) but little is known about the downstream genes from the H2O2-signaling network that mediate the cell death. To address this question, a novel system for studying H2O2-induced programmed cell death in Arabidopsis thaliana was

  15. Coordinate reduction in cell proliferation and cell death in mouse olfactory epithelium from birth to maturity

    NARCIS (Netherlands)

    Fung, KM; Peringa, J; Venkatachalam, S; Lee, VMY; Trojanowski, JQ

    1997-01-01

    We investigated cell proliferation and cell death in the olfactory epithelium (OE) of mice from birth to maturity using bromodeoxyuridine and terminal deoxynucleotidyl transferase nick end labeling. We show that cell death events and proliferative activity diminish concomitantly with age in the OE.

  16. Immunohistochemical Aspects of Cell Death in Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Bălăşescu Elena

    2016-03-01

    Full Text Available Introduction. Diabetes Mellitus causes ultrastructural changes triggered by partially clarified cellular mechanisms. Since cell death is an important mechanism in the appearance and progression of diabetic nephropathy, we studied alteration of several markers of apoptotic pathways signaling in renal tissue of diabetic or prediabetic patients.

  17. Mitochondrial and Cell Death Mechanisms in Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Lee J. Martin

    2010-03-01

    Full Text Available Alzheimer’s disease (AD, Parkinson’s disease (PD and amyotrophic lateral sclerosis (ALS are the most common human adult-onset neurodegenerative diseases. They are characterized by prominent age-related neurodegeneration in selectively vulnerable neural systems. Some forms of AD, PD, and ALS are inherited, and genes causing these diseases have been identified. Nevertheless, the mechanisms of the neuronal cell death are unresolved. Morphological, biochemical, genetic, as well as cell and animal model studies reveal that mitochondria could have roles in this neurodegeneration. The functions and properties of mitochondria might render subsets of selectively vulnerable neurons intrinsically susceptible to cellular aging and stress and overlying genetic variations, triggering neurodegeneration according to a cell death matrix theory. In AD, alterations in enzymes involved in oxidative phosphorylation, oxidative damage, and mitochondrial binding of Aβ and amyloid precursor protein have been reported. In PD, mutations in putative mitochondrial proteins have been identified and mitochondrial DNA mutations have been found in neurons in the substantia nigra. In ALS, changes occur in mitochondrial respiratory chain enzymes and mitochondrial cell death proteins. Transgenic mouse models of human neurodegenerative disease are beginning to reveal possible principles governing the biology of selective neuronal vulnerability that implicate mitochondria and the mitochondrial permeability transition pore. This review summarizes how mitochondrial pathobiology might contribute to neuronal death in AD, PD, and ALS and could serve as a target for drug therapy.

  18. Mastoparan-Induced Cell Death Signalling in Chlamydomonas Reinhardtii

    NARCIS (Netherlands)

    Yordanova, Z.P.; Kapchina-Toteva, V.M.; Woltering, E.J.; Cristescu, S.M.; Harren, F.J.M.; Yakimova, E.T.

    2009-01-01

    The present study was focused on the elucidation of stress-induced cell death signaling events in the unicellular alga Chlamydomonas reinhardtii exposed to treatment with wasp venom mastoparan. By applying pharmacological approach with specific inhibitors, we have investigated the involvement of eth

  19. PROGRAMMED CELL DEATH IN EXTRAOCULAR MUSCLE TENDON/SCLERA PRECURSORS

    Science.gov (United States)

    AbstractPurpose: This study was designed to examine the occurrence of natural cell death in the periocular mesenchyme of mouse embryos. Methods: Vital staining with LysoTracker Red and Nile blue sulphate as well as terminal nick end labeling (TUNEL) were utiliz...

  20. Calcium and cell death signaling in neurodegeneration and aging.

    Science.gov (United States)

    Smaili, Soraya; Hirata, Hanako; Ureshino, Rodrigo; Monteforte, Priscila T; Morales, Ana P; Muler, Mari L; Terashima, Juliana; Oseki, Karen; Rosenstock, Tatiana R; Lopes, Guiomar S; Bincoletto, Claudia

    2009-09-01

    Transient increase in cytosolic (Cac2+) and mitochondrial Ca2+ (Ca m2+) are essential elements in the control of many physiological processes. However, sustained increases in Ca c2+ and Ca m2+ may contribute to oxidative stress and cell death. Several events are related to the increase in Ca m2+, including regulation and activation of a number of Ca2+ dependent enzymes, such as phospholipases, proteases and nucleases. Mitochondria and endoplasmic reticulum (ER) play pivotal roles in the maintenance of intracellular Ca2+ homeostasis and regulation of cell death. Several lines of evidence have shown that, in the presence of some apoptotic stimuli, the activation of mitochondrial processes may lead to the release of cytochrome c followed by the activation of caspases, nuclear fragmentation and apoptotic cell death. The aim of this review was to show how changes in calcium signaling can be related to the apoptotic cell death induction. Calcium homeostasis was also shown to be an important mechanism involved in neurodegenerative and aging processes.

  1. Retinal Cell Death Caused by Sodium Iodate Involves Multiple Caspase-Dependent and Caspase-Independent Cell-Death Pathways

    Directory of Open Access Journals (Sweden)

    Jasmin Balmer

    2015-07-01

    Full Text Available Herein, we have investigated retinal cell-death pathways in response to the retina toxin sodium iodate (NaIO3 both in vivo and in vitro. C57/BL6 mice were treated with a single intravenous injection of NaIO3 (35 mg/kg. Morphological changes in the retina post NaIO3 injection in comparison to untreated controls were assessed using electron microscopy. Cell death was determined by TdT-mediated dUTP-biotin nick end labeling (TUNEL staining. The activation of caspases and calpain was measured using immunohistochemistry. Additionally, cytotoxicity and apoptosis in retinal pigment epithelial (RPE cells, primary retinal cells, and the cone photoreceptor (PRC cell line 661W were assessed in vitro after NaIO3 treatment using the ApoToxGlo™ assay. The 7-AAD/Annexin-V staining was performed and necrostatin (Nec-1 was administered to the NaIO3-treated cells to confirm the results. In vivo, degenerating RPE cells displayed a rounded shape and retracted microvilli, whereas PRCs featured apoptotic nuclei. Caspase and calpain activity was significantly upregulated in retinal sections and protein samples from NaIO3-treated animals. In vitro, NaIO3 induced necrosis in RPE cells and apoptosis in PRCs. Furthermore, Nec-1 significantly decreased NaIO3-induced RPE cell death, but had no rescue effect on treated PRCs. In summary, several different cell-death pathways are activated in retinal cells as a result of NaIO3.

  2. Activation-induced cell death in B lymphocytes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Upon encountering the antigen (Ag), the immune system can either develop a specific immune response or enter a specific state of unresponsiveness, tolerance. The response of B cells to their specific Ag can be activation and proliferation, leading to the immune response, or anergy and activation-induced cell death (AICD), leading to tolerance. AICD in B lymphocytes is a highly regulated event initiated by crosslinking of the B cell receptor (BCR). BCR engagement initiates several signaling events such as activation of PLCγ, Ras, and PI3K, which generally speaking, lead to survival However, in the absence of survival signals (CD40 or IL-4R engagement), BCR crosslinking can also promote apoptotic signal transduction pathways such as activation of effector caspases, expression of pro-apoptotic genes, and inhibition of pro-survival genes. The complex interplay between survival and death signals determines the B cell fate and, consequently, the immune response.

  3. Combinatorial strategies for the induction of immunogenic cell death

    Directory of Open Access Journals (Sweden)

    Lorenzo eGalluzzi

    2015-04-01

    Full Text Available The term immunogenic cell death (ICD is commonly employed to indicate a peculiar instance of regulated cell death (RCD that engages the adaptive arm of the immune system. The inoculation of cancer cells undergoing ICD into immunocompetent animals elicits a specific immune response associated with the establishment of immunological memory. Only a few agents are intrinsically endowed with the ability to trigger ICD. These include a few chemotherapeutics that are routinely employed in the clinic, like doxorubicin, mitoxantrone, oxaliplatin and cyclophosphamide, as well as some agents that have not yet been approved for use in humans. Accumulating clinical data indicate that the activation of adaptive immune responses against dying cancer cells is associated with improved disease outcome in patients affected by various neoplasms. Thus, novel therapeutic regimens that trigger ICD are urgently awaited. Here, we discuss current combinatorial approaches to convert otherwise non-immunogenic instances of RCD into bona fide ICD.

  4. Plant caspase-like proteases in plant programmed cell death

    OpenAIRE

    Xu, Qixian; Zhang, Lingrui

    2009-01-01

    Programmed cell death (PCD) is a genetically-controlled disassembly of the cell. In animal systems, the central core execution switch for apoptotic PCD is the activation of caspases (Cysteine-containing Aspartate-specific proteases). Accumulating evidence in recent years suggests the existence of caspase-like activity in plants and its functional involvement in various types of plant PCD, although no functional homologs of animal caspases were identified in plant genome. In this mini-review, ...

  5. Necrosis: a specific form of programmed cell death?

    Science.gov (United States)

    Proskuryakov, Sergey Ya; Konoplyannikov, Anatoli G; Gabai, Vladimir L

    2003-02-01

    For a long time necrosis was considered as an alternative to programmed cell death, apoptosis. Indeed, necrosis has distinct morphological features and it is accompanied by rapid permeabilization of plasma membrane. However, recent data indicate that, in contrast to necrosis caused by very extreme conditions, there are many examples when this form of cell death may be a normal physiological and regulated (programmed) event. Various stimuli (e.g., cytokines, ischemia, heat, irradiation, pathogens) can cause both apoptosis and necrosis in the same cell population. Furthermore, signaling pathways, such as death receptors, kinase cascades, and mitochondria, participate in both processes, and by modulating these pathways, it is possible to switch between apoptosis and necrosis. Moreover, antiapoptotic mechanisms (e.g., Bcl-2/Bcl-x proteins, heat shock proteins) are equally effective in protection against apoptosis and necrosis. Therefore, necrosis, along with apoptosis, appears to be a specific form of execution phase of programmed cell death, and there are several examples of necrosis during embryogenesis, a normal tissue renewal, and immune response. However, the consequences of necrotic and apoptotic cell death for a whole organism are quite different. In the case of necrosis, cytosolic constituents that spill into extracellular space through damaged plasma membrane may provoke inflammatory response; during apoptosis these products are safely isolated by membranes and then are consumed by macrophages. The inflammatory response caused by necrosis, however, may have obvious adaptive significance (i.e., emergence of a strong immune response) under some pathological conditions (such as cancer and infection). On the other hand, disturbance of a fine balance between necrosis and apoptosis may be a key element in development of some diseases.

  6. Networked T cell death following macrophage infection by Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Stephen H-F Macdonald

    Full Text Available BACKGROUND: Depletion of T cells following infection by Mycobacterium tuberculosis (Mtb impairs disease resolution, and interferes with clinical test performance that relies on cell-mediated immunity. A number of mechanisms contribute to this T cell suppression, such as activation-induced death and trafficking of T cells out of the peripheral circulation and into the diseased lungs. The extent to which Mtb infection of human macrophages affects T cell viability however, is not well characterised. METHODOLOGY/PRINCIPAL FINDINGS: We found that lymphopenia (<1.5 × 10(9 cells/l was prevalent among culture-positive tuberculosis patients, and lymphocyte counts significantly improved post-therapy. We previously reported that Mtb-infected human macrophages resulted in death of infected and uninfected bystander macrophages. In the current study, we sought to examine the influence of infected human alveolar macrophages on T cells. We infected primary human alveolar macrophages (the primary host cell for Mtb or PMA-differentiated THP-1 cells with Mtb H37Ra, then prepared cell-free supernatants. The supernatants of Mtb-infected macrophages caused dose-dependent, caspase-dependent, T cell apoptosis. This toxic effect of infected macrophage secreted factors did not require TNF-α or Fas. The supernatant cytotoxic signal(s were heat-labile and greater than 50 kDa in molecular size. Although ESAT-6 was toxic to T cells, other Mtb-secreted factors tested did not influence T cell viability; nor did macrophage-free Mtb bacilli or broth from Mtb cultures. Furthermore, supernatants from Mycobacterium bovis Bacille de Calmette et Guerin (BCG- infected macrophages also elicited T cell death suggesting that ESAT-6 itself, although cytotoxic, was not the principal mediator of T cell death in our system. CONCLUSIONS: Mtb-Infected macrophages secrete heat-labile factors that are toxic to T cells, and may contribute to the immunosuppression seen in tuberculosis as well as

  7. Overexpression of smooth muscle myosin heavy chain leads to activation of the unfolded protein response and autophagic turnover of thick filament-associated proteins in vascular smooth muscle cells.

    Science.gov (United States)

    Kwartler, Callie S; Chen, Jiyuan; Thakur, Dhananjay; Li, Shumin; Baskin, Kedryn; Wang, Shanzhi; Wang, Zhao V; Walker, Lori; Hill, Joseph A; Epstein, Henry F; Taegtmeyer, Heinrich; Milewicz, Dianna M

    2014-05-16

    Duplications spanning nine genes at the genomic locus 16p13.1 predispose individuals to acute aortic dissections. The most likely candidate gene in this region leading to the predisposition for dissection is MYH11, which encodes smooth muscle myosin heavy chain (SM-MHC). The effects of increased expression of MYH11 on smooth muscle cell (SMC) phenotypes were explored using mouse aortic SMCs with transgenic overexpression of one isoform of SM-MHC. We found that these cells show increased expression of Myh11 and myosin filament-associated contractile genes at the message level when compared with control SMCs, but not at the protein level due to increased protein degradation. Increased expression of Myh11 resulted in endoplasmic reticulum (ER) stress in SMCs, which led to a paradoxical decrease of protein levels through increased autophagic degradation. An additional consequence of ER stress in SMCs was increased intracellular calcium ion concentration, resulting in increased contractile signaling and contraction. The increased signals for contraction further promote transcription of contractile genes, leading to a feedback loop of metabolic abnormalities in these SMCs. We suggest that overexpression of MYH11 can lead to increased ER stress and autophagy, findings that may be globally implicated in disease processes associated with genomic duplications.

  8. Overexpression of Smooth Muscle Myosin Heavy Chain Leads to Activation of the Unfolded Protein Response and Autophagic Turnover of Thick Filament-associated Proteins in Vascular Smooth Muscle Cells*

    Science.gov (United States)

    Kwartler, Callie S.; Chen, Jiyuan; Thakur, Dhananjay; Li, Shumin; Baskin, Kedryn; Wang, Shanzhi; Wang, Zhao V.; Walker, Lori; Hill, Joseph A.; Epstein, Henry F.; Taegtmeyer, Heinrich; Milewicz, Dianna M.

    2014-01-01

    Duplications spanning nine genes at the genomic locus 16p13.1 predispose individuals to acute aortic dissections. The most likely candidate gene in this region leading to the predisposition for dissection is MYH11, which encodes smooth muscle myosin heavy chain (SM-MHC). The effects of increased expression of MYH11 on smooth muscle cell (SMC) phenotypes were explored using mouse aortic SMCs with transgenic overexpression of one isoform of SM-MHC. We found that these cells show increased expression of Myh11 and myosin filament-associated contractile genes at the message level when compared with control SMCs, but not at the protein level due to increased protein degradation. Increased expression of Myh11 resulted in endoplasmic reticulum (ER) stress in SMCs, which led to a paradoxical decrease of protein levels through increased autophagic degradation. An additional consequence of ER stress in SMCs was increased intracellular calcium ion concentration, resulting in increased contractile signaling and contraction. The increased signals for contraction further promote transcription of contractile genes, leading to a feedback loop of metabolic abnormalities in these SMCs. We suggest that overexpression of MYH11 can lead to increased ER stress and autophagy, findings that may be globally implicated in disease processes associated with genomic duplications. PMID:24711452

  9. Overexpression of alpha-synuclein at non-toxic levels increases dopaminergic cell death induced by copper exposure via modulation of protein degradation pathways.

    Science.gov (United States)

    Anandhan, Annadurai; Rodriguez-Rocha, Humberto; Bohovych, Iryna; Griggs, Amy M; Zavala-Flores, Laura; Reyes-Reyes, Elsa M; Seravalli, Javier; Stanciu, Lia A; Lee, Jaekwon; Rochet, Jean-Christophe; Khalimonchuk, Oleh; Franco, Rodrigo

    2015-09-01

    Gene multiplications or point mutations in alpha (α)-synuclein are associated with familial and sporadic Parkinson's disease (PD). An increase in copper (Cu) levels has been reported in the cerebrospinal fluid and blood of PD patients, while occupational exposure to Cu has been suggested to augment the risk to develop PD. We aimed to elucidate the mechanisms by which α-synuclein and Cu regulate dopaminergic cell death. Short-term overexpression of wild type (WT) or mutant A53T α-synuclein had no toxic effect in human dopaminergic cells and primary midbrain cultures, but it exerted a synergistic effect on Cu-induced cell death. Cell death induced by Cu was potentiated by overexpression of the Cu transporter protein 1 (Ctr1) and depletion of intracellular glutathione (GSH) indicating that the toxic effects of Cu are linked to alterations in its intracellular homeostasis. Using the redox sensor roGFP, we demonstrated that Cu-induced oxidative stress was primarily localized in the cytosol and not in the mitochondria. However, α-synuclein overexpression had no effect on Cu-induced oxidative stress. WT or A53T α-synuclein overexpression exacerbated Cu toxicity in dopaminergic and yeast cells in the absence of α-synuclein aggregation. Cu increased autophagic flux and protein ubiquitination. Impairment of autophagy by overexpression of a dominant negative Atg5 form or inhibition of the ubiquitin/proteasome system (UPS) with MG132 enhanced Cu-induced cell death. However, only inhibition of the UPS stimulated the synergistic toxic effects of Cu and α-synuclein overexpression. Our results demonstrate that α-synuclein stimulates Cu toxicity in dopaminergic cells independent from its aggregation via modulation of protein degradation pathways.

  10. Imipramine protects mouse hippocampus against tunicamycin-induced cell death.

    Science.gov (United States)

    Ono, Yoko; Shimazawa, Masamitsu; Ishisaka, Mitsue; Oyagi, Atsushi; Tsuruma, Kazuhiro; Hara, Hideaki

    2012-12-05

    Endoplasmic reticulum (ER) stress is implicated in various diseases. Recently, some reports have suggested that the sigma-1 receptor may play a role in ER stress, and many antidepressants have a high affinity for the sigma-1 receptor. In the present study, we focused on imipramine, a widely used antidepressant, and investigated whether it might protect against the neuronal cell death induced by tunicamycin, an ER stress inducer. In mouse cultured hippocampal HT22 cells, imipramine inhibited cell death and caspase-3 activation induced by tunicamycin, although it did not alter the elevated expressions of 78 kDa glucose-regulated protein (GRP78) and C/EBP-homologous protein (CHOP). Interestingly, in such cells application of imipramine normalized the expression of the sigma-1 receptor, which was decreased by treatment with tunicamycin alone. Additionally, NE-100, a selective sigma-1 receptor antagonist, abolished the protective effect of imipramine against such tunicamycin-induced cell death. Imipramine inhibited the reduction of mitochondrial membrane potential induced by tunicamycin, and NE-100 blocked this modulating effect of imipramine. Furthermore, in anesthetized mice intracerebroventricular administration of tunicamycin decreased the number of neuronal cells in the hippocampus, particularly in the CA1 and dentate gyrus (DG) areas, and 7 days' imipramine treatment (10mg/kg/day; i.p.) significantly suppressed these reductions in CA1 and DG. These findings suggest that imipramine protects against ER stress-induced hippocampal neuronal cell death both in vitro and in vivo. Such protection may be partly due to the sigma-1 receptor.

  11. Internalization of NK cells into tumor cells requires ezrin and leads to programmed cell-in-cell death

    Institute of Scientific and Technical Information of China (English)

    Shan Wang; Zhen Guo; Peng Xia; Tingting Liu; Jufang Wang; Shan Li; Lihua Sun; Jianxin Lu; Qian Wen; Mingqian Zhou; Li Ma; Xia Ding; Xiaoning Wang; Xuebiao Yao

    2009-01-01

    Cytotoxic lymphocytes are key players in the orchestration of immune response and elimination of defective cells. We have previously reported that natural killer (NK) cells enter target tumor cells, leading to either target cell death or self-destruction within tumor cells. However, it has remained elusive as to the fate of NK cells after internaliza-tion and whether the heterotypic cell-in-cell process is different from that of the homotypic cell-in-cell event recently named entosis. Here, we show that NK cells undergo a cell-in-cell process with the ultimate fate of apoptosis within tumor cells and reveal that the internalization process requires the actin cytoskeletal regulator, ezrin. To visualize how NK cells enter into tumor cells, we carried out real-time dual color imaging analyses of NK cell internalization into tumor cells. Surprisingly, most NK cells commit to programmed cell death after their entry into tumor cells, which is distinctively different from entosis observed in the homotypic cell-in-cell process. The apoptotic cell death of the internalized NK cells was evident by activation of caspase 3 and DNA fragmentation. Furthermore, NK cell death after internalization is attenuated by the caspase inhibitor, Z-VAD-FMK, confirming apoptosis as the mode of NK cell death within tumor cells. To determine protein factors essential for the entry of NK cells into tumor cells, we car-ried out siRNA-based knockdown analysis and discovered a critical role of ezrin in NK cell internalization. Impor-tantly, PKA-mediated phosphorylation of ezrin promotes the NK cell internalization process. Our findings suggest a novel regulatory mechanism by which ezrin governs NK cell internalization into tumor cells.

  12. Molecular and Translational Classifications of DAMPs in Immunogenic Cell Death

    Directory of Open Access Journals (Sweden)

    Abhishek D Garg

    2015-11-01

    Full Text Available The immunogenicity of malignant cells has recently been acknowledged as a critical determinant of efficacy in cancer therapy. Thus, besides developing direct immunostimulatory regimens including dendritic cell-based vaccines, checkpoint-blocking therapies, and adoptive T-cell transfer, researchers have started to focus on the overall immunobiology of neoplastic cells. It is now clear that cancer cells can succumb to some anticancer therapies by undergoing a peculiar form of cell death that is characterized by an increased immunogenic potential, owing to the emission of so-called damage-associated molecular patterns (DAMPs. The emission of DAMPs and other immunostimulatory factors by cells succumbing to immunogenic cell death (ICD favors the establishment of a productive interface with the immune system. This results in the elicitation of tumor-targeting immune responses associated with the elimination of residual, treatment-resistant cancer cells, as well as with the establishment of immunological memory. Although ICD has been characterized with increased precision since its discovery, several questions remain to be addressed. Here, we summarize and tabulate the main molecular, immunological, preclinical and clinical aspects of ICD, in an attempt to capture the essence of this clinically relevant phenomenon, and identify future challenges for this rapidly expanding field of investigation.

  13. The cellular energy crisis: mitochondria and cell death.

    Science.gov (United States)

    Waterhouse, Nigel J

    2003-01-01

    Exploding nuclear reactors, environmental destruction, and global warming; the danger of energy production is clear. It is quite remarkable that in this modern age, where power usage is at a premium, we find that even on a cellular level, generation of large quantities of power comes at a cost. Mitochondria, which produce the majority of cellular energy in the form of ATP, have recently been shown to play an essential role in the death of a cell by a process known as apoptosis. During apoptosis, the integrity of mitochondria is compromised and various pro-apoptotic proteins are released into the cytoplasm. This results in activation of caspases, proteases that orchestrate the death of the cell. Cells in which apoptosis is inhibited upstream of mitochondria generally maintain the potential to proliferate, whereas inhibition of caspases downstream of mitochondria generally only delays cell death. Although breaches of the mitochondrial outer membrane result in the release of proteins that are important for respiration, mitochondria appear capable of maintaining at least some of their functions, including ATP production, even after this event. This has important implications both for the mechanism of outer-membrane permeabilization and the mechanism by which the cells eventually die in the absence of caspase activity. The events surrounding the breach of the mitochondrial outer membrane during apoptosis have therefore received much interest over the past few years.

  14. Aquatic viruses induce host cell death pathways and its application.

    Science.gov (United States)

    Reshi, Latif; Wu, Jen-Leih; Wang, Hao-Ven; Hong, Jiann-Ruey

    2016-01-01

    Virus infections of mammalian and animal cells consist of a series of events. As intracellular parasites, viruses rely on the use of host cellular machinery. Through the use of cell culture and molecular approaches over the past decade, our knowledge of the biology of aquatic viruses has grown exponentially. The increase in aquaculture operations worldwide has provided new approaches for the transmission of aquatic viruses that include RNA and DNA viruses. Therefore, the struggle between the virus and the host for control of the cell's death machinery is crucial for survival. Viruses are obligatory intracellular parasites and, as such, must modulate apoptotic pathways to control the lifespan of their host to complete their replication cycle. This paper updates the discussion on the detailed mechanisms of action that various aquatic viruses use to induce cell death pathways in the host, such as Bad-mediated, mitochondria-mediated, ROS-mediated and Fas-mediated cell death circuits. Understanding how viruses exploit the apoptotic pathways of their hosts may provide great opportunities for the development of future potential therapeutic strategies and pathogenic insights into different aquatic viral diseases.

  15. Huperzine A provides neuroprotection against several cell death inducers using in vitro model systems of motor neuron cell death.

    Science.gov (United States)

    Hemendinger, Richelle A; Armstrong, Edward J; Persinski, Rafal; Todd, Julianne; Mougeot, Jean-Luc; Volvovitz, Franklin; Rosenfeld, Jeffrey

    2008-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease resulting from the progressive loss of motor neurons in the spinal cord and brain. To date, clinically effective neuroprotective agents have not been available. The current study demonstrates for the first time that huperzine A, a potential neuroprotective agent, has the ability to protect a motor neuron-like cell line and motor neurons in spinal cord organotypic cultures from toxin-induced cell death. The neuroblastoma-spinal motor neuron fusion cell line, NSC34 and rat spinal cord organotypic cultures (OTC) were exposed to cell death inducers for 24 h or 14 d, respectively, with and without pre-treatment with huperzine A. The inducers used here include: staurosporine, thapsigargin, hydrogen peroxide (H2O2), carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and L-(-)-threo-3-hydroxyaspartic acid (THA). These agents were selected as they induce apoptosis/necrosis via mechanisms implicated in patients with generalized motor neuron disease. Cell death was determined in NSC34 cells by metabolic activity, caspase activity/expression and by nuclear morphology and in the OTCs, using immunohistochemistry and Western blot analysis. Nuclear staining of NSC34 cells revealed cell death induced by staurosporine, thapsigargin, H2O2 and CCCP. This induction was significantly reduced with 2 h pre-treatment with 10 microM huperzine A (maximum, 35% rescue; p 0.05) following exposure to staurosporine, thapsigargin and H2O2 but not with CCCP. These data were supported by the metabolic assays and caspase activity. In addition, pre-treatment with huperzine A dramatically improved motor neuron survival, based on choline acetyltransferase (ChAT) expression analysis in OTCs following exposure to THA, and compared to THA-treated control cultures. These studies are currently being extended to include other inducers and with additional compounds as potential drug therapies that could be used in combination for the treatment of

  16. Induction of necrotic cell death by oxidative stress in retinal pigment epithelial cells.

    Science.gov (United States)

    Hanus, J; Zhang, H; Wang, Z; Liu, Q; Zhou, Q; Wang, S

    2013-12-12

    Age-related macular degeneration (AMD) is a degenerative disease of the retina and the leading cause of blindness in the elderly. Retinal pigment epithelial (RPE) cell death and the resultant photoreceptor apoptosis are characteristic of late-stage dry AMD, especially geographic atrophy (GA). Although oxidative stress and inflammation have been associated with GA, the nature and underlying mechanism for RPE cell death remains controversial, which hinders the development of targeted therapy for dry AMD. The purpose of this study is to systematically dissect the mechanism of RPE cell death induced by oxidative stress. Our results show that characteristic features of apoptosis, including DNA fragmentation, caspase 3 activation, chromatin condensation and apoptotic body formation, were not observed during RPE cell death induced by either hydrogen peroxide or tert-Butyl hydroperoxide. Instead, this kind of cell death can be prevented by RIP kinase inhibitors necrostatins but not caspase inhibitor z-VAD, suggesting necrotic feature of RPE cell death. Moreover, ATP depletion, receptor interacting protein kinase 3 (RIPK3) aggregation, nuclear and plasma membrane leakage and breakdown, which are the cardinal features of necrosis, were observed in RPE cells upon oxidative stress. Silencing of RIPK3, a key protein in necrosis, largely prevented oxidative stress-induced RPE death. The necrotic nature of RPE death is consistent with the release of nuclear protein high mobility group protein B1 into the cytoplasm and cell medium, which induces the expression of inflammatory gene TNFα in healthy RPE and THP-1 cells. Interestingly, features of pyroptosis or autophagy were not observed in oxidative stress-treated RPE cells. Our results unequivocally show that necrosis, but not apoptosis, is a major type of cell death in RPE cells in response to oxidative stress. This suggests that preventing oxidative stress-induced necrotic RPE death may be a viable approach for late-stage dry

  17. Autophagy inhibits cell death induced by the anti-cancer drug morusin

    Science.gov (United States)

    Cho, Sang Woo; Na, Wooju; Choi, Minji; Kang, Shin Jung; Lee, Seok-Geun; Choi, Cheol Yong

    2017-01-01

    Autophagy is a cellular process by which damaged organelles and dysfunctional proteins are degraded. Morusin is an anti-cancer drug isolated from the root bark of Morus alba. Morusin induces apoptosis in human prostate cancer cells by reducing STAT3 activity. In this study, we examined whether morusin induces autophagy and also examined the effects of autophagy on the morusin-induced apoptosis. Morusin induces LC3-II accumulation and ULK1 activation in HeLa cells. In addition, we found that induction of ULK1 Ser317 phosphorylation and reduction of ULK1 Ser757 phosphorylation occurred simultaneously during morusin-induced autophagy. Consistently, morusin induces autophagy by activation of AMPK and inhibition of mTOR activity. Next, we investigated the role of autophagy in morusin-induced apoptosis. Inhibition of autophagy by treating cells with the 3-methyladenine (3-MA) autophagic inhibitor induces high levels of morusin-mediated apoptosis, while treatment of cells with morusin alone induces moderate levels of apoptosis. Cell survival was greatly reduced when cells were treated with morusin and 3-MA. Taken together, morusin induces autophagy, which is an impediment for morusin-induced apoptosis, suggesting combined treatment of morusin with an autophagic inhibitor would increase the efficacy of morusin as an anti-cancer drug.

  18. [Selective "death programs" or pleiotropic"life programs"? Looking for programmed cell death in the light of evolution].

    Science.gov (United States)

    Ameisen, Jean-Claude

    2005-01-01

    "Nothing in biology makes sense except in the light of evolution", wrote Theodosius Dobzhansky, one of the founders of the Modern Synthesis that led to the unification of evolutionary theory and genetics in the midst of the 20th century. Programmed cell death is a genetically regulated process of cell suicide that is central to the development, homeostasis and integrity of multicellular organisms. Conversely, the dysregulation of mechanisms controlling cell suicide plays a role in the pathogenesis of a wide range of diseases. While great progress has been achieved in the unveiling of the molecular mechanisms of programmed cell death, a new, and somehow puzzling level of complexity has recently begun to emerge, suggesting i) that several different self destruction pathways may exist and operate in parallel in our cells, and ii) that molecular effectors of cell suicide might also perform other functions unrelated to cell death induction and crucial to cell survival, such as cell differentiation, metabolism, and the regulation of the cell cycle. These new findings, with important physiopathological and therapeutic implications, seem at odds with the paradigm of programmed cell death derived from the studies of Caenorhabditis elegans, which led to the concept of the existence of selective, bona fide death genes that emerged and became selected for their sole capacity to execute or repress cell death. In this review, I will argue that this new level of complexity might only make sense and be understood when considered in a broader evolutionary context than that of our phylogenetic divergence from C. elegans. A new view of the regulated cell death pathways emerges when one attempts to ask the question of when and how they may have become selected during a timeline of 4 billion years, at the level of ancestral single-celled organisms, including the bacteria. I will argue that there may be no such thing as a bona fide genetic cell death program. Rather, in the framework of

  19. Different Types of Cell Death Induced by Enterotoxins

    Directory of Open Access Journals (Sweden)

    Ming-Yuan Hong

    2010-08-01

    Full Text Available The infection of bacterial organisms generally causes cell death to facilitate microbial invasion and immune escape, both of which are involved in the pathogenesis of infectious diseases. In addition to the intercellular infectious processes, pathogen-produced/secreted enterotoxins (mostly exotoxins are the major weapons that kill host cells and cause diseases by inducing different types of cell death, particularly apoptosis and necrosis. Blocking these enterotoxins with synthetic drugs and vaccines is important for treating patients with infectious diseases. Studies of enterotoxin-induced apoptotic and necrotic mechanisms have helped us to create efficient strategies to use against these well-characterized cytopathic toxins. In this article, we review the induction of the different types of cell death from various bacterial enterotoxins, such as staphylococcal enterotoxin B, staphylococcal alpha-toxin, Panton-Valentine leukocidin, alpha-hemolysin of Escherichia coli, Shiga toxins, cytotoxic necrotizing factor 1, heat-labile enterotoxins, and the cholera toxin, Vibrio cholerae. In addition, necrosis caused by pore-forming toxins, apoptotic signaling through cross-talk pathways involving mitochondrial damage, endoplasmic reticulum stress, and lysosomal injury is discussed.

  20. Different types of cell death induced by enterotoxins.

    Science.gov (United States)

    Lin, Chiou-Feng; Chen, Chia-Ling; Huang, Wei-Ching; Cheng, Yi-Lin; Hsieh, Chia-Yuan; Wang, Chi-Yun; Hong, Ming-Yuan

    2010-08-01

    The infection of bacterial organisms generally causes cell death to facilitate microbial invasion and immune escape, both of which are involved in the pathogenesis of infectious diseases. In addition to the intercellular infectious processes, pathogen-produced/secreted enterotoxins (mostly exotoxins) are the major weapons that kill host cells and cause diseases by inducing different types of cell death, particularly apoptosis and necrosis. Blocking these enterotoxins with synthetic drugs and vaccines is important for treating patients with infectious diseases. Studies of enterotoxin-induced apoptotic and necrotic mechanisms have helped us to create efficient strategies to use against these well-characterized cytopathic toxins. In this article, we review the induction of the different types of cell death from various bacterial enterotoxins, such as staphylococcal enterotoxin B, staphylococcal alpha-toxin, Panton-Valentine leukocidin, alpha-hemolysin of Escherichia coli, Shiga toxins, cytotoxic necrotizing factor 1, heat-labile enterotoxins, and the cholera toxin, Vibrio cholerae. In addition, necrosis caused by pore-forming toxins, apoptotic signaling through cross-talk pathways involving mitochondrial damage, endoplasmic reticulum stress, and lysosomal injury is discussed.

  1. Comparative analysis of cell death induction by Taurolidine in different malignant human cancer cell lines

    Directory of Open Access Journals (Sweden)

    Ritter Peter R

    2010-03-01

    Full Text Available Abstract Background Taurolidine (TRD represents an anti-infective substance with anti-neoplastic activity in many malignant cell lines. So far, the knowledge about the cell death inducing mechanisms and pathways activated by TRD is limited. The aim of this study was therefore, to perform a comparative analysis of cell death induction by TRD simultaneously in different malignant cell lines. Materials and methods Five different malignant cell lines (HT29/Colon, Chang Liver/Liver, HT1080/fibrosarcoma, AsPC-1/pancreas and BxPC-3/pancreas were incubated with increasing concentrations of TRD (100 μM, 250 μM and 1000 μM for 6 h and 24 h. Cell viability, apoptosis and necrosis were analyzed by FACS analysis (Propidiumiodide/AnnexinV staining. Additionally, cells were co-incubated with the caspase Inhibitor z-VAD, the radical scavenger N-Acetylcystein (NAC and the Gluthation depleting agent BSO to examine the contribution of caspase activation and reactive oxygen species in TRD induced cell death. Results All cell lines were susceptible to TRD induced cell death without resistance toward this anti-neoplastic agent. However, the dose response effects were varying largely between different cell lines. The effect of NAC and BSO co-treatment were highly different among cell lines - suggesting a cell line specific involvement of ROS in TRD induced cell death. Furthermore, impact of z-VAD mediated inhibition of caspases was differing strongly among the cell lines. Conclusion This is the first study providing a simultaneous evaluation of the anti-neoplastic action of TRD across several malignant cell lines. The involvement of ROS and caspase activation was highly variable among the five cell lines, although all were susceptible to TRD induced cell death. Our results indicate, that TRD is likely to provide multifaceted cell death mechanisms leading to a cell line specific diversity.

  2. Mitochondria and cell death pathways in plants: Actions speak louder than words

    OpenAIRE

    Scott, Iain; Logan, David C

    2008-01-01

    The mitochondrion has a central role during programmed cell death (PCD) in animals, acting as both a sensor of death signals, and as an initiator of the biochemical processes which lead to the controlled destruction of the cell. In contrast to our extensive knowledge of animal cell death, the part played by mitochondria in the death of plant cells has received relatively little attention. Using a combination of whole-organism and cell-based models, we recently demonstrated that changes in mit...

  3. Phenoxide-bridged Zinc(II)-Bis(dipicolylamine) Probes for Molecular Imaging of Cell Death

    OpenAIRE

    Clear, Kasey J.; Harmatys, Kara M.; Rice, Douglas R.; Wolter, William R.; Suckow, Mark A.; Wang, Yuzhen; Rusckowski, Mary; Smith, Bradley D.

