WorldWideScience

Sample records for cell death response

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

    Science.gov (United States)

    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.

  2. PKC activation induces inflammatory response and cell death in human bronchial epithelial cells.

    Directory of Open Access Journals (Sweden)

    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.

  3. 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.

  4. Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid

    Directory of Open Access Journals (Sweden)

    Sergio eGiannattasio

    2013-02-01

    Full Text Available Beyond its classical biotechnological applications such as food and beverage production or as a cell factory, the yeast Saccharomyces cerevisiae is a valuable model organism to study fundamental mechanisms of cell response to stressful environmental changes. Acetic acid is a physiological product of yeast fermentation and it is a well-known food preservative due to its antimicrobial action. Acetic acid has recently been shown to cause yeast cell death and aging. Here we shall focus on the molecular mechanisms of S. cerevisiae stress adaptation and programmed cell death in response to acetic acid. We shall elaborate on the intracellular signaling pathways involved in the cross-talk of pro-survival and pro-death pathways underlying the importance of understanding fundamental aspects of yeast cell homeostasis to improve the performance of a given yeast strain in biotechnological applications.

  5. Cell death and the immune responses of the sipunculan worm Themiste petricola

    Directory of Open Access Journals (Sweden)

    GA Blanco

    2010-10-01

    Full Text Available We have recently studied the role of cell death in the immune system of the sipunculan worm Themiste petricola. Typical biochemical and morphological changes of apoptosis were induced in celomocytes of these marine worms after in vitro exposure of cells to hydrogen peroxide. Apoptosis was time and dose dependent, and required several hours to become apparent. Surprisingly, in unexposed samples a subtype of granulocyte was observed to undergo homotypic aggregation, extensive cytoskeletal changes, and degranulation followed by cell death. This spontaneous response ending in cell death occurred in a divalent cation-dependent manner, served to entrap foreign particles, and was blocked by EDTA-containing saline solutions. Even though the mode of granulocyte cell death shares some features with apoptosis, it appears to be a different form of programmed cell death since it occurs within minutes and does not produce single cell-derived apoptotic bodies but transforms itself into one or several syncytial masses with haemostatic and immune purposes. Since numerous granulocyte types and multicellular masses involved in cellular immunity have been described in sipunculan worms, the review also discusses the potential influence of activation of granulocytes by sea water in expanding the variety of morphological types and multicellular structures identified through morphological studies among sipunculan species.

  6. Apoptosis and tumor cell death in response to HAMLET (human alpha-lactalbumin made lethal to tumor cells).

    Science.gov (United States)

    Hallgren, Oskar; Aits, Sonja; Brest, Patrick; Gustafsson, Lotta; Mossberg, Ann-Kristin; Wullt, Björn; Svanborg, Catharina

    2008-01-01

    HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a molecular complex derived from human milk that kills tumor cells by a process resembling programmed cell death. The complex consists of partially unfolded alpha-lactalbumin and oleic acid, and both the protein and the fatty acid are required for cell death. HAMLET has broad antitumor activity in vitro, and its therapeutic effect has been confirmed in vivo in a human glioblastoma rat xenograft model, in patients with skin papillomas and in patients with bladder cancer. The mechanisms of tumor cell death remain unclear, however. Immediately after the encounter with tumor cells, HAMLET invades the cells and causes mitochondrial membrane depolarization, cytochrome c release, phosphatidyl serine exposure, and a low caspase response. A fraction of the cells undergoes morphological changes characteristic of apoptosis, but caspase inhibition does not rescue the cells and Bcl-2 overexpression or altered p53 status does not influence the sensitivity of tumor cells to HAMLET. HAMLET also creates a state of unfolded protein overload and activates 20S proteasomes, which contributes to cell death. In parallel, HAMLET translocates to tumor cell nuclei, where high-affinity interactions with histones cause chromatin disruption, loss of transcription, and nuclear condensation. The dying cells also show morphological changes compatible with macroautophagy, and recent studies indicate that macroautophagy is involved in the cell death response to HAMLET. The results suggest that HAMLET, like a hydra with many heads, may interact with several crucial cellular organelles, thereby activating several forms of cell death, in parallel. This complexity might underlie the rapid death response of tumor cells and the broad antitumor activity of HAMLET.