    2015-01-01

    Cell death is involved in many pathological conditions, and there is a need for clinical and preclinical imaging agents that can target and report cell death. One of the best known biomarkers of cell death is exposure of the anionic phospholipid phosphatidylserine (PS) on the surface of dead and dying cells. Synthetic zinc(II)-bis(dipicolylamine) (Zn2BDPA) coordination complexes are known to selectively recognize PS-rich membranes and act as cell death molecular imaging agents. However, there...

  4. Ayanin diacetate-induced cell death is amplified by TRAIL in human leukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Marrero, Maria Teresa; Estevez, Sara; Negrin, Gledy; Quintana, Jose [Departamento de Bioquimica, Unidad Asociada al Consejo Superior de Investigaciones Cientificas, Universidad de Las Palmas de Gran Canaria, Plaza Dr. Pasteur s/n, 35016 Las Palmas de Gran Canaria (Spain); Lopez, Mariana; Perez, Francisco J.; Triana, Jorge [Departamento de Quimica, Universidad de Las Palmas de Gran Canaria, Instituto Canario de Investigacion del Cancer, 35017 Las Palmas de Gran Canaria (Spain); Leon, Francisco [Instituto de Productos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Avda. Astrofisico F. Sanchez 3, 38206 La Laguna, Tenerife (Spain); Estevez, Francisco, E-mail: festevez@dbbf.ulpgc.es [Departamento de Bioquimica, Unidad Asociada al Consejo Superior de Investigaciones Cientificas, Universidad de Las Palmas de Gran Canaria, Plaza Dr. Pasteur s/n, 35016 Las Palmas de Gran Canaria (Spain)

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer Ayanin diacetate as apoptotic inducer in leukemia cells. Black-Right-Pointing-Pointer Cell death was prevented by caspase inhibitors and by the overexpression of Bcl-x{sub L}. Black-Right-Pointing-Pointer The intrinsic and the extrinsic pathways are involved in the mechanism of action. Black-Right-Pointing-Pointer Death receptors are up-regulated and TRAIL enhances apoptotic cell death. -- Abstract: Here we demonstrate that the semi-synthetic flavonoid ayanin diacetate induces cell death selectively in leukemia cells without affecting the proliferation of normal lymphocytes. Incubation of human leukemia cells with ayanin diacetate induced G{sub 2}-M phase cell cycle arrest and apoptosis which was prevented by the non-specific caspase inhibitor z-VAD-fmk and reduced by the overexpression of Bcl-x{sub L}. Ayanin diacetate-induced cell death was found to be associated with: (i) loss of inner mitochondrial membrane potential, (ii) the release of cytochrome c, (iii) the activation of multiple caspases, (iv) cleavage of poly(ADP-ribose) polymerase and (v) the up-regulation of death receptors for TRAIL, DR4 and DR5. Moreover, the combined treatment with ayanin diacetate and TRAIL amplified cell death, compared to single treatments. These results provide a basis for further exploring the potential applications of this combination for the treatment of cancer.

  5. Two programmed cell death systems in Escherichia coli: an apoptotic-like death is inhibited by the mazEF-mediated death pathway.

    Directory of Open Access Journals (Sweden)

    Ariel Erental

    Full Text Available In eukaryotes, the classical form of programmed cell death (PCD is apoptosis, which has as its specific characteristics DNA fragmentation and membrane depolarization. In Escherichia coli a different PCD system has been reported. It is mediated by the toxin-antitoxin system module mazEF. The E. coli mazEF module is one of the most thoroughly studied toxin-antitoxin systems. mazF encodes a stable toxin, MazF, and mazE encodes a labile antitoxin, MazE, which prevents the lethal effect of MazF. mazEF-mediated cell death is a population phenomenon requiring the quorum-sensing pentapeptide NNWNN designated Extracellular Death Factor (EDF. mazEF is triggered by several stressful conditions, including severe damage to the DNA. Here, using confocal microscopy and FACS analysis, we show that under conditions of severe DNA damage, the triggered mazEF-mediated cell death pathway leads to the inhibition of a second cell death pathway. The latter is an apoptotic-like death (ALD; ALD is mediated by recA and lexA. The mazEF-mediated pathway reduces recA mRNA levels. Based on these results, we offer a molecular model for the maintenance of an altruistic characteristic in cell populations. In our model, the ALD pathway is inhibited by the altruistic EDF-mazEF-mediated death pathway.

  6. Crystalline Nickel Sulfide Induced Malignant Transformation of 16HBE Cells through Autophagic Pathway%结晶型硫化镍通过自噬途径诱导16HBE细胞恶性转化癌变

    Institute of Scientific and Technical Information of China (English)

    张岚; 杨磊; 吕嘉春

    2012-01-01

    Nickel compounds, which widely exist in the environment of human occupation, are the major risk factor for human lung cancer. Our previous studies had confirmed that exposure to toxic,metallic crystalline nickel sulfide (NiS) was an important cause of lung cancer, but the concrete carcinogenic mechanism is still unclear. In this study, we used the previouslyestablished human bronchial epithelial (16HBE-T) cells malignant transformation model, which was induced by crystalline NiS. For the first time, fluorescence intensity and position of the GFP-LC3 protein in malignant transformed (16HBE-T) cells and normal cell (16HBE-N), were real-time monitored with the technique of confocal laser scanning microscopy imaging without damaging the condition. Moreover, we used Western Blotting to detect the intracellular autophagic signal which is expressed by key effective molecule pathway. Confocal experimental results showed that: Compared with that of 16HBE-N-cells, the GFP-LC3 protein punctate aggregation of 16HBE-T cells significantly reduced to the merely 1/3 amount of 16HBE-N-cells, suggesting that autophagy levels declined. At the same time, it was found that the mTOR kinase activity increased, and that Beclin 1 expression decreased. The above research result demonstrated that the mechanism of crystalline NiS induced 16HBE cell malignant transformation was through multiple autophagic pathway and it will provide an important message in the prevention and treatment of lung cancer.%镍化合物广泛存在于人类职业环境中,是人类发生肺癌的主要危险因素.我们前期研究已证实金属毒物结晶型硫化镍(NiS)的暴露是发生肺癌的重要病因,但具体的致癌机制仍未明了.本研究利用前期建立的结晶型NiS恶性转化人支气管上皮细胞的细胞模型,首次采用激光共聚焦扫描显微镜成像技术,在无损伤状态下,实时观测恶性转化细胞(16HBE-T)和正常细胞(16HBE-N)中自噬体标记蛋白GFP-LC3

  7. Vacuolar processing enzyme in plant programmed cell death

    Directory of Open Access Journals (Sweden)

    Noriyuki eHatsugai

    2015-04-01

    Full Text Available Vacuolar processing enzyme (VPE is a cysteine proteinase originally identified as the proteinase responsible for the maturation and activation of vacuolar proteins in plants, and it is known to be an orthologue of animal asparaginyl endopeptidase (AEP/VPE/legumain. VPE has been shown to exhibit enzymatic properties similar to that of caspase 1, which is a cysteine protease that mediates the programmed cell death (PCD pathway in animals. Although there is limited sequence identity between VPE and caspase 1, their predicted three-dimensional structures revealed that the essential amino-acid residues for these enzymes form similar pockets for the substrate peptide YVAD. In contrast to the cytosolic localization of caspases, VPE is localized in vacuoles. VPE provokes vacuolar rupture, initiating the proteolytic cascade leading to PCD in the plant immune response. It has become apparent that the VPE-dependent PCD pathway is involved not only in the immune response, but also in the responses to a variety of stress inducers and in the development of various tissues. This review summarizes the current knowledge on the contribution of VPE to plant PCD and its role in vacuole-mediated cell death, and it also compares VPE with the animal cell death executor caspase 1.

  8. Involvement of Autophagic Pathway in the Progression of Retinal Degeneration in a Mouse Model of Diabetes.

    Science.gov (United States)

    Piano, Ilaria; Novelli, Elena; Della Santina, Luca; Strettoi, Enrica; Cervetto, Luigi; Gargini, Claudia

    2016-01-01

    The notion that diabetic retinopathy (DR) is essentially a micro-vascular disease has been recently challenged by studies reporting that vascular changes are preceded by signs of damage and loss of retinal neurons. As to the mode by which neuronal death occurs, the evidence that apoptosis is the main cause of neuronal loss is far from compelling. The objective of this study was to investigate these controversies in a mouse model of streptozotocin (STZ) induced diabetes. Starting from 8 weeks after diabetes induction there was loss of rod but not of cone photoreceptors, together with reduced thickness of the outer and inner synaptic layers. Correspondingly, rhodopsin expression was downregulated and the scotopic electroretinogram (ERG) is suppressed. In contrast, cone opsin expression and photopic ERG response were not affected. Suppression of the scotopic ERG preceded morphological changes as well as any detectable sign of vascular alteration. Only sparse apoptotic figures were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and glia was not activated. The physiological autophagy flow was altered instead, as seen by increased LC3 immunostaining at the level of outer plexiform layer (OPL) and upregulation of the autophagic proteins Beclin-1 and Atg5. Collectively, our results show that the streptozotocin induced DR in mouse initiates with a functional loss of the rod visual pathway. The pathogenic pathways leading to cell death develop with the initial dysregulation of autophagy well before the appearance of signs of vascular damage and without strong involvement of apoptosis.

  9. Targeted cancer cell death induced by biofunctionalized magnetic nanowires

    KAUST Repository

    Contreras, Maria F.

    2014-02-01

    Magnetic micro and nanomaterials are increasingly interesting for biomedical applications since they possess many advantageous properties: they can become biocompatible, they can be functionalized to target specific cells and they can be remotely manipulated by magnetic fields. The goal of this study is to use antibody-functionalized nickel nanowires (Ab-NWs) as an alternative method in cancer therapy overcoming the limitations of current treatments that lack specificity and are highly cytotoxic. Ab-NWs have been incubated with cancer cells and a 12% drop on cell viability was observed for a treatment of only 10 minutes and an alternating magnetic field of low intensity and low frequency. It is believed that the Ab-NWs vibrate transmitting a mechanical force to the targeted cells inducing cell death. © 2014 IEEE.

  10. Thymoquinone causes multiple effects, including cell death, on dividing plant cells.

    Science.gov (United States)

    Hassanien, Sameh E; Ramadan, Ahmed M; Azeiz, Ahmed Z Abdel; Mohammed, Rasha A; Hassan, Sabah M; Shokry, Ahmed M; Atef, Ahmed; Kamal, Khalid B H; Rabah, Samar; Sabir, Jamal S M; Abuzinadah, Osama A; El-Domyati, Fotouh M; Martin, Gregory B; Bahieldin, Ahmed

    2013-01-01

    Thymoquinone (TQ) is a major constituent of Nigella sativa oil with reported anti-oxidative activity and anti-inflammatory activity in animal cells. It also inhibits proliferation and induces programmed cell death (apoptosis) in human skin cancer cells. The present study sought to detect the influence of TQ on dividing cells of three plant systems and on expression of Bcl2-associated athanogene-like (BAG-like) genes that might be involved during the process of cell death. BAG genes are known for the regulation of diverse physiological processes in animals, including apoptosis, tumorigenesis, stress responses, and cell division. Synthetic TQ at 0.1mg/mL greatly reduced wheat seed germination rate, whereas 0.2mg/mL completely inhibited germination. An Evans blue assay revealed moderate cell death in the meristematic zone of Glycine max roots after 1h of TQ treatment (0.2mg/mL), with severe cell death occurring in this zone after 2h of treatment. Light microscopy of TQ-treated (0.2mg/mL) onion hairy root tips for 1h revealed anti-mitotic activity and also cell death-associated changes, including nuclear membrane disruption and nuclear fragmentation. Transmission electron microscopy of TQ-treated cells (0.2mg/mL) for 1h revealed shrinkage of the plasma membrane, leakage of cell lysate, degradation of cell walls, enlargement of vacuoles and condensation of nuclei. Expression of one BAG-like gene, previously associated with cell death, was induced 20 min after TQ treatment in Glycine max root tip cells. Thus, TQ has multiple effects, including cell death, on dividing plant cells and plants may serve as a useful system to further investigate the mechanisms underlying the response of eukaryotic cells to TQ.

  11. Curcumin induces apoptosis-independent death in oesophageal cancer cells.

    LENUS (Irish Health Repository)

    O'Sullivan-Coyne, G

    2009-10-06

    Background:Oesophageal cancer incidence is increasing and survival rates remain extremely poor. Natural agents with potential for chemoprevention include the phytochemical curcumin (diferuloylmethane). We have examined the effects of curcumin on a panel of oesophageal cancer cell lines.Methods:MTT (3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assays and propidium iodide staining were used to assess viability and DNA content, respectively. Mitotic catastrophe (MC), apoptosis and autophagy were defined by both morphological criteria and markers such as MPM-2, caspase 3 cleavage and monodansylcadaverine (MDC) staining. Cyclin B and poly-ubiquitinated proteins were assessed by western blotting.Results:Curcumin treatment reduces viability of all cell lines within 24 h of treatment in a 5-50 muM range. Cytotoxicity is associated with accumulation in G2\\/M cell-cycle phases and distinct chromatin morphology, consistent with MC. Caspase-3 activation was detected in two out of four cell lines, but was a minor event. The addition of a caspase inhibitor zVAD had a marginal or no effect on cell viability, indicating predominance of a non-apoptotic form of cell death. In two cell lines, features of both MC and autophagy were apparent. Curcumin-responsive cells were found to accumulate poly-ubiquitinated proteins and cyclin B, consistent with a disturbance of the ubiquitin-proteasome system. This effect on a key cell-cycle checkpoint regulator may be responsible for the mitotic disturbances and consequent cytotoxicity of this drug.Conclusion:Curcumin can induce cell death by a mechanism that is not reliant on apoptosis induction, and thus represents a promising anticancer agent for prevention and treatment of oesophageal cancer.British Journal of Cancer advance online publication, 6 October 2009; doi:10.1038\\/sj.bjc.6605308 www.bjcancer.com.

  12. Curcumin induces apoptosis-independent death in oesophageal cancer cells.

    LENUS (Irish Health Repository)

    O'Sullivan-Coyne, G

    2012-01-31

    BACKGROUND: Oesophageal cancer incidence is increasing and survival rates remain extremely poor. Natural agents with potential for chemoprevention include the phytochemical curcumin (diferuloylmethane). We have examined the effects of curcumin on a panel of oesophageal cancer cell lines. METHODS: MTT (3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assays and propidium iodide staining were used to assess viability and DNA content, respectively. Mitotic catastrophe (MC), apoptosis and autophagy were defined by both morphological criteria and markers such as MPM-2, caspase 3 cleavage and monodansylcadaverine (MDC) staining. Cyclin B and poly-ubiquitinated proteins were assessed by western blotting. RESULTS: Curcumin treatment reduces viability of all cell lines within 24 h of treatment in a 5-50 muM range. Cytotoxicity is associated with accumulation in G2\\/M cell-cycle phases and distinct chromatin morphology, consistent with MC. Caspase-3 activation was detected in two out of four cell lines, but was a minor event. The addition of a caspase inhibitor zVAD had a marginal or no effect on cell viability, indicating predominance of a non-apoptotic form of cell death. In two cell lines, features of both MC and autophagy were apparent. Curcumin-responsive cells were found to accumulate poly-ubiquitinated proteins and cyclin B, consistent with a disturbance of the ubiquitin-proteasome system. This effect on a key cell-cycle checkpoint regulator may be responsible for the mitotic disturbances and consequent cytotoxicity of this drug. CONCLUSION: Curcumin can induce cell death by a mechanism that is not reliant on apoptosis induction, and thus represents a promising anticancer agent for prevention and treatment of oesophageal cancer.

  13. Heat shock genes – integrating cell survival and death

    Indian Academy of Sciences (India)

    Richa Arya; Moushami Mallik; Subhash C Lakhotia

    2007-04-01

    Heat shock induced gene expression and other cellular responses help limit the damage caused by stress and thus facilitate cellular recovery. Cellular damage also triggers apoptotic cell death through several pathways. This paper briefly reviews interactions of the major heat shock proteins with components of the apoptotic pathways. Hsp90, which acts as a chaperone for unstable signal transducers to keep them poised for activation, interacts with RIP and Akt and promotes NF-B mediated inhibition of apoptosis; in addition it also blocks some steps in the apoptotic pathways. Hsp70 is mostly anti-apoptotic and acts at several levels like inhibition of translocation of Bax into mitochondria, release of cytochrome c from mitochondria, formation of apoptosome and inhibition of activation of initiator caspases. Hsp70 also modulates JNK, NF-B and Akt signaling pathways in the apoptotic cascade. In contrast, Hsp60 has both anti- and pro-apoptotic roles. Cytosolic Hsp60 prevents translocation of the pro-apoptotic protein Bax into mitochondria and thus promotes cell survival but it also promotes maturation of procaspase-3, essential for caspase mediated cell death. Our recent in vivo studies show that RNAi for the Hsp60D in Drosophila melanogaster prevents induced apoptosis. Hsp27 exerts its anti-apoptotic influence by inhibiting cytochrome c and TNF-mediated cell death. crystallin suppresses caspase-8 and cytochrome c mediated activation of caspase-3. Studies in our laboratory also reveal that absence or reduced levels of the developmentally active as well as stress induced non-coding hsr transcripts, which are known to sequester diverse hnRNPs and related nuclear RNA-binding proteins, block induced apoptosis in Drosophila. Modulation of the apoptotic pathways by Hsps reflects their roles as ``weak links” between various ``hubs” in cellular networks. On the other hand, non-coding RNAs, by virtue of their potential to bind with multiple proteins, can act as ``hubs” in

  14. Embryonic death and the creation of human embryonic stem cells

    OpenAIRE

    Landry, Donald W.; Zucker, Howard A.

    2004-01-01

    The creation of human embryonic stem cells through the destruction of a human embryo pits the value of a potential therapeutic tool against that of an early human life. This contest of values has resulted in a polarized debate that neglects areas of common interest and perspective. We suggest that a common ground for pursuing research on human embryonic stem cells can be found by reconsidering the death of the human embryo and by applying to this research the ethical norms of essential organ ...

  15. Embryonic death and the creation of human embryonic stem cells.

    Science.gov (United States)

    Landry, Donald W; Zucker, Howard A

    2004-11-01

    The creation of human embryonic stem cells through the destruction of a human embryo pits the value of a potential therapeutic tool against that of an early human life. This contest of values has resulted in a polarized debate that neglects areas of common interest and perspective. We suggest that a common ground for pursuing research on human embryonic stem cells can be found by reconsidering the death of the human embryo and by applying to this research the ethical norms of essential organ donation.

  16. Low zinc environment induces stress signaling, senescence and mixed cell death modalities in colon cancer cells.

    Science.gov (United States)

    Rudolf, Emil; Rudolf, Kamil

    2015-12-01

    Currently it is not clear what type of the final cellular response (i.e. cell death modality or senescence) is induced upon chronic intracellular zinc depletion in colon cancer cells. To address this question, isogenic colon cancer lines SW480 and SW620 exposed to low zinc environment were studied over the period of 6 weeks. Low zinc environment reduced total as well as free intracellular zinc content in both cell lines. Decreased intracellular zinc content resulted in changes in cellular proliferation, cell cycle distribution and activation of stress signaling. In addition, colonocytes with low zinc content displayed increased levels of oxidative stress, changes in mitochondrial activity but in the absence of significant DNA damage. Towards the end of treatment (4th-6th week), exposed cells started to change morphologically, and typical markers of senescence as well as cell death appeared. Of two examined colon cancer cell lines, SW480 cells proved to activate predominantly senescent phenotype, with frequent form of demise being necrosis and mixed cell death modality but not apoptosis. Conversely, SW620 cells activated mostly cell death, with relatively equal distribution of apoptosis and mixed types, while senescent phenotypes and necrosis were present only in a small fraction of cell populations. Addition of zinc at the beginning of 4th week of treatment significantly suppressed cell death phenotypes in both cell lines but had no significant effect on senescence. In conclusion, presented results demonstrate variability of responses to chronic zinc depletion in colon cancer as modeled in vitro.

  17. EFFECTS OF ETHANOL AND HYDROGEN PEROXIDE ON MOUSE LIMB BUD MESENCHYME DIFFERENTIATION AND CELL DEATH

    Science.gov (United States)

    Many of the morphological defects associated with embryonic alcohol exposure are a result of cell death. During limb development, ethanol administration produces cell death in the limb and digital defects, including postaxial ectrodactyly. Because an accumulation of reactive oxyg...

  18. Secretory phospholipase A2-mediated neuronal cell death involves glutamate ionotropic receptors

    DEFF Research Database (Denmark)

    de Turco, Elena B; Diemer, Nils Henrik; Bazan, Nicolas G

    2002-01-01

    To define the significance of glutamate ionotropic receptors in sPLA -mediated neuronal cell death we used the NMDA receptor antagonist MK-801 and the AMPA receptor antagonist PNQX. In primary neuronal cell cultures both MK-801 and PNQX inhibited sPLA - and glutamate-induced neuronal death. [ H...... neuronal cell death. We conclude that glutamatergic synaptic activity modulates sPLA -induced neuronal cell death....

  19. Ex vivo detection of primary leukemia cells resistant to granule cytotoxin-induced cell death: a rapid isolation method to study granzyme-B-mediated cell death.

    Science.gov (United States)

    Grüllich, Carsten; Friske, Viktoria; Finke, Jürgen

    2008-09-01

    Cytotoxic T lymphocytes and natural killer cells (CTL/NK) induce cell death in leukemia cells by the granzyme B (grB)-dependent granule cytotoxin (GC) pathway. Resistance to GC may be involved in immune evasion of leukemia cells. The delivery of active grB into the cytoplasma is dependent on the presence of perforin (PFN) and grB complexes. We developed a rapid method for the isolation of GC to investigate GC-mediated cell death in primary leukemia cells. We isolated GC containing grB, grB complexes and PFN by detergent free hypotonic lysis of the human NK cell leukemia line YT. The GC induce grB-mediated, caspase-dependent apoptosis in live cells. The human leukemia cell lines KG-1, U937, K562 (myeloid leukemia), Jurkat, Daudi, and BV173 (lymphoblastic leukemia) treated with GC internalized grB and underwent cell death. In primary leukemia cells analyzed ex vivo, we found GC-resistant leukemia cells in three out of seven patients with acute myeloid leukemia and one out of six patients with acute lymphoblastic leukemia. We conclude that our method is fast (approximately 1 h) and yields active GC that induce grB-dependent cell death. Furthermore, resistance to GC can be observed in acute leukemias and may be an important mechanism contributing to leukemia cell immune evasion.

  20. Mitochondrial control of cell death induced by hyperosmotic stress.

    Science.gov (United States)

    Criollo, Alfredo; Galluzzi, Lorenzo; Maiuri, M Chiara; Tasdemir, Ezgi; Lavandero, Sergio; Kroemer, Guido

    2007-01-01

    HeLa and HCT116 cells respond differentially to sorbitol, an osmolyte able to induce hypertonic stress. In these models, sorbitol promoted the phenotypic manifestations of early apoptosis followed by complete loss of viability in a time-, dose-, and cell type-specific fashion, by eliciting distinct yet partially overlapping molecular pathways. In HCT116 but not in HeLa cells, sorbitol caused the mitochondrial release of the caspase-independent death effector AIF, whereas in both cell lines cytochrome c was retained in mitochondria. Despite cytochrome c retention, HeLa cells exhibited the progressive activation of caspase-3, presumably due to the prior activation of caspase-8. Accordingly, caspase inhibition prevented sorbitol-induced killing in HeLa, but only partially in HCT116 cells. Both the knock-out of Bax in HCT116 cells and the knock-down of Bax in A549 cells by RNA interference reduced the AIF release and/or the mitochondrial alterations. While the knock-down of Bcl-2/Bcl-X(L) sensitized to sorbitol-induced killing, overexpression of a Bcl-2 variant that specifically localizes to mitochondria (but not of the wild-type nor of a endoplasmic reticulum-targeted form) strongly inhibited sorbitol effects. Thus, hyperosmotic stress kills cells by triggering different molecular pathways, which converge at mitochondria where pro- and anti-apoptotic members of the Bcl-2 family exert their control.

  1. Cell-to-Cell stochastic fluctuations in apoptotic signaling can decide between life and death

    CERN Document Server

    Raychaudhuri, S; Nguyen, T; Khan, E M; Goldkorn, T

    2007-01-01

    Apoptosis, or genetically programmed cell death, is a crucial cellular process that maintains the balance between life and death in cells. The precise molecular mechanism of apoptosis signaling and how these two pathways are differentially activated under distinct apoptotic stimuli is poorly understood. We developed a Monte Carlo-based stochastic simulation model that can characterize distinct signaling behaviors in the two major pathways of apoptotic signaling using a novel probability distribution-based approach. Specifically, we show that for a weak death signal, such as low levels of death ligand Fas (CD95) binding or under stress conditions, the type 2 mitochondrial pathway dominates apoptotic signaling. Our results also show signaling in the type 2 pathway is stochastic, where the population average over many cells does not capture the cell-to-cell fluctuations in the time course (~1 - 10 hours) of downstream caspase-3 activation. On the contrary, the probability distribution of caspase-3 activation for...

  2. From DNA radiation damage to cell death: theoretical approaches.

    Science.gov (United States)

    Ballarini, Francesca

    2010-10-05

    Some representative models of radiation-induced cell death, which is a crucial endpoint in radiobiology, were reviewed. The basic assumptions were identified, their consequences on predicted cell survival were analyzed, and the advantages and drawbacks of each approach were outlined. In addition to "historical" approaches such as the Target Theory, the Linear-Quadratic model, the Theory of Dual Radiation Action and Katz' model, the more recent Local Effect Model was discussed, focusing on its application in Carbon-ion hadrontherapy. Furthermore, a mechanistic model developed at the University of Pavia and based on the relationship between cell inactivation and chromosome aberrations was presented, together with recent results; the good agreement between model predictions and literature experimental data on different radiation types (photons, protons, alpha particles, and Carbon ions) supported the idea that asymmetric chromosome aberrations like dicentrics and rings play a fundamental role for cell death. Basing on these results, a reinterpretation of the TDRA was also proposed, identifying the TDRA "sublesions" and "lesions" as clustered DNA double-strand breaks and (lethal) chromosome aberrations, respectively.

  3. From DNA Radiation Damage to Cell Death: Theoretical Approaches

    Directory of Open Access Journals (Sweden)

    Francesca Ballarini

    2010-01-01

    Full Text Available Some representative models of radiation-induced cell death, which is a crucial endpoint in radiobiology, were reviewed. The basic assumptions were identified, their consequences on predicted cell survival were analyzed, and the advantages and drawbacks of each approach were outlined. In addition to “historical” approaches such as the Target Theory, the Linear-Quadratic model, the Theory of Dual Radiation Action and Katz' model, the more recent Local Effect Model was discussed, focusing on its application in Carbon-ion hadrontherapy. Furthermore, a mechanistic model developed at the University of Pavia and based on the relationship between cell inactivation and chromosome aberrations was presented, together with recent results; the good agreement between model predictions and literature experimental data on different radiation types (photons, protons, alpha particles, and Carbon ions supported the idea that asymmetric chromosome aberrations like dicentrics and rings play a fundamental role for cell death. Basing on these results, a reinterpretation of the TDRA was also proposed, identifying the TDRA “sublesions” and “lesions” as clustered DNA double-strand breaks and (lethal chromosome aberrations, respectively.

  4. Statins and voriconazole induce programmed cell death in Acanthamoeba castellanii.

    Science.gov (United States)

    Martín-Navarro, Carmen M; López-Arencibia, Atteneri; Sifaoui, Ines; Reyes-Batlle, María; Valladares, Basilio; Martínez-Carretero, Enrique; Piñero, José E; Maciver, Sutherland K; Lorenzo-Morales, Jacob

    2015-05-01

    Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a life-threatening encephalitis. In order to treat those infections properly, it is necessary to target the treatment not only to the trophozoite but also to the cyst. Furthermore, it may be advantageous to avoid parasite killing by necrosis, which may induce local inflammation. We must also avoid toxicity of host tissue. Many drugs which target eukaryotes are known to induce programmed cell death (PCD), but this process is poorly characterized in Acanthamoeba. Here, we study the processes of programmed cell death in Acanthamoeba, induced by several drugs, such as statins and voriconazole. We tested atorvastatin, fluvastatin, simvastatin, and voriconazole at the 50% inhibitory concentrations (IC50s) and IC90s that we have previously established. In order to evaluate this phenomenon, we investigated the DNA fragmentation, one of the main characteristics of PCD, with quantitative and qualitative techniques. Also, the changes related to phosphatidylserine exposure on the external cell membrane and cell permeability were studied. Finally, because caspases are key to PCD pathways, caspase activity was evaluated in Acanthamoeba. All the drugs assayed in this study induced PCD in Acanthamoeba. To the best of our knowledge, this is the first study where PCD induced by drugs is described quantitatively and qualitatively in Acanthamoeba.

  5. Programmed cell death in C. elegans, mammals and plants.

    Science.gov (United States)

    Lord, Christina E N; Gunawardena, Arunika H L A N

    2012-08-01

    Programmed cell death (PCD) is the regulated removal of cells within an organism and plays a fundamental role in growth and development in nearly all eukaryotes. In animals, the model organism Caenorhabditis elegans (C. elegans) has aided in elucidating many of the pathways involved in the cell death process. Various analogous PCD processes can also be found within mammalian PCD systems, including vertebrate limb development. Plants and animals also appear to share hallmarks of PCD, both on the cellular and molecular level. Cellular events visualized during plant PCD resemble those seen in animals including: nuclear condensation, DNA fragmentation, cytoplasmic condensation, and plasma membrane shrinkage. Recently the molecular mechanisms involved in plant PCD have begun to be elucidated. Although few regulatory proteins have been identified as conserved across all eukaryotes, molecular features such as the participation of caspase-like proteases, Bcl-2-like family members and mitochondrial proteins appear to be conserved between plant and animal systems. Transgenic expression of mammalian and C. elegans pro- and anti-apoptotic genes in plants has been observed to dramatically influence the regulatory pathways of plant PCD. Although these genes often show little to no sequence similarity they can frequently act as functional substitutes for one another, thus suggesting that action may be more important than sequence resemblance. Here we present a summary of these findings, focusing on the similarities, between mammals, C. elegans, and plants. An emphasis will be placed on the mitochondria and its role in the cell death pathway within each organism. Through the comparison of these systems on both a cellular and molecular level we can begin to better understand PCD in plant systems, and perhaps shed light on the pathways, which are controlling the process. This manuscript adds to the field of PCD in plant systems by profiling apoptotic factors, to scale on a protein

  6. Mycobacterium tuberculosis infection induces non-apoptotic cell death of human dendritic cells

    LENUS (Irish Health Repository)

    Ryan, Ruth CM

    2011-10-24

    Abstract Background Dendritic cells (DCs) connect innate and adaptive immunity, and are necessary for an efficient CD4+ and CD8+ T cell response after infection with Mycobacterium tuberculosis (Mtb). We previously described the macrophage cell death response to Mtb infection. To investigate the effect of Mtb infection on human DC viability, we infected these phagocytes with different strains of Mtb and assessed viability, as well as DNA fragmentation and caspase activity. In parallel studies, we assessed the impact of infection on DC maturation, cytokine production and bacillary survival. Results Infection of DCs with live Mtb (H37Ra or H37Rv) led to cell death. This cell death proceeded in a caspase-independent manner, and without nuclear fragmentation. In fact, substrate assays demonstrated that Mtb H37Ra-induced cell death progressed without the activation of the executioner caspases, 3\\/7. Although the death pathway was triggered after infection, the DCs successfully underwent maturation and produced a host-protective cytokine profile. Finally, dying infected DCs were permissive for Mtb H37Ra growth. Conclusions Human DCs undergo cell death after infection with live Mtb, in a manner that does not involve executioner caspases, and results in no mycobactericidal effect. Nonetheless, the DC maturation and cytokine profile observed suggests that the infected cells can still contribute to TB immunity.

  7. Pirarubicin induces an autophagic cytoprotective response through suppression of the mammalian target of rapamycin signaling pathway in human bladder cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kuiqing; Chen, Xu [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Liu, Cheng [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Gu, Peng; Li, Zhuohang; Wu, Shaoxu [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Xu, Kewei [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Lin, Tianxin, E-mail: tianxinl@sina.com [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China); Huang, Jian, E-mail: urolhj@sina.com [Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 (China)

    2015-05-01

    Pirarubicin is widely used in intravesical chemotherapy for bladder cancer, but its efficacy is limited due to drug resistance; the mechanism has not been well studied. Emerging evidence shows that autophagy can be a novel target for cancer therapy. This study aimed to investigate the role of autophagy in pirarubicin-treated bladder cancer cells. Bladder cancer cells EJ and J82 were treated with pirarubicin, siRNA, 3-methyladenine or hydroxychloroquine. Cell proliferation and apoptosis were tested by cell survival assay and flow cytometric analysis, respectively. Autophagy was evaluated by immunoblotting before and after the treatments. The phosphorylated mammalian target of rapamycin, serine/threonine kinase p70 S6 kinase, and eukaryotic translation initiation factor 4E binding protein 1 were also investigated by immunoblotting. We found that pirarubicin could induce autophagy in bladder cancer cells. Inhibition of autophagy by 3-methyladenine, hydroxychloroquine or knockdown of autophagy related gene 3 significantly increased apoptosis in pirarubicin-treated bladder cancer cells. Pirarubicin-induced autophagy was mediated via the mTOR/p70S6K/4E-BP1 signaling pathway. In conclusion, autophagy induced by pirarubicin plays a cytoprotective role in bladder cancer cells, suggesting that inhibition of autophagy may improve efficacy over traditional pirarubicin chemotherapy in bladder cancer patients. - Highlights: • Pirarubicin induced autophagy in bladder cancer cells. • Inhibition of autophagy enhanced pirarubicin-induced apoptosis. • Pirarubicin induced autophagy through inhibition of mTOR signaling pathway.

  8. Turmeric toxicity in A431 epidermoid cancer cells associates with autophagy degradation of anti-apoptotic and anti-autophagic p53 mutant.

    Science.gov (United States)

    Thongrakard, Visa; Titone, Rossella; Follo, Carlo; Morani, Federica; Suksamrarn, Apichart; Tencomnao, Tewin; Isidoro, Ciro

    2014-12-01

    The keratinocyte-derived A431 Squamous Cell Carcinoma cells express the p53R273H mutant, which has been reported to inhibit apoptosis and autophagy. Here, we show that the crude extract of turmeric (Curcuma longa), similarly to its bioactive component Curcumin, could induce both apoptosis and autophagy in A431 cells, and these effects were concomitant with degradation of p53. Turmeric and curcumin also stimulated the activity of mTOR, which notoriously promotes cell growth and acts negatively on basal autophagy. Rapamycin-mediated inhibition of mTOR synergized with turmeric and curcumin in causing p53 degradation, increased the production of autophagosomes and exacerbated cell toxicity leading to cell necrosis. Small-interference mediated silencing of the autophagy proteins BECLIN 1 or ATG7 abrogated the induction of autophagy and largely rescued p53 stability in Turmeric-treated or Curcumin-treated cells, indicating that macroautophagy was mainly responsible for mutant p53 degradation. These data uncover a novel mechanism of turmeric and curcumin toxicity in chemoresistant cancer cells bearing mutant p53.

  9. Early death during chemotherapy in patients with small-cell lung cancer

    DEFF Research Database (Denmark)

    Lassen, U N; Osterlind, K; Hirsch, F R

    1999-01-01

    Based on an increased frequency of early death (death within the first treatment cycle) in our two latest randomized trials of combination chemotherapy in small-cell lung cancer (SCLC), we wanted to identify patients at risk of early non-toxic death (ENTD) and early toxic death (ETD). Data were...

  10. Inhibition of Autophagy via Activation of PI3K/Akt Pathway Contributes to the Protection of Ginsenoside Rb1 against Neuronal Death Caused by Ischemic Insults

    Directory of Open Access Journals (Sweden)

    Tianfei Luo

    2014-09-01

    Full Text Available Lethal autophagy is a pathway leading to neuronal death caused by transient global ischemia. In this study, we examined the effect of Ginsenoside Rb1 (GRb1 on ischemia/reperfusion-induced autophagic neuronal death and investigated the role of PI3K/Akt. Ischemic neuronal death in vitro was induced by using oxygen glucose deprivation (OGD in SH-SY5Y cells, and transient global ischemia was produced by using two vessels occlusion in rats. Cellular viability of SH-SY5Y cells was assessed by MTT assay, and CA1 neuronal death was evaluated by Hematoxylin-eosin staining. Autophagic vacuoles were detected by using both fluorescent microscopy in combination with acridine orange (AO and Monodansylcadaverine (MDC staining and transmission electronic microscopy. Protein levels of LC3II, Beclin1, total Akt and phosphor-Akt at Ser473 were examined by western blotting analysis. GRb1 inhibited both OGD and transient ischemia-induced neuronal death and mitigated OGD-induced autophagic vacuoles in SH-SY5Y cells. By contrast, PI3K inhibitor LY294002 counteracted the protection of GRb1 against neuronal death caused by either OGD or transient ischemia. LY294002 not only mitigated the up-regulated protein level of phosphor Akt at Ser473 caused by GRb1, but also reversed the inhibitory effect of GRb1 on OGD and transient ischemia-induced elevation in protein levels of LC3II and Beclin1.