  7. Induction of interferon and cell death in response to cytosolic DNA in chicken macrophages.

    Science.gov (United States)

    Vitak, Nazarii; Hume, David A; Chappell, Keith J; Sester, David P; Stacey, Katryn J

    2016-06-01

    Responses to cytosolic DNA can protect against both infectious organisms and the mutagenic effect of DNA integration. Recognition of invading DNA is likely to be fundamental to eukaryotic cellular life, but has been described only in mammals. Introduction of DNA into chicken macrophages induced type I interferon mRNA via a pathway conserved with mammals, requiring the receptor cGAS and the signalling protein STING. A second pathway of cytosolic DNA recognition in mammalian macrophages, initiated by absent in melanoma 2 (AIM2), results in rapid inflammasome-mediated pyroptotic cell death. AIM2 is restricted to mammals. Nevertheless, chicken macrophages underwent lytic cell death within 15 min of DNA transfection. The mouse AIM2-mediated response requires double stranded DNA, but chicken cell death was maintained with denatured DNA. This appears to be a novel form of rapid necrotic cell death, which we propose is an ancient response rendered redundant in mammalian macrophages by the appearance of the AIM2 inflammasome. The retention of these cytosolic DNA responses through evolution, with both conserved and non-conserved mechanisms, suggests a fundamental importance in cellular defence.

  8. Erwinia amylovora type three-secreted proteins trigger cell death and defense responses in Arabidopsis thaliana.

    Science.gov (United States)

    Degrave, A; Fagard, M; Perino, C; Brisset, M N; Gaubert, S; Laroche, S; Patrit, O; Barny, M-A

    2008-08-01

    Erwinia amylovora is the bacterium responsible for fire blight, a necrotic disease affecting plants of the rosaceous family. E. amylovora pathogenicity requires a functional type three secretion system (T3SS). We show here that E. amylovora triggers a T3SS-dependent cell death on Arabidopsis thaliana. The plants respond by inducing T3SS-dependent defense responses, including salicylic acid (SA)-independent callose deposition, activation of the SA defense pathway, reactive oxygen species (ROS) accumulation, and part of the jasmonic acid/ethylene defense pathway. Several of these reactions are similar to what is observed in host plants. We show that the cell death triggered by E. amylovora on A. thaliana could not be simply explained by the recognition of AvrRpt2 ea by the resistance gene product RPS2. We then analyzed the role of type three-secreted proteins (T3SPs) DspA/E, HrpN, and HrpW in the induction of cell death and defense reactions in A. thaliana following infection with the corresponding E. amylovora mutant strains. HrpN and DspA/E were found to play an important role in the induction of cell death, activation of defense pathways, and ROS accumulation. None of the T3SPs tested played a major role in the induction of SA-independent callose deposition. The relative importance of T3SPs in A. thaliana is correlated with their relative importance in the disease process on host plants, indicating that A. thaliana can be used as a model to study their role.

  9. Enniatin B-induced cell death and inflammatory responses in RAW 267.4 murine macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Gammelsrud, A. [Norwegian Veterinary Institute, P.O. Box 750, Centrum, N-0106 Oslo (Norway); Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo (Norway); Solhaug, A. [Norwegian Veterinary Institute, P.O. Box 750, Centrum, N-0106 Oslo (Norway); Dendelé, B. [EA 4427 SeRAIC, IRSET, Université de Rennes 1, IFR 140, Rennes (France); Sandberg, W.J. [Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo (Norway); Ivanova, L. [Norwegian Veterinary Institute, P.O. Box 750, Centrum, N-0106 Oslo (Norway); Kocbach Bølling, A. [Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo (Norway); Lagadic-Gossmann, D. [EA 4427 SeRAIC, IRSET, Université de Rennes 1, IFR 140, Rennes (France); Refsnes, M.; Becher, R. [Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo (Norway); Eriksen, G. [Norwegian Veterinary Institute, P.O. Box 750, Centrum, N-0106 Oslo (Norway); Holme, J.A., E-mail: jorn.holme@fhi.no [Department of Air Pollution and Noise, Division of Environmental Medicine, Norwegian Institute of Public Health, N-0403 Oslo (Norway)