  11. Anhydrobiosis and programmed cell death in plants: Commonalities and Differences

    Directory of Open Access Journals (Sweden)

    Samer Singh

    2015-05-01

    Full Text Available Anhydrobiosis is an adaptive strategy of certain organisms or specialised propagules to survive in the absence of water while programmed cell death (PCD is a finely tuned cellular process of the selective elimination of targeted cell during developmental programme and perturbed biotic and abiotic conditions. Particularly during water stress both the strategies serve single purpose i.e., survival indicating PCD may also function as an adaptive process under certain conditions. During stress conditions PCD cause targeted cells death in order to keep the homeostatic balance required for the organism survival, whereas anhydrobiosis suspends cellular metabolic functions mimicking a state similar to death until reestablishment of the favourable conditions. Anhydrobiosis is commonly observed among organisms that have ability to revive their metabolism on rehydration after removal of all or almost all cellular water without damage. This feature is widely represented in terrestrial cyanobacteria and bryophytes where it is very common in both vegetative and reproductive stages of life-cycle. In the course of evolution, with the development of advanced vascular system in higher plants, anhydrobiosis was gradually lost from the vegetative phase of life-cycle. Though it is retained in resurrection plants that primarily belong to thallophytes and a small group of vascular angiosperm, it can be mostly found restricted in orthodox seeds of higher plants. On the contrary, PCD is a common process in all eukaryotes from unicellular to multicellular organisms including higher plants and mammals. In this review we discuss physiological and biochemical commonalities and differences between anhydrobiosis and PCD.

  12. Ras and Rheb Signaling in Survival and Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Ehrkamp, Anja [Molecular Neurobiochemistry, Ruhr University of Bochum, 44780 Bochum (Germany); Herrmann, Christian [Department of Physical Chemistry1, Protein Interaction, Ruhr University of Bochum, 44780 Bochum (Germany); Stoll, Raphael [Biomolecular NMR, Ruhr University of Bochum, 44780 Bochum (Germany); Heumann, Rolf, E-mail: rolf.heumann@rub.de [Molecular Neurobiochemistry, Ruhr University of Bochum, 44780 Bochum (Germany)

    2013-05-28

    One of the most obvious hallmarks of cancer is uncontrolled proliferation of cells partly due to independence of growth factor supply. A major component of mitogenic signaling is Ras, a small GTPase. It was the first identified human protooncogene and is known since more than three decades to promote cellular proliferation and growth. Ras was shown to support growth factor-independent survival during development and to protect from chemical or mechanical lesion-induced neuronal degeneration in postmitotic neurons. In contrast, for specific patho-physiological cases and cellular systems it has been shown that Ras may also promote cell death. Proteins from the Ras association family (Rassf, especially Rassf1 and Rassf5) are tumor suppressors that are activated by Ras-GTP, triggering apoptosis via e.g., activation of mammalian sterile 20-like (MST1) kinase. In contrast to Ras, their expression is suppressed in many types of tumours, which makes Rassf proteins an exciting model for understanding the divergent effects of Ras activity. It seems likely that the outcome of Ras signaling depends on the balance between the activation of its various downstream effectors, thus determining cellular fate towards either proliferation or apoptosis. Ras homologue enriched in brain (Rheb) is a protein from the Ras superfamily that is also known to promote proliferation, growth, and regeneration through the mammalian target of rapamycin (mTor) pathway. However, recent evidences indicate that the Rheb-mTor pathway may switch its function from a pro-growth into a cell death pathway, depending on the cellular situation. In contrast to Ras signaling, for Rheb, the cellular context is likely to modulate the whole Rheb-mTor pathway towards cellular death or survival, respectively.

  13. Activated microglia cause reversible apoptosis of pheochromocytoma cells, inducing their cell death by phagocytosis.

    Science.gov (United States)

    Hornik, Tamara C; Vilalta, Anna; Brown, Guy C

    2016-01-01

    Some apoptotic processes, such as phosphatidylserine exposure, are potentially reversible and do not necessarily lead to cell death. However, phosphatidylserine exposure can induce phagocytosis of a cell, resulting in cell death by phagocytosis: phagoptosis. Phagoptosis of neurons by microglia might contribute to neuropathology, whereas phagoptosis of tumour cells by macrophages might limit cancer. Here, we examined the mechanisms by which BV-2 microglia killed co-cultured pheochromocytoma (PC12) cells that were either undifferentiated or differentiated into neuronal cells. We found that microglia activated by lipopolysaccharide rapidly phagocytosed PC12 cells. Activated microglia caused reversible phosphatidylserine exposure on and reversible caspase activation in PC12 cells, and caspase inhibition prevented phosphatidylserine exposur and decreased subsequent phagocytosis. Nitric oxide was necessary and sufficient to induce the reversible phosphatidylserine exposure and phagocytosis. The PC12 cells were not dead at the time they were phagocytised, and inhibition of their phagocytosis left viable cells. Cell loss was inhibited by blocking phagocytosis mediated by phosphatidylserine, MFG-E8, vitronectin receptors or P2Y6 receptors. Thus, activated microglia can induce reversible apoptosis of target cells, which is insufficient to cause apoptotic cell death, but sufficient to induce their phagocytosis and therefore cell death by phagoptosis.

  14. Mitochondrial Extrusion through the cytoplasmic vacuoles during cell death.

    Science.gov (United States)

    Nakajima, Akihito; Kurihara, Hidetake; Yagita, Hideo; Okumura, Ko; Nakano, Hiroyasu

    2008-08-29

    Under various conditions, noxious stimuli damage mitochondria, resulting in mitochondrial fragmentation; however, the mechanisms by which fragmented mitochondria are eliminated from the cells remain largely unknown. Here we show that cytoplasmic vacuoles originating from the plasma membrane engulfed fragmented mitochondria and subsequently extruded them into the extracellular spaces in undergoing acute tumor necrosis factor alpha-induced cell death in a caspase-dependent fashion. Notably, upon fusion of the membrane encapsulating mitochondria to the plasma membrane, naked mitochondria were released into the extracellular spaces in an exocytotic manner. Mitochondrial extrusion was specific to tumor necrosis factor alpha-induced cell death, because a genotoxic stress-inducing agent such as cisplatin did not elicit mitochondrial extrusion. Moreover, intact actin and tubulin cytoskeletons were required for mitochondrial extrusion as well as membrane blebbing. Furthermore, fragmented mitochondria were engulfed by cytoplasmic vacuoles and extruded from hepatocytes of mice injected with anti-Fas antibody, suggesting that mitochondrial extrusion can be observed in vivo under pathological conditions. Mitochondria are eliminated during erythrocyte maturation under physiological conditions, and anti-mitochondrial antibody is detected in some autoimmune diseases. Thus, elucidating the mechanism underlying mitochondrial extrusion will open a novel avenue leading to better understanding of various diseases caused by mitochondrial malfunction as well as mitochondrial biology.

  15. Using microfluidics to study programmed cell death: A new approach

    DEFF Research Database (Denmark)

    Mark, Christina; Zor, Kinga; Heiskanen, Arto

    This project focuses on applying microfluidic tissue culture for electrochemical or optical measurements during programmed cell death (PCD) in barley aleurone layer to increase understanding of the underlying mechanisms of PCD in plants. Microfluidic tissue culture enables in vitro experiments to...... a double-fluorescent probe-system also used by Fath et al5. Future challenges include integrating both these systems into a microfluidic device for plant tissue culture.......This project focuses on applying microfluidic tissue culture for electrochemical or optical measurements during programmed cell death (PCD) in barley aleurone layer to increase understanding of the underlying mechanisms of PCD in plants. Microfluidic tissue culture enables in vitro experiments...... to approach in vivo conditions. Microfluidics also allow implementation of a wide range of electrochemical or optical assays for online, real-time, parallel analysis of important parameters such as redox activity, O2 and H2O2 concentration, extracellular pH, cell viability and enzyme activity1,2. Currently...

  16. Mechanisms of ethanol-induced death of cerebellar granule cells.

    Science.gov (United States)

    Luo, Jia

    2012-03-01

    Maternal ethanol exposure during pregnancy may cause fetal alcohol spectrum disorders (FASD). FASD is the leading cause of mental retardation. The most deleterious effect of fetal alcohol exposure is inducing neuroapoptosis in the developing brain. Ethanol-induced loss of neurons in the central nervous system underlies many of the behavioral deficits observed in FASD. The cerebellum is one of the brain areas that are most susceptible to ethanol during development. Ethanol exposure causes a loss of both cerebellar Purkinje cells and granule cells. This review focuses on the toxic effect of ethanol on cerebellar granule cells (CGC) and the underlying mechanisms. Both in vitro and in vivo studies indicate that ethanol induces apoptotic death of CGC. The vulnerability of CGC to ethanol-induced death diminishes over time as neurons mature. Several mechanisms for ethanol-induced apoptosis of CGC have been suggested. These include inhibition of N-methyl-D-aspartate receptors, interference with signaling by neurotrophic factors, induction of oxidative stress, modulation of retinoid acid signaling, disturbance of potassium channel currents, thiamine deficiency, and disruption of translational regulation. Cultures of CGC provide an excellent system to investigate cellular/molecular mechanisms of ethanol-induced neurodegeneration and to evaluate interventional strategies. This review will also discuss the approaches leading to neuroprotection against ethanol-induced neuroapoptosis.

  17. Calcium and cell death signaling in neurodegeneration and aging

    Directory of Open Access Journals (Sweden)

    Soraya Smaili

    2009-09-01

    Full Text Available Transient increase in cytosolic (Cac2+ and mitochondrial Ca2+ (Ca m2+ are essential elements in the control of many physiological processes. However, sustained increases in Ca c2+ and Ca m2+ may contribute to oxidative stress and cell death. Several events are related to the increase in Ca m2+, including regulation and activation of a number of Ca2+ dependent enzymes, such as phospholipases, proteases and nucleases. Mitochondria and endoplasmic reticulum (ER play pivotal roles in the maintenance of intracellular Ca2+ homeostasis and regulation of cell death. Several lines of evidence have shown that, in the presence of some apoptotic stimuli, the activation of mitochondrial processes maylead to the release of cytochrome c followed by the activation of caspases, nuclear fragmentation and apoptotic cell death. The aim of this review was to show how changes in calcium signaling can be related to the apoptotic cell death induction. Calcium homeostasis was also shown to be an important mechanism involved in neurodegenerative and aging processes.Aumentos transientes no cálcio citosólico (Ca c2+ e mitocondrial (Ca m2+ são elementos essenciais no controle de muitos processos fisiológicos. No entanto, aumentos sustentados do Ca c2+ e do Ca m2+ podem contribuir para o estresse oxidativo ea morte celular. Muitos eventos estão relacionados ao aumentono Ca c2+, incluindo a regulação e ativação de várias enzimas dependentes de Ca2+ como as fosfolipases, proteases e nucleases. A mitocôndria e o retículo endoplasmático têm um papel central na manutenção da homeostase intracellular de Ca c2+ e na regulação da morte celular. Várias evidências mostraram que, na presença de certos estímulos apoptóticos, a ativação dos processos mitocondriais pode promover a liberação de citocromo c, seguida da ativação de caspases, fragmentação nuclear e morte celular por apoptose. O objetivo desta revisão é mostrar como aumentos na sinalização de

  18. Cell death in the injured brain: roles of metallothioneins

    DEFF Research Database (Denmark)

    Pedersen, Mie Ø; Larsen, Agnete; Stoltenberg, Meredin;

    2009-01-01

    oxygen species (ROS). ROS promote oxidative stress, which leads to neurodegeneration and ultimately results in programmed cell death (secondary injury). Since this delayed, secondary tissue loss occurs days to months following the primary injury it provides a therapeutic window where potential......, and caspase inhibitors. However, most of the scientific efforts have failed in translating the experimental results into clinical trials. Despite intensive research, effective neuroprotective therapies are lacking in the clinic, and TBI continues to be a major cause of morbidity and mortality. This paper...

  19. Autophagic flux regulates microglial phenotype according to the time of oxygen-glucose deprivation/reperfusion.

    Science.gov (United States)

    Xia, Cong-Yuan; Zhang, Shuai; Chu, Shi-Feng; Wang, Zhen-Zhen; Song, Xiu-Yun; Zuo, Wei; Gao, Yan; Yang, Peng-Fei; Chen, Nai-Hong

    2016-10-01

    Microglial phenotype alternation is a potential novel pathogenic mechanism for cerebral ischemia. Cerebral ischemia induced autophagy aggravates inflammation and neural injury. However, the effect of autophagy in the modulation of microglial phenotype is still unknown. In this study, we investigated the role of autophagic flux in the alternation of microglial phenotype following oxygen glucose deprivation/reperfusion (OGD/R) in BV-2 cells. Inhibition of autophagic flux by NH4Cl exposure significantly increased the level of microtubule-associated protein 1 light chain 3 (LC3)-II and p62 in control and OGD/R (12h, 24h and 48h) groups, but did not change their expression in OGD/R 72h group, indicating that autophagic flux was inhibited at OGD/R 72h. Once autophagic flux was inhibited at OGD/R 72h or at OGD/R 24h (with NH4Cl), BV-2 cells mainly showed M1 phenotype with increased tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and decreased M2 markers including interleukin-10 (IL-10), Arginase 1 (Arg-1), and brain derived neurotrophic factor (BDNF). Further study indicated that inhibition of autophagic flux activated NF-κB pathway and decreased the activity of cAMP-response element binding protein (CREB), which contributed to the alternation of microglial phenotype. Therefore, inhibition of autophagic flux regulated the alternation of microglial phenotype by modulating the balance between NF-κB and CREB.

  20. Peroxide-induced cell death and lipid peroxidation in C6 glioma cells.

    Science.gov (United States)

    Linden, Arne; Gülden, Michael; Martin, Hans-Jörg; Maser, Edmund; Seibert, Hasso

    2008-08-01

    Peroxides are often used as models to induce oxidative damage in cells in vitro. The aim of the present study was to elucidate the role of lipid peroxidation in peroxide-induced cell death. To this end (i) the ability to induce lipid peroxidation in C6 rat astroglioma cells of hydrogen peroxide (H2O2), cumene hydroperoxide (CHP) and t-butyl hydroperoxide (t-BuOOH) (ii) the relation between peroxide-induced lipid peroxidation and cell death in terms of time and concentration dependency and (iii) the capability of the lipid peroxidation chain breaking alpha-tocopherol to prevent peroxide-induced lipid peroxidation and/or cell death were investigated. Lipid peroxidation was characterised by measuring thiobarbituric acid reactive substances (TBARS) and, by HPLC, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE) and hexanal. Within 2 h CHP, t-BuOOH and H2O2 induced cell death with EC50 values of 59+/-9 microM, 290+/-30 microM and 12+/-1.1 mM, respectively. CHP and t-BuOOH, but not H2O2 induced lipid peroxidation in C6 cells with EC50 values of 15+/-14 microM and 130+/-33 microM, respectively. The TBARS measured almost exclusively consisted of MDA. 4-HNE was mostly not detectable. The concentration of hexanal slightly increased with increasing concentrations of organic peroxides. Regarding time and concentration dependency lipid peroxidation preceded cell death. Pretreatment with alpha-tocopherol (10 microM, 24 h) prevented both, peroxide-induced lipid peroxidation and cell death. The results strongly indicate a major role of lipid peroxidation in the killing of C6 cells by organic peroxides but also that lipid peroxidation is not involved in H2O2 induced cell death.

  1. High dose of ascorbic acid induces cell death in mesothelioma cells.

    Science.gov (United States)

    Takemura, Yukitoshi; Satoh, Motohiko; Satoh, Kiyotoshi; Hamada, Hironobu; Sekido, Yoshitaka; Kubota, Shunichiro

    2010-04-02

    Malignant mesothelioma is an asbestos-related fatal disease with no effective cure. Recently, high dose of ascorbate in cancer treatment has been reexamined. We studied whether high dose of ascorbic acid induced cell death of four human mesothelioma cell lines. High dose of ascorbic acid induced cell death of all mesothelioma cell lines in a dose-dependent manner. We further clarified the cell killing mechanism that ascorbic acid induced reactive oxygen species and impaired mitochondrial membrane potential. In vivo experiment, intravenous administration of ascorbic acid significantly decreased the growth rate of mesothelioma tumor inoculated in mice. These data suggest that ascorbic acid may have benefits for patients with mesothelioma.

  2. Involvement of p53 in cell death following cell cycle arrest and mitotic catastrophe induced by rotenone

    OpenAIRE

    Gonçalves, António Pedro; Máximo, Valdemar; Lima, Jorge; Keshav K Singh; Soares, Paula; Videira, Arnaldo

    2011-01-01

    In order to investigate the cell death-inducing effects of rotenone, a plant extract commonly used as a mitochondrial complex I inhibitor, we studied cancer cell lines with different genetic backgrounds. Rotenone inhibits cell growth through the induction of cell death and cell cycle arrest, associated with the development of mitotic catastrophe. The cell death inducer staurosporine potentiates the inhibition of cell growth by rotenone in a dose-dependent synergistic manner. The tumor suppres...

  3. The role of mislocalized phototransduction in photoreceptor cell death of retinitis pigmentosa.

    Directory of Open Access Journals (Sweden)

    Takeshi Nakao

    Full Text Available Most of inherited retinal diseases such as retinitis pigmentosa (RP cause photoreceptor cell death resulting in blindness. RP is a large family of diseases in which the photoreceptor cell death can be caused by a number of pathways. Among them, light exposure has been reported to induce photoreceptor cell death. However, the detailed mechanism by which photoreceptor cell death is caused by light exposure is unclear. In this study, we have shown that even a mild light exposure can induce ectopic phototransduction and result in the acceleration of rod photoreceptor cell death in some vertebrate models. In ovl, a zebrafish model of outer segment deficiency, photoreceptor cell death is associated with light exposure. The ovl larvae show ectopic accumulation of rhodopsin and knockdown of ectopic rhodopsin and transducin rescue rod photoreceptor cell death. However, knockdown of phosphodiesterase, the enzyme that mediates the next step of phototransduction, does not. So, ectopic phototransduction activated by light exposure, which leads to rod photoreceptor cell death, is through the action of transducin. Furthermore, we have demonstrated that forced activation of adenylyl cyclase in the inner segment leads to rod photoreceptor cell death. For further confirmation, we have also generated a transgenic fish which possesses a human rhodopsin mutation, Q344X. This fish and rd10 model mice show photoreceptor cell death caused by adenylyl cyclase. In short, our study indicates that in some RP, adenylyl cyclase is involved in photoreceptor cell death pathway; its inhibition is potentially a logical approach for a novel RP therapy.

  4. Normal autophagic activity in macrophages from mice lacking Gαi3, AGS3, or RGS19.

    Directory of Open Access Journals (Sweden)

    Ali Vural

    Full Text Available In macrophages autophagy assists antigen presentation, affects cytokine release, and promotes intracellular pathogen elimination. In some cells autophagy is modulated by a signaling pathway that employs Gαi3, Activator of G-protein Signaling-3 (AGS3/GPSM1, and Regulator of G-protein Signaling 19 (RGS19. As macrophages express each of these proteins, we tested their importance in regulating macrophage autophagy. We assessed LC3 processing and the formation of LC3 puncta in bone marrow derived macrophages prepared from wild type, Gnai3(-/-, Gpsm1(-/-, or Rgs19(-/- mice following amino acid starvation or Nigericin treatment. In addition, we evaluated rapamycin-induced autophagic proteolysis rates by long-lived protein degradation assays and anti-autophagic action after rapamycin induction in wild type, Gnai3(-/-, and Gpsm1(-/- macrophages. In similar assays we compared macrophages treated or not with pertussis toxin, an inhibitor of GPCR (G-protein couple receptor triggered Gαi nucleotide exchange. Despite previous findings, the level of basal autophagy, autophagic induction, autophagic flux, autophagic degradation and the anti-autophagic action in macrophages that lacked Gαi3, AGS3, or RGS19; or had been treated with pertussis toxin, were similar to controls. These results indicate that while Gαi signaling may impact autophagy in some cell types it does not in macrophages.

  5. Attenuation of oxidative neuronal cell death by coffee phenolic phytochemicals

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Eun Sun; Jang, Young Jin [Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921 (Korea, Republic of); Hwang, Mun Kyung; Kang, Nam Joo [Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921 (Korea, Republic of); Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea, Republic of); Lee, Ki Won [Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea, Republic of)], E-mail: kiwon@konkuk.ac.kr; Lee, Hyong Joo [Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921 (Korea, Republic of)], E-mail: leehyjo@snu.ac.kr

    2009-02-10

    Neurodegenerative disorders such as Alzheimer's disease (AD) are strongly associated with oxidative stress, which is induced by reactive oxygen species (ROS) including hydrogen peroxide (H{sub 2}O{sub 2}). Recent studies suggest that moderate coffee consumption may reduce the risk of neurodegenerative diseases such as AD, but the molecular mechanisms underlying this effect remain to be clarified. In this study, we investigated the protective effects of chlorogenic acid (5-O-caffeoylquinic acid; CGA), a major phenolic phytochemical found in instant decaffeinated coffee (IDC), and IDC against oxidative PC12 neuronal cell death. IDC (1 and 5 {mu}g/ml) or CGA (1 and 5 {mu}M) attenuated H{sub 2}O{sub 2}-induced PC12 cell death. H{sub 2}O{sub 2}-induced nuclear condensation and DNA fragmentation were strongly inhibited by pretreatment with IDC or CGA. Pretreatment with IDC or CGA also inhibited the H{sub 2}O{sub 2}-induced cleavage of poly(ADP-ribose) polymerase (PARP), and downregulation of Bcl-X{sub L} and caspase-3. The accumulation of intracellular ROS in H{sub 2}O{sub 2}-treated PC12 cells was dose-dependently diminished by IDC or CGA. The activation of c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) by H{sub 2}O{sub 2} in PC12 cells was also inhibited by IDC or CGA. Collectively, these results indicate that IDC and CGA protect PC12 cells from H{sub 2}O{sub 2}-induced apoptosis by blocking the accumulation of intracellular ROS and the activation of MAPKs.

  6. ROS-induced autophagy in cancer cells assists in evasion from determinants of immunogenic cell death

    NARCIS (Netherlands)

    Garg, A.D.; Dudek, A.M.D.; Ferreira, G.B.; Verfaillie, T.; Vandenabeele, P.; Krysko, D.V.; Mathieu, C.; Agostinis, P.

    2013-01-01

    Calreticulin surface exposure (ecto-CALR), ATP secretion, maturation of dendritic cells (DCs) and stimulation of T cells are prerequisites for anticancer therapy-induced immunogenic cell death (ICD). Recent evidence suggests that chemotherapy-induced autophagy may positively regulate ICD by favoring

  7. Cell death mechanisms vary with photodynamic therapy dose and photosensitizer

    Science.gov (United States)

    He, Jin; Oleinick, Nancy L.

    1995-03-01

    Mouse lymphoma L5178Y-R cells respond to photodynamic therapy (PDT) by undergoing rapid apoptosis, which is induced by PDT-activated signal transduction initiating in the damaged cellular membranes. To relate the level of PDT damage and photosensitizer to the mechanism of cell death, apoptosis has been detected by agarose gel electrophoresis of fragmented DNA and quantified by flow cytometry of cells after staining with Hoechst33342 and propidium iodide, a technique which can distinguish between live, apoptotic, and necrotic cells. When the silicon phthalocyanine Pc 4 or Pc 12 served as photosensitizer, lethal doses (as defined by clonogenic assay) of PDT induced apoptosis in essentially all cells, whereas supralethal doses prevented the characteristic degradation of DNA into oligonucleosomal fragments. In contrast with aluminum phthalocyanine (AlPc) cells died by apoptosis after all doses studied. It appears that high PDT doses with Pc 4 or Pc 12 damage enzymes needed to carry out the program of apoptosis; the absence of this effect with AlPc suggests either a different intracellular location or different photocytotoxic mechanism for the two photosensitizers.

  8. Regulation of cell survival and death during Flavivirus infections

    Institute of Scientific and Technical Information of China (English)

    Sounak; Ghosh; Roy; Beata; Sadigh; Emmanuel; Datan; Richard; A; Lockshin; Zahra; Zakeri

    2014-01-01

    Flaviviruses, ss(+) RNA viruses, include many of mankind’s most important pathogens. Their pathogenicity derives from their ability to infect many types of cells including neurons, to replicate, and eventually to kill the cells. Flaviviruses can activate tumor necrosis factor α and both intrinsic(Bax-mediated) and extrinsic pathways to apoptosis. Thus they can use many approaches for activating these pathways. Infection can lead to necrosis if viral load is extremely high or to other types of cell death if routes to apoptosis are blocked. Dengue and Japanese Encephalitis Virus can also activate autophagy. In this case the autophagy temporarily spares the infected cell, allowing a longer period of reproduction for the virus, and the autophagy further protects the cell against other stresses such as those caused by reactive oxygen species. Several of the viral proteins have been shown to induce apoptosis or autophagy on their own, independent of the presence of other viral proteins. Given the versatility of these viruses to adapt to and manipulate the metabolism, and thus to control the survival of, the infected cells, we need to understand much better how the specific viral proteins affect the pathways to apoptosis and autophagy. Only in this manner will we be able to minimize the pathology that they cause.

  9. Primary observations of the existence of Fas-like cytoplasmic death factor in plant cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The main activity of Fas is to trigger cytoplasm death program in animal cells. In G2 pea, vacuole plays a pivotal role in inducing cell death in the cytoplasm of longday (LD) grown apical meristem cells. Expression patterns of the Fas in G2 pea cells revealed that the Fas is mainly localized in the vacuole of cells undergoing programmed cell death (PCD). The Fas expression is corresponding to the initiation of menadione-induced PCD in tobacco protoplasts.The results suggest the existence of the Fas-like mediated cytoplasmic death pathway in plant cells.``

  10. The Molecular Ecophysiology of Programmed Cell Death in Marine Phytoplankton

    Science.gov (United States)

    Bidle, Kay D.

    2015-01-01

    Planktonic, prokaryotic, and eukaryotic photoautotrophs (phytoplankton) share a diverse and ancient evolutionary history, during which time they have played key roles in regulating marine food webs, biogeochemical cycles, and Earth's climate. Because phytoplankton represent the basis of marine ecosystems, the manner in which they die critically determines the flow and fate of photosynthetically fixed organic matter (and associated elements), ultimately constraining upper-ocean biogeochemistry. Programmed cell death (PCD) and associated pathway genes, which are triggered by a variety of nutrient stressors and are employed by parasitic viruses, play an integral role in determining the cell fate of diverse photoautotrophs in the modern ocean. Indeed, these multifaceted death pathways continue to shape the success and evolutionary trajectory of diverse phytoplankton lineages at sea. Research over the past two decades has employed physiological, biochemical, and genetic techniques to provide a novel, comprehensive, mechanistic understanding of the factors controlling this key process. Here, I discuss the current understanding of the genetics, activation, and regulation of PCD pathways in marine model systems; how PCD evolved in unicellular photoautotrophs; how it mechanistically interfaces with viral infection pathways; how stress signals are sensed and transduced into cellular responses; and how novel molecular and biochemical tools are revealing the impact of PCD genes on the fate of natural phytoplankton assemblages.

  11. Photodynamic Efficiency: From Molecular Photochemistry to Cell Death

    Directory of Open Access Journals (Sweden)

    Isabel O. L. Bacellar

    2015-08-01

    Full Text Available Photodynamic therapy (PDT is a clinical modality used to treat cancer and infectious diseases. The main agent is the photosensitizer (PS, which is excited by light and converted to a triplet excited state. This latter species leads to the formation of singlet oxygen and radicals that oxidize biomolecules. The main motivation for this review is to suggest alternatives for achieving high-efficiency PDT protocols, by taking advantage of knowledge on the chemical and biological processes taking place during and after photosensitization. We defend that in order to obtain specific mechanisms of cell death and maximize PDT efficiency, PSes should oxidize specific molecular targets. We consider the role of subcellular localization, how PS photochemistry and photophysics can change according to its nanoenvironment, and how can all these trigger specific cell death mechanisms. We propose that in order to develop PSes that will cause a breakthrough enhancement in the efficiency of PDT, researchers should first consider tissue and intracellular localization, instead of trying to maximize singlet oxygen quantum yields in in vitro tests. In addition to this, we also indicate many open questions and challenges remaining in this field, hoping to encourage future research.

  12. Cell death versus cell survival instructed by supramolecular cohesion of nanostructures

    Science.gov (United States)

    Newcomb, Christina J.; Sur, Shantanu; Ortony, Julia H.; Lee, One-Sun; Matson, John B.; Boekhoven, Job; Yu, Jeong Min; Schatz, George C.; Stupp, Samuel I.

    2014-02-01

    Many naturally occurring peptides containing cationic and hydrophobic domains have evolved to interact with mammalian cell membranes and have been incorporated into materials for non-viral gene delivery, cancer therapy or treatment of microbial infections. Their electrostatic attraction to the negatively charged cell surface and hydrophobic interactions with the membrane lipids enable intracellular delivery or cell lysis. Although the effects of hydrophobicity and cationic charge of soluble molecules on the cell membrane are well known, the interactions between materials with these molecular features and cells remain poorly understood. Here we report that varying the cohesive forces within nanofibres of supramolecular materials with nearly identical cationic and hydrophobic structure instruct cell death or cell survival. Weak intermolecular bonds promote cell death through disruption of lipid membranes, while materials reinforced by hydrogen bonds support cell viability. These findings provide new strategies to design biomaterials that interact with the cell membrane.

  13. A Versatile Cell Death Screening Assay Using Dye-Stained Cells and Multivariate Image Analysis.

    Science.gov (United States)

    Collins, Tony J; Ylanko, Jarkko; Geng, Fei; Andrews, David W

    2015-11-01

    A novel dye-based method for measuring cell death in image-based screens is presented. Unlike conventional high- and medium-throughput cell death assays that measure only one form of cell death accurately, using multivariate analysis of micrographs of cells stained with the inexpensive mix, red dye nonyl acridine orange, and a nuclear stain, it was possible to quantify cell death induced by a variety of different agonists even without a positive control. Surprisingly, using a single known cytotoxic agent as a positive control for training a multivariate classifier allowed accurate quantification of cytotoxicity for mechanistically unrelated compounds enabling generation of dose-response curves. Comparison with low throughput biochemical methods suggested that cell death was accurately distinguished from cell stress induced by low concentrations of the bioactive compounds Tunicamycin and Brefeldin A. High-throughput image-based format analyses of more than 300 kinase inhibitors correctly identified 11 as cytotoxic with only 1 false positive. The simplicity and robustness of this dye-based assay makes it particularly suited to live cell screening for toxic compounds.

  14. PDK2-mediated alternative splicing switches Bnip3 from cell death to cell survival.

    Science.gov (United States)

    Gang, Hongying; Dhingra, Rimpy; Lin, Junjun; Hai, Yan; Aviv, Yaron; Margulets, Victoria; Hamedani, Mohammad; Thanasupawat, Thatchawan; Leygue, Etienne; Klonisch, Thomas; Davie, James R; Kirshenbaum, Lorrie A

    2015-09-28

    Herein we describe a novel survival pathway that operationally links alternative pre-mRNA splicing of the hypoxia-inducible death protein Bcl-2 19-kD interacting protein 3 (Bnip3) to the unique glycolytic phenotype in cancer cells. While a full-length Bnip3 protein (Bnip3FL) encoded by exons 1-6 was expressed as an isoform in normal cells and promoted cell death, a truncated spliced variant of Bnip3 mRNA deleted for exon 3 (Bnip3Δex3) was preferentially expressed in several human adenocarcinomas and promoted survival. Reciprocal inhibition of the Bnip3Δex3/Bnip3FL isoform ratio by inhibiting pyruvate dehydrogenase kinase isoform 2 (PDK2) in Panc-1 cells rapidly induced mitochondrial perturbations and cell death. The findings of the present study reveal a novel survival pathway that functionally couples the unique glycolytic phenotype in cancer cells to hypoxia resistance via a PDK2-dependent mechanism that switches Bnip3 from cell death to survival. Discovery of the survival Bnip3Δex3 isoform may fundamentally explain how certain cells resist Bnip3 and avert death during hypoxia.

  15. Smac mimetic and oleanolic acid synergize to induce cell death in human hepatocellular carcinoma cells.

    Science.gov (United States)

    Liese, Juliane; Abhari, Behnaz Ahangarian; Fulda, Simone

    2015-08-28

    Chemotherapy resistance of hepatocellular carcinoma (HCC) is still a major unsolved problem highlighting the need to develop novel therapeutic strategies. Here, we identify a novel synergistic induction of cell death by the combination of the Smac mimetic BV6, which antagonizes Inhibitor of apoptosis (IAP) proteins, and the triterpenoid oleanolic acid (OA) in human HCC cells. Importantly, BV6 and OA also cooperate to suppress long-term clonogenic survival as well as tumor growth in a preclinical in vivo model of HCC underscoring the clinical relevance of our findings. In contrast, BV6/OA cotreatment does not exert cytotoxic effects against normal primary hepatocytes, pointing to some tumor selectivity. Mechanistic studies show that BV6/OA cotreatment leads to DNA fragmentation and caspase-3 cleavage, while supply of the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD.fmk) revealed a cell type-dependent requirement of caspases for BV6/OA-induced cell death. The receptor interacting protein (RIP)1 kinase Inhibitor Necrostatin-1 (Nec-1) or genetic knockdown of RIP1 fails to rescue BV6/OA-mediated cell death, indicating that BV6/OA cotreatment does not primarily engage necroptotic cell death. Notably, the addition of several reactive oxygen species (ROS) scavengers significantly decreases BV6/OA-triggered cell death, indicating that ROS production contributes to BV6/OA-induced cell death. In conclusion, cotreatment of Smac mimetic and OA represents a novel approach for the induction of cell death in HCC and implicates further studies.

  16. Programmed cell death of Ulmus pumila L. seeds during aging

    Institute of Scientific and Technical Information of China (English)

    Yulan ZHANG; Ming ZHANG; Fang LI; Xiaofeng WANG

    2008-01-01

    The programmed cell death (PCD) character-istics of Ulmus pumila L. seeds were investigated. The seeds were treated at a high temperature of 37℃ and 100% relative humidity for six days. DAPI (4'6-diami-dino-2-phenylindole) staining revealed that the aging treatment induced condensation and margination of chro-matin, as well as the formation of apoptotic bodies. DNA electrophoresis results of U. pumila seeds on an agarose gel showed a characteristic "ladder" pattern. Levels of electrolyte leakage of seed cells showed that membranes retained their integral form during almost the entire aging time. There was an immediate increase in the production rate of superoxide anion (O2-) and in the amount of hydrogen peroxide (H2O2), which remained at a μmol level. All of these common characteristics indicate that seed aging can be classified as PCD.

  17. POSH misexpression induces caspase-dependent cell death in Drosophila.

    Science.gov (United States)

    Lennox, Ashley L; Stronach, Beth

    2010-02-01

    POSH (Plenty of SH3 domains) is a scaffold for signaling proteins regulating cell survival. Specifically, POSH promotes assembly of a complex including Rac GTPase, mixed lineage kinase (MLK), MKK7, and Jun kinase (JNK). In Drosophila, genetic analysis implicated POSH in Tak1-dependent innate immune response, in part through regulation of JNK signaling. Homologs of the POSH signaling complex components, MLK and MKK7, are essential in Drosophila embryonic dorsal closure. Using a gain-of-function approach, we tested whether POSH plays a role in this process. Ectopic expression of POSH in the embryo causes dorsal closure defects due to apoptosis of the amnioserosa, but ectodermal JNK signaling is normal. Phenotypic consequences of POSH expression were found to be dependent on Drosophila Nc, the caspase-9 homolog, but only partially on Tak1 and not at all on Slpr and Hep. These results suggest that POSH may use different signaling complexes to promote cell death in distinct contexts.

  18. IAP family of cell death and signaling regulators.

    Science.gov (United States)

    Silke, John; Vucic, Domagoj

    2014-01-01

    Inhibitor of apoptosis (IAP) proteins interface with, and regulate a large number of, cell signaling pathways. If there is a common theme to these pathways, it is that they are involved in the development of the immune system, immune responses, and unsurprisingly, given their name, cell death. Beyond that it is difficult to discover an underlying logic because sometimes IAPs are required to inhibit or prevent signaling, whereas in other cases they are required for signaling to take place. In whatever role they play, they are recruited into signaling complexes and function as ubiquitin E3 ligases, via their RING domains. This review discusses IAP regulation of signaling pathways and focuses on the mammalian IAPs, XIAP, c-IAP1, and c-IAP2, with a particular emphasis on techniques and methods that were used to uncover their roles. We also provide a perspective on targeting IAP proteins for therapeutic intervention and methods used to define the clinical relevance of IAP proteins.

  19. Uropathogenic Escherichia coli Epigenetically Manipulate Host Cell Death Pathways.

    Science.gov (United States)

    Zhang, Zhengguo; Wang, Ming; Eisel, Florian; Tchatalbachev, Svetlin; Chakraborty, Trinad; Meinhardt, Andreas; Bhushan, Sudhanshu

    2016-04-01

    Urinary tract infections caused by uropathogenic Escherichia coli (UPEC) pathovars belong to the most frequent infections in human. It is well established that UPEC can subvert innate immune responses, but the role of UPEC in interfering with host cell death pathways is not known. Here, we show that UPEC abrogates activation of the host cell prosurvival protein kinase B signaling pathway, which results in the activation of mammalian forkhead box O (FOXO) transcription factors. Although FOXOs were localized in the nucleus and showed increased DNA-binding activity, no change in the expression levels of FOXO target genes were observed. UPEC can suppress BIM expression induced by LY249002, which results in attenuation of caspase 3 activation and blockage of apoptosis. Mechanistically, BIM expression appears to be epigenetically silenced by a decrease in histone 4 acetylation at the BIM promoter site. Taken together, these results suggest that UPEC can epigenetically silence BIM expression, a molecular switch that prevents apoptosis.