    2012-05-15

    The mycotoxin enniatin B (EnnB) is predominantly produced by species of the Fusarium genera, and often found in grain. The cytotoxic effect of EnnB has been suggested to be related to its ability to form ionophores in cell membranes. The present study examines the effects of EnnB on cell death, differentiation, proliferation and pro-inflammatory responses in the murine monocyte–macrophage cell line RAW 264.7. Exposure to EnnB for 24 h caused an accumulation of cells in the G0/G1-phase with a corresponding decrease in cyclin D1. This cell cycle-arrest was possibly also linked to the reduced cellular ability to capture and internalize receptors as illustrated by the lipid marker ganglioside GM1. EnnB also increased the number of apoptotic, early apoptotic and necrotic cells, as well as cells with elongated spindle-like morphology. The Neutral Red assay indicated that EnnB induced lysosomal damage; supported by transmission electron microscopy (TEM) showing accumulation of lipids inside the lysosomes forming lamellar structures/myelin bodies. Enhanced levels of activated caspase-1 were observed after EnnB exposure and the caspase-1 specific inhibitor ZYVAD-FMK reduced EnnB-induced apoptosis. Moreover, EnnB increased the release of interleukin-1beta (IL-1β) in cells primed with lipopolysaccharide (LPS), and this response was reduced by both ZYVAD-FMK and the cathepsin B inhibitor CA-074Me. In conclusion, EnnB was found to induce cell cycle arrest, cell death and inflammation. Caspase-1 appeared to be involved in the apoptosis and release of IL-1β and possibly activation of the inflammasome through lysosomal damage and leakage of cathepsin B. -- Highlights: ► The mycotoxin EnnB induced cell cycle arrest, cell death and inflammation. ► The G0/G1-arrest was linked to a reduced ability to internalize receptors. ► EnnB caused lysosomal damage, leakage of cathepsin B and caspase-1 cleavage. ► Caspase-1 was partly involved in both apoptosis and release of IL-1

  10. 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.

  11. Programmed cell death in barley aleurone cells is not directly stimulated by reactive oxygen species produced in response to gibberellin.

    Science.gov (United States)

    Aoki, Nozomi; Ishibashi, Yushi; Kai, Kyohei; Tomokiyo, Reisa; Yuasa, Takashi; Iwaya-Inoue, Mari

    2014-05-01

    The cereal aleurone layer is a secretory tissue that produces enzymes to hydrolyze the starchy endosperm during germination. We recently demonstrated that reactive oxygen species (ROS), produced in response to gibberellins (GA), promoted GAMyb expression, which induces α-amylase expression in barley aleurone cells. On the other hand, ROS levels increase during programmed cell death (PCD) in barley aleurone cells, and GAMyb is involved in PCD of these cells. In this study, we investigated whether the ROS produced in response to GA regulate PCD directly by using mutants of Slender1 (SLN1), a DELLA protein that negatively regulates GA signaling. The wild-type, the sln1c mutant (which exhibits gibberellin-type signaling even in the absence of GA), and the Sln1d mutant (which is gibberellin-insensitive with respect to α-amylase production) all produced ROS in response to GA, suggesting that ROS production in aleurone cells in response to GA is independent of GA signaling through this DELLA protein. Exogenous GA promoted PCD in the wild-type. PCD in sln1c was induced even without exogenous GA (and so without induction of ROS), whereas PCD in Sln1d was not induced in the presence of exogenous GA, even though the ROS content increased significantly in response to GA. These results suggest that PCD in barley aleurone cells is not directly stimulated by ROS produced in response to GA but is regulated by GA signaling through DELLA protein.

  12. Categorizing extent of tumor cell death response to cancer therapy using quantitative ultrasound spectroscopy and maximum mean discrepancy.

    Science.gov (United States)

    Gangeh, Mehrdad J; Sadeghi-Naini, Ali; Diu, Michael; Tadayyon, Hadi; Kamel, Mohamed S; Czarnota, Gregory J

    2014-06-01

    Quantitative ultrasound (QUS) spectroscopic techniques in conjunction with maximum mean discrepancy (MMD) have been proposed to detect, and to classify noninvasively the levels of cell death in response to cancer therapy administration in tumor models. Evaluation of xenograft tumor responses to cancer treatments were carried out using conventional-frequency ultrasound at different times after chemotherapy exposure. Ultrasound data were analyzed using spectroscopic techniques and multi-parametric QUS spectral maps were generated. MMD was applied as a distance criterion, measuring alterations in each tumor in response to chemotherapy, and the extent of cell death was classified into less/more than 20% and 40% categories. Statistically significant differences were observed between "pre-" and "post-treatment" groups at different times after chemotherapy exposure, suggesting a high capability of proposed framework for detecting tumor response noninvasively. Promising results were also obtained for categorizing the extent of cell death response in each tumor using the proposed framework, with gold standard histological quantification of cell death as ground truth. The best classification results were obtained using MMD when applied on histograms of QUS parametric maps. In this case, classification accuracies of 84.7% and 88.2% were achieved for categorizing extent of tumor cell death into less/more than 20% and 40%, respectively.