  20. GSK-3: A Bifunctional Role in Cell Death Pathways

    Directory of Open Access Journals (Sweden)

    Keith M. Jacobs

    2012-01-01

    Full Text Available Although glycogen synthase kinase-3 beta (GSK-3β was originally named for its ability to phosphorylate glycogen synthase and regulate glucose metabolism, this multifunctional kinase is presently known to be a key regulator of a wide range of cellular functions. GSK-3β is involved in modulating a variety of functions including cell signaling, growth metabolism, and various transcription factors that determine the survival or death of the organism. Secondary to the role of GSK-3β in various diseases including Alzheimer’s disease, inflammation, diabetes, and cancer, small molecule inhibitors of GSK-3β are gaining significant attention. This paper is primarily focused on addressing the bifunctional or conflicting roles of GSK-3β in both the promotion of cell survival and of apoptosis. GSK-3β has emerged as an important molecular target for drug development.

  1. GSK-3β: A Bifunctional Role in Cell Death Pathways

    Science.gov (United States)

    Jacobs, Keith M.; Bhave, Sandeep R.; Ferraro, Daniel J.; Jaboin, Jerry J.; Hallahan, Dennis E.; Thotala, Dinesh

    2012-01-01

    Although glycogen synthase kinase-3 beta (GSK-3β) was originally named for its ability to phosphorylate glycogen synthase and regulate glucose metabolism, this multifunctional kinase is presently known to be a key regulator of a wide range of cellular functions. GSK-3β is involved in modulating a variety of functions including cell signaling, growth metabolism, and various transcription factors that determine the survival or death of the organism. Secondary to the role of GSK-3β in various diseases including Alzheimer's disease, inflammation, diabetes, and cancer, small molecule inhibitors of GSK-3β are gaining significant attention. This paper is primarily focused on addressing the bifunctional or conflicting roles of GSK-3β in both the promotion of cell survival and of apoptosis. GSK-3β has emerged as an important molecular target for drug development. PMID:22675363

  2. Tumor-derived death receptor 6 modulates dendritic cell development.

    Science.gov (United States)

    DeRosa, David C; Ryan, Paul J; Okragly, Angela; Witcher, Derrick R; Benschop, Robert J

    2008-06-01

    Studies in murine models of cancer as well as in cancer patients have demonstrated that the immune response to cancer is often compromised. This paradigm is viewed as one of the major mechanisms of tumor escape. Many therapies focus on employing the professional antigen presenting dendritic cells (DC) as a strategy to overcome immune inhibition in cancer patients. Death receptor 6 (DR6) is an orphan member of the tumor necrosis factor receptor superfamily (TNFRSF21). It is overexpressed on many tumor cells and DR6(-/-) mice display altered immunity. We investigated whether DR6 plays a role in tumorigenesis by negatively affecting the generation of anti-tumor activity. We show that DR6 is uniquely cleaved from the cell surface of tumor cell lines by the membrane-associated matrix metalloproteinase (MMP)-14, which is often overexpressed on tumor cells and is associated with malignancy. We also demonstrate that >50% of monocytes differentiating into DC die when the extracellular domain of DR6 is present. In addition, DR6 affects the cell surface phenotype of the resulting immature DC and changes their cytokine production upon stimulation with LPS/IFN-gamma. The effects of DR6 are mostly amended when these immature DC are matured with IL-1beta/TNF-alpha, as measured by cell surface phenotype and their ability to present antigen. These results implicate MMP-14 and DR6 as a mechanism tumor cells can employ to actively escape detection by the immune system by affecting the generation of antigen presenting cells.

  3. How Heme Oxygenase-1 Prevents Heme-Induced Cell Death.

    Directory of Open Access Journals (Sweden)

    Lilibeth Lanceta

    Full Text Available Earlier observations indicate that free heme is selectively toxic to cells lacking heme oxygenase-1 (HO-1 but how this enzyme prevents heme toxicity remains unexplained. Here, using A549 (human lung cancer and immortalized human bronchial epithelial cells incubated with exogenous heme, we find knock-down of HO-1 using siRNA does promote the accumulation of cell-associated heme and heme-induced cell death. However, it appears that the toxic effects of heme are exerted by "loose" (probably intralysosomal iron because cytotoxic effects of heme are lessened by pre-incubation of HO-1 deficient cells with desferrioxamine (which localizes preferentially in the lysosomal compartment. Desferrioxamine also decreases lysosomal rupture promoted by intracellularly generated hydrogen peroxide. Supporting the importance of endogenous oxidant production, both chemical and siRNA inhibition of catalase activity predisposes HO-1 deficient cells to heme-mediated killing. Importantly, it appears that HO-1 deficiency somehow blocks the induction of ferritin; control cells exposed to heme show ~10-fold increases in ferritin heavy chain expression whereas in heme-exposed HO-1 deficient cells ferritin expression is unchanged. Finally, overexpression of ferritin H chain in HO-1 deficient cells completely prevents heme-induced cytotoxicity. Although two other products of HO-1 activity--CO and bilirubin--have been invoked to explain HO-1-mediated cytoprotection, we conclude that, at least in this experimental system, HO-1 activity triggers the induction of ferritin and the latter is actually responsible for the cytoprotective effects of HO-1 activity.

  4. Statins induce differentiation and cell death in neurons and astroglia.

    Science.gov (United States)

    März, Pia; Otten, Uwe; Miserez, André R

    2007-01-01

    Statins are potent inhibitors of the hydroxy-methyl-glutaryl-coenzyme A reductase, the rate limiting enzyme for cholesterol biosynthesis. Experimental and clinical studies with statins suggest that they have beneficial effects on neurodegenerative disorders. Thus, it was of interest to characterize the direct effects of statins on CNS neurons and glial cells. We have treated defined cultures of neurons and astrocytes of newborn rats with two lipophilic statins, atorvastatin and simvastatin, and analyzed their effects on morphology and survival. Treatment of astrocytes with statins induced a time- and dose-dependent stellation, followed by apoptosis. Similarly, statins elicited programmed cell death of cerebellar granule neurons but with a higher sensitivity. Analysis of different signaling cascades revealed that statins fail to influence classical pathways such as Akt or MAP kinases, known to be activated in CNS cells. In addition, astrocyte stellation triggered by statins resembled dibutryl-cyclic AMP (db-cAMP) induced morphological differentiation. However, in contrast to db-cAMP, statins induced upregulation of low-density lipoprotein receptors, without affecting GFAP expression, indicating separate underlying mechanisms. Analysis of the cholesterol biosynthetic pathway revealed that lack of mevalonate and of its downstream metabolites, mainly geranylgeranyl-pyrophosphate (GGPP), is responsible for the statin-induced apoptosis of neurons and astrocytes. Moreover, astrocytic stellation triggered by statins was inhibited by mevalonate and GGPP. Interestingly, neuronal cell death was significantly reduced in astrocyte/neuron co-cultures treated with statins. We postulate that under these conditions signals provided by astrocytes, e.g., isoprenoids play a key role in neuronal survival.

  5. DNA damage-induced cell death: lessons from the central nervous system

    Institute of Scientific and Technical Information of China (English)

    Helena Lobo Borges; Rafael Linden; Jean YJ Wang

    2008-01-01

    DNA damage can, but does not always, induce cell death. While several pathways linking DNA damage signals to mitochondria-dependent and -independent death machineries have been elucidated, the connectivity of these pathways is subject to regulation by multiple other factors that are not well understood. We have proposed two conceptual models to explain the delayed and variable cell death response to DNA damage: integrative surveillance versus autonomous pathways. In this review, we discuss how these two models may explain the in vivo regulation of cell death induced by ionizing radiation (IR) in the developing central nervous system, where the death response is regulated by radiation dose, cell cycle status and neuronal development.

  6. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death

    OpenAIRE

    Deepak Jain; Gesine Weber; Daniel Eberhard; Mehana, Amir E; Jan Eglinger; Alena Welters; Barbara Bartosinska; Kay Jeruschke; Jürgen Weiss; Günter Päth; Hiroyoshi Ariga; Jochen Seufert; Eckhard Lammert

    2015-01-01

    A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson's disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO) were treated with multiple low doses of streptozotocin (MLDS) to induce inflam...

  7. Role of reactive oxygen species-mediated mitochondrial dysregulation in 3-bromopyruvate induced cell death in hepatoma cells : ROS-mediated cell death by 3-BrPA.

    Science.gov (United States)

    Kim, Ji Su; Ahn, Keun Jae; Kim, Jeong-Ah; Kim, Hye Mi; Lee, Jong Doo; Lee, Jae Myun; Kim, Se Jong; Park, Jeon Han

    2008-12-01

    Hexokinase type II (HK II) is the key enzyme for maintaining increased glycolysis in cancer cells where it is overexpressed. 3-bromopyruvate (3-BrPA), an inhibitor of HK II, induces cell death in cancer cells. To elucidate the molecular mechanism of 3-BrPA-induced cell death, we used the hepatoma cell lines SNU449 (low expression of HKII) and Hep3B (high expression of HKII). 3-BrPA induced ATP depletion-dependent necrosis and apoptosis in both cell lines. 3-BrPA increased intracellular reactive oxygen species (ROS) leading to mitochondrial dysregulation. NAC (N-acetyl-L: -cysteine), an antioxidant, blocked 3-BrPA-induced ROS production, loss of mitochondrial membrane potential and cell death. 3-BrPA-mediated oxidative stress not only activated poly-ADP-ribose (PAR) but also translocated AIF from the mitochondria to the nucleus. Taken together, 3-BrPA induced ATP depletion-dependent necrosis and apoptosis and mitochondrial dysregulation due to ROS production are involved in 3-BrPA-induced cell death in hepatoma cells.

  8. In Vivo Evidence for Lysosome Depletion and Impaired Autophagic Clearance in Hereditary Spastic Paraplegia Type SPG11.

    Directory of Open Access Journals (Sweden)

    Rita-Eva Varga

    2015-08-01

    Full Text Available Hereditary spastic paraplegia (HSP is characterized by a dying back degeneration of corticospinal axons which leads to progressive weakness and spasticity of the legs. SPG11 is the most common autosomal-recessive form of HSPs and is caused by mutations in SPG11. A recent in vitro study suggested that Spatacsin, the respective gene product, is needed for the recycling of lysosomes from autolysosomes, a process known as autophagic lysosome reformation. The relevance of this observation for hereditary spastic paraplegia, however, has remained unclear. Here, we report that disruption of Spatacsin in mice indeed causes hereditary spastic paraplegia-like phenotypes with loss of cortical neurons and Purkinje cells. Degenerating neurons accumulate autofluorescent material, which stains for the lysosomal protein Lamp1 and for p62, a marker of substrate destined to be degraded by autophagy, and hence appears to be related to autolysosomes. Supporting a more generalized defect of autophagy, levels of lipidated LC3 are increased in Spatacsin knockout mouse embryonic fibrobasts (MEFs. Though distinct parameters of lysosomal function like processing of cathepsin D and lysosomal pH are preserved, lysosome numbers are reduced in knockout MEFs and the recovery of lysosomes during sustained starvation impaired consistent with a defect of autophagic lysosome reformation. Because lysosomes are reduced in cortical neurons and Purkinje cells in vivo, we propose that the decreased number of lysosomes available for fusion with autophagosomes impairs autolysosomal clearance, results in the accumulation of undegraded material and finally causes death of particularly sensitive neurons like cortical motoneurons and Purkinje cells in knockout mice.

  9. In Vivo Evidence for Lysosome Depletion and Impaired Autophagic Clearance in Hereditary Spastic Paraplegia Type SPG11.

    Science.gov (United States)

    Varga, Rita-Eva; Khundadze, Mukhran; Damme, Markus; Nietzsche, Sandor; Hoffmann, Birgit; Stauber, Tobias; Koch, Nicole; Hennings, J Christopher; Franzka, Patricia; Huebner, Antje K; Kessels, Michael M; Biskup, Christoph; Jentsch, Thomas J; Qualmann, Britta; Braulke, Thomas; Kurth, Ingo; Beetz, Christian; Hübner, Christian A

    2015-08-01

    Hereditary spastic paraplegia (HSP) is characterized by a dying back degeneration of corticospinal axons which leads to progressive weakness and spasticity of the legs. SPG11 is the most common autosomal-recessive form of HSPs and is caused by mutations in SPG11. A recent in vitro study suggested that Spatacsin, the respective gene product, is needed for the recycling of lysosomes from autolysosomes, a process known as autophagic lysosome reformation. The relevance of this observation for hereditary spastic paraplegia, however, has remained unclear. Here, we report that disruption of Spatacsin in mice indeed causes hereditary spastic paraplegia-like phenotypes with loss of cortical neurons and Purkinje cells. Degenerating neurons accumulate autofluorescent material, which stains for the lysosomal protein Lamp1 and for p62, a marker of substrate destined to be degraded by autophagy, and hence appears to be related to autolysosomes. Supporting a more generalized defect of autophagy, levels of lipidated LC3 are increased in Spatacsin knockout mouse embryonic fibrobasts (MEFs). Though distinct parameters of lysosomal function like processing of cathepsin D and lysosomal pH are preserved, lysosome numbers are reduced in knockout MEFs and the recovery of lysosomes during sustained starvation impaired consistent with a defect of autophagic lysosome reformation. Because lysosomes are reduced in cortical neurons and Purkinje cells in vivo, we propose that the decreased number of lysosomes available for fusion with autophagosomes impairs autolysosomal clearance, results in the accumulation of undegraded material and finally causes death of particularly sensitive neurons like cortical motoneurons and Purkinje cells in knockout mice.

  10. In Vivo Evidence for Lysosome Depletion and Impaired Autophagic Clearance in Hereditary Spastic Paraplegia Type SPG11

    Science.gov (United States)

    Varga, Rita-Eva; Khundadze, Mukhran; Damme, Markus; Nietzsche, Sandor; Hoffmann, Birgit; Stauber, Tobias; Koch, Nicole; Hennings, J. Christopher; Franzka, Patricia; Huebner, Antje K.; Kessels, Michael M.; Biskup, Christoph; Jentsch, Thomas J.; Qualmann, Britta; Braulke, Thomas; Kurth, Ingo; Beetz, Christian; Hübner, Christian A.

    2015-01-01

    Hereditary spastic paraplegia (HSP) is characterized by a dying back degeneration of corticospinal axons which leads to progressive weakness and spasticity of the legs. SPG11 is the most common autosomal-recessive form of HSPs and is caused by mutations in SPG11. A recent in vitro study suggested that Spatacsin, the respective gene product, is needed for the recycling of lysosomes from autolysosomes, a process known as autophagic lysosome reformation. The relevance of this observation for hereditary spastic paraplegia, however, has remained unclear. Here, we report that disruption of Spatacsin in mice indeed causes hereditary spastic paraplegia-like phenotypes with loss of cortical neurons and Purkinje cells. Degenerating neurons accumulate autofluorescent material, which stains for the lysosomal protein Lamp1 and for p62, a marker of substrate destined to be degraded by autophagy, and hence appears to be related to autolysosomes. Supporting a more generalized defect of autophagy, levels of lipidated LC3 are increased in Spatacsin knockout mouse embryonic fibrobasts (MEFs). Though distinct parameters of lysosomal function like processing of cathepsin D and lysosomal pH are preserved, lysosome numbers are reduced in knockout MEFs and the recovery of lysosomes during sustained starvation impaired consistent with a defect of autophagic lysosome reformation. Because lysosomes are reduced in cortical neurons and Purkinje cells in vivo, we propose that the decreased number of lysosomes available for fusion with autophagosomes impairs autolysosomal clearance, results in the accumulation of undegraded material and finally causes death of particularly sensitive neurons like cortical motoneurons and Purkinje cells in knockout mice. PMID:26284655

  11. Prune melanoidins protect against oxidative stress and endothelial cell death.

    Science.gov (United States)

    Posadino, Anna Maria; Cossu, Annalisa; Piga, Antonio; Madrau, Monica Assunta; Del Caro, Alessandra; Colombino, Maria; Paglietti, Bianca; Rubino, Salvatore; Iaccarino, Ciro; Crosio, Claudia; Sanna, Bastiano; Pintus, Gianfranco

    2011-06-01

    The health-promoting effects of fruit and vegetable consumption are thought to be due to phytochemicals contained in fresh plant material. Whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed plums (prunes) were isolated and their presence confirmed by hydroxymethylfurfural content and browning index. Oxidative-induced endothelial cell (EC) damage is the trigger for the development of cardiovascular diseases (CVD); therefore the potential protective effect of prune melanoidins on hydrogen peroxide-induced oxidative cell damage was investigated on human endothelial ECV304 cells. Cytoplasmic and mitochondrial redox status was assessed by using the novel, redox-sensitive, ratiometric fluorescent protein sensor (roGFP), while mitochondrial membrane potential (MMP) was investigated with the fluorescent dye, JC-1. Treatment of ECV304 cells with hydrogen peroxide dose-dependently induced both mitochondrial and cytoplasmic oxidation, in addition to MMP dissipation, with ensuing cell death. Pretreatment of ECV304 with prune melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide elicited phenomena, clearly indicating that these polymers protect human EC against oxidative stress.

  12. Cyclosporin A inhibits programmed cell death and cytochrome c release induced by fusicoccin in sycamore cells.

    Science.gov (United States)

    Contran, N; Cerana, R; Crosti, P; Malerba, M

    2007-01-01

    Programmed cell death plays a vital role in normal plant development, response to environmental stresses, and defense against pathogen attack. Different types of programmed cell death occur in plants and the involvement of mitochondria is still under investigation. In sycamore (Acer pseudoplatanus L.) cultured cells, the phytotoxin fusicoccin induces cell death that shows apoptotic features, including chromatin condensation, DNA fragmentation, and release of cytochrome c from mitochondria. In this work, we show that cyclosporin A, an inhibitor of the permeability transition pore of animal mitochondria, inhibits the cell death, DNA fragmentation, and cytochrome c release induced by fusicoccin. In addition, we show that fusicoccin induces a change in the shape of mitochondria which is not prevented by cyclosporin A. These results suggest that the release of cytochrome c induced by fusicoccin occurs through a cyclosporin A-sensitive system that is similar to the permeability transition pore of animal mitochondria and they make it tempting to speculate that this release may be involved in the phytotoxin-induced programmed cell death of sycamore cells.

  13. Effects of epigallocatechin gallate on ultra-violet-induced cell death in PC12 cells

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    Takahashi, Hideo; Seki, Sakiko; Sakamoto, Naotaka; Nakagawa, Shigeki [Nihon Univ., Tokyo (Japan). School of Medicine

    2002-04-01

    We examined the effects of catechin on ultra-violet-induced cell death in PC12 cells. PC12 cells were irradiated by ultra-violet C (254 nm) (UVC). We found that the lactate dehydrogenase (LDH) activities in culture media and lipid peroxide in PC12 cells, which indicate cell death and cell membrane damage, respectively, were increased by UVC irradiation in a time-dependent manner. Cell death was gradually stimulated for 9 hours of cultivation after a UVC irradiation period of 10 or 30 min. Epigallocatechin gallate (EGCG), which is one of the main catechins found in green tea, suppressed the increase in LDH activity in culture medium and also inhibited the formation of lipid peroxide. I{kappa}B, a member of the cell death signaling system, was phosphorylated at 1 hour after 10 min of UVC irradiation. Stimulation of phosphorylation of I{kappa}B by UVC was suppressed by the addition of EGCG. We concluded that EGCG protects the PC12 cell from cell damage caused by UVC irradiation. (author)

  14. Photodynamic therapy-induced programmed cell death in carcinoma cell lines

    Science.gov (United States)

    He, Xiao-Yan; Sikes, Robert A.; Thomsen, Sharon L.; Chung, L.; Jacques, Steven L.

    1993-06-01

    The mode of cell death following photodynamic therapy (PDT) was investigated from the perspective of programmed cell death (apoptosis). Human prostate carcinoma cells (PC3), human non-small cell lung carcinoma (H322a), and rat mammary carcinoma (MTF7) were treated by PDT following sensitization with dihematoporphyrin ether (DHE). The response of these carcinoma cell lines to PDT was variable. An examination of extracted cellular DNA by gel electrophoresis showed the characteristic DNA ladder pattern indicative of internucleosomal cleavage of DNA during apoptosis. MTF7 and PC3 responded to PDT by inducing apoptosis while H322a had no apoptotic response. The magnitude of the response and the PDT dosage required to induce the effect were different in PC3 and MTF7. MTF7 cells responded with rapid apoptosis at the dose of light and drug that yielded 50% cell death (LD50). In contrast, PC3 showed only marginal apoptosis at the LD50 but had a marked response at the LD85. Furthermore, the onset of apoptosis followed slower kinetics in PC3 (2 hr - 4 hr) than in MTF7 (cells were killed by PDT but failed to exhibit any apoptotic response. This study indicates that apoptosis may occur during PDT induced cell death, but this pathway is not universal for all cancer cell lines.

  15. Increasing RpoS expression causes cell death in Borrelia burgdorferi.

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    Linxu Chen

    Full Text Available RpoS, one of the two alternative σ factors in Borrelia burgdorferi, is tightly controlled by multiple regulators and, in turn, determines expression of many critical virulence factors. Here we show that increasing RpoS expression causes cell death. The immediate effect of increasing RpoS expression was to promote bacterial division and as a consequence result in a rapid increase in cell number before causing bacterial death. No DNA fragmentation or degradation was observed during this induced cell death. Cryo-electron microscopy showed induced cells first formed blebs, which were eventually released from dying cells. Apparently blebbing initiated cell disintegration leading to cell death. These findings led us to hypothesize that increasing RpoS expression triggers intracellular programs and/or pathways that cause spirochete death. The potential biological significance of induced cell death may help B. burgdorferi regulate its population to maintain its life cycle in nature.

  16. Activation of intracellular angiotensin AT₂ receptors induces rapid cell death in human uterine leiomyosarcoma cells.

    Science.gov (United States)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen; Zuhayra, Maaz; Schütze, Stefan; Steckelings, Ulrike M; Recanti, Chiara; Namsoleck, Pawel; Unger, Thomas; Culman, Juraj

    2015-05-01

    The presence of angiotensin type 2 (AT₂) receptors in mitochondria and their role in NO generation and cell aging were recently demonstrated in various human and mouse non-tumour cells. We investigated the intracellular distribution of AT₂ receptors including their presence in mitochondria and their role in the induction of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT₂ receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high densities in mitochondria. Activation of the cell membrane AT₂ receptors by a concomitant treatment with angiotensin II and the AT₁ receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT₂ receptor agonist, Compound 21 (C21), penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT₂ receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped cell death, displayed activation of the mitochondrial apoptotic pathway, i.e. down-regulation of the Bcl-2 protein, induction of the Bax protein and activation of caspase-3. All quiescent SK-UT-1 cells died within 5 days after treatment with a single dose of C21. C21 was devoid of cytotoxic effects in proliferating SK-UT-1 cells and in quiescent HutSMC. Our results point to a new, unique approach enabling the elimination non-cycling uterine leiomyosarcoma cells providing that they over-express the AT₂ receptor.

  17. Taxifolin synergizes Andrographolide-induced cell death by attenuation of autophagy and augmentation of caspase dependent and independent cell death in HeLa cells.

    Science.gov (United States)

    Alzaharna, Mazen; Alqouqa, Iyad; Cheung, Hon-Yeung

    2017-01-01

    Andrographolide (Andro) has emerged recently as a potential and effective anticancer agent with induction of apoptosis in some cancer cell lines while induction of G2/M arrest with weak apoptosis in others. Few studies have proved that Andro is also effective in combination therapy. The flavonoid Taxifolin (Taxi) has showed anti-oxidant and antiproliferative effects against different cancer cells. Therefore, the present study investigated the cytotoxic effects of Andro alone or in combination with Taxi on HeLa cells. The combination of Andro with Taxi was synergistic at all tested concentrations and combination ratios. Andro alone induced caspase-dependent apoptosis which was enhanced by the combination with Taxi and attenuated partly by using Z-Vad-Fmk. Andro induced a protective reactive oxygen species (ROS)-dependent autophagy which was attenuated by Taxi. The activation of p53 was involved in Andro-induced autophagy where the use of Taxi or pifithrin-α (PFT-α) decreased it while the activation of JNK was involved in the cell death of HeLa cells but not in the induction of autophagy. The mitochondrial outer-membrane permeabilization (MOMP) plays an important role in Andro-induced cell death in HeLa cells. Andro alone increased the MOMP which was further increased in the case of combination. This led to the increase in AIF and cytochrome c release from mitochondria which consequently increased caspase-dependent and independent cell death. In conclusion, Andro induced a protective autophagy in HeLa cells which was reduced by Taxi and the cell death was increased by increasing the MOMP and subsequently the caspase-dependent and independent cell death.

  18. A role for programmed cell death in the microbial loop.

    Directory of Open Access Journals (Sweden)

    Mónica V Orellana

    Full Text Available The microbial loop is the conventional model by which nutrients and minerals are recycled in aquatic eco-systems. Biochemical pathways in different organisms become metabolically inter-connected such that nutrients are utilized, processed, released and re-utilized by others. The result is that unrelated individuals end up impacting each others' fitness directly through their metabolic activities. This study focused on the impact of programmed cell death (PCD on a population's growth as well as its role in the exchange of carbon between two naturally co-occurring halophilic organisms. Flow cytometric, biochemical, ¹⁴C radioisotope tracing assays, and global transcriptomic analyses show that organic algal photosynthate released by Dunalliela salina cells undergoing PCD complements the nutritional needs of other non-PCD D. salina cells. This occurs in vitro in a carbon limited environment and enhances the growth of the population. In addition, a co-occurring heterotroph Halobacterium salinarum re-mineralizes the carbon providing elemental nutrients for the mixoheterotrophic chlorophyte. The significance of this is uncertain and the archaeon can also subsist entirely on the lysate of apoptotic algae. PCD is now well established in unicellular organisms; however its ecological relevance has been difficult to decipher. In this study we found that PCD in D. salina causes the release of organic nutrients such as glycerol, which can be used by others in the population as well as a co-occurring halophilic archaeon. H. salinarum also re-mineralizes the dissolved material promoting algal growth. PCD in D. salina was the mechanism for the flow of dissolved photosynthate between unrelated organisms. Ironically, programmed death plays a central role in an organism's own population growth and in the exchange of nutrients in the microbial loop.

  19. Lung autophagic response following exposure of mice to whole body irradiation, with and without amifostine

    Energy Technology Data Exchange (ETDEWEB)

    Zois, Christos E. [Department of Radiotherapy - Oncology, Democritus University of Thrace, Alexandroupolis 68100 (Greece); Giatromanolaki, Alexandra [Department of Pathology, Democritus University of Thrace, Alexandroupolis (Greece); Kainulainen, Heikki [Department of Biology of Physical Activity, University of Jyvaeskylae (Finland); Botaitis, Sotirios [Department of Experimental Surgery, Democritus University of Thrace, Alexandroupolis (Greece); Torvinen, Sira [Department of Biology of Physical Activity, University of Jyvaeskylae (Finland); Simopoulos, Constantinos [Department of Experimental Surgery, Democritus University of Thrace, Alexandroupolis (Greece); Kortsaris, Alexandros [Department of Biochemistry, Democritus University of Thrace, Alexandroupolis (Greece); Sivridis, Efthimios [Department of Pathology, Democritus University of Thrace, Alexandroupolis (Greece); Koukourakis, Michael I., E-mail: targ@her.forthnet.gr [Department of Radiotherapy - Oncology, Democritus University of Thrace, Alexandroupolis 68100 (Greece)

    2011-01-07

    Research highlights: {yields} We investigated the effect 6 Gy of WBI on the autophagic machinery of normal mouse lung. {yields} Irradiation induces dysfunction of the autophagic machinery in normal lung, characterized by decreased transcription of the LC3A/Beclin-1 mRNA and accumulation of the LC3A, and p62 proteins. {yields} The membrane bound LC3A-II protein levels increased in the cytosolic fraction (not in the pellet), contrasting the patterns noted after starvation-induced autophagy. {yields} Administration of amifostine, reversed all the LC3A and p62 findings, suggesting protection of the normal autophagic function. -- Abstract: Purpose: The effect of ionizing irradiation on the autophagic response of normal tissues is largely unexplored. Abnormal autophagic function may interfere the protein quality control leading to cell degeneration and dysfunction. This study investigates its effect on the autophagic machinery of normal mouse lung. Methods and materials: Mice were exposed to 6 Gy of whole body {gamma}-radiation and sacrificed at various time points. The expression of MAP1LC3A/LC3A/Atg8, beclin-1, p62/sequestosome-1 and of the Bnip3 proteins was analyzed. Results: Following irradiation, the LC3A-I and LC3A-II protein levels increased significantly at 72 h and 7 days. Strikingly, LC3A-II protein was increased (5.6-fold at 7 days; p < 0.001) only in the cytosolic fraction, but remained unchanged in the membrane fraction. The p62 protein, was significantly increased in both supernatant and pellet fraction (p < 0.001), suggesting an autophagosome turnover deregulation. These findings contrast the patterns of starvation-induced autophagy up-regulation. Beclin-1 levels remained unchanged. The Bnip3 protein was significantly increased at 8 h, but it sharply decreased at 72 h (p < 0.05). Administration of amifostine (200 mg/kg), 30 min before irradiation, reversed all the LC3A and p62 findings on blots, suggesting restoration of the normal autophagic function

  20. Consensus guidelines for the detection of immunogenic cell death

    Science.gov (United States)

    Kepp, Oliver; Senovilla, Laura; Vitale, Ilio; Vacchelli, Erika; Adjemian, Sandy; Agostinis, Patrizia; Apetoh, Lionel; Aranda, Fernando; Barnaba, Vincenzo; Bloy, Norma; Bracci, Laura; Breckpot, Karine; Brough, David; Buqué, Aitziber; Castro, Maria G.; Cirone, Mara; Colombo, Maria I.; Cremer, Isabelle; Demaria, Sandra; Dini, Luciana; Eliopoulos, Aristides G.; Faggioni, Alberto; Formenti, Silvia C.; Fučíková, Jitka; Gabriele, Lucia; Gaipl, Udo S.; Galon, Jérôme; Garg, Abhishek; Ghiringhelli, François; Giese, Nathalia A.; Guo, Zong Sheng; Hemminki, Akseli; Herrmann, Martin; Hodge, James W.; Holdenrieder, Stefan; Honeychurch, Jamie; Hu, Hong-Min; Huang, Xing; Illidge, Tim M.; Kono, Koji; Korbelik, Mladen; Krysko, Dmitri V.; Loi, Sherene; Lowenstein, Pedro R.; Lugli, Enrico; Ma, Yuting; Madeo, Frank; Manfredi, Angelo A.; Martins, Isabelle; Mavilio, Domenico; Menger, Laurie; Merendino, Nicolò; Michaud, Michael; Mignot, Gregoire; Mossman, Karen L.; Multhoff, Gabriele; Oehler, Rudolf; Palombo, Fabio; Panaretakis, Theocharis; Pol, Jonathan; Proietti, Enrico; Ricci, Jean-Ehrland; Riganti, Chiara; Rovere-Querini, Patrizia; Rubartelli, Anna; Sistigu, Antonella; Smyth, Mark J.; Sonnemann, Juergen; Spisek, Radek; Stagg, John; Sukkurwala, Abdul Qader; Tartour, Eric; Thorburn, Andrew; Thorne, Stephen H.; Vandenabeele, Peter; Velotti, Francesca; Workenhe, Samuel T.; Yang, Haining; Zong, Wei-Xing; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    Apoptotic cells have long been considered as intrinsically tolerogenic or unable to elicit immune responses specific for dead cell-associated antigens. However, multiple stimuli can trigger a functionally peculiar type of apoptotic demise that does not go unnoticed by the adaptive arm of the immune system, which we named “immunogenic cell death” (ICD). ICD is preceded or accompanied by the emission of a series of immunostimulatory damage-associated molecular patterns (DAMPs) in a precise spatiotemporal configuration. Several anticancer agents that have been successfully employed in the clinic for decades, including various chemotherapeutics and radiotherapy, can elicit ICD. Moreover, defects in the components that underlie the capacity of the immune system to perceive cell death as immunogenic negatively influence disease outcome among cancer patients treated with ICD inducers. Thus, ICD has profound clinical and therapeutic implications. Unfortunately, the gold-standard approach to detect ICD relies on vaccination experiments involving immunocompetent murine models and syngeneic cancer cells, an approach that is incompatible with large screening campaigns. Here, we outline strategies conceived to detect surrogate markers of ICD in vitro and to screen large chemical libraries for putative ICD inducers, based on a high-content, high-throughput platform that we recently developed. Such a platform allows for the detection of multiple DAMPs, like cell surface-exposed calreticulin, extracellular ATP and high mobility group box 1 (HMGB1), and/or the processes that underlie their emission, such as endoplasmic reticulum stress, autophagy and necrotic plasma membrane permeabilization. We surmise that this technology will facilitate the development of next-generation anticancer regimens, which kill malignant cells and simultaneously convert them into a cancer-specific therapeutic vaccine. PMID:25941621

  1. The calcimimetic R-568 induces apoptotic cell death in prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Cheng Guangming

    2009-07-01

    Full Text Available Abstract Background Increased serum level of parathyroid hormone (PTH was found in metastatic prostate cancers. Calcimimetic R-568 was reported to reduce PTH expression, to suppress cell proliferation and to induce apoptosis in parathyroid cells. In this study, we investigated the effect of R-568 on cellular survival of prostate cancer cells. Methods Prostate cancer cell lines LNCaP and PC-3 were used in this study. Cellular survival was determined with MTT, trypan blue exclusion and fluorescent Live/Death assays. Western blot assay was utilized to assess apoptotic events induced by R-568 treatment. JC-1 staining was used to evaluate mitochondrial membrane potential. Results In cultured prostate cancer LNCaP and PC-3 cells, R-568 treatment significantly reduced cellular survival in a dose- and time-dependent manner. R-568-induced cell death was an apoptotic event, as evidenced by caspase-3 processing and PARP cleavage, as well as JC-1 color change in mitochondria. Knocking down calcium sensing receptor (CaSR significantly reduced R-568-induced cytotoxicity. Enforced expression of Bcl-xL gene abolished R-568-induced cell death, while loss of Bcl-xL expression led to increased cell death in R-568-treated LNCaP cells,. Conclusion Taken together, our data demonstrated that calcimimetic R-568 triggers an intrinsic mitochondria-related apoptotic pathway, which is dependent on the CaSR and is modulated by Bcl-xL anti-apoptotic pathway.

  2. Caspase-3-mediated degradation of condensin Cap-H regulates mitotic cell death.

    Science.gov (United States)

    Lai, S-K; Wong, C-H; Lee, Y-P; Li, H-Y

    2011-06-01

    Mitotic death is a major form of cell death in cancer cells that have been treated with chemotherapeutic drugs. However, the mechanisms underlying this form of cell death is poorly understood. Here, we report that the loss of chromosome integrity is an important determinant of mitotic death. During prolonged mitotic arrest, caspase-3 is activated and it cleaves Cap-H, a subunit of condensin I. The depletion of Cap-H results in the loss of condensin I complex at the chromosomes, thus affecting the integrity of the chromosomes. Consequently, DNA fragmentation by caspase-activated DNase is facilitated, thus driving the cell towards mitotic death. By expressing a caspase-resistant form of Cap-H, mitotic death is abrogated and the cells are able to reenter interphase after a long mitotic delay. Taken together, we provide new insights into the molecular events that occur during mitotic death.

  3. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death.

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    Deepak Jain

    Full Text Available A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson's disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO were treated with multiple low doses of streptozotocin (MLDS to induce inflammatory beta cell stress and cell death. Subsequently, glucose tolerance tests were performed, and plasma insulin as well as fasting and random blood glucose concentrations were monitored. Mitochondrial morphology and number of insulin granules were quantified in beta cells. Moreover, islet cell damage was determined in vitro after streptozotocin and cytokine treatment of isolated wild type and DJ-1 KO islets using calcein AM/ethidium homodimer-1 staining and TUNEL staining. Compared to wild type mice, DJ-1 KO mice became diabetic following MLDS treatment. Insulin concentrations were substantially reduced, and fasting blood glucose concentrations were significantly higher in MLDS-treated DJ-1 KO mice compared to equally treated wild type mice. Rates of beta cell apoptosis upon MLDS treatment were twofold higher in DJ-1 KO mice compared to wild type mice, and in vitro inflammatory cytokines led to twice as much beta cell death in pancreatic islets from DJ-1 KO mice versus those of wild type mice. In conclusion, this study identified the anti-oxidant protein DJ-1 as being capable of protecting pancreatic islet cells from cell death induced by an inflammatory and cytotoxic setting.

  4. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death.

    Science.gov (United States)

    Jain, Deepak; Weber, Gesine; Eberhard, Daniel; Mehana, Amir E; Eglinger, Jan; Welters, Alena; Bartosinska, Barbara; Jeruschke, Kay; Weiss, Jürgen; Päth, Günter; Ariga, Hiroyoshi; Seufert, Jochen; Lammert, Eckhard

    2015-01-01

    A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson's disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO) were treated with multiple low doses of streptozotocin (MLDS) to induce inflammatory beta cell stress and cell death. Subsequently, glucose tolerance tests were performed, and plasma insulin as well as fasting and random blood glucose concentrations were monitored. Mitochondrial morphology and number of insulin granules were quantified in beta cells. Moreover, islet cell damage was determined in vitro after streptozotocin and cytokine treatment of isolated wild type and DJ-1 KO islets using calcein AM/ethidium homodimer-1 staining and TUNEL staining. Compared to wild type mice, DJ-1 KO mice became diabetic following MLDS treatment. Insulin concentrations were substantially reduced, and fasting blood glucose concentrations were significantly higher in MLDS-treated DJ-1 KO mice compared to equally treated wild type mice. Rates of beta cell apoptosis upon MLDS treatment were twofold higher in DJ-1 KO mice compared to wild type mice, and in vitro inflammatory cytokines led to twice as much beta cell death in pancreatic islets from DJ-1 KO mice versus those of wild type mice. In conclusion, this study identified the anti-oxidant protein DJ-1 as being capable of protecting pancreatic islet cells from cell death induced by an inflammatory and cytotoxic setting.

  5. The Autophagy Machinery Controls Cell Death Switching between Apoptosis and Necroptosis.

    Science.gov (United States)

    Goodall, Megan L; Fitzwalter, Brent E; Zahedi, Shadi; Wu, Min; Rodriguez, Diego; Mulcahy-Levy, Jean M; Green, Douglas R; Morgan, Michael; Cramer, Scott D; Thorburn, Andrew

    2016-05-23

    Although autophagy controls cell death and survival, underlying mechanisms are poorly understood, and it is unknown whether autophagy affects only whether or not cells die or also controls other aspects of programmed cell death. MAP3K7 is a tumor suppressor gene associated with poor disease-free survival in prostate cancer. Here, we report that Map3k7 deletion in mouse prostate cells sensitizes to cell death by TRAIL (TNF-related apoptosis-inducing ligand). Surprisingly, this death occurs primarily through necroptosis, not apoptosis, due to assembly of the necrosome in association with the autophagy machinery, mediated by p62/SQSTM1 recruitment of RIPK1. The mechanism of cell death switches to apoptosis if p62-dependent recruitment of the necrosome to the autophagy machinery is blocked. These data show that the autophagy machinery can control the mechanism of programmed cell death by serving as a scaffold rather than by degrading cargo.

  6. Cell-Centric View of Apoptosis and Apoptotic Cell Death-Inducing Antitumoral Strategies

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    Maria Dolores Boyano

    2011-03-01

    Full Text Available Programmed cell death and especially apoptotic cell death, occurs under physiological conditions and is also desirable under pathological circumstances. However, the more we learn about cellular signaling cascades, the less plausible it becomes to find restricted and well-limited signaling pathways. In this context, an extensive description of pathway-connections is necessary in order to point out the main regulatory molecules as well as to select the most appropriate therapeutic targets. On the other hand, irregularities in programmed cell death pathways often lead to tumor development and cancer-related mortality is projected to continue increasing despite the effort to develop more active and selective antitumoral compounds. In fact, tumor cell plasticity represents a major challenge in chemotherapy and improvement on anticancer therapies seems to rely on appropriate drug combinations. An overview of the current status regarding apoptotic pathways as well as available chemotherapeutic compounds provides a new perspective of possible future anticancer strategies.

  7. Calcium signaling as a mediator of cell energy demand and a trigger to cell death.

    Science.gov (United States)

    Bhosale, Gauri; Sharpe, Jenny A; Sundier, Stephanie Y; Duchen, Michael R

    2015-09-01

    Calcium signaling is pivotal to a host of physiological pathways. A rise in calcium concentration almost invariably signals an increased cellular energy demand. Consistent with this, calcium signals mediate a number of pathways that together serve to balance energy supply and demand. In pathological states, calcium signals can precipitate mitochondrial injury and cell death, especially when coupled to energy depletion and oxidative or nitrosative stress. This review explores the mechanisms that couple cell signaling pathways to metabolic regulation or to cell death. The significance of these pathways is exemplified by pathological case studies, such as those showing loss of mitochondrial calcium uptake 1 in patients and ischemia/reperfusion injury.

  8. Melatonina: modulador de morte celular Melatonin: cell death modulator

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    Cecília da Silva Ferreira

    2010-01-01

    Full Text Available A apoptose ou morte programada é um fenômeno biológico essencial para o desenvolvimento e manutenção de uma população celular. Neste processo, as células senescentes ou indesejáveis são eliminadas após ativação de um programa de morte celular, que envolve a participação de moléculas pró-apoptóticas (Fas, FasL, Bax, Caspases 2, 3, 6, 7, 8 e 9. A ativação destas moléculas provoca típicas alterações morfológicas como a retração celular, perda de aderência à matriz extracelular e às células vizinhas, condensação da cromatina, fragmentação do DNA e formação de corpos apoptóticos. Moléculas antiapoptóticas (Bcl2, FLIP bloqueiam o surgimento e a evolução destas alterações celulares e evitam a morte celular. É o equilíbrio entre moléculas pró e antiapoptóticas que assegura a homeostase tecidual. O descontrole da apoptose pode contribuir para o aparecimento de diversas doenças neoplásicas, autoimunes e neurodegenerativas. Diversos agentes indutores e inibidores de apoptose são reconhecidos como armas potenciais no combate a doenças relacionadas a distúrbios de proliferação e morte celular, dentre eles, destacam-se os hormônios. A melatonina tem sido relatada com importante ação antiápoptótica em diversos tecidos, modulando a expressão de agentes, reduzindo a entrada de cálcio na célula, bem como atenuando a produção de espécies reativas de oxigênio e de proteínas pró-apoptóticas, tal como, diminuição da Bax. O conhecimento de novos agentes capazes de atuar nas vias da apoptose é de grande valia para o desenvolvimento de futuras terapias no tratamento de diversas doenças. Assim, o objetivo dessa revisão é elucidar os principais aspectos da morte celular pela apoptose e o papel da melatonina neste processo.Apoptosis or programmed death is a biological phenomenon, which is essential for the development and maintenance of a cell population. In this process, senescent or damaged

  9. Programmed cell death in developing human fetal CNS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The spatial and temporal distributions of programmed cell death (PCD) in developing central nervous system (CNS) of human fetuses ranging from 12 to 39 weeks of gestation were investigated using techniques of flow cytometry and terminal transferase-mediated nick end labeling (TUNEL). The results showed that PCD did occur in every representative brain region of all fetuses examined in different stages. It was found that there were two peaks of PCD appearing at the 12th and 39th weeks respectively, which suggested that the first peak of apoptosis may be involved in the selective elimination of neurons overproduced during the early development and the second may play an important role in establishing the correct neuronal circuitry.

  10. Fine-mapping of an Arabidopsis cell death mutation locus

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An Arabidopsis cell death mutation locus was mapped to chromosome 2 between IGS1 and mi421. The YAC clone ends, CIC9A3R, CIC11C7L, CIC2G5R and RFLP marker CDs3 within this interval, were used to probe TAMU BAC library and 31 BAC clones were obtained. A BAC contig encompassing the mutation locus, which consists of T6P5, T7M23, T12A21, T8L6 and T18A18, was identified by Southern hybridization with the BAC ends as probes. 11 CAPS and 12 STS markers were developed in this region. These results will facilitate map-based cloning of the genes and sequencing of the genomic DNA in this region.

  11. Fine-mapping of an Arabidopsis cell death mutation locus

    Institute of Scientific and Technical Information of China (English)

    牟中林; 戴亚; 李家洋

    2000-01-01

    An Arabidopsis cell death mutation locus was mapped to chromosome 2 between lGS1 and mi421. The YAC clone ends, CIC9A3R, CIC11C7L, CIC2G5R and RFLP marker CDs3 within this interval, were used to probe TAMU BAC library and 31 BAC clones were obtained. A BAC contig encompassing the mutation locus, which consists of T6P5, T7M23, T12A21, T8L6 and T18A18, was identified by Southern hybridization with the BAC ends as probes. 11 CAPS and 12 STS markers were developed in this region. These results will facilitate map-based cloning of the genes and sequencing of the genomic DNA in this region.

  12. The Bacillus cereus spoIIS programmed cell death system

    Directory of Open Access Journals (Sweden)

    Jana eMelnicakova

    2015-08-01

    Full Text Available Programmed cell death in bacteria is generally associated with two¬ component toxin antitoxin systems. The SpoIIS toxin-antitoxin system, consisting of a membrane bound SpoIISA toxin and a small, cytosolic antitoxin SpoIISB, was originally identified in Bacillus subtilis. In this work we describe the Bacillus cereus SpoIIS system which is a three-component system, harbouring an additional gene spoIISC. Its protein product serves as an antitoxin, and similarly as SpoIISB, is able to bind SpoIISA and abolish its toxic effect. Our results indicate that SpoIISC seems to be present not only in B. cereus but also in other Bacilli containing a SpoIIS toxin antitoxin system. In addition, we show that B. cereus SpoIISA can form higher oligomers and we discuss the possible role of this multimerization for the protein’s toxic function.

  13. Induction of immunogenic cell death by chemotherapeutic platinum complexes.

    Science.gov (United States)

    Wong, Daniel Yuan Qiang; Ong, Wendy Wei Fang; Ang, Wee Han

    2015-05-26

    There is compelling evidence suggesting that the immune-modulating effects of many conventional chemotherapeutics, including platinum-based agents, play a crucial role in achieving clinical response. One way in which chemotherapeutics can engage a tumor-specific immune response is by triggering an immunogenic mode of tumor cell death (ICD), which then acts as an "anticancer vaccine". In spite of being a mainstay of chemotherapy, there has not been a systematic attempt to screen both existing and upcoming Pt agents for their ICD ability. A library of chemotherapeutically active Pt agents was evaluated in an in vitro phagocytosis assay, and no correlation between cytotoxicity and phagocytosis was observed. A Pt(II) N-heterocyclic carbene complex was found to display the characteristic hallmarks of a type II ICD inducer, namely focused oxidative endoplasmic reticulum (ER) stress, calreticulin exposure, and both HMGB1 and ATP release, and thus identified as the first small-molecule immuno-chemotherapeutic agent.

  14. Para-toluenesulfonamide induces tongue squamous cell carcinoma cell death through disturbing lysosomal stability.

    Science.gov (United States)

    Liu, Zhe; Liang, Chenyuan; Zhang, Zhuoyuan; Pan, Jian; Xia, Hui; Zhong, Nanshan; Li, Longjiang

    2015-11-01

    Para-toluenesulfonamide (PTS) has been implicated with anticancer effects against a variety of tumors. In the present study, we investigated the inhibitory effects of PTS on tongue squamous cell carcinoma (Tca-8113) and explored the lysosomal and mitochondrial changes after PTS treatment in vitro. High-performance liquid chromatography showed that PTS selectively accumulated in Tca-8113 cells with a relatively low concentration in normal fibroblasts. Next, the effects of PTS on cell viability, invasion, and cell death were determined. PTS significantly inhibited Tca-8113 cells' viability and invasive ability with increased cancer cell death. Flow cytometric analysis and the lactate dehydrogenase release assay showed that PTS induced cancer cell death by activating apoptosis and necrosis simultaneously. Morphological changes, such as cellular shrinkage, nuclear condensation as well as formation of apoptotic body and secondary lysosomes, were observed, indicating that PTS might induce cell death through disturbing lysosomal stability. Lysosomal integrity assay and western blot showed that PTS increased lysosomal membrane permeabilization associated with activation of lysosomal cathepsin B. Finally, PTS was shown to inhibit ATP biosynthesis and induce the release of mitochondrial cytochrome c. Therefore, our findings provide a novel insight into the use of PTS in cancer therapy.

  15. Furan fatty acids efficiently rescue brain cells from cell death induced by oxidative stress

    NARCIS (Netherlands)

    Teixeira, A.; Cox, R.C.; Egmond, M.R.

    2013-01-01

    Treatment of rat brain C6 astroglioma cells with furan fatty acid F6 prior to exposure to hydrogen peroxide shows a strong protective effect of F6 against cell death resulting from oxidative stress. This protective effect is obtained only for F6 administered as a free fatty acid and with an intact f

  16. L-carnitine protects C2C12 cells against mitochondrial superoxide overproduction and cell death

    Science.gov (United States)

    Le Borgne, Françoise; Ravaut, Gaétan; Bernard, Arnaud; Demarquoy, Jean

    2017-01-01

    AIM To identify and characterize the protective effect that L-carnitine exerted against an oxidative stress in C2C12 cells. METHODS Myoblastic C2C12 cells were treated with menadione, a vitamin K analog that engenders oxidative stress, and the protective effect of L-carnitine (a nutrient involved in fatty acid metabolism and the control of the oxidative process), was assessed by monitoring various parameters related to the oxidative stress, autophagy and cell death. RESULTS Associated with its physiological function, a muscle cell metabolism is highly dependent on oxygen and may produce reactive oxygen species (ROS), especially under pathological conditions. High levels of ROS are known to induce injuries in cell structure as they interact at many levels in cell function. In C2C12 cells, a treatment with menadione induced a loss of transmembrane mitochondrial potential, an increase in mitochondrial production of ROS; it also induces autophagy and was able to provoke cell death. Pre-treatment of the cells with L-carnitine reduced ROS production, diminished autophagy and protected C2C12 cells against menadione-induced deleterious effects. CONCLUSION In conclusion, L-carnitine limits the oxidative stress in these cells and prevents cell death.

  17. Cellular redox status determines sensitivity to BNIP3-mediated cell death in cardiac myocytes

    OpenAIRE

    Lee, Youngil; Kubli, Dieter A.; Hanna, Rita A.; Cortez, Melissa Q.; Lee, Hwa-Youn; Miyamoto, Shigeki; Gustafsson, Åsa B.

    2015-01-01

    The atypical BH3-only protein Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (BNIP3) is an important regulator of hypoxia-mediated cell death. Interestingly, the susceptibility to BNIP3-mediated cell death differs between cells. In this study we examined whether there are mechanistic differences in BNIP3-mediated cell death between neonatal and adult cardiac myocytes. We discovered that BNIP3 is a potent inducer of cell death in neonatal myocytes, whereas adult myocytes are remarkably resi...

  18. A High-Throughput Small Molecule Screen for C. elegans Linker Cell Death Inhibitors

    Science.gov (United States)

    Schwendeman, Andrew R.; Shaham, Shai

    2016-01-01

    Programmed cell death is a ubiquitous process in metazoan development. Apoptosis, one cell death form, has been studied extensively. However, mutations inactivating key mammalian apoptosis regulators do not block most developmental cell culling, suggesting that other cell death pathways are likely important. Recent work in the nematode Caenorhabditis elegans identified a non-apoptotic cell death form mediating the demise of the male-specific linker cell. This cell death process (LCD, linker cell-type death) is morphologically conserved, and its molecular effectors also mediate axon degeneration in mammals and Drosophila. To develop reagents to manipulate LCD, we established a simple high-throughput screening protocol for interrogating the effects of small molecules on C. elegans linker cell death in vivo. From 23,797 compounds assayed, 11 reproducibly block linker cell death onset. Of these, five induce animal lethality, and six promote a reversible developmental delay. These results provide proof-of principle validation of our screening protocol, demonstrate that developmental progression is required for linker cell death, and suggest that larger scale screens may identify LCD-specific small-molecule regulators that target the LCD execution machinery. PMID:27716809

  19. Catching up with solid tumor oncology: what is the evidence for a prognostic role of programmed cell death-ligand 1/programmed cell death-1 expression in B-cell lymphomas?

    Science.gov (United States)

    McClanahan, Fabienne; Sharp, Thomas G.; Gribben, John G.

    2016-01-01

    Therapeutic strategies targeting the programmed cell death-ligand 1/programmed cell death-1 pathway have shown significant responses and good tolerability in solid malignancies. Although preclinical studies suggest that inhibiting programmed cell death-ligand 1/programmed cell death-1 interactions might also be highly effective in hematological malignancies, remarkably few clinical trials have been published. Determining patients who will benefit most from programmed cell death-ligand 1/programmed cell death-1-directed immunotherapy and whether programmed cell death-ligand 1/programmed cell death-1 are adequate prognostic markers becomes an increasingly important clinical question, especially as aberrant programmed cell death-ligand 1/programmed cell death-1 expression are key mediators of impaired anti-tumor immune responses in a range of B-cell lymphomas. Herein, we systematically review the published literature on the expression and prognostic value of programmed cell death-ligand 1/programmed cell death-1 in these patients and identify considerable differences in expression patterns, distribution and numbers of programmed cell death-ligand 1+/programmed cell death-1+cells, both between and within lymphoma subtypes, which is reflected in conflicting findings regarding the prognostic value of programmed cell death-ligand 1+/programmed cell death-1+ cells. This can be partly explained by differences in methodologies (techniques, protocols, cutoff values) and definitions of positivity. Moreover, lymphomagenesis, disease progression, and prognosis appear to be determined not only by the presence, numbers and distribution of specific subtypes of T cells, but also by other cells and additional immune checkpoints. Collectively, our findings indicate that programmed cell death-ligand 1/programmed cell death-1 interactions play an essential role in B-cell lymphoma biology and are of clinical importance, but that the overall outcome is determined by additional components

  20. alpha-Toxin is a mediator of Staphylococcus aureus-induced cell death and activates caspases via the intrinsic death pathway independently of death receptor signaling

    NARCIS (Netherlands)

    Bantel, H; Sinha, B; Domschke, W; Peters, G; Schulze-Osthoff, K; Jänicke, R U

    2001-01-01

    Infections with Staphylococcus aureus, a common inducer of septic and toxic shock, often result in tissue damage and death of various cell types. Although S. aureus was suggested to induce apoptosis, the underlying signal transduction pathways remained elusive. We show that caspase activation and DN

  1. Cell death induced by tamoxifen in human blood lymphocytes cultivated in vitro = Morte celular induzida pelo tamoxifeno em linfócitos humanos cultivados in vitro

    Directory of Open Access Journals (Sweden)

    Selma Candelária Genari

    2010-10-01

    Full Text Available Many chemotherapeutic agents with a potential against solid tumors or leukemia can cause lymphopenia. Tamoxifen (TAM is a synthetic non-steroidal anti-estrogen drug employed in female breast cancer treatment. The present study investigated the capacity of TAM to induce cell death in human lymphocytes cultivated in vitro. Lymphocytes were obtained from young (25-30 years; n = 3 and elderly women (58-77 years; n = 3 and cultivated for 24 or 48h, with or without TAM (20 ƒÊM. After the culture, cell viability, immunocytochemical response and ultrastructure were evaluated. TAM affected lymphocytes in a time- dependent manner, and cells obtained from elderly women were the most sensitive to TAM. Immunocytochemicalanalysis evidenced higher frequency of apoptosis in treated cells, and the ultrastructural study revealed autophagic vacuoles, differing from the controls. In summary, the treated lymphocytes were affected by TAM, leading to cell death by apoptosis and autophagy.Muitos agentes quimioterapicos com potencial contra tumores solidos ou leucemias podem causar linfopenia. O Tamoxifeno (TAM e um agente antiestrogeno nao-esteroidal empregado no tratamento de cancer de mama feminino. O presente trabalho investigou a capacidade do TAM em induzir morte celular em linfocitos humanos cultivados in vitro. Oslinfocitos foram obtidos de mulheres jovens (25-30 anos; n = 3 e idosas (58-77 anos; n = 3 e cultivados por 24 ou 48h, com ou sem TAM (20 ƒÊM. Apos a cultura, foram analisadas a viabilidade celular, a resposta imunocitoquimica e a ultraestrutura. Os resultados indicam que o Tamoxifeno induziu morte celular em linfocitos de ambos os grupos, entretanto, as celulas das mulheres idosas apresentaram-se mais sensiveis ao tratamento. A analise imunocitoquimica mostrou maior frequencia de apoptose nas celulas tratadas e o estudo ultraestrutural revelou vacuolos autofagicos nos linfocitos expostos ao Tamoxifeno. Em conclusao, nosso estudo revelou que o TAM

  2. Type I collagen gel protects murine fibrosarcoma L929 cells from TNFα-induced cell death

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hong-Ju; He, Wen-Qi; Chen, Ling; Liu, Wei-Wei; Xu, Qian; Xia, Ming-Yu; Hayashi, Toshihiko [China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016 (China); Fujisaki, Hitomi; Hattori, Shunji [Nippi Research Institute of Biomatrix, Toride, Ibaraki 302-0017 (Japan); Tashiro, Shin-ichi [Institute for Clinical and Biomedical Sciences, Kyoto 603-8072 (Japan); Onodera, Satoshi [Department of Clinical and Pharmaceutical Sciences, Showa Pharmaceutical University, Tokyo 194-8543 (Japan); Ikejima, Takashi, E-mail: ikejimat@vip.sina.com [China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016 (China)

    2015-02-20

    Murine fibrosarcoma L929 cells have been used to test efficacy of proinflammatory cytokine TNFα. In the present study, we reported on protective effect of type I collagen gel used as L929 cell culture. L929 cell grew and proliferated well on collagen gel. However, the L929 cells exhibited cobblestone-like morphology which was much different from the spread fusiform shape when cultured on conventional cell dishes as well as the cells tended to aggregate. On conventional cell culture dishes, the cells treated with TNFα became round in shape and eventually died in a necroptotic manner. The cells cultured on collagen gel, however, were completely unaffected. TNFα treatment was reported to induce autophagy in L929 cells on the plastic dish, and therefore we investigated the effect of collagen gel on induction of autophagy. The results indicated that autophagy induced by TNFα treatment was much reduced when the cells were cultured on collagen gel. In conclusion, type I collagen gel protected L929 cell from TNFα-induced cell death. - Highlights: • Collagen gel culture changed the morphology of L929 cells. • L929 cell cultured on collagen gel were resistant to TNFα-induced cell death. • Collagen gel culture inhibited TNFα-induced autophagy in L929 cells.

  3. Induction of cell death by graphene in Arabidopsis thaliana (Columbia ecotype) T87 cell suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Begum, Parvin, E-mail: parvinchy@ees.hokudai.ac.jp; Fugetsu, Bunshi

    2013-09-15

    Highlights: • This study was set up to explore potential influence of graphene on T87 cells. • Fragmented nuclei, membrane damage, mitochondrial dysfunction were observed. • ROS increased, ROS are key mediators in the cell death signaling pathway. • Translocation of graphene into cells and an endocytosis-like structure was observed. • Graphene entering into the cells by endocytosis. -- Abstract: The toxicity of graphene on suspensions of Arabidopsis thaliana (Columbia ecotype) T87 cells was investigated by examining the morphology, mitochondrial dysfunction, reactive oxygen species generation (ROS), and translocation of graphene as the toxicological endpoints. The cells were grown in Jouanneau and Péaud-Lenoel (JPL) media and exposed to graphene at concentrations 0–80 mg/L. Morphological changes were observed by scanning electron microscope and the adverse effects such as fragmented nuclei, membrane damage, mitochondrial dysfunction was observed with fluorescence microscopy by staining with Hoechst 33342/propidium iodide and succinate dehydrogenase (mitochondrial bioenergetic enzyme). Analysis of intracellular ROS by 2′,7′-dichlorofluorescein diacetate demonstrated that graphene induced a 3.3-fold increase in ROS, suggesting that ROS are key mediators in the cell death signaling pathway. Transmission electron microscopy verified the translocation of graphene into cells and an endocytosis-like structure was observed which suggested graphene entering into the cells by endocytosis. In conclusion, our results show that graphene induced cell death in T87 cells through mitochondrial damage mediated by ROS.

  4. Neuroprotection by GH against excitotoxic-induced cell death in retinal ganglion cells.

    Science.gov (United States)

    Martínez-Moreno, Carlos G; Ávila-Mendoza, José; Wu, Yilun; Arellanes-Licea, Elvira Del Carmen; Louie, Marcela; Luna, Maricela; Arámburo, Carlos; Harvey, Steve

    2016-08-01

    Retinal growth hormone (GH) has been shown to promote cell survival in retinal ganglion cells (RGCs) during developmental waves of apoptosis during chicken embryonic development. The possibility that it might also against excitotoxicity-induced cell death was therefore examined in the present study, which utilized quail-derived QNR/D cells as an in vitro RGC model. QNR/D cell death was induced by glutamate in the presence of BSO (buthionine sulfoxamide) (an enhancer of oxidative stress), but this was significantly reduced (PGH (rcGH). Similarly, QNR/D cells that had been prior transfected with a GH plasmid to overexpress secreted and non-secreted GH. This treatment reduced the number of TUNEL-labeled cells and blocked their release of lactate dehydrogenase (LDH). In a further experiment with dissected neuroretinal explants from ED (embryonic day) 10 embryos, rcGH treatment of the explants also reduced (PGH-overexpressing QNR/D cells. As rcGH treatment and GH-overexpression cells also increased the content of IGF-1 and IGF-1 mRNA this neuroprotective action of GH is likely to be mediated, at least partially, through an IGF-1 mechanism. This possibility is supported by the fact that the siRNA knockdown of GH or IGF-1 significantly reduced QNR/D cell viability, as did the immunoneutralization of IGF-1. GH is therefore neuroprotective against excitotoxicity-induced RGC cell death by anti-apoptotic actions involving IGF-1 stimulation.

  5. Oxidative Stress, Cell Death, and Other Damage to Alveolar Epithelial Cells Induced by Cigarette Smoke

    Directory of Open Access Journals (Sweden)

    Nagai A

    2003-09-01

    Full Text Available Abstract Cigarette smoking is a major risk factor in the development of various lung diseases, including pulmonary emphysema, pulmonary fibrosis, and lung cancer. The mechanisms of these diseases include alterations in alveolar epithelial cells, which are essential in the maintenance of normal alveolar architecture and function. Following cigarette smoking, alterations in alveolar epithelial cells induce an increase in epithelial permeability, a decrease in surfactant production, the inappropriate production of inflammatory cytokines and growth factors, and an increased risk of lung cancer. However, the most deleterious effect of cigarette smoke on alveolar epithelial cells is cell death, i.e., either apoptosis or necrosis depending on the magnitude of cigarette smoke exposure. Cell death induced by cigarette smoke exposure can largely be accounted for by an enhancement in oxidative stress. In fact, cigarette smoke contains and generates many reactive oxygen species that damage alveolar epithelial cells. Whether apoptosis and/or necrosis in alveolar epithelial cells is enhanced in healthy cigarette smokers is presently unclear. However, recent evidence indicates that the apoptosis of alveolar epithelial cells and alveolar endothelial cells is involved in the pathogenesis of pulmonary emphysema, an important cigarette smoke-induced lung disease characterized by the loss of alveolar structures. This review will discuss oxidative stress, cell death, and other damage to alveolar epithelial cells induced by cigarette smoke.

  6. Contact-independent cell death of human microglial cells due to pathogenic Naegleria fowleri trophozoites.

    Science.gov (United States)

    Kim, Jong-Hyun; Kim, Daesik; Shin, Ho-Joon

    2008-12-01

    Free-living Naegleria fowleri leads to a fatal infection known as primary amebic meningoencephalitis in humans. Previously, the target cell death could be induced by phagocytic activity of N. fowleri as a contact-dependent mechanism. However, in this study we investigated the target cell death under a non-contact system using a tissue-culture insert. The human microglial cells, U87MG cells, co-cultured with N. fowleri trophozoites for 30 min in a non-contact system showed morphological changes such as the cell membrane destruction and a reduction in the number. By fluorescence-activated cell sorter (FACS) analysis, U87MG cells co-cultured with N. fowleri trophozoites in a non-contact system showed a significant increase of apoptotic cells (16%) in comparison with that of the control or N. fowleri lysate. When U87MG cells were co-cultured with N. fowleri trophozoites in a non-contact system for 30 min, 2 hr, and 4 hr, the cytotoxicity of amebae against target cells was 40.5, 44.2, and 45.6%, respectively. By contrast, the cytotoxicity of non-pathogenic N. gruberi trophozoites was 10.2, 12.4, and 13.2%, respectively. These results suggest that the molecules released from N. fowleri in a contact-independent manner as well as phagocytosis in a contact-dependent manner may induce the host cell death.

  7. Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model

    Directory of Open Access Journals (Sweden)

    Imène Achour

    2016-08-01

    Full Text Available Parkinson’s disease (PD is a progressive neurodegenerative disorder, primarily affecting dopaminergic neurons in the substantia nigra. There is currently no cure for PD and present medications aim to alleviate clinical symptoms, thus prevention remains the ideal strategy to reduce the prevalence of this disease. The goal of this study was to investigate whether oleuropein (OLE, the major phenolic compound in olive derivatives, may prevent neuronal degeneration in a cellular dopaminergic model of PD, differentiated PC12 cells exposed to the potent parkinsonian toxin 6-hydroxydopamine (6-OHDA. We also investigated OLE’s ability to mitigate mitochondrial oxidative stress and modulate the autophagic flux. Our results obtained by measuring cytotoxicity and apoptotic events demonstrate that OLE significantly decreases neuronal death. OLE could also reduce mitochondrial production of reactive oxygen species resulting from blocking superoxide dismutase activity. Moreover, quantification of autophagic and acidic vesicles in the cytoplasm alongside expression of specific autophagic markers uncovered a regulatory role for OLE against autophagic flux impairment induced by bafilomycin A1. Altogether, our results define OLE as a neuroprotective, anti-oxidative and autophagy-regulating molecule, in a neuronal dopaminergic cellular model.

  8. Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model

    Science.gov (United States)

    Achour, Imène; Arel-Dubeau, Anne-Marie; Renaud, Justine; Legrand, Manon; Attard, Everaldo; Germain, Marc; Martinoli, Maria-Grazia

    2016-01-01

    Parkinson’s disease (PD) is a progressive neurodegenerative disorder, primarily affecting dopaminergic neurons in the substantia nigra. There is currently no cure for PD and present medications aim to alleviate clinical symptoms, thus prevention remains the ideal strategy to reduce the prevalence of this disease. The goal of this study was to investigate whether oleuropein (OLE), the major phenolic compound in olive derivatives, may prevent neuronal degeneration in a cellular dopaminergic model of PD, differentiated PC12 cells exposed to the potent parkinsonian toxin 6-hydroxydopamine (6-OHDA). We also investigated OLE’s ability to mitigate mitochondrial oxidative stress and modulate the autophagic flux. Our results obtained by measuring cytotoxicity and apoptotic events demonstrate that OLE significantly decreases neuronal death. OLE could also reduce mitochondrial production of reactive oxygen species resulting from blocking superoxide dismutase activity. Moreover, quantification of autophagic and acidic vesicles in the cytoplasm alongside expression of specific autophagic markers uncovered a regulatory role for OLE against autophagic flux impairment induced by bafilomycin A1. Altogether, our results define OLE as a neuroprotective, anti-oxidative and autophagy-regulating molecule, in a neuronal dopaminergic cellular model. PMID:27517912

  9. The root hair assay facilitates the use of genetic and pharmacological tools in order to dissect multiple signalling pathways that lead to programmed cell death.

    Directory of Open Access Journals (Sweden)

    Joanna Kacprzyk

    Full Text Available The activation of programmed cell death (PCD is often a result of complex signalling pathways whose relationship and intersection are not well understood. We recently described a PCD root hair assay and proposed that it could be used to rapidly screen genetic or pharmacological modulators of PCD. To further assess the applicability of the root hair assay for studying multiple signalling pathways leading to PCD activation we have investigated the crosstalk between salicylic acid, autophagy and apoptosis-like PCD (AL-PCD in Arabidopsis thaliana. The root hair assay was used to determine rates of AL-PCD induced by a panel of cell death inducing treatments in wild type plants treated with chemical modulators of salicylic acid synthesis or autophagy, and in genetic lines defective in autophagy or salicylic acid signalling. The assay demonstrated that PCD induced by exogenous salicylic acid or fumonisin B1 displayed a requirement for salicylic acid signalling and was partially dependent on the salicylic acid signal transducer NPR1. Autophagy deficiency resulted in an increase in the rates of AL-PCD induced by salicylic acid and fumonisin B1, but not by gibberellic acid or abiotic stress. The phenylalanine ammonia lyase-dependent salicylic acid synthesis pathway contributed only to death induced by salicylic acid and fumonisin B1. 3-Methyladenine, which is commonly used as an inhibitor of autophagy, appeared to influence PCD induction in all treatments suggesting a possible secondary, non-autophagic, effect on a core component of the plant PCD pathway. The results suggest that salicylic acid signalling is negatively regulated by autophagy during salicylic acid and mycotoxin-induced AL-PCD. However, this crosstalk does not appear to be directly involved in PCD induced by gibberellic acid or abiotic stress. This study demonstrates that the root hair assay is an effective tool for relatively rapid investigation of complex signalling pathways leading to

  10. Gingerol sensitizes TRAIL-induced apoptotic cell death of glioblastoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae-Hee, E-mail: leedneo@gmail.com [Departments of Surgery and Pharmacology and Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA (United States); Kim, Dong-Wook [Department of Microbiology, Immunology, and Cancer Biology, University of VA (United States); Jung, Chang-Hwa [Division of Metabolism and Functionality Research, Korea Food Research Institute (Korea, Republic of); Lee, Yong J. [Departments of Surgery and Pharmacology and Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA (United States); Park, Daeho, E-mail: daehopark@gist.ac.kr [School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2014-09-15

    Glioblastoma multiforme (GBM) is the most lethal and aggressive astrocytoma of primary brain tumors in adults. Although there are many clinical trials to induce the cell death of glioblastoma cells, most glioblastoma cells have been reported to be resistant to TRAIL-induced apoptosis. Here, we showed that gingerol as a major component of ginger can induce TRAIL-mediated apoptosis of glioblastoma. Gingerol increased death receptor (DR) 5 levels in a p53-dependent manner. Furthermore, gingerol decreased the expression level of anti-apoptotic proteins (survivin, c-FLIP, Bcl-2, and XIAP) and increased pro-apoptotic protein, Bax and truncate Bid, by generating reactive oxygen species (ROS). We also found that the sensitizing effects of gingerol in TRAIL-induced cell death were blocked by scavenging ROS or overexpressing anti-apoptotic protein (Bcl-2). Therefore, we showed the functions of gingerol as a sensitizing agent to induce cell death of TRAIL-resistant glioblastoma cells. This study gives rise to the possibility of applying gingerol as an anti-tumor agent that can be used for the purpose of combination treatment with TRAIL in TRAIL-resistant glioblastoma tumor therapy. - Highlights: • Most GBM cells have been reported to be resistant to TRAIL-induced apoptosis. • Gingerol enhances the expression level of anti-apoptotic proteins by ROS. • Gingerol enhances TRAIL-induced apoptosis through actions on the ROS–Bcl2 pathway.

  11. Toll pathway modulates TNF-induced JNK-dependent cell death in Drosophila

    Science.gov (United States)

    Wu, Chenxi; Chen, Changyan; Dai, Jianli; Zhang, Fan; Chen, Yujun; Li, Wenzhe; Pastor-Pareja, José Carlos; Xue, Lei

    2015-01-01

    Signalling networks that control the life or death of a cell are of central interest in modern biology. While the defined roles of the c-Jun N-terminal kinase (JNK) pathway in regulating cell death have been well-established, additional factors that modulate JNK-mediated cell death have yet to be fully elucidated. To identify novel regulators of JNK-dependent cell death, we performed a dominant-modifier screen in Drosophila and found that the Toll pathway participates in JNK-mediated cell death. Loss of Toll signalling suppresses ectopically and physiologically activated JNK signalling-induced cell death. Our epistasis analysis suggests that the Toll pathway acts as a downstream modulator for JNK-dependent cell death. In addition, gain of JNK signalling results in Toll pathway activation, revealed by stimulated transcription of Drosomycin (Drs) and increased cytoplasm-to-nucleus translocation of Dorsal. Furthermore, the Spätzle (Spz) family ligands for the Toll receptor are transcriptionally upregulated by activated JNK signalling in a non-cell-autonomous manner, providing a molecular mechanism for JNK-induced Toll pathway activation. Finally, gain of Toll signalling exacerbates JNK-mediated cell death and promotes cell death independent of caspases. Thus, we have identified another important function for the evolutionarily conserved Toll pathway, in addition to its well-studied roles in embryonic dorso-ventral patterning and innate immunity. PMID:26202785

  12. Calprotectin induces cell death in human prostate cancer cell (LNCaP) through survivin protein alteration.

    Science.gov (United States)

    Sattari, Mina; Pazhang, Yaghub; Imani, Mehdi

    2014-11-01

    Calprotectin (CP), an abundant heterodimeric cytosolic protein of neutrophils, conveys a variety of functions such as tumor cell growth arrest and antimicrobial activity. We investigated CP activity and its possible apoptosis-inducing mechanism of action against an antiandrogen therapy-resistance prostate cancer cell line LNCaP. Cell viability and Annexin V FITC assays were performed in order to investigate its cell death activity and apoptosis, respectively. In order to address cell death inducing mechanism(s), immunocytochemistry and immunobloting analysis, reactive oxygen species (ROS) and nitric oxide (NO) measurements were performed. The effective concentration of CP against LNCaP promoting LNCaP cell death was 200 µg/mL. ROS and NO levels of cells remarkably were enhanced following treatment with 50 and 100 µg/mL of CP, respectively. Protein expression of anti-apoptotic protein survivin was significantly decreased after administration of tumor cells with CP. Our data indicate that CP regulates the LNCaP cells viability via survivin-mediated pathway and ROS and NO enhancement. Thus, inhibition of survivin expression, enhancement of ROS and NO level by CP or other similar pharmaceutical agents might be effective in lowering the malignant proliferation of human prostate cancer cells.