  13. 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.

  14. Caspase-2-dependent dendritic cell death, maturation, and priming of T cells in response to Brucella abortus infection.

    Directory of Open Access Journals (Sweden)

    Xinna Li

    Full Text Available Smooth virulent Brucella abortus strain 2308 (S2308 causes zoonotic brucellosis in cattle and humans. Rough B. abortus strain RB51, derived from S2308, is a live attenuated cattle vaccine strain licensed in the USA and many other countries. Our previous report indicated that RB51, but not S2308, induces a caspase-2-dependent apoptotic and necrotic macrophage cell death. Dendritic cells (DCs are professional antigen presenting cells critical for bridging innate and adaptive immune responses. In contrast to Brucella-infected macrophages, here we report that S2308 induced higher levels of apoptotic and necrotic cell death in wild type bone marrow-derived DCs (WT BMDCs than RB51. The RB51 and S2308-induced BMDC cell death was regulated by caspase-2, indicated by the minimal cell death in RB51 and S2308-infected BMDCs isolated from caspase-2 knockout mice (Casp2KO BMDCs. More S2308 bacteria were taken up by Casp2KO BMDCs than wild type BMDCs. Higher levels of S2308 and RB51 cells were found in infected Casp2KO BMDCs compared to infected WT BMDCs at different time points. RB51-infected wild type BMDCs were mature and activated as shown by significantly up-regulated expression of CD40, CD80, CD86, MHC-I, and MHC-II. RB51 induced the production of cytokines TNF-α, IL-6, IFN-γ and IL12/IL23p40 in infected BMDCs. RB51-infected WT BMDCs also stimulated the proliferation of CD4(+ and CD8(+ T cells compared to uninfected WT BMDCs. However, the maturation, activation, and cytokine secretion are significantly impaired in Casp2KO BMDCs infected with RB51 or Salmonella (control. S2308-infected WT and Casp2KO BMDCs were not activated and could not induce cytokine production. These results demonstrated that virulent smooth strain S2308 induced more apoptotic and necrotic dendritic cell death than live attenuated rough vaccine strain RB51; however, RB51, but not its parent strain S2308, induced caspase-2-mediated DC maturation, cytokine production, antigen

  15. The NRF2 Activation and Antioxidative Response Are Not Impaired Overall during Hyperoxia-Induced Lung Epithelial Cell Death

    Directory of Open Access Journals (Sweden)

    Haranatha R. Potteti

    2013-01-01

    Full Text Available Lung epithelial and endothelial cell death caused by pro-oxidant insults is a cardinal feature of acute lung injury/acute respiratory distress syndrome (ALI/ARDS patients. The NF-E2-related factor 2 (NRF2 activation in response to oxidant exposure is crucial to the induction of several antioxidative and cytoprotective enzymes that mitigate cellular stress. Since prolonged exposure to hyperoxia causes cell death, we hypothesized that chronic hyperoxia impairs NRF2 activation, resulting in cell death. To test this hypothesis, we exposed nonmalignant small airway epithelial cells (AECs to acute (1–12 h and chronic (36–48 h hyperoxia and evaluated cell death, NRF2 nuclear accumulation and target gene expression, and NRF2 recruitment to the endogenous HMOX1 and NQO1 promoters. As expected, hyperoxia gradually induced death in AECs, noticeably and significantly by 36 h; ~60% of cells were dead by 48 h. However, we unexpectedly found increased expression levels of NRF2-regulated antioxidative genes and nuclear NRF2 in AECs exposed to chronic hyperoxia as compared to acute hyperoxia. Chromatin Immunoprecipitation (ChIP assays revealed an increased recruitment of NRF2 to the endogenous HMOX1 and NQO1 promoters in AECs exposed to acute or chronic hyperoxia. Thus, our findings demonstrate that NRF2 activation and antioxidant gene expression are functional during hyperoxia-induced lung epithelial cell death and that chronic hyperoxia does not impair NRF2 signaling overall.

  16. Salicylic acid antagonism of EDS1-driven cell death is important for immune and oxidative stress responses in Arabidopsis.

    Science.gov (United States)

    Straus, Marco R; Rietz, Steffen