  13. Capsaicin-induced cell death in a human gastric adenocarcinoma cell line

    Institute of Scientific and Technical Information of China (English)

    Yi-Ching Lo; Yuan-Chen Yang; I-Chieh Wu; Fu-Chen Kuo; Chi-Ming Liu; Hao-Wei Wang; Chao-Hung Kuo; Jeng-Yi Wu; Deng-Chyang Wu

    2005-01-01

    AIM: Capsaicin, a pungent ingredient found in red pepper,has long been used in spices, food additives, and drugs.Cell death induced by the binding of capsaicin was examined in a human gastric adenocarcinoma cell line (AGS cells).METHODS: By using XTT-based cytotoxicityassay, flow cytometry using the TUNEL method, and quantitation of DNA fragmentation, both cell death and DNA fragmentation were detected in AGS cells treated with capsaicin. By using Western blotting methods, capsaicin reduced the expression of Bcl-2, the antiapoptotic protein, in AGS cells in a concentration-dependent manner.RESULTS: After incubation of AGS cells with capsaicin for 24 h, cell viability decreased significantly in a dose-dependent manner. After incubation of AGS cells with capsaicin for 24 h, apoptotic bodies also significantly increased, and were again correlated with the dose of capsaicin. When the concentration of capsaicin was 1 mmol/L, the amount of DNA fragments also increased. Similar results werealso in the lower traces.CONCLUSION: These results suggest that capsaicininduced cell death might be via a Bcl-2 sensitive apoptotic pathway. Therefore, capsaicin might induce protection from gastric cancer.

  14. Non-canonical kinase signaling by the death ligand TRAIL in cancer cells : discord in the death receptor family

    NARCIS (Netherlands)

    Azijli, K.; Weyhenmeyer, B.; Peters, G. J.; de Jong, S.; Kruyt, F. A. E.

    2013-01-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-based therapy is currently evaluated in clinical studies as a tumor cell selective pro-apoptotic approach. However, besides activating canonical caspase-dependent apoptosis by binding to TRAIL-specific death receptors, the TRAIL ligand

  15. Involvement of ethylene and lipid signalling in cadmium-induced programmed cell death in tomato suspension cells

    NARCIS (Netherlands)

    Iakimova, E.T.; Kapchina-Toteva, V.M.; Laarhoven, L.J.; Harren, F.; Woltering, E.J.

    2006-01-01

    Cadmium-induced cell death was studied in suspension-cultured tomato (Lycopersicon esculentum Mill.) cells (line MsK8) treated with CdSO4. Within 24 h, cadmium treatment induced cell death in a concentration-dependent manner. Cell cultures showed recovery after 2¿3 days which indicates the existence

  16. Involvement of ethylene and lipid signalling in cadmium-induced programmed cell death in tomato suspension cells

    NARCIS (Netherlands)

    Yakimova, E.T.; Kapchina-Toteva, V.M.; Laarhoven, L.J.J.; Harren, F.J.M.; Woltering, E.J.

    2006-01-01

    Cadmium-induced cell death was studied in suspension-cultured tomato (Lycopersicon esculentum Mill.) cells (line MsK8) treated with CdSO4. Within 24 h, cadmium treatment induced cell death in a concentration-dependent manner. Cell cultures showed recovery after 23 days which indicates the existence

  17. Tissue decellularization by activation of programmed cell death.

    Science.gov (United States)

    Bourgine, Paul E; Pippenger, Benjamin E; Todorov, Atanas; Tchang, Laurent; Martin, Ivan

    2013-08-01

    Decellularized tissues, native or engineered, are receiving increasing interest in the field of regenerative medicine as scaffolds or implants for tissue and organ repair. The approach, which offers the opportunity to deliver off-the-shelf bioactive materials without immuno-matching requirements, is based on the rationale that extracellular matrix (ECM)-presented cues can be potently instructive towards regeneration. However, existing decellularization protocols typically result in damage to the source ECM and do not allow the controlled preservation of its structural, biochemical and/or biomechanical features. Here we propose the deliberate activation of programmed cell death as a method to selectively target the cellular component of a tissue and thereby to preserve the integrity of the decellularized ECM. In the case of engineered tissues, the approach could be complemented by the use of (i) an immortalized cell line, engineered to undergo apoptosis upon exposure to a chemical inducer, and (ii) a perfusion bioreactor system, supporting efficient removal of cellular material. The combination of these tools may lead to the streamlined development of more appropriate materials, based on engineered and decellularized ECM and including a customized set of signals specifically designed to activate endogenous regenerative processes.

  18. Pathways to ischemic neuronal cell death: are sex differences relevant?

    Directory of Open Access Journals (Sweden)

    McCullough Louise D

    2008-06-01

    Full Text Available Abstract We have known for some time that the epidemiology of human stroke is sexually dimorphic until late in life, well beyond the years of reproductive senescence and menopause. Now, a new concept is emerging: the mechanisms and outcome of cerebral ischemic injury are influenced strongly by biological sex as well as the availability of sex steroids to the brain. The principal mammalian estrogen (17 β estradiol or E2 is neuroprotective in many types of brain injury and has been the major focus of investigation over the past several decades. However, it is becoming increasingly clear that although hormones are a major contributor to sex-specific outcomes, they do not fully account for sex-specific responses to cerebral ischemia. The purpose of this review is to highlight recent studies in cell culture and animal models that suggest that genetic sex determines experimental stroke outcome and that divergent cell death pathways are activated after an ischemic insult. These sex differences need to be identified if we are to develop efficacious neuroprotective agents for use in stroke patients.

  19. Activation of Cyclin-Dependent Kinase 5 Is a Consequence of Cell Death

    Directory of Open Access Journals (Sweden)

    Yixia Ye

    2009-01-01

    Full Text Available Cyclin-dependent kinase 5 (Cdk5 is similar to other Cdks but is activated during cell differentiation and cell death rather than cell division. Since activation of Cdk5 has been reported in many situations leading to cell death, we attempted to determine if it was required for any form of cell death. We found that Cdk5 is activated during apoptotic deaths and that the activation can be detected even when the cells continue to secondary necrosis. This activation can occur in the absence of Bim, calpain, or neutral cathepsins. The kinase is typically activated by p25, derived from p35 by calpain-mediated cleavage, but inhibition of calpain does not affect cell death or the activation of Cdk5. Likewise, RNAi-forced suppression of the synthesis of Cdk5 does not affect the incidence or kinetics of cell death. We conclude that Cdk5 is activated as a consequence of metabolic changes that are common to many forms of cell death. Thus its activation suggests processes during cell death that will be interesting or important to understand, but activation of Cdk5 is not necessary for cells to die.

  20. Lysine suppresses protein degradation through autophagic-lysosomal system in C2C12 myotubes.

    Science.gov (United States)

    Sato, Tomonori; Ito, Yoshiaki; Nedachi, Taku; Nagasawa, Takashi

    2014-06-01

    Muscle mass is determined between protein synthesis and protein degradation. Reduction of muscle mass leads to bedridden condition and attenuation of resistance to diseases. Moreover, bedridden condition leads to additional muscle loss due to disuse muscle atrophy. In our previous study (Sato et al. 2013), we showed that administered lysine (Lys), one of essential amino acid, suppressed protein degradation in skeletal muscle. In this study, we investigated that the mechanism of the suppressive effects of Lys on skeletal muscle proteolysis in C2C12 cell line. C2C12 myotubes were incubated in the serum-free medium containing 10 mM Lys or 20 mM Lys, and myofibrillar protein degradation was determined by the rates of 3-methylhistidine (MeHis) release from the cells. The mammalian target of rapamycin (mTOR) activity from the phosphorylation levels of p70-ribosormal protein S6 kinase 1 and eIF4E-binding protein 1 and the autophagic-lysosomal system activity from the ratio of LC3-II/I in C2C12 myotubes stimulated by 10 mM Lys for 0-3 h were measured. The rates of MeHis release were markedly reduced by addition of Lys. The autophagic-lysosomal system activity was inhibited upon 30 min of Lys supplementation. The activity of mTOR was significantly increased upon 30 min of Lys supplementation. The suppressive effect of Lys on the proteolysis by the autophagic-lysosomal system was maintained partially when mTOR activity was inhibited by 100 nM rapamycin, suggesting that some regulator other than mTOR signaling, for example, Akt, might also suppress the autophagic-lysosomal system. From these results, we suggested that Lys suppressed the activity of the autophagic-lysosomal system in part through activation of mTOR and reduced myofibrillar protein degradation in C2C12 myotubes.

  1. Granzyme H induces cell death primarily via a Bcl-2-sensitive mitochondrial cell death pathway that does not require direct Bid activation.

    Science.gov (United States)

    Ewen, Catherine L; Kane, Kevin P; Bleackley, R Chris

    2013-07-01

    Natural killer and T cell-mediated cytotoxicity is important for the elimination of viruses and transformed cells. The granule lytic pathway utilizes perforin and granzymes to induce cell death, while receptor-mediated lytic pathways rely on molecules such as FasL. Pro-apoptotic activities of Granzyme B (GrB) and Fas are well-established, and many of their cellular targets have been identified. However, humans express additional related granzymes - GrA, GrM, GrK, and GrH. Neither the cytotoxic potential of GrH, nor the mechanism by which GrH may induce target cell death is currently understood. We proposed that GrH would have pro-apoptotic activity that would be distinct from that of GrB and FasL, which could be relevant when Fas/FasL or GrB activity or death pathways were impaired. Our results, using a purified recombinant form of GrH, revealed that GrH induced cell death via a Bcl-2-sensitive mitochondrial pathway without direct processing of Bid. Additionally, neither the apoptosome nor caspase-3 was essential to the induction of GrH-mediated cell death. However, GrH did directly process DFF45, potentially leading to DNA damage. Our findings support the idea that multiple, non-redundant death pathways may be initiated by cytotoxic cells to counteract various immune evasion strategies.

  2. The influence of cell and nanoparticle properties on heating and cell death in a radiofrequency field.

    Science.gov (United States)

    Mackeyev, Yuri; Mark, Colette; Kumar, Natasha; Serda, Rita E

    2017-02-05

    The use of non-invasive radiofrequency (RF) energy to induce mild thermal and non-thermal effects in cancer tissue is under study as an adjuvant to chemo, radio or immuno therapy. This study examines cell specific sensitivities to RF exposure and the potential of nanoparticles to elevate heating rates or enhance biological effects. Increases in the heating rate of water in an RF field operating at 13.56MHz (0.004-0.028°C/s) were positively correlated with concentration of hybrid nanoparticles (1-10mg/ml) consisting of water soluble malonodiserinolamide [60]fullerene (C60-ser) conjugated to the surface of mesoporous silica nanoparticles (SiO2-C60). The heating rate of highly conductive cell culture media (0.024°C/s) was similar to that of the highest concentration of nanoparticles in water, with no significant increase due to addition of nanoparticles at relevant doses (cell viability, anionic (SiO2 and SiO2-C60) or neutral (C60) nanoparticles did not influence RF-induced cell death, however, cationic nanoparticles (4-100μg/ml) caused dose-dependent increases in RF-induced cell death (24-42% compared to RF only). The effect of cell type, size and immortalization on sensitivity of cells to RF fields was examined in endothelial (HUVEC and HMVEC), fibroblast (primary dermal and L939) and cancer cells (HeLa and 4T1). While the state of cellular immortalization itself did not consistently influence the rate of RF-induced cell death compared to normal cell counter parts, cell size (ranging from 7 to 30μm) negatively correlated with cell sensitivity to RF (21-97% cell death following 6min irradiation). In summary, while nanoparticles do not alter the heating rate of biologically-relevant solutions, they can increase RF-induced cell death based on intrinsic cytotoxicity; and cells with smaller radii, and thereby greater surface membrane, are more susceptible to cell damage in an RF field than larger cells.

  3. M1 muscarinic receptor activation mediates cell death in M1-HEK293 cells.

    Science.gov (United States)

    Graham, E Scott; Woo, Kerhan K; Aalderink, Miranda; Fry, Sandie; Greenwood, Jeffrey M; Glass, Michelle; Dragunow, Mike

    2013-01-01

    HEK293 cells have been used extensively to generate stable cell lines to study G protein-coupled receptors, such as muscarinic acetylcholine receptors (mAChRs). The activation of M1 mAChRs in various cell types in vitro has been shown to be protective. To further investigate M1 mAChR-mediated cell survival, we generated stable HEK293 cell-lines expressing the human M1 mAChR. M1 mAChRs were efficiently expressed at the cell surface and efficiently internalised within 1 h by carbachol. Carbachol also induced early signalling cascades similar to previous reports. Thus, ectopically expressed M1 receptors behaved in a similar fashion to the native receptor over short time periods of analysis. However, substantial cell death was observed in HEK293-M1 cells within 24 h after carbachol application. Death was only observed in HEK cells expressing M1 receptors and fully blocked by M1 antagonists. M1 mAChR-stimulation mediated prolonged activation of the MEK-ERK pathway and resulted in prolonged induction of the transcription factor EGR-1 (>24 h). Blockade of ERK signalling with U0126 did not reduce M1 mAChR-mediated cell-death significantly but inhibited the acute induction of EGR-1. We investigated the time-course of cell death using time-lapse microscopy and xCELLigence technology. Both revealed the M1 mAChR cytotoxicity occurs within several hours of M1 activation. The xCELLigence assay also confirmed that the ERK pathway was not involved in cell-death. Interestingly, the MEK blocker did reduce carbachol-mediated cleaved caspase 3 expression in HEK293-M1 cells. The HEK293 cell line is a widely used pharmacological tool for studying G-protein coupled receptors, including mAChRs. Our results highlight the importance of investigating the longer term fate of these cells in short term signalling studies. Identifying how and why activation of the M1 mAChR signals apoptosis in these cells may lead to a better understanding of how mAChRs regulate cell-fate decisions.

  4. Thioredoxin reductase deficiency potentiates oxidative stress, mitochondrial dysfunction and cell death in dopaminergic cells.

    Directory of Open Access Journals (Sweden)

    Pamela Lopert

    Full Text Available Mitochondria are considered major generators of cellular reactive oxygen species (ROS which are implicated in the pathogenesis of neurodegenerative diseases such as Parkinson's disease (PD. We have recently shown that isolated mitochondria consume hydrogen peroxide (H₂O₂ in a substrate- and respiration-dependent manner predominantly via the thioredoxin/peroxiredoxin (Trx/Prx system. The goal of this study was to determine the role of Trx/Prx system in dopaminergic cell death. We asked if pharmacological and lentiviral inhibition of the Trx/Prx system sensitized dopaminergic cells to mitochondrial dysfunction, increased steady-state H₂O₂ levels and death in response to toxicants implicated in PD. Incubation of N27 dopaminergic cells or primary rat mesencephalic cultures with the Trx reductase (TrxR inhibitor auranofin in the presence of sub-toxic concentrations of parkinsonian toxicants paraquat; PQ or 6-hydroxydopamine; 6OHDA (for N27 cells resulted in a synergistic increase in H₂O₂ levels and subsequent cell death. shRNA targeting the mitochondrial thioredoxin reductase (TrxR2 in N27 cells confirmed the effects of pharmacological inhibition. A synergistic decrease in maximal and reserve respiratory capacity was observed in auranofin treated cells and TrxR2 deficient cells following incubation with PQ or 6OHDA. Additionally, TrxR2 deficient cells showed decreased basal mitochondrial oxygen consumption rates. These data demonstrate that inhibition of the mitochondrial Trx/Prx system sensitizes dopaminergic cells to mitochondrial dysfunction, increased steady-state H₂O₂, and cell death. Therefore, in addition to their role in the production of cellular H₂O₂ the mitochondrial Trx/Prx system serve as a major sink for cellular H₂O₂ and its disruption may contribute to dopaminergic pathology associated with PD.

  5. Intracellular growth of Mycobacterium tuberculosis after macrophage cell death leads to serial killing of host cells

    Science.gov (United States)

    Mahamed, Deeqa; Boulle, Mikael; Ganga, Yashica; Mc Arthur, Chanelle; Skroch, Steven; Oom, Lance; Catinas, Oana; Pillay, Kelly; Naicker, Myshnee; Rampersad, Sanisha; Mathonsi, Colisile; Hunter, Jessica; Sreejit, Gopalkrishna; Pym, Alexander S; Lustig, Gila; Sigal, Alex

    2017-01-01

    A hallmark of pulmonary tuberculosis is the formation of macrophage-rich granulomas. These may restrict Mycobacterium tuberculosis (Mtb) growth, or progress to central necrosis and cavitation, facilitating pathogen growth. To determine factors leading to Mtb proliferation and host cell death, we used live cell imaging to track Mtb infection outcomes in individual primary human macrophages. Internalization of Mtb aggregates caused macrophage death, and phagocytosis of large aggregates was more cytotoxic than multiple small aggregates containing similar numbers of bacilli. Macrophage death did not result in clearance of Mtb. Rather, it led to accelerated intracellular Mtb growth regardless of prior activation or macrophage type. In contrast, bacillary replication was controlled in live phagocytes. Mtb grew as a clump in dead cells, and macrophages which internalized dead infected cells were very likely to die themselves, leading to a cell death cascade. This demonstrates how pathogen virulence can be achieved through numbers and aggregation states. DOI: http://dx.doi.org/10.7554/eLife.22028.001 PMID:28130921

  6. Creation and characterization of a cell-death reporter cell line for hepatitis C virus infection

    Science.gov (United States)

    Chen, Zhilei; Simeon, Rudo; Chockalingam, Karuppiah; Rice, Charles M.

    2010-01-01

    The present study describes the creation and characterization of a hepatoma cell line, n4mBid, that supports all stages of the hepatitis C virus (HCV) life cycle and strongly reports HCV infection by a cell-death phenotype. The n4mBid cell line is derived from the highly HCV-permissive Huh-7.5 hepatoma cell line and contains a modified Bid protein (mBid) that is cleaved and activated by the HCV serine protease NS3-4A. N4mBid exhibited a 10–20 fold difference in cell viability between the HCV-infected and mock-infected states, while the parental Huh-7.5 cells showed <2 fold difference under the same conditions. The pronounced difference in n4mBid cell viability between the HCV- and mock-infected states in a 96-well plate format points to its usefulness in cell survival-based high-throughput screens for anti-HCV molecules. The degree of cell death was found to be proportional to the intracellular load of HCV. HCV-low n4mBid cells, expressing an anti-HCV short hairpin RNA, showed a significant growth advantage over naïve cells and could be rapidly enriched after HCV infection, suggesting the possibility of using n4mBid cells for the cell survival-based selection of genetic anti-HCV factors. PMID:20188762

  7. Effects of 3-styrylchromones on metabolic profiles and cell death in oral squamous cell carcinoma cells

    Directory of Open Access Journals (Sweden)

    Hiroshi Sakagami

    2015-01-01

    Full Text Available 4H-1-benzopyran-4-ones (chromones are important naturally-distributing compounds. As compared with flavones, isoflavones and 2-styrylchromones, there are only few papers of 3-styrylchromones that have been published. We have previously reported that among fifteen 3-styrylchromone derivatives, three new synthetic compounds that have OCH3 group at the C-6 position of chromone ring, (E-3-(4-hydroxystyryl-6-methoxy-4H-chromen-4-one (compound 11, (E-6-methoxy-3-(4-methoxystyryl-4H-chromen-4-one (compound 4, (E-6-methoxy-3-(3,4,5-trimethoxystyryl-4H-chromen-4-one (compound 6 showed much higher cytotoxicities against four epithelial human oral squamous cell carcinoma (OSCC lines than human normal oral mesenchymal cells. In order to further confirm the tumor specificities of these compounds, we compared their cytotoxicities against both human epithelial malignant and non-malignant cells, and then investigated their effects on fine cell structures and metabolic profiles and cell death in human OSCC cell line HSC-2. Cytotoxicities of compounds 4, 6, 11 were assayed with MTT method. Fine cell structures were observed under transmission electron microscope. Cellular metabolites were extracted with methanol and subjected to CE-TOFMS analysis. Compounds 4, 6, 11 showed much weaker cytotoxicity against human oral keratinocyte and primary human gingival epithelial cells, as compared with HSC-2, confirming their tumor-specificity, whereas doxorubicin and 5-FU were highly cytotoxic to these normal epithelial cells, giving unexpectedly lower tumor-specificity. The most cytotoxic compound 11, induced the mitochondrial vacuolization, autophagy suppression followed by apoptosis induction, and changes in the metabolites involved in amino acid and glycerophospholipid metabolisms. Chemical modification of lead compound 11 may be a potential choice for designing new type of anticancer drugs.

  8. Human colon cancer HT-29 cell death responses to doxorubicin and Morus Alba leaves flavonoid extract.

    Science.gov (United States)

    Fallah, S; Karimi, A; Panahi, G; Gerayesh Nejad, S; Fadaei, R; Seifi, M

    2016-03-31

    The mechanistic basis for the biological properties of Morus alba flavonoid extract (MFE) and chemotherapy drug of doxorubicin on human colon cancer HT-29 cell line death are unknown. The effect of doxorubicin and flavonoid extract on colon cancer HT-29 cell line death and identification of APC gene expression and PARP concentration of HT-29 cell line were investigated. The results showed that flavonoid extract and doxorubicin induce a dose dependent cell death in HT-29 cell line. MFE and doxorubicin exert a cytotoxic effect on human colon cancer HT-29 cell line by probably promoting or induction of apoptosis.

  9. Cell proliferation and cell death are disturbed during prenatal and postnatal brain development after uranium exposure.

    Science.gov (United States)

    Legrand, M; Elie, C; Stefani, J; N Florès; Culeux, C; Delissen, O; Ibanez, C; Lestaevel, P; Eriksson, P; Dinocourt, C

    2016-01-01

    The developing brain is more susceptible to neurotoxic compounds than adult brain. It is also well known that disturbances during brain development cause neurological disorders in adulthood. The brain is known to be a target organ of uranium (U) exposure and previous studies have noted that internal U contamination of adult rats induces behavioral disorders as well as affects neurochemistry and neurophysiological properties. In this study, we investigated whether depleted uranium (DU) exposure affects neurogenesis during prenatal and postnatal brain development. We examined the structural morphology of the brain, cell death and finally cell proliferation in animals exposed to DU during gestation and lactation compared to control animals. Our results showed that DU decreases cell death in the cortical neuroepithelium of gestational day (GD) 13 embryos exposed at 40mg/L and 120mg/L and of GD18 fetuses exposed at 120mg/L without modification of the number of apoptotic cells. Cell proliferation analysis showed an increase of BrdU labeling in the dentate neuroepithelium of fetuses from GD18 at 120mg/L. Postnatally, cell death is increased in the dentate gyrus of postnatal day (PND) 0 and PND5 exposed pups at 120mg/L and is associated with an increase of apoptotic cell number only at PND5. Finally, a decrease in dividing cells is observed in the dentate gyrus of PND21 rats developmentally exposed to 120mg/L DU, but not at PND0 and PND5. These results show that DU exposure during brain development causes opposite effects on cell proliferation and cell death processes between prenatal and postnatal development mainly at the highest dose. Although these modifications do not have a major impact in brain morphology, they could affect the next steps of neurogenesis and thus might disrupt the fine organization of the neuronal network.

  10. Glutathione transferases as mediators of signaling pathways involved in cell proliferation and cell death.

    Science.gov (United States)

    Laborde, E

    2010-09-01

    Glutathione transferases (GSTs) are enzymes that catalyze the conjugation of glutathione (GSH) to a variety of electrophilic substances. Their best known role is as cell housekeepers engaged in the detoxification of xenobiotics. Recently, GSTs have also been shown to act as modulators of signal transduction pathways that control cell proliferation and cell death. Their involvement in cancer cell growth and differentiation, and in the development of resistance to anticancer agents, has made them attractive drug targets. This review is focused on the inhibition of GSTs, in particular GSTP1-1, as a potential therapeutic approach for the treatment of cancer and other diseases associated with aberrant cell proliferation.

  11. HTLV-1 Tax deregulates autophagy by recruiting autophagic molecules into lipid raft microdomains.

    Science.gov (United States)

    Ren, T; Takahashi, Y; Liu, X; Loughran, T P; Sun, S-C; Wang, H-G; Cheng, H

    2015-01-15

    The retroviral oncoprotein Tax from human T-cell leukemia virus type 1 (HTLV-1), an etiological factor that causes adult T-cell leukemia and lymphoma, has a crucial role in initiating T-lymphocyte transformation by inducing oncogenic signaling activation. We here report that Tax is a determining factor for dysregulation of autophagy in HTLV-1-transformed T cells and Tax-immortalized CD4 memory T cells. Tax facilitated autophagic process by activating inhibitor of κB (IκB) kinase (IKK) complex, which subsequently recruited an autophagy molecular complex containing Beclin1 and Bif-1 to the lipid raft microdomains. Tax engaged a crosstalk between IKK complex and autophagic molecule complex by directly interacting with both complexes, promoting assembly of LC3+ autophagosomes. Moreover, expression of lipid raft-targeted Bif-1 or Beclin1 was sufficient to induce formation of LC3+ autophagosomes, suggesting that Tax recruitment of autophagic molecules to lipid rafts is a dominant strategy to deregulate autophagy in the context of HTLV-1 transformation of T cells. Furthermore, depletion of autophagy molecules such as Beclin1 and PI3 kinase class III resulted in impaired growth of HTLV-1-transformed T cells, indicating a critical role of Tax-deregulated autophagy in promoting survival and transformation of virally infected T cells.

  12. Demonstration of different modes of cell death upon herpes simplex virus 1 infection in different types of oral cells.

    Science.gov (United States)

    Huang, C R; Lin, S S; Chou, M Y; Ho, C C; Wang, L; Lee, Y L; Chen, C S; Yang, C C

    2005-01-01

    The effects of Herpes simplex virus 1 (HSV-1) infection on five different types of oral cancerous cells (neck metastasis of gingival carcinoma (GNM) cells and tongue squamous cells of carcinoma (TSCCa) and non-cancerous cells (buccal mucosal fibroblasts (BF), gingival fibroblasts (GF), oral submucosal fibrosis cells (OSF)) and one type of non-oral cancerous cells (KB cells) were investigated. In HSV-1-infected cells the cell viability, CPE, viral antigens accumulation, caspase-3 activity, annexin V binding and DNA fragmentation were estimated. Three different forms or pathways of cell death were considered: apoptosis (the presence or rise of caspase-3 activity, DNA fragmentation and annexin V binding), slow cell death (the presence or rise of DNA fragmentation, the absence or decline of caspase-3 activity and annexin V binding), and necrosis (the absence of decline of caspase-3 activity, DNA fragmentation and annexin V binding). The viability of all cell types, except for KB cells, was reduced by the infection. CPE and viral antigens data demonstrated that all six types of cells could be infected with HSV-1. Upon HSV-1 infection there occurred (i) a classical apoptosis in GF cells, (ii) apoptosis in the early phase of infection and necrosis in the late phase of infection in GNM and TSCCa cells, (iii) slow cell death followed by necrosis in BF and OSF cells (however, these cells showed a different type of CPE), (iv) a classical slow cell death in KB cells. It is hypothesized that HSV-1 infection has a potential to induce several distinct pathways leading to cell death or several forms of cell death. Moreover, more than one pathway may be involved in the death of particular cell type. As HSV-1 was demonstrated to infect different oral and non-oral cells and cause different pathways or forms of cell death, the safety of using HSV-1 as a vector for gene therapy should be re-considered.

  13. A central role for carbon-overflow pathways in the modulation of bacterial cell death.

    Directory of Open Access Journals (Sweden)

    Vinai Chittezham Thomas

    2014-06-01

    Full Text Available Similar to developmental programs in eukaryotes, the death of a subpopulation of cells is thought to benefit bacterial biofilm development. However mechanisms that mediate a tight control over cell death are not clearly understood at the population level. Here we reveal that CidR dependent pyruvate oxidase (CidC and α-acetolactate synthase/decarboxylase (AlsSD overflow metabolic pathways, which are active during staphylococcal biofilm development, modulate cell death to achieve optimal biofilm biomass. Whereas acetate derived from CidC activity potentiates cell death in cells by a mechanism dependent on intracellular acidification and respiratory inhibition, AlsSD activity effectively counters CidC action by diverting carbon flux towards neutral rather than acidic byproducts and consuming intracellular protons in the process. Furthermore, the physiological features that accompany metabolic activation of cell death bears remarkable similarities to hallmarks of eukaryotic programmed cell death, including the generation of reactive oxygen species and DNA damage. Finally, we demonstrate that the metabolic modulation of cell death not only affects biofilm development but also biofilm-dependent disease outcomes. Given the ubiquity of such carbon overflow pathways in diverse bacterial species, we propose that the metabolic control of cell death may be a fundamental feature of prokaryotic development.

  14. Apocynin attenuates cholesterol oxidation product-induced programmed cell death by suppressing NF-κB-mediated cell death process in differentiated PC12 cells.

    Science.gov (United States)

    Lee, Da Hee; Nam, Yoon Jeong; Lee, Chung Soo

    2015-10-01

    Cholesterol oxidation products are suggested to be involved in neuronal degeneration. Apocynin has demonstrated to have anti-inflammatory and anti-oxidant effects. We assessed the effect of apocynin on the cholesterol oxidation product-induced programmed cell death in neuronal cells using differentiated PC12 cells in relation to NF-κB-mediated cell death process. 7-Ketocholesterol and 25-hydroxycholesterol decreased the levels of Bid and Bcl-2, increased the levels of Bax and p53, and induced loss of the mitochondrial transmembrane potential, release of cytochrome c and activation of caspases (-8, -9 and -3). 7-Ketocholesterol caused an increase in the levels of cytosolic and nuclear NF-κB p65, cytosolic NF-κB p50 and cytosolic phospho-IκB-α, which was inhibited by the addition of 0.5 μM Bay11-7085 (an inhibitor of NF-κB activation). Apocynin attenuated the cholesterol oxidation product-induced changes in the programmed cell death-related protein levels, NF-κB activation, production of reactive oxygen species, and depletion of GSH. The results show that apocynin appears to attenuate the cholesterol oxidation product-induced programmed cell death in PC12 cells by suppressing the activation of the mitochondrial pathway and the caspase-8- and Bid-dependent pathways that are mediated by NF-κB activation. The preventive effect appears to be associated with the inhibitory effect on the production of reactive oxygen species and depletion of GSH.

  15. γ-Tocotrienol induces paraptosis-like cell death in human colon carcinoma SW620 cells.

    Directory of Open Access Journals (Sweden)

    Jing-Shu Zhang

    Full Text Available Colorectal cancer is one of the most serious illnesses among diagnosed cancer. As a new type of anti-cancer composition from tocotrienol-rich fraction of palm oil, γ-tocotrienol is widely used in anti-cancer research. The objectives of this study were to investigate the effects of γ-tocotrienol on human colon cancer SW620 and HCT-8 cells. We showed that treatment with different concentrations of γ-tocotrienol resulted in a dose dependent inhibition of cell growth. Cell death induced by γ-tocotrienol was mediated by a paraptosis-like cell death in SW620 and HCT-8 cells. Real-time RT-PCR and western blot analyses showed that γ-tocotrienol inhibited the expression level of β-catenin, cyclin D1 and c-jun. These data suggest that a paraptosis-like cell death induced by γ-tocotrienol in SW620 cells is associated with the suppression of the Wnt signaling pathway, which offers a novel tool for treating apoptosis-resistance colon cancer.

  16. Crocin suppresses tumor necrosis factor-alpha-induced cell death of neuronally differentiated PC-12 cells.

    Science.gov (United States)

    Soeda, S; Ochiai, T; Paopong, L; Tanaka, H; Shoyama, Y; Shimeno, H

    2001-11-01

    Crocus sativus L. is used in Chinese traditional medicine to treat some disorders of the central nervous system. Crocin is an ethanol-extractable component of Crocus sativus L.; it is reported to prevent ethanol-induced impairment of learning and memory in mice. In this study, we demonstrate that crocin suppresses the effect of tumor necrosis factor (TNF)-alpha on neuronally differentiated PC-12 cells. PC-12 cells dead from exposure to TNF-alpha show apoptotic morphological changes and DNA fragmentation. These hallmark features of cell death did not appear in cells treated in the co-presence of 10 microM crocin. Moreover, crocin suppressed the TNF-alpha-induced expression of Bcl-Xs and LICE mRNAs and simultaneously restored the cytokine-induced reduction of Bcl-X(L) mRNA expression. The modulating effects of crocin on the expression of Bcl-2 family proteins led to a marked reduction of a TNF-alpha-induced release of cytochrome c from the mitochondria. Crocin also blocked the cytochrome c-induced activation of caspase-3. To learn how crocin exhibits these anti-apoptotic actions in PC-12 cells, we tested the effect of crocin on PC-12 cell death induced by daunorubicin. We found that crocin inhibited the effect of daunorubicin as well. Our findings suggest that crocin inhibits neuronal cell death induced by both internal and external apoptotic stimuli.

  17. Mechanisms of Ionizing Radiation-Induced Cell Death in Primary Lung Cells

    Science.gov (United States)

    2013-03-05

    journal of radiation biology:epublished ahead of print 35. Coggle JE, Lambert BE, Moores SR. 1986. Radiation effects in the lung. Environmental health...caspases and mitochondria. Cell Death Differ 8:829-40 46. Dimri GP, Lee X, Basile G, Acosta M, Scott G, et al. 1995. A biomarker that identifies senescent

  18. Autophagy in response to photodynamic therapy: cell survival vs. cell death

    Science.gov (United States)

    Oleinick, Nancy L.; Xue, Liang-yan; Chiu, Song-mao; Joseph, Sheeba

    2009-02-01

    Autophagy (or more properly, macroautophagy) is a pathway whereby damaged organelles or other cell components are encased in a double membrane, the autophagosome, which fuses with lysosomes for digestion by lysosomal hydrolases. This process can promote cell survival by removing damaged organelles, but when damage is extensive, it can also be a mechanism of cell death. Similar to the Kessel and Agostinis laboratories, we have reported the vigorous induction of autophagy by PDT; this was found in human breast cancer MCF-7 cells whether or not they were able to efficiently induce apoptosis. One way to evaluate the role of autophagy in PDT-treated cells is to silence one of the essential genes in the pathway. Kessel and Reiners silenced the Atg7 gene of murine leukemia L1210 cells using inhibitory RNA and found sensitization to PDT-induced cell death at a low dose of PDT, implying that autophagy is protective when PDT damage is modest. We have examined the role of autophagy in an epithelium-derived cancer cell by comparing parental and Atg7-silenced MCF-7 cells to varying doses of PDT with the phthalocyanine photosensitizer Pc 4. In contrast to L1210 cells, autophagy-deficient MCF-7 cells were more resistant to the lethal effects of PDT, as judged by clonogenic assays. A possible explanation for the difference in outcome for L1210 vs. MCF-7 cells is the greatly reduced ability of the latter to undergo apoptosis, a deficiency that may convert autophagy into a cell-death process even at low PDT doses. Experiments to investigate the mechanism(s) responsible are in process.

  19. Transcranial amelioration of inflammation and cell death after brain injury

    Science.gov (United States)

    Roth, Theodore L.; Nayak, Debasis; Atanasijevic, Tatjana; Koretsky, Alan P.; Latour, Lawrence L.; McGavern, Dorian B.

    2014-01-01

    Traumatic brain injury (TBI) is increasingly appreciated to be highly prevalent and deleterious to neurological function. At present, no effective treatment options are available, and little is known about the complex cellular response to TBI during its acute phase. To gain insights into TBI pathogenesis, we developed a novel murine closed-skull brain injury model that mirrors some pathological features associated with mild TBI in humans and used long-term intravital microscopy to study the dynamics of the injury response from its inception. Here we demonstrate that acute brain injury induces vascular damage, meningeal cell death, and the generation of reactive oxygen species (ROS) that ultimately breach the glial limitans and promote spread of the injury into the parenchyma. In response, the brain elicits a neuroprotective, purinergic-receptor-dependent inflammatory response characterized by meningeal neutrophil swarming and microglial reconstitution of the damaged glial limitans. We also show that the skull bone is permeable to small-molecular-weight compounds, and use this delivery route to modulate inflammation and therapeutically ameliorate brain injury through transcranial administration of the ROS scavenger, glutathione. Our results shed light on the acute cellular response to TBI and provide a means to locally deliver therapeutic compounds to the site of injury.

  20. Cell Death Pathways in Photodynamic Therapy of Cancer

    Directory of Open Access Journals (Sweden)

    Michael R. Hamblin

    2011-06-01

    Full Text Available Photodynamic therapy (PDT is an emerging cancer therapy that uses the combination of non-toxic dyes or photosensitizers (PS and harmless visible light to produce reactive oxygen species and destroy tumors. The PS can be localized in various organelles such as mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus and plasma membranes and this sub-cellular location governs much of the signaling that occurs after PDT. There is an acute stress response that leads to changes in calcium and lipid metabolism and causes the production of cytokines and stress response mediators. Enzymes (particularly protein kinases are activated and transcription factors are expressed. Many of the cellular responses center on mitochondria and frequently lead to induction of apoptosis by the mitochondrial pathway involving caspase activation and release of cytochrome c. Certain specific proteins (such as Bcl-2 are damaged by PDT-induced oxidation thereby increasing apoptosis, and a build-up of oxidized proteins leads to an ER-stress response that may be increased by proteasome inhibition. Autophagy plays a role in either inhibiting or enhancing cell death after PDT.

  1. Cell Death Pathways in Photodynamic Therapy of Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mroz, Pawel, E-mail: pmroz@partners.org [Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114 (United States); Department of Dermatology, Harvard Medical School, Boston, MA 02114 (United States); Yaroslavsky, Anastasia [Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114 (United States); Boston University College of Engineering, Boston, MA 02114 (United States); Kharkwal, Gitika B [Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114 (United States); Department of Dermatology, Harvard Medical School, Boston, MA 02114 (United States); Hamblin, Michael R. [Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114 (United States); Department of Dermatology, Harvard Medical School, Boston, MA 02114 (United States); Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139 (United States)

    2011-06-03

    Photodynamic therapy (PDT) is an emerging cancer therapy that uses the combination of non-toxic dyes or photosensitizers (PS) and harmless visible light to produce reactive oxygen species and destroy tumors. The PS can be localized in various organelles such as mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus and plasma membranes and this sub-cellular location governs much of the signaling that occurs after PDT. There is an acute stress response that leads to changes in calcium and lipid metabolism and causes the production of cytokines and stress response mediators. Enzymes (particularly protein kinases) are activated and transcription factors are expressed. Many of the cellular responses center on mitochondria and frequently lead to induction of apoptosis by the mitochondrial pathway involving caspase activation and release of cytochrome c. Certain specific proteins (such as Bcl-2) are damaged by PDT-induced oxidation thereby increasing apoptosis, and a build-up of oxidized proteins leads to an ER-stress response that may be increased by proteasome inhibition. Autophagy plays a role in either inhibiting or enhancing cell death after PDT.

  2. Inhibition of autophagy induced by proteasome inhibition increases cell death in human SHG-44 glioma cells

    Institute of Scientific and Technical Information of China (English)

    Peng-fei GE; Ji-zhou ZHANG; Xiao-fei WANG; Fan-kai MENG; Wen-chen LI; Yong-xin LUAN; Feng LING; Yi-nan LUO

    2009-01-01

    Aim:The ubiquitin-proteasome system (UPS) and lysosome-dependent macroautophagy (autophagy) are two major intracellular pathways for protein degradation.Recent studies suggest that proteasome inhibitors may reduce tumor growth and activate autophagy.Due to the dual roles of autophagy in tumor cell survival and death,the effect of autophagy on the destiny of glioma cells remains unclear.In this study,we sought to investigate whether inhibition of the proteasome can induce autophagy and the effects of autophagy on the fate of human SHG-44 glioma cells.Methods:The proteasome inhibitor MG-132 was used to induce autophagy in SHG-44 glioma cells,and the effect of autophagy on the survival of SHG-44 glioma cells was investigated using an autophagy inhibitor 3-MA.Cell viability was measured by MTT assay.Apoptosis and cell cycle were detected by flow cytometry.The expression of autophagy related proteins was determined by Western blot.Results:MG-132 inhibited cell proliferation,induced cell death and cell cycle arrest at G~JM phase,and activated autophagy in SHG-44 glioma cells.The expression of autophagy-related Beclin-1 and LC3-1 was significantly up-regulated and part of LC3-1 was converted into LC3-11.However,when SHG-44 glioma cells were co-treated with MG-132 and 3-MA,the cells became less viable,but cell death and cell numbers at G2/M phase increased.Moreover,the accumulation of acidic vesicular organelles was decreased,the expression of Beclin-1 and LC3 was significantly down-regulated and the conversion of LC3-11 from LC3-1 was also inhibited.Conclusion:Inhibition of the proteasome can induce autophagy in human SHG-44 glioma cells,and inhibition of autophagy increases cell death.This discovery may shed new light on the effect of autophagy on modulating the fate of SHG-44 glioma cells.

  3. Prodigiosin activates endoplasmic reticulum stress cell death pathway in human breast carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Mu-Yun [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Shen, Yuh-Chiang [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); National Research Institute of Chinese Medicine, Taipei, Taiwan (China); Lu, Chien-Hsing [Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Obstetrics and Gynecology, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Yang, Shu-Yi [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Ho, Tsing-Fen [Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Peng, Yu-Ta [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chang, Chia-Che, E-mail: chia_che@dragon.nchu.edu.tw [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China)

    2012-12-15

    Prodigiosin is a bacterial tripyrrole pigment with potent cytotoxicity against diverse human cancer cell lines. Endoplasmic reticulum (ER) stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable. In this study, the role of ER stress in prodigiosin-induced cytotoxicity was elucidated for the first time. Comparable to the ER stress inducer thapsigargin, prodigiosin up-regulated signature ER stress markers GRP78 and CHOP in addition to activating the IRE1, PERK and ATF6 branches of the unfolded protein response (UPR) in multiple human breast carcinoma cell lines, confirming prodigiosin as an ER stress inducer. Prodigiosin transcriptionally up-regulated CHOP, as evidenced by its promoting effect on the CHOP promoter activity. Of note, knockdown of CHOP effectively lowered prodigiosin's capacity to evoke PARP cleavage, reduce cell viability and suppress colony formation, highlighting an essential role of CHOP in prodigiosin-induced cytotoxic ER stress response. In addition, prodigiosin down-regulated BCL2 in a CHOP-dependent manner. Importantly, restoration of BCL2 expression blocked prodigiosin-induced PARP cleavage and greatly enhanced the survival of prodigiosin-treated cells, suggesting that CHOP-dependent BCL2 suppression mediates prodigiosin-elicited cell death. Moreover, pharmacological inhibition of JNK by SP600125 or dominant-negative blockade of PERK-mediated eIF2α phosphorylation impaired prodigiosin-induced CHOP up-regulation and PARP cleavage. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Mechanistically, prodigiosin engages the IRE1–JNK and PERK–eIF2α branches of the UPR signaling to up-regulate CHOP, which in turn mediates BCL2 suppression to induce cell death. Highlights: ► Prodigiosin is a bacterial tripyrrole pigment with potent anticancer effect. ► Prodigiosin is herein identified

  4. c-di-GMP induction of Dictyostelium cell death requires the polyketide DIF-1.

    Science.gov (United States)

    Song, Yu; Luciani, Marie-Françoise; Giusti, Corinne; Golstein, Pierre

    2015-02-15

    Cell death in the model organism Dictyostelium, as studied in monolayers in vitro, can be induced by the polyketide DIF-1 or by the cyclical dinucleotide c-di-GMP. c-di-GMP, a universal bacterial second messenger, can trigger innate immunity in bacterially infected animal cells and is involved in developmental cell death in Dictyostelium. We show here that c-di-GMP was not sufficient to induce cell death in Dictyostelium cell monolayers. Unexpectedly, it also required the DIF-1 polyketide. The latter could be exogenous, as revealed by a telling synergy between c-di-GMP and DIF-1. The required DIF-1 polyketide could also be endogenous, as shown by the inability of c-di-GMP to induce cell death in Dictyostelium HMX44A cells and DH1 cells upon pharmacological or genetic inhibition of DIF-1 biosynthesis. In these cases, c-di-GMP-induced cell death was rescued by complementation with exogenous DIF-1. Taken together, these results demonstrated that c-di-GMP could trigger cell death in Dictyostelium only in the presence of the DIF-1 polyketide or its metabolites. This identified another element of control to this cell death and perhaps also to c-di-GMP effects in other situations and organisms.

  5. Depletion of the AP-1 repressor JDP2 induces cell death similar to apoptosis

    DEFF Research Database (Denmark)

    Lerdrup, Mads; Holmberg, Christian Henrik; Dietrich, Nikolaj;

    2005-01-01

    depletion of JDP2 resulted in p53-independent cell death that resembles apoptosis and was evident at 72 h. The death mechanism was caspase dependent as the cells could be rescued by treatment with caspase inhibitor zVAD. Our studies suggest that JDP2 functions as a general survival protein, not only...

  6. Reversal of an immunity associated plant cell death program by the growth regulator auxin

    Directory of Open Access Journals (Sweden)

    Gopalan Suresh

    2008-12-01

    Full Text Available Abstract Background One form of plant immunity against pathogens involves a rapid host programmed cell death at the site of infection accompanied by the activation of local and systemic resistance to pathogens, termed the hypersensitive response (HR. In this work it was tested (i if the plant growth regulator auxin can inhibit the cell death elicited by a purified proteinaceous HR elicitor, (ii how far down the process this inhibition can be achieved, and (iii if the inhibition affects reporters of immune response. The effect of constitutive modulation of endogenous auxin levels in transgenic plants on this cell death program was also evaluated. Results The HR programmed cell death initiated by a bacterial type III secretion system dependent proteinaceous elicitor harpin (from Erwinia amylovora can be reversed till very late in the process by the plant growth regulator auxin. Early inhibition or late reversal of this cell death program does not affect marker genes correlated with local and systemic resistance. Transgenic plants constitutively modulated in endogenous levels of auxin are not affected in ability or timing of cell death initiated by harpin. Conclusion These data indicate that the cell death program initiated by harpin can be reversed till late in the process without effect on markers strongly correlated with local and systemic immunity. The constitutive modulation of endogenous auxin does not affect equivalent signaling processes affecting cell death or buffers these signals. The concept and its further study has utility in choosing better strategies for treating mammalian and agricultural diseases.

  7. Hypermutator Salmonella Heidelberg induces an early cell death in epithelial cells.

    Science.gov (United States)

    Le Gall-David, Sandrine; Zenbaa, Neila; Bouchard, Damien; Lavault, Marie-Thérèse; Bonnaure-Mallet, Martine; Jolivet-Gougeon, Anne; Bousarghin, Latifa

    2015-10-22

    We have previously described that a strain of Salmonella Heidelberg with a hypermutator phenotype, B182, adhered strongly to HeLa cells. In this work, we showed that this hypermutator Salmonella strain invaded HeLa epithelial cells and induced cytoskeleton alteration. Those changes lead to HeLa cell death which was characteristic of apoptosis. For the first time, we showed that this hypermutator strain induced apoptosis associated with the activation of caspases 2, 9 and 3. Complementation of B182 strain showed a decrease in cells death induction. In the presence of other Salmonella Heidelberg with a normomutator phenotype, such as WT and SL486, cell death and caspase 3 were undetectable. These results suggested that early apoptosis and caspase 3 activation were specific to B182. Besides, B182 induced LDH release and caspase 3 activation in CaCo-2 and HCT116 cells. Heat-treated B182 and diffusible products failed to induce this phenotype. Epithelial cells treatment with cytochalasin D caused the inhibition of B182 internalisation and caspase 3 activation. These results showed that this cell death required active S. Heidelberg B182 protein synthesis and bacterial internalisation. However sipB and sopB, usually involved in apoptosis induced by Salmonella were not overexpressed in B182, contrary to fimA and fliC. Comparative genome analysis showed numerous mutations as in rpoS which would be more investigated. The role of the hypermutator phenotype might be suspected to be implicated in these specific features. This result expands our knowledge about strong mutators frequently found in bacterial organisms isolated from clinical specimens.

  8. Cell death associated with abnormal mitosis observed by confocal imaging in live cancer cells.

    Science.gov (United States)

    Castiel, Asher; Visochek, Leonid; Mittelman, Leonid; Zilberstein, Yael; Dantzer, Francoise; Izraeli, Shai; Cohen-Armon, Malka

    2013-08-21

    Phenanthrene derivatives acting as potent PARP1 inhibitors prevented the bi-focal clustering of supernumerary centrosomes in multi-centrosomal human cancer cells in mitosis. The phenanthridine PJ-34 was the most potent molecule. Declustering of extra-centrosomes causes mitotic failure and cell death in multi-centrosomal cells. Most solid human cancers have high occurrence of extra-centrosomes. The activity of PJ-34 was documented in real-time by confocal imaging of live human breast cancer MDA-MB-231 cells transfected with vectors encoding for fluorescent γ-tubulin, which is highly abundant in the centrosomes and for fluorescent histone H2b present in the chromosomes. Aberrant chromosomes arrangements and de-clustered γ-tubulin foci representing declustered centrosomes were detected in the transfected MDA-MB-231 cells after treatment with PJ-34. Un-clustered extra-centrosomes in the two spindle poles preceded their cell death. These results linked for the first time the recently detected exclusive cytotoxic activity of PJ-34 in human cancer cells with extra-centrosomes de-clustering in mitosis, and mitotic failure leading to cell death. According to previous findings observed by confocal imaging of fixed cells, PJ-34 exclusively eradicated cancer cells with multi-centrosomes without impairing normal cells undergoing mitosis with two centrosomes and bi-focal spindles. This cytotoxic activity of PJ-34 was not shared by other potent PARP1 inhibitors, and was observed in PARP1 deficient MEF harboring extracentrosomes, suggesting its independency of PARP1 inhibition. Live confocal imaging offered a useful tool for identifying new molecules eradicating cells during mitosis.

  9. Etoposide Induces Mitochondria-Associated Apoptotic Cell Death in Human Gastric Carcinoma Cells

    Institute of Scientific and Technical Information of China (English)

    LI Jing-hua; CHEN Yue; WANG Jia-si; KONG Wei; JIN Ying-hua

    2008-01-01

    Recent observations indicate that the resistance of apoptosis is an important process of tumor metastasis and metastases are the cause of 90% of human cancer death.Etoposide,a semisynthetic derivative of the podophyllotoxins,is a clinically used anti-cancer reagent,but the effects of it on metastatic gastric carcinoma cells are totally unknown.In this study,etoposide induced apoptotic cell death in human gastric adenocareinoma cell line SGC-7901,derived from metastatic lymph nodes,as evidenced by the analysis of DNA fragmentation,apoptotic body formation,caspase activation,and apoptosis specific changes in cell morphology is demonstrated.The depolarization of mitochondrial membrane and the release of cytochrome c were most early events in etoposide treated SGC-7901 cells,and were followed by caspase-3 activation and PARP cleavage.Caspase-8 activation was not detected under the same condition.Thus,it was proposed that etoposide induces caspase-associated apoptotic cell death in human metastatic gastric carcinoma,which is initiated by mitochondrial cytochrome c release.

  10. Programmed cell death features in apple suspension cells under low oxygen culture.

    Science.gov (United States)

    Xu, Chang-jie; Chen, Kun-song; Ferguson, Ian B

    2004-02-01

    Suspension-cultured apple fruit cells (Malus pumila Mill. cv. Braeburn) were exposed to a low oxygen atmosphere to test whether programmed cell death (PCD) has a role in cell dysfunction and death under hypoxic conditions. Protoplasts were prepared at various times after low oxygen conditions were established, and viability tested by triple staining with fluorescein diacetate (FDA), propidium iodide (PI) and Hoechst33342 (HO342). DNA breakdown and phosphatidylserine exposure on the plasma membrane were observed using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and annexin V binding. About 30% of protoplasts from cells after 48 h under low oxygen showed an increased accumulation of HO342, indicating increased membrane permeability. Positive TUNEL and annexin V results were also only obtained with protoplasts from cells under low oxygen. The results suggest that apple cell death under low oxygen is at least partially PCD mediated, and may explain tissue breakdown under controlled atmosphere (low oxygen) conditions in apple fruit.

  11. Programmed cell death features in apple suspension cells under low oxygen culture

    Institute of Scientific and Technical Information of China (English)

    XU Chang-jie(徐昌杰); CHEN Kun-song(陈昆松); FERGUSON Ian B.

    2004-01-01

    Suspension-cultured apple fruit cells (Malus pumila Mill. cv. Braeburn) were exposed to a low oxygen atmosphere to test whether programmed cell death (PCD) has a role in cell dysfunction and death under hypoxic conditions. Protoplasts were prepared at various times after low oxygen conditions were established, and viability tested by triple staining with fluorescein diacetate (FDA), propidium iodide (PI) and Hoechst33342 (HO342). DNA breakdown and phosphatidylserine exposure on the plasma membrane were observed using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and annexin V binding. About 30% of protoplasts from cells after 48 h under low oxygen showed an increased accumulation of HO342, indicating increased membrane permeability. Positive TUNEL and annexin V results were also only obtained with protoplasts from cells under low oxygen. The results suggest that apple cell death under low oxygen is at least partially PCD mediated, and may explain tissue breakdown under controlled atmosphere (low oxygen) conditions in apple fruit.

  12. Crotamine and crotoxin interact with tumor cells and trigger cell death

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Marcella Araugio; Pujatti, Priscilla Brunelli; Santos, Raquel Gouvea dos [Centro de Desenvolvimento da Tecnologia Nuclear CDTN/CNEN-MG, Belo Horizonte, MG (Brazil)]. E-mails: maso@cdtn.br; santosr@cdtn.br; Dias, Consuelo Latorre Fortes [Fundacao Ezequiel Dias FUNED, Belo Horizonte, MG (Brazil); Chavez Olortegui, Carlos Delfin [Universidade Federal de Minas Gerais UFMG, Belo Horizonte, MG (Brazil). Inst. de Ciencias Biologicas; Santos, Wagner Gouvea dos [Medical College of Virginia, Richmond, VA (United States). Neurosurgery Dept.

    2007-07-01

    Crotoxin (Crtx) and Crotamine (Crota) are polypeptides isolated from Crotalus durissus terrificus snake venom (CV). Previous reports have been shown therapeutic effects of Crotalus durissus terrificus venom and Crtx on skin, breast and lung tumours, although, the mechanisms of this antitumoral effect are still unknown. The aim of this work was to investigate the antitumoral effect of Crtx and Crota on brain tumours cells (GH3 and RT2) in vitro and their capacity of interaction with these tumour cells membranes. Cell survival after Crtx and Crota treatment was evaluated by MTT assay in different times post-treatment and apoptosis was evaluated by DAPI staining. In order to evaluate the specific interaction of Crtx and Crota, these polypeptides were radiolabelled, using {sup 125}I as radiotracer and binding assays were performed. The results were compared with the binding in nontumoral brain tissue. Crtx and Crota induced apoptosis on both tumour cells lineages but, Crota was more powerful than Crtx 90% and 20% cell death for RT2 cells; 80% and 20% cell death for GH3 cells, respectively). Both {sup 125}I-Crtx and {sup 125}I-Crota bound specifically in glioblastoma membranes. Nonetheless, CV polypeptides recognised glioblastoma cells with higher specificity than normal brain tissue. These results suggest that the Crtx and Crota interactions with the plasmatic membrane of tumour cells may be the first step of the cascade of signalling that trigger their antitumoral effect. (author)

  13. Breast cancer cells with acquired antiestrogen resistance are sensitized to cisplatin-induced cell death

    DEFF Research Database (Denmark)

    Yde, Christina Westmose; Gyrd-Hansen, Mads; Lykkesfeldt, Anne E

    2007-01-01

    for future breast cancer treatment. In this study, we have investigated the effect of the chemotherapeutic compound cisplatin using a panel of antiestrogen-resistant breast cancer cell lines established from the human breast cancer cell line MCF-7. We show that the antiestrogen-resistant cells...... with parental MCF-7 cells. Our data show that Bcl-2 can protect antiestrogen-resistant breast cancer cells from cisplatin-induced cell death, indicating that the reduced expression of Bcl-2 in the antiestrogen-resistant cells plays a role in sensitizing the cells to cisplatin treatment.......Antiestrogens are currently used for treating breast cancer patients who have estrogen receptor-positive tumors. However, patients with advanced disease will eventually develop resistance to the drugs. Therefore, compounds effective on antiestrogen-resistant tumors will be of great importance...

  14. Berberine induces caspase-independent cell death in colon tumor cells through activation of apoptosis-inducing factor.

    Directory of Open Access Journals (Sweden)

    Lihong Wang

    Full Text Available Berberine, an isoquinoline alkaloid derived from plants, is a traditional medicine for treating bacterial diarrhea and intestinal parasite infections. Although berberine has recently been shown to suppress growth of several tumor cell lines, information regarding the effect of berberine on colon tumor growth is limited. Here, we investigated the mechanisms underlying the effects of berberine on regulating the fate of colon tumor cells, specifically the mouse immorto-Min colonic epithelial (IMCE cells carrying the Apc(min mutation, and of normal colon epithelial cells, namely young adult mouse colonic epithelium (YAMC cells. Berberine decreased colon tumor colony formation in agar, and induced cell death and LDH release in a time- and concentration-dependent manner in IMCE cells. In contrast, YAMC cells were not sensitive to berberine-induced cell death. Berberine did not stimulate caspase activation, and PARP cleavage and berberine-induced cell death were not affected by a caspase inhibitor in IMCE cells. Rather, berberine stimulated a caspase-independent cell death mediator, apoptosis-inducing factor (AIF release from mitochondria and nuclear translocation in a ROS production-dependent manner. Amelioration of berberine-stimulated ROS production or suppression of AIF expression blocked berberine-induced cell death and LDH release in IMCE cells. Furthermore, two targets of ROS production in cells, cathepsin B release from lysosomes and PARP activation were induced by berberine. Blockage of either of these pathways decreased berberine-induced AIF activation and cell death in IMCE cells. Thus, berberine-stimulated ROS production leads to cathepsin B release and PARP activation-dependent AIF activation, resulting in caspase-independent cell death in colon tumor cells. Notably, normal colon epithelial cells are less susceptible to berberine-induced cell death, which suggests the specific inhibitory effects of berberine on colon tumor cell growth.

  15. Delayed cell death associated with mitotic catastrophe in γ-irradiated stem-like glioma cells

    Directory of Open Access Journals (Sweden)

    Esser Norbert

    2011-06-01

    Full Text Available Abstract Background and Purpose Stem-like tumor cells are regarded as highly resistant to ionizing radiation (IR. Previous studies have focused on apoptosis early after irradiation, and the apoptosis resistance observed has been attributed to reduced DNA damage or enhanced DNA repair compared to non-stem tumor cells. Here, early and late radioresponse of patient-derived stem-like glioma cells (SLGCs and differentiated cells directly derived from them were examined for cell death mode and the influence of stem cell-specific growth factors. Materials and methods Primary SLGCs were propagated in serum-free medium with the stem-cell mitogens epidermal growth factor (EGF and fibroblast growth factor-2 (FGF-2. Differentiation was induced by serum-containing medium without EGF and FGF. Radiation sensitivity was evaluated by assessing proliferation, clonogenic survival, apoptosis, and mitotic catastrophe. DNA damage-associated γH2AX as well as p53 and p21 expression were determined by Western blots. Results SLGCs failed to apoptose in the first 4 days after irradiation even at high single doses up to 10 Gy, but we observed substantial cell death later than 4 days postirradiation in 3 of 6 SLGC lines treated with 5 or 10 Gy. This delayed cell death was observed in 3 of the 4 SLGC lines with nonfunctional p53, was associated with mitotic catastrophe and occurred via apoptosis. The early apoptosis resistance of the SLGCs was associated with lower γH2AX compared to differentiated cells, but we found that the stem-cell culture cytokines EGF plus FGF-2 strongly reduce γH2AX levels. Nonetheless, in two p53-deficient SLGC lines examined γIR-induced apoptosis even correlated with EGF/FGF-induced proliferation and mitotic catastrophe. In a line containing CD133-positive and -negative stem-like cells, the CD133-positive cells proliferated faster and underwent more γIR-induced mitotic catastrophe. Conclusions Our results suggest the importance of delayed

  16. Cell death induced by the application of alternating magnetic fields to nanoparticle-loaded dendritic cells

    Energy Technology Data Exchange (ETDEWEB)

    Marcos-Campos, I; AsIn, L; Torres, T E; Tres, A; Ibarra, M R; Goya, G F [Instituto de Nanociencia de Aragon (INA), Mariano Esquillor s/n, CP 50018, Zaragoza (Spain); Marquina, C, E-mail: goya@unizar.es [Condensed Matter Department, Sciences Faculty, University of Zaragoza, 50009 (Spain)

    2011-05-20

    In this work, the capability of primary, monocyte-derived dendritic cells (DCs) to uptake iron oxide magnetic nanoparticles (MNPs) is assessed and a strategy to induce selective cell death in these MNP-loaded DCs using external alternating magnetic fields (AMFs) is reported. No significant decrease in the cell viability of MNP-loaded DCs, compared to the control samples, was observed after five days of culture. The number of MNPs incorporated into the cytoplasm was measured by magnetometry, which confirmed that 1-5 pg of the particles were uploaded per cell. The intracellular distribution of these MNPs, assessed by transmission electron microscopy, was found to be primarily inside the endosomic structures. These cells were then subjected to an AMF for 30 min and the viability of the blank DCs (i.e. without MNPs), which were used as control samples, remained essentially unaffected. However, a remarkable decrease of viability from approximately 90% to 2-5% of DCs previously loaded with MNPs was observed after the same 30 min exposure to an AMF. The same results were obtained using MNPs having either positive (NH{sub 2}{sup +}) or negative (COOH{sup -}) surface functional groups. In spite of the massive cell death induced by application of AMF to MNP-loaded DCs, the number of incorporated magnetic particles did not raise the temperature of the cell culture. Clear morphological changes at the cell structure after magnetic field application were observed using scanning electron microscopy. Therefore, local damage produced by the MNPs could be the main mechanism for the selective cell death of MNP-loaded DCs under an AMF. Based on the ability of these cells to evade the reticuloendothelial system, these complexes combined with an AMF should be considered as a potentially powerful tool for tumour therapy.

  17. Cell death induced by the application of alternating magnetic fields to nanoparticle-loaded dendritic cells

    Science.gov (United States)

    Marcos-Campos, I.; Asín, L.; Torres, T. E.; Marquina, C.; Tres, A.; Ibarra, M. R.; Goya, G. F.

    2011-05-01

    In this work, the capability of primary, monocyte-derived dendritic cells (DCs) to uptake iron oxide magnetic nanoparticles (MNPs) is assessed and a strategy to induce selective cell death in these MNP-loaded DCs using external alternating magnetic fields (AMFs) is reported. No significant decrease in the cell viability of MNP-loaded DCs, compared to the control samples, was observed after five days of culture. The number of MNPs incorporated into the cytoplasm was measured by magnetometry, which confirmed that 1-5 pg of the particles were uploaded per cell. The intracellular distribution of these MNPs, assessed by transmission electron microscopy, was found to be primarily inside the endosomic structures. These cells were then subjected to an AMF for 30 min and the viability of the blank DCs (i.e. without MNPs), which were used as control samples, remained essentially unaffected. However, a remarkable decrease of viability from approximately 90% to 2-5% of DCs previously loaded with MNPs was observed after the same 30 min exposure to an AMF. The same results were obtained using MNPs having either positive (NH2 + ) or negative (COOH - ) surface functional groups. In spite of the massive cell death induced by application of AMF to MNP-loaded DCs, the number of incorporated magnetic particles did not raise the temperature of the cell culture. Clear morphological changes at the cell structure after magnetic field application were observed using scanning electron microscopy. Therefore, local damage produced by the MNPs could be the main mechanism for the selective cell death of MNP-loaded DCs under an AMF. Based on the ability of these cells to evade the reticuloendothelial system, these complexes combined with an AMF should be considered as a potentially powerful tool for tumour therapy.

  18. HAMLET triggers apoptosis but tumor cell death is independent of caspases, Bcl-2 and p53.

    Science.gov (United States)

    Hallgren, O; Gustafsson, L; Irjala, H; Selivanova, G; Orrenius, S; Svanborg, C

    2006-02-01

    HAMLET (Human alpha-lactalbumin Made Lethal to Tumor cells) triggers selective tumor cell death in vitro and limits tumor progression in vivo. Dying cells show features of apoptosis but it is not clear if the apoptotic response explains tumor cell death. This study examined the contribution of apoptosis to cell death in response to HAMLET. Apoptotic changes like caspase activation, phosphatidyl serine externalization, chromatin condensation were detected in HAMLET-treated tumor cells, but caspase inhibition or Bcl-2 over-expression did not prolong cell survival and the caspase response was Bcl-2 independent. HAMLET translocates to the nuclei and binds directly to chromatin, but the death response was unrelated to the p53 status of the tumor cells. p53 deletions or gain of function mutations did not influence the HAMLET sensitivity of tumor cells. Chromatin condensation was partly caspase dependent, but apoptosis-like marginalization of chromatin was also observed. The results show that tumor cell death in response to HAMLET is independent of caspases, p53 and Bcl-2 even though HAMLET activates an apoptotic response. The use of other cell death pathways allows HAMLET to successfully circumvent fundamental anti-apoptotic strategies that are present in many tumor cells.

  19. Role of cell death in the propagation of PrP(Sc) in immune cells.

    Science.gov (United States)

    Takahashi, Kenichi; Inoshima, Yasuo; Ishiguro, Naotaka

    2015-03-01

    A number of studies have suggested that macrophages, dendritic cells, and follicular dendritic cells play an important role in the propagation of PrP(Sc). Both accumulation and proteolysis of PrP(Sc) have been demonstrated in peripheral macrophages. Macrophages may act as reservoirs for PrP(Sc) particles if the cells die during transient PrP(Sc) propagation. However, whether cell death plays a role in PrP(Sc) propagation in macrophages remains unclear. In this study, we investigated the possibility of propagation and transmission of PrP(Sc) between dead immune cells and living neural cells. We found that under specific conditions, transient PrP(Sc) propagation occurs in dead cells, indicating that interaction between PrP(C) and PrP(Sc) on plasma membrane lipid rafts might be important for PrP(Sc) propagation. Co-culturing of killed donor PrP(Sc)-infected macrophages with recipient N2a-3 neuroblastoma cells accelerated PrP(Sc) transmission. Our results suggest that cell death may play an important role in PrP(Sc) propagation, whereas transient PrP(Sc) propagation in macrophages has little effect on PrP(Sc) transmission.

  20. The phytoalexin resveratrol regulates the initiation of hypersensitive cell death in Vitis cell.

    Directory of Open Access Journals (Sweden)

    Xiaoli Chang

    Full Text Available Resveratrol is a major phytoalexin produced by plants in response to various stresses and promotes disease resistance. The resistance of North American grapevine Vitis rupestris is correlated with a hypersensitive reaction (HR, while susceptible European Vitis vinifera cv. 'Pinot Noir' does not exhibit HR, but expresses basal defence. We have shown previously that in cell lines derived from the two Vitis species, the bacterial effector Harpin induced a rapid and sensitive accumulation of stilbene synthase (StSy transcripts, followed by massive cell death in V. rupestris. In the present work, we analysed the function of the phytoalexin resveratrol, the product of StSy. We found that cv. 'Pinot Noir' accumulated low resveratrol and its glycoside trans-piceid, whereas V. rupestris produced massive trans-resveratrol and the toxic oxidative δ-viniferin, indicating that the preferred metabolitism of resveratrol plays role in Vitis resistance. Cellular responses to resveratrol included rapid alkalinisation, accumulation of pathogenesis-related protein 5 (PR5 transcripts, oxidative burst, actin bundling, and cell death. Microtubule disruption and induction of StSy were triggered by Harpin, but not by resveratrol. Whereas most responses proceeded with different amplitude for the two cell lines, the accumulation of resveratrol, and the competence for resveratrol-induced oxidative burst differed in quality. The data lead to a model, where resveratrol, in addition to its classical role as antimicrobial phytoalexin, represents an important regulator for initiation of HR-related cell death.

  1. Programmed cell death features in apple suspension cells under low oxygen culture

    Institute of Scientific and Technical Information of China (English)

    徐昌杰; 陈昆松; FERGUSONIanB

    2004-01-01

    Suspension-cultured apple fruit cells (Malus pumila Mill. cv. Braeburn) were exposed to a low oxygen atmosphere to test whether programmed cell death (PCD) has a role in cell dysfunction and death under hypoxic conditions. Protoplasts were prepared at various times after low oxygen conditions were established, and viability tested by triple staining with fluorescein diacetate (FDA), propidium iodide (PI) and Hoechst33342 (HO342). DNA breakdown and phosphatidylserine exposure on the plasma membrane were observed using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and annexin V binding. About 30% of protoplasts from cells after 48 h under low oxygen showed an increased accumulation of HO342, indicating increased membrane permeability. Positive TUNEL and annexin V results were also only obtained with protoplasts from cells under low oxygen. The results suggest that apple celi death under low oxygen is at least partially PCD mediated, and may explain tissue breakdown under controlled atmosphere (low oxygen) conditions in apple fruit.

  2. Non-cell autonomous influence of the astrocyte system xc− on hypoglycaemic neuronal cell death

    Directory of Open Access Journals (Sweden)

    Sandra J Hewett

    2012-02-01

    Full Text Available Despite longstanding evidence that hypoglycaemic neuronal injury is mediated by glutamate excitotoxicity, the cellular and molecular mechanisms involved remain incompletely defined. Here, we demonstrate that the excitotoxic neuronal death that follows GD (glucose deprivation is initiated by glutamate extruded from astrocytes via system xc− – an amino acid transporter that imports l-cystine and exports l-glutamate. Specifically, we find that depriving mixed cortical cell cultures of glucose for up to 8 h injures neurons, but not astrocytes. Neuronal death is prevented by ionotropic glutamate receptor antagonism and is partially sensitive to tetanus toxin. Removal of amino acids during the deprivation period prevents – whereas addition of l-cystine restores – GD-induced neuronal death, implicating the cystine/glutamate antiporter, system xc−. Indeed, drugs known to inhibit system xc− ameliorate GD-induced neuronal death. Further, a dramatic reduction in neuronal death is observed in chimaeric cultures consisting of neurons derived from WT (wild-type mice plated on top of astrocytes derived from sut mice, which harbour a naturally occurring null mutation in the gene (Slc7a11 that encodes the substrate-specific light chain of system xc− (xCT. Finally, enhancement of astrocytic system xc− expression and function via IL-1β (interleukin-1β exposure potentiates hypoglycaemic neuronal death, the process of which is prevented by removal of l-cystine and/or addition of system xc− inhibitors. Thus, under the conditions of GD, our studies demonstrate that astrocytes, via system xc−, have a direct, non-cell autonomous effect on cortical neuron survival.

  3. Non-cell autonomous influence of the astrocyte system xc- on hypoglycaemic neuronal cell death.

    Science.gov (United States)

    Jackman, Nicole A; Melchior, Shannon E; Hewett, James A; Hewett, Sandra J

    2012-02-08

    Despite longstanding evidence that hypoglycaemic neuronal injury is mediated by glutamate excitotoxicity, the cellular and molecular mechanisms involved remain incompletely defined. Here, we demonstrate that the excitotoxic neuronal death that follows GD (glucose deprivation) is initiated by glutamate extruded from astrocytes via system xc---an amino acid transporter that imports L-cystine and exports L-glutamate. Specifically, we find that depriving mixed cortical cell cultures of glucose for up to 8 h injures neurons, but not astrocytes. Neuronal death is prevented by ionotropic glutamate receptor antagonism and is partially sensitive to tetanus toxin. Removal of amino acids during the deprivation period prevents--whereas addition of L-cystine restores--GD-induced neuronal death, implicating the cystine/glutamate antiporter, system xc-. Indeed, drugs known to inhibit system xc- ameliorate GD-induced neuronal death. Further, a dramatic reduction in neuronal death is observed in chimaeric cultures consisting of neurons derived from WT (wild-type) mice plated on top of astrocytes derived from sut mice, which harbour a naturally occurring null mutation in the gene (Slc7a11) that encodes the substrate-specific light chain of system xc- (xCT). Finally, enhancement of astrocytic system xc- expression and function via IL-1β (interleukin-1β) exposure potentiates hypoglycaemic neuronal death, the process of which is prevented by removal of l-cystine and/or addition of system xc- inhibitors. Thus, under the conditions of GD, our studies demonstrate that astrocytes, via system xc-, have a direct, non-cell autonomous effect on cortical neuron survival.

  4. Non-Cell Autonomous Influence of the Astrocyte System xc − on Hypoglycaemic Neuronal Cell Death

    Directory of Open Access Journals (Sweden)

    Nicole A Jackman

    2012-01-01

    Full Text Available Despite longstanding evidence that hypoglycaemic neuronal injury is mediated by glutamate excitotoxicity, the cellular and molecular mechanisms involved remain incompletely defined. Here, we demonstrate that the excitotoxic neuronal death that follows GD (glucose deprivation is initiated by glutamate extruded from astrocytes via system xc −– – an amino acid transporter that imports L-cystine and exports L-glutamate. Specifically, we find that depriving mixed cortical cell cultures of glucose for up to 8 h injures neurons, but not astrocytes. Neuronal death is prevented by ionotropic glutamate receptor antagonism and is partially sensitive to tetanus toxin. Removal of amino acids during the deprivation period prevents – whereas addition of L-cystine restores – GD-induced neuronal death, implicating the cystine/glutamate antiporter, system xc−–. Indeed, drugs known to inhibit system xc −– ameliorate GD-induced neuronal death. Further, a dramatic reduction in neuronal death is observed in chimaeric cultures consisting of neurons derived from WT (wild-type mice plated on top of astrocytes derived from sut mice, which harbour a naturally occurring null mutation in the gene (Slc7a11 that encodes the substrate-specific light chain of system xc −– (xCT. Finally, enhancement of astrocytic system xc −– expression and function via IL-1β (interleukin-1β exposure potentiates hypoglycaemic neuronal death, the process of which is prevented by removal of L-cystine and/or addition of system xc −– inhibitors. Thus, under the conditions of GD, our studies demonstrate that astrocytes, via system xc −–, have a direct, non-cell autonomous effect on cortical neuron survival.

  5. Interleukin-1ß, seizures and neuronal cell death

    OpenAIRE

    Medel-Matus, Jesús S.; Postgrado en Neuroetología, Universidad Veracruzana. Xalapa, México. Centro de Investigaciones Cerebrales, Universidad Veracruzana. Xalapa, México. Químico clínico maestro en Neuroetología.; Cortijo-Palacios, Libia X.; Postgrado en Neuroetología, Universidad Veracruzana. Xalapa, México. química clínica.; Álvarez-Croda, Dulce M.; Postgrado en Neuroetología, Universidad Veracruzana. Xalapa, México. Centro de Investigaciones Cerebrales, Universidad Veracruzana. Xalapa, México. química farmacéutica bióloga.; Martínez-Quiroz, Joel; Facultad de Química Farmacéutica Biológica, Universidad Veracruzana. Xalapa, México. químico farmacéutico biólogo maestro en Ciencias Químico-Biológicas.; López-Meraz, María L.; Centro de Investigaciones Cerebrales, Universidad Veracruzana. Xalapa, México. Facultad de Medicina, Universidad Veracruzana. Xalapa, México. química farmacéutica bióloga doctora en Neurofarmacología y Terapéutica Experimental.

    2014-01-01

    Epilepsy is a neurological disorder affecting almost 1% of the world population. Experimental human and animal studies suggest that inflammation mediators, like cytokines, participate in the physiopathology of epilepsy. Interleukin-1beta (IL-1β) could influence susceptibility for seizures, as well as neuronal death caused by seizures, although some findings are contradictory. This document reviews the current knowledge establishing a connection between IL-1β, seizures and neuronal death. L...

  6. Involvement of p53 in cell death following cell cycle arrest and mitotic catastrophe induced by rotenone.

    Science.gov (United States)

    Gonçalves, António Pedro; Máximo, Valdemar; Lima, Jorge; Singh, Keshav K; Soares, Paula; Videira, Arnaldo

    2011-03-01

    In order to investigate the cell death-inducing effects of rotenone, a plant extract commonly used as a mitochondrial complex I inhibitor, we studied cancer cell lines with different genetic backgrounds. Rotenone inhibits cell growth through the induction of cell death and cell cycle arrest, associated with the development of mitotic catastrophe. The cell death inducer staurosporine potentiates the inhibition of cell growth by rotenone in a dose-dependent synergistic manner. The tumor suppressor p53 is involved in rotenone-induced cell death, since the drug treatment results in increased expression, phosphorylation and nuclear localization of the protein. The evaluation of the effects of rotenone on a p53-deficient cell line revealed that although not required for the promotion of mitotic catastrophe, functional p53 appears to be essential for the extensive cell death that occurs afterwards. Our results suggest that mitotic slippage also occurs subsequently to the rotenone-induced mitotic arrest and cells treated with the drug for a longer period become senescent. Treatment of mtDNA-depleted cells with rotenone induces cell death and cell cycle arrest as in cells containing wild-type mtDNA, but not formation of reactive oxygen species. This suggests that the effects of rotenone are not dependent from the production of reactive oxygen species. This work highlights the multiple effects of rotenone in cancer cells related to its action as an anti-mitotic drug.

  7. Proteasome inhibition-induces endoplasmic reticulum dysfunction and cell death of human cholangiocarcinoma cells

    Institute of Scientific and Technical Information of China (English)

    Yucel Ustundag; Steven F Bronk; Gregory J Gores

    2007-01-01

    AIM: To determine if proteasome inhibition induces apoptosis in human cholangiocarcinoma cells, and if so, to elucidate the cellular mechanisms.METHODS: Studies were performed in the human KMCH, KMBC, and Mz-ChA-1 cholangiocarcinoma, and normal rat cell lines. MG132, a peptide aldehyde, which inhibits the chymotrypsin-like activity of the proteaosome was employed for this study. Apoptosis was assessed morphologically by 4'-6-Diamidino-2-phenylindole (DAPI) nuclear staining and fluorescence microscopy. Mitochondrial membrane potential was examined using a fluorescent unquenching assay. Ultrastructural changes during cell death were examined using transmission electron microscopy (TEM). Caspase 3/7 activity was assessed using an enzymatic-based fluorescent assay. Cytosolic-free calcium concentrations were measured using Fura-2 and digitized fluorescent microscopy.RESULTS: MG132, a proteasome inhibitor, induced apoptosis in all the cholangiocarcinoma cell lines examined. In contrast, minimal cytotoxicity was observed in normal rat cholangiocytes. Apoptosis was time- and -concentration-dependent. There was no change in the mitochondrial membrane potential between treated and untreated cells. Ultrastructural examination by transmission electron microscopy displayed the classic features of apoptosis, but in addition, there was also dramatic vacuolization of the endoplasmic reticulum (ER). Unexpectedly, no increase in caspase 3/7 activity was observed in MG132 treated cells, nor did the pancaspase inhibitor, Q-VD-OPh prevent cell death. The protein synthesis inhibitor, cycloheximide, blocked apoptosis induced by proteosome inhibitor indicating that ER dysfunction was dependent upon the formation of new proteins.CONCLUSION:Proteosome inhibition induces ER dysfunction and caspase-independent cell death selectively in human cholangiocarcinoma cells. Proteasome inhibitors warrant evaluation as anticancer agents for the treatment of human cholangiocarcinoma.

  8. Gene expression analysis of cell death induction by Taurolidine in different malignant cell lines

    Directory of Open Access Journals (Sweden)

    Weyhe Dirk

    2010-10-01

    Full Text Available Abstract Background The anti-infective agent Taurolidine (TRD has been shown to have cell death inducing properties, but the mechanism of its action is largely unknown. The aim of this study was to identify potential common target genes modulated at the transcriptional level following TRD treatment in tumour cell lines originating from different cancer types. Methods Five different malignant cell lines (HT29, Chang Liver, HT1080, AsPC-1 and BxPC-3 were incubated with TRD (100 μM, 250 μM and 1000 μM. Proliferation after 8 h and cell viability after 24 h were analyzed by BrdU assay and FACS analysis, respectively. Gene expression analyses were carried out using the Agilent -microarray platform to indentify genes which displayed conjoint regulation following the addition of TRD in all cell lines. Candidate genes were subjected to Ingenuity Pathways Analysis and selected genes were validated by qRT-PCR and Western Blot. Results TRD 250 μM caused a significant inhibition of proliferation as well as apoptotic cell death in all cell lines. Among cell death associated genes with the strongest regulation in gene expression, we identified pro-apoptotic transcription factors (EGR1, ATF3 as well as genes involved in the ER stress response (PPP1R15A, in ubiquitination (TRAF6 and mitochondrial apoptotic pathways (PMAIP1. Conclusions This is the first conjoint analysis of potential target genes of TRD which was performed simultaneously in different malignant cell lines. The results indicate that TRD might be involved in different signal transduction pathways leading to apoptosis.

  9. Activation of ERK signaling and induction of colon cancer cell death by piperlongumine.

    Science.gov (United States)

    Randhawa, H; Kibble, K; Zeng, H; Moyer, M P; Reindl, K M

    2013-09-01

    Piperlongumine (PPLGM) is a bioactive compound isolated from long peppers that shows selective toxicity towards a variety of cancer cell types including colon cancer. The signaling pathways that lead to cancer cell death in response to PPLGM exposure have not been previously identified. Our objective was to identify the intracellular signaling mechanisms by which PPLGM leads to enhanced colon cancer cell death. We found that PPLGM inhibited the growth of colon cancer cells in time- and concentration-dependent manners, but was not toxic toward normal colon mucosal cells at concentrations below 10 μM. Acute (0-60 min) and prolonged (24h) exposure of HT-29 cells to PPLGM resulted in phosphorylation of ERK. To investigate whether ERK signaling was involved in PPLGM-mediated cell death, we treated HT-29 cells with the MEK inhibitor U0126, prior to treating with PPLGM. We found that U0126 attenuated PPLGM-induced activation of ERK and partially protected against PPLGM-induced cell death. These results suggest that PPLGM works, at least in part, through the MEK/ERK pathway to result in colon cancer cell death. A more thorough understanding of the molecular mechanisms by which PPLGM induces colon cancer cell death will be useful in developing therapeutic strategies to treat colon cancer.

  10. M867, a novel selective inhibitor of caspase-3 enhances cell death and extends tumor growth delay in irradiated lung cancer models.

    Directory of Open Access Journals (Sweden)

    Kwang Woon Kim

    Full Text Available BACKGROUND: Lung cancer remains the leading cause of cancer death worldwide. Radioresistance of lung cancer cells results in unacceptable rate of loco-regional failure. Although radiation is known to induce apoptosis, our recent study showed that knockdown of pro-apoptotic proteins Bak and Bax resulted in an increase in autophagic cell death and lung cancer radiosensitivity in vitro. To further explore the potential of apoptosis inhibition as a way to sensitize lung cancer for therapy, we tested M867, a novel chemical and reversible caspase-3 inhibitor, in combination with ionizing radiation in vivo and in vitro. METHODS AND FINDINGS: M867 reduced clonogenic survival in H460 lung cancer cells (DER = 1.27, p = 0.007 compared to the vehicle-treated treated cells. We found that administration of M867 with ionizing radiation in an in vivo mouse hind limb lung cancer model was well tolerated, and produced a significant tumor growth delay compared to radiation alone. A dramatic decrease in tumor vasculature was observed with M867 and radiation using von Willebrand factor staining. In addition, Ki67 index showed >5-fold reduction of tumor proliferation in the combination therapy group, despite the reduced levels of apoptosis observed with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining. Radiosensitizing effect of M867 through inhibiting caspases was validated using caspase-3/-7 double-knockout (DKO mouse embryonic fibroblasts (MEF cell model. Consistent with our previous study, autophagy contributed to the mechanism of increased cell death, following inhibition of apoptosis. In addition, matrigel assay showed a decrease in in vitro endothelial tubule formation during the M867/radiation combination treatment. CONCLUSIONS: M867 enhances the cytotoxic effects of radiation on lung cancer and its vasculature both in vitro and in vivo. M867 has the potential to prolong tumor growth delay by inhibiting tumor proliferation

  11. Induction of cell death by ascorbic acid derivatives in human renal carcinoma and glioblastoma cell lines.

    Science.gov (United States)

    Makino, Y; Sakagami, H; Takeda, M

    1999-01-01

    Sodium-L-ascorbate, L-ascorbic acid, D-isoascorbic acid, sodium 5,6-benzylidene-L-ascorbate and sodium-6-beta-O-galactosyl-L-ascorbate, which produce ascorbyl radicals during the oxidative degradation, also induced cytotoxicity against cultured human renal carcinoma (TC-1) and glioblastoma multiform tumor (T98G) cell lines. On the other hand, L-ascorbic acid 2-phosphate magnesium and L-ascorbic acid 2-sulfate dipotassium salt, which do not produce the ascorbyl radical, were inactive. This suggests the possible role of the ascorbyl radical for cell death induction. T98G cells were more resistant to ascorbate analogs than TC-1 and HL-60 cells, possibly due to higher intracellular glutathione concentrations. Ascorbate treatment induced rapid elevation of both intracellular concentration of cAMP and Ca2+ in HL-60 cells, but not in TC-1 and T98G cells. However, the elevation of cAMP by theophyline and N,2-dibutyryl adenosine 3,5 cyclic monophosphate (dibutyryl cAMP) resulted in a decrease in the viable cell number. This suggests the possible role of cAMP for ascorbate-induced cell death.

  12. Altered T cell surface glycosylation in HIV-1 infection results in increased susceptibility to galectin-1-induced cell death.

    Science.gov (United States)

    Lantéri, Marion; Giordanengo, Valérie; Hiraoka, Nobuyoshi; Fuzibet, Jean-Gabriel; Auberger, Patrick; Fukuda, Minoru; Baum, Linda G; Lefebvre, Jean-Claude

    2003-12-01

    The massive T cell death that occurs in HIV type 1 (HIV-1) infection contributes profoundly to the pathophysiology associated with AIDS. The mechanisms controlling cell death of both infected and uninfected T cells ("bystander" death) are not completely understood. We have shown that HIV-1 infection of T cells results in altered glycosylation of cell surface glycoproteins; specifically, it decreased sialylation and increased expression of core 2 O-glycans. Galectin-1 is an endogenous human lectin that recognizes these types of glycosylation changes and induces cell death of activated lymphocytes. Therefore we studied the possible contribution of galectin-1 in the pathophysiology of AIDS. O-glycan modifications were investigated on peripheral lymphocytes from AIDS patients. Oligosaccharides from CD43 and CD45 of CEM cells latently infected with HIV-1 were chemically analyzed. Consistent with our previous results, we show that HIV-1 infection results in accumulation of exposed lactosamine residues, oligosaccharides recognized by galectin-1 on cell surface glycoproteins. Both latently HIV-1-infected T cell lines and peripheral CD4 and CD8 T cells from AIDS patients exhibited exposed lactosamine residues and demonstrated marked susceptibility to galectin-1-induced cell death, in contrast to control cultures or cells from uninfected donors. The fraction of cells that died in response to galectin-1 exceeded the fraction of infected cells, indicating that death of uninfected cells occurred. Altered cell surface glycosylation of T cells during HIV-1 infection increases the susceptibility to galectin-1-induced cell death, and this death pathway can contribute to loss of both infected and uninfected T cells in AIDS.

  13. Spiral Phyllotaxis Pattern in an Animal Cell: A Fluid- Driven Mechanism for Red Cell Echinocytosis and Programmed Cell Death

    OpenAIRE

    Lofthouse, J. T.

    2004-01-01

    This paper demonstrates that the pattern of lipid spiculesthat emerge on the surface of red blood cells in the classic 'Discocyte to Echinocyte' shape change is a generative spiral, and presents a qualitative, fluid- driven mechanism for their production, compatible with the work of Douady and Couder. Implications for the dynamics of cell growth, plant cell phyllotaxy, programmed cell death and gravity sensitivity are explained in terms of a new qualitative model of cellular fluid dynamics.

  14. Different cell death modes of pancreatic acinar cells on macrophage activation in rats

    Institute of Scientific and Technical Information of China (English)

    LIANG Tao; LIU Tie-fu; XUE Dong-bo; SUN Bei; SHI Li-jun

    2008-01-01

    Background The pathogenesis of acute pancreatitis is complex and largely unclear. The aim of this study was to explore the relationship between modes of cell death in pancreatic acinar cells, the release of cell contents and the inflammatory response of macrophagas.Methods Our experiment included four groups: group A (the control group), group B (AR42J cells overstimulated by caerulein), group C (AR42J cells treated with lipopolysaccharide and caerulein), and group D (AR42J cells treated with octreotide and caerulein). Apoptosis and oncosis, and the release of amylase and lactate dehydrogenase (LDH) from AR42J cells were detected. Rat macrophages were stimulated by 1 ml supematant of culture medium of AR42J cells.Finally, NF-кB activation and TNF-α and IL-1β secretion by macrophages were detected.Results Oncotlc cells in group C increased while apoptctic cells decreased (P <0.05); cells in group D had the inverse reaction. The release of amylase and LDH changed directly with the occurrence of oncosis. The transcription factor NF-кB was activated and secretion of TNF-α and IL-1β were significantly higher in group C than in group B (P <0.05); in group D, these actions were significantly lower than in group B (P<0.05). This trend was in line with changes in amylase and LDH production.Conclusion There is a close relationship between modes of pancreatic acinar cell death, the release of cell contents and the inflammatory reaction of macrophages.

  15. Signal transduction pathway of nitric oxide inducing PC12 cell death

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To study signal transduction pathway of nitric oxideinducing death of PC12 cells.Methods: Cell survival rate was measured with MTT assay, and caspase-3 activity with caspase-3 assay kits after PC12 cells were incubated with sodium nitroprusside (SNP), caspase-3 inhibitor Ⅱ plus SNP or p38 inhibitor-SB203580 plus SNP.Results: SNP induced death of PC12 cells in dose- and time-dependent manner and enhanced caspase-3 activity gradually. Both caspase-3 inhibitor Ⅱ and SB203580 reduced cell death, but SB203580 reduced caspase-3 activity significantly.Conclusions: NO may induce death of PC12 cells through activation of p38 and caspase-3.

  16. Mitotic cell death in BEL-7402 cells induced by enediyne antibiotic lidamycin is associated with centrosome overduplication

    Institute of Scientific and Technical Information of China (English)

    Yue-Xin Liang; Wei Zhang; Dian-Dong Li; Hui-Tu Liu; Ping Gao; Yi-Na Sun; Rong-Guang Shao

    2004-01-01

    AIM: Mitotic cell death has been focused on in tumor therapy.However, the precise mechanisms underlying it remain unclear. We have reported previously that enediyne antibiotic lidamycin induces mitotic cell death at low concentrations in human epithelial tumor cells. The aim of this study was to investigate the possible link between centrosome dynamics and lidamycin-induced mitotic cell death in human hepatoma BEL-7402 cells. METHODS: Growth curve was established by MTT assay. Cell multinucleation was detected by staining with Hoechst 33342. Flow cytometry was used to analyze cell cycle.Aberrant centrosomes were detected by indirect immunofluorescence. Western blot and senescenceassociated β-galactosidase (SA-β-gal) staining were used to analyze protein expression and senescence-like phenotype, respectively.RESULTS: Exposure of BEL-7402 cells to a low concentration of lidamycin resulted in an increase in cells containing multiple centrosomes in association with the appearance of mitotic cell death and activation of SA-β-gal in some cells, accompanied by the changes of protein expression for the regulation of proliferation and apoptosis. The mitochondrial signaling pathway, one of the major apoptotic pathways, was not activated during mitotic cell death. The aberrant centrosomes contributed to the multipolar mitotic spindles formation, which might lead to an unbalanced division of chromosomes and mitotic cell death characterized by the manifestation of multi- or micronucleated giant cells. Cell cycle analysis revealed that the lidamycin treatment provoked the retardation at G2/M phase, which might be involved in the centrosome overduplication. CONCLUSION: Mitotic cell death and senescence can be induced by treatment of BEL-7402 cells with a low concentration of lidamycin. Centrosome dysregulation may play a critical role in mitotic failure and ultimate cell death following exposure to intermediate dose of lidamycin.

  17. Discovery of Small Molecules That Induce Lysosomal Cell Death in Cancer Cell Lines Using an Image-Based Screening Platform

    NARCIS (Netherlands)

    Pagliero, Romina J; D'Astolfo, Diego S; Lelieveld, Daphne; Pratiwi, Riyona D; Aits, Sonja; Jaattela, Marja; Martin, Nathaniel I; Klumperman, Judith; Egan, David A

    2016-01-01

    The lysosomal cell death (LCD) pathway is a caspase 3-independent cell death pathway that has been suggested as a possible target for cancer therapy, making the development of sensitive and specific high-throughput (HT) assays to identify LCD inducers highly desirable. In this study, we report a two

  18. NOPO modulates Egr-induced JNK-independent cell death in Drosophila

    Institute of Scientific and Technical Information of China (English)

    Xianjue Ma; Jiuhong Huang; Lixia Yang; Yang Yang; Wenzhe Li; Lei Xue

    2012-01-01

    Tumor necrosis factor (TNF) family ligands play essential roles in regulating a variety of cellular processes including proliferation,differentiation and survival.Expression of Drosophila TNF ortholog Eiger (Egr) induces JNK-dependent cell death,while the roles of caspases in this process remain elusive.To further delineate the Egr-triggered cell death pathway,we performed a genetic screen to identify dominant modifiers of the Egr-induced cell death phenotype.Here we report that Egr elicits a caspase-mediated cell death pathway independent of JNK signaling.Furthermore,we show NOPO,the Drosophila ortholog of TRIP (TRAF interacting protein) encoding an E3 ubiquitin ligase,modulates Egr-induced Caspase-mediated cell death through transcriptional activation of pro-apoptotic genes reaper and hid.Finally,we found Bendless and dUEV1a,an ubiquitin-conjugating E2 enzyme complex,regulates NOPO-triggered cell death.Our results indicate that the Ben-dUEV1a complex constitutes a molecular switch that bifurcates the Egr-induced cell death signaling into two pathways mediated by JNK and caspases respectively.

  19. BNip3 is a mediator of TNF-induced necrotic cell death.

    Science.gov (United States)

    Kim, Jee-Youn; Kim, Yong-Jun; Lee, Sun; Park, Jae-Hoon

    2011-02-01

    Tumor necrosis factor (TNF) is a pleiotropic cytokine involved in immune modulation, inflammatory reactions, and target cell death in many pathologic conditions. The cell death pathways triggered by TNF include the caspase-8/Bid-dependent apoptotic pathway and the caspase-independent necrosis pathway (necroptosis). While the signaling pathways activated after binding of TNF to the TNF receptor (TNFR) and subsequent insertion of Bid/Bax/Bik into the outer mitochondrial membrane are relatively well known, other cell death pathways and the participating signaling molecules remain to be clarified. BNip3 is a pro-death protein and a member of the BH3-only Bcl-2 family. When ectopically overexpressed or induced by hypoxia, BNip3 induces various types of cell death via mitochondrial or non-mitochondrial death cascades. In this study using A549 alveolar epithelial cells of the lung, we show that BNip3 is transcriptionally and translationally upregulated by TNF, and its expression level determines the sensitivity to necroptosis induced by TNF. However, BNip3 does not appear to be involved in caspase-8/Bid-dependent apoptotic cell death in these alveolar lung cells. Finally, we show that the generation of reactive oxygen species (ROS) is essential for mitochondrial insertion of BNip3, which is an important step in BNip3-induced mitochondrial catastrophe. Our results indicate that BNip3 is a candidate therapeutic target in pathologic conditions in which TNF causes tissue damage.

  20. PKC activation induces inflammatory response and cell death in human bronchial epithelial cells.

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    Hyunhee Kim

    Full Text Available A variety of airborne pathogens can induce inflammatory responses in airway epithelial cells, which is a crucial component of host defence. However, excessive inflammatory responses and chronic inflammation also contribute to different diseases of the respiratory system. We hypothesized that the activation of protein kinase C (PKC is one of the essential mechanisms of inflammatory response in airway epithelial cells. In the present study, we stimulated human bronchial lung epithelial (BEAS-2B cells with the phorbol ester Phorbol 12, 13-dibutyrate (PDBu, and examined gene expression profile using microarrays. Microarray analysis suggests that PKC activation induced dramatic changes in gene expression related to multiple cellular functions. The top two interaction networks generated from these changes were centered on NFκB and TNF-α, which are two commonly known pathways for cell death and inflammation. Subsequent tests confirmed the decrease in cell viability and an increase in the production of various cytokines. Interestingly, each of the increased cytokines was differentially regulated at mRNA and/or protein levels by different sub-classes of PKC isozymes. We conclude that pathological cell death and cytokine production in airway epithelial cells in various situations may be mediated through PKC related signaling pathways. These findings suggest that PKCs can be new targets for treatment of lung diseases.

  1. Ubiquinone-binding site mutagenesis reveals the role of mitochondrial complex II in cell death initiation.

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    Kluckova, K; Sticha, M; Cerny, J; Mracek, T; Dong, L; Drahota, Z; Gottlieb, E; Neuzil, J; Rohlena, J

    2015-05-07

    Respiratory complex II (CII, succinate dehydrogenase, SDH) inhibition can induce cell death, but the mechanistic details need clarification. To elucidate the role of reactive oxygen species (ROS) formation upon the ubiquinone-binding (Qp) site blockade, we substituted CII subunit C (SDHC) residues lining the Qp site by site-directed mutagenesis. Cell lines carrying these mutations were characterized on the bases of CII activity and exposed to Qp site inhibitors MitoVES, thenoyltrifluoroacetone (TTFA) and Atpenin A5. We found that I56F and S68A SDHC variants, which support succinate-mediated respiration and maintain low intracellular succinate, were less efficiently inhibited by MitoVES than the wild-type (WT) variant. Importantly, associated ROS generation and cell death induction was also impaired, and cell death in the WT cells was malonate and catalase sensitive. In contrast, the S68A variant was much more susceptible to TTFA inhibition than the I56F variant or the WT CII, which was again reflected by enhanced ROS formation and increased malonate- and catalase-sensitive cell death induction. The R72C variant that accumulates intracellular succinate due to compromised CII activity was resistant to MitoVES and TTFA treatment and did not increase ROS, even though TTFA efficiently generated ROS at low succinate in mitochondria isolated from R72C cells. Similarly, the high-affinity Qp site inhibitor Atpenin A5 rapidly increased intracellular succinate in WT cells but did not induce ROS or cell death, unlike MitoVES and TTFA that upregulated succinate only moderately. These results demonstrate that cell death initiation upon CII inhibition depends on ROS and that the extent of cell death correlates with the potency of inhibition at the Qp site unless intracellular succinate is high. In addition, this validates the Qp site of CII as a target for cell death induction with relevance to cancer therapy.

  2. In vitro measurement of cell death with the annexin A5 affinity assay.

    Science.gov (United States)

    van Genderen, Hugo; Kenis, Heidi; Lux, Petra; Ungeth, Lisette; Maassen, Cecile; Deckers, Niko; Narula, Jagat; Hofstra, Leo; Reutelingsperger, Chris

    2006-01-01

    One of the hallmarks of cell death is the cell surface-expression of phosphatidylserine. Expression of phosphatidylserine at the cell surface can be measured in vitro with the phosphatidylserine-binding protein annexin A5 conjugated to fluorochromes. This measurement can be made by flow cytometry or by confocal scanning-laser microscopy. The annexin A5 affinity assay comprises the incubation of cells stimulated to execute cell death with fluorescence-labeled annexin A5 and propidium iodide. Living cells are annexin A5-negative and propidium iodide negative, cells in the early phases of cell death are annexin A5 positive-and propidium iodide-negative, and secondary necrotic cells are annexin A5-positive and propidium iodide-positive. The entire procedure takes about 30 minutes for flow cytometry and 45 minutes for confocal scanning-laser microscopy. Various precautions and considerations are discussed further in the protocol described here.

  3. Deletion of Rb1 induces both hyperproliferation and cell death in murine germinal center B cells.

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    He, Zhiwen; O'Neal, Julie; Wilson, William C; Mahajan, Nitin; Luo, Jun; Wang, Yinan; Su, Mack Y; Lu, Lan; Skeath, James B; Bhattacharya, Deepta; Tomasson, Michael H

    2016-03-01

    The retinoblastoma gene (RB1) has been implicated as a tumor suppressor in multiple myeloma (MM), yet its role remains unclear because in the majority of cases with 13q14 deletions, un-mutated RB1 remains expressed from the retained allele. To explore the role of Rb1 in MM, we examined the functional consequences of single- and double-copy Rb1 loss in germinal center B cells, the cells of origin of MM. We generated mice without Rb1 function in germinal center B cells by crossing Rb1(Flox/Flox) with C-γ-1-Cre (Cγ1) mice expressing the Cre recombinase in class-switched B cells in a p107(-/-) background to prevent p107 from compensating for Rb1 loss (Cγ1-Rb1(F/F)-p107(-/-)). All mice developed normally, but B cells with two copies of Rb1 deleted (Cγ1-Rb1(F/F)-p107(-/-)) exhibited increased proliferation and cell death compared with Cγ1-Rb1(+/+)-p107(-/-) controls ex vivo. In vivo, Cγ1-Rb1(F/F)-p107(-/-) mice had a lower percentage of splenic B220+ cells and reduced numbers of bone marrow antigen-specific secreting cells compared with control mice. Our data indicate that Rb1 loss induces both cell proliferation and death in germinal center B cells. Because no B-cell malignancies developed after 1 year of observation, our data also suggest that Rb1 loss is not sufficient to transform post-germinal center B cells and that additional, specific mutations are likely required to cooperate with Rb1 loss to induce malignant transformation.

  4. Cytoprotective effects of fisetin against hypoxia-induced cell death in PC12 cells.

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    Chen, Pei-Yi; Ho, Yi-Ru; Wu, Ming-Jiuan; Huang, Shun-Ping; Chen, Po-Kong; Tai, Mi-Hsueh; Ho, Chi-Tang; Yen, Jui-Hung

    2015-01-01

    Fisetin (3,7,3',4'-tetrahydroxyflavone), a flavonol compound of flavonoids, exhibits a broad spectrum of biological activities including anti-oxidant, anti-inflammatory, anti-cancer and neuroprotective effects. The aim of this study is to investigate the cytoprotective effect of fisetin and the underlying molecular mechanism against hypoxia-induced cell death in PC12 cells. The results of this study showed that fisetin significantly restored the cell viability of PC12 cells under both cobalt chloride (CoCl₂)- and low oxygen-induced hypoxic conditions. Treatment with fisetin successfully reduced the CoCl₂-mediated reactive oxygen species (ROS) production, which was accompanied by an increase in the cell viability of PC12 cells. Furthermore, we found that treatment of PC12 cells with fisetin markedly upregulated hypoxia-inducible factor 1α (HIF-1α), its nuclear accumulation and the hypoxia-response element (HRE)-driven transcriptional activation. The fisetin-mediated cytoprotection during CoCl₂ exposure was significantly attenuated through the administration of HIF-1α siRNA. Moreover, we demonstrated that MAPK/ERK kinase 1/2 (MEK1/2), p38 MAPK and phosphatidylinositol 3-kinase (PI3 K) inhibitors significantly blocked the increase in cell survival that was induced by fisetin treatment under hypoxic conditions. Consistently, increased phosphorylation of ERK, p38 and Akt proteins was observed in PC12 cells treated with fisetin. However, the fisetin-induced HRE-driven transcription was not affected by inhibition of these kinase signaling pathways. Current results reveal for the first time that fisetin promotes cell survival and protects against hypoxia-induced cell death through ROS scavenging and the activation of HIF1α-, MAPK/ERK-, p38 MAPK- and PI3 K/Akt-dependent signaling pathways in PC12 cells.

  5. Nitric oxide induces cell death by regulating anti-apoptotic BCL-2 family members.

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    Colleen M Snyder

    Full Text Available Nitric oxide (NO activates the intrinsic apoptotic pathway to induce cell death. However, the mechanism by which this pathway is activated in cells exposed to NO is not known. Here we report that BAX and BAK are activated by NO and that cytochrome c is released from the mitochondria. Cells deficient in Bax and Bak or Caspase-9 are completely protected from NO-induced cell death. The individual loss of the BH3-only proteins, Bim, Bid, Puma, Bad or Noxa, or Bid knockdown in Bim(-/-/Puma(-/- MEFs, does not prevent NO-induced cell death. Our data show that the anti-apoptotic protein MCL-1 undergoes ASK1-JNK1 mediated degradation upon exposure to NO, and that cells deficient in either Ask1 or Jnk1 are protected against NO-induced cell death. NO can inhibit the mitochondrial electron transport chain resulting in an increase in superoxide generation and peroxynitrite formation. However, scavengers of ROS or peroxynitrite do not prevent NO-induced cell death. Collectively, these data indicate that NO degrades MCL-1 through the ASK1-JNK1 axis to induce BAX/BAK-dependent cell death.

  6. Phenoxide-Bridged Zinc(II)-Bis(dipicolylamine) Probes for Molecular Imaging of Cell Death.

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    Clear, Kasey J; Harmatys, Kara M; Rice, Douglas R; Wolter, William R; Suckow, Mark A; Wang, Yuzhen; Rusckowski, Mary; Smith, Bradley D

    2016-02-17

    Cell death is involved in many pathological conditions, and there is a need for clinical and preclinical imaging agents that can target and report cell death. One of the best known biomarkers of cell death is exposure of the anionic phospholipid phosphatidylserine (PS) on the surface of dead and dying cells. Synthetic zinc(II)-bis(dipicolylamine) (Zn2BDPA) coordination complexes are known to selectively recognize PS-rich membranes and act as cell death molecular imaging agents. However, there is a need to improve in vivo imaging performance by selectively increasing target affinity and decreasing off-target accumulation. This present study compared the cell death targeting ability of two new deep-red fluorescent probes containing phenoxide-bridged Zn2BDPA complexes. One probe was a bivalent version of the other and associated more strongly with PS-rich liposome membranes. However, the bivalent probe exhibited self-quenching on the membrane surface, so the monovalent version produced brighter micrographs of dead and dying cells in cell culture and also better fluorescence imaging contrast in two living animal models of cell death (rat implanted tumor with necrotic core and mouse thymus atrophy). An (111)In-labeled radiotracer version of the monovalent probe also exhibited selective cell death targeting ability in the mouse thymus atrophy model, with relatively high amounts detected in dead and dying tissue and low off-target accumulation in nonclearance organs. The in vivo biodistribution profile is the most favorable yet reported for a Zn2BDPA complex; thus, the monovalent phenoxide-bridged Zn2BDPA scaffold is a promising candidate for further development as a cell death imaging agent in living subjects.

  7. HIV-1 Vpr-induced cell death in Schizosaccharomyces pombe is reminiscent of apoptosis

    Institute of Scientific and Technical Information of China (English)

    Sylvain Huard; Mingzhong Chen; Kristen E Burdette; Csaba Fenyvuesvolgyi; Min Yu; Robert T Elder; Richard Y Zhao

    2008-01-01

    Human immunodeficiency virus type 1 (HIV-1) Vpr induces cell death in mammalian and fission yeast cells,suggesting that Vpr may affect a conserved cellular process. It is unclear,however,whether Vpr-induced yeast cell death mimics Vpr-mediated apoptosis in mammalian cells. We have recently identified a number of Vpr suppressors that not only suppress Vpr-induced cell death in fission yeast,but also block Vpr-induced apoptosis in mammalian cells. These findings suggest that Vpr-induced cell death in yeast may resemble some of the apoptotic processes of mammalian cells.The goal of this study was to develop and validate a fission yeast model system for future studies of apoptosis. Similar to Vpr-induced apoptosis in mammalian cells,we show here that Vpr in fission yeast promotes phosphatidylserine externalization and induces hyperpolarization of mitochondria,leading to changes of mitochondrial membrane potential. Moreover,Vpr triggers production of reactive oxygen species (ROS),indicating that the apoptotic-like cell death might be mediated by ROS. Interestingly,Vpr induces unique morphologic changes in mitochondria that may provide a simple marker for measuring the apoptotic-like process in fission yeast. To verify this possibility,we tested two Vpr suppressors (EF2 and Hspl6) that suppress Vpr-induced apoptosis in mammalian cells in addition to a newly identified Vpr suppressor (Skp1). All three proteins abolished cell death mediated by Vpr and restored normal mitochondrialmorphology in the yeast cells. In conclusion,Vpr-induced cell death in fission yeast resembles the mammalian apoptotic process. Fission yeast may thus potentially be used as a simple model organism for the future study of the apoptotic-like process induced by Vpr and other proapoptotic agents.

  8. Melatonin attenuates 1-methyl-4-phenylpyridinium-induced PC12 cell death

    Institute of Scientific and Technical Information of China (English)

    Jin-feng BAO; Ren-gang WU; Xiao-ping ZHANG; Yan SONG; Chang-ling LI

    2005-01-01

    Aim: To explore the effect of melatonin on PC12 cell death induced by 1-methyl-4-phenylpyridinium (MPP+). Methods: MTT assay, lactate dehydrogenase (LDH)efflux assay, and immunohistochemistry methods were used to measure neurotoxicity of PC 12 cells treated acutely with MPP+ in low glucose and high glucose conditions, and to assess the neuroprotective effect of melatonin on PC 12 cell death induced by MPP+. Results: In a low glucose condition, MPP+ significantly induced PC 12 cell death, which showed time and concentration dependence. In a serum-free low glucose condition, the percentages of viability of cells treated with MPP+ for 12, 24, 48, 72, and 96 h were 85.1%, 75.4%, 64.9%, 28.15%, and 9%, respectively. The level of LDH in the culture medium increased and tyrosine hydroxylase positive (TH+) cell count decreased. However, in a serum-free high glucose condition, MPP+ did not significantly induce PC12 cell death compared with control at various concentrations and time regimens. When the cells were preincubated with melatonin 250 μmol/L for 48, 72, and 96 h in a serum-free low glucose condition, cell survival rate significantly increased to 78.1%, 58.8%, and 31.6%, respectively. Melatonin abolished the LDH leakage of cells treated with MPP+ and increased TH+ cells count. Conclusion: MPP+ caused concentrationdependent PC12 cell death. The level of glucose was an important factor to MPP+induced dopaminergic PC12 cell death. Low glucose level could potentiate MPP+toxicity, while high glucose level could reduce the toxicity. In addition, melatonin attenuated PC12 cell death induced by MPP+.

  9. Oxytocin Protects against Stress-Induced Cell Death in Murine Pancreatic β-Cells

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    Watanabe, Sayaka; Wei, Fan-Yan; Matsunaga, Tomomi; Matsunaga, Nanami; Kaitsuka, Taku; Tomizawa, Kazuhito

    2016-01-01

    Oxytocin (Oxt) is a key neuropeptide that regulates maternal behaviors as well as social behaviors in mammals. Interestingly, recent studies have shown that the impairment of Oxt signaling is associated with the disturbance of metabolic homeostasis, resulting in obesity and diabetes. However, the molecular mechanism by which Oxt signaling controls metabolic responses is largely unknown. Here, we report that Oxt signaling attenuates the death of pancreatic beta cells in islets exposed to cytotoxic stresses. The protective effect of Oxt was diminished in islets isolated from oxytocin receptor knockout (Oxtr−/−) mice. Oxtr−/− mice developed normally, but exhibited impaired insulin secretion and showed glucose intolerance under a high-fat diet. Mechanistically, the deficiency of Oxtr impaired MAPK/ERK-CREB signaling, which exaggerated the endoplasmic reticulum stress response and ultimately increased the death of beta cells in pancreatic islets under stressed conditions. These results reveal that Oxt protects pancreatic beta cells against death caused by metabolic stress, and Oxt signaling may be a potential therapeutic target. PMID:27143105

  10. Engagement of SIRPα inhibits growth and induces programmed cell death in acute myeloid leukemia cells.

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    Mahban Irandoust

    Full Text Available BACKGROUND: Recent studies show the importance of interactions between CD47 expressed on acute myeloid leukemia (AML cells and the inhibitory immunoreceptor, signal regulatory protein-alpha (SIRPα on macrophages. Although AML cells express SIRPα, its function has not been investigated in these cells. In this study we aimed to determine the role of the SIRPα in acute myeloid leukemia. DESIGN AND METHODS: We analyzed the expression of SIRPα, both on mRNA and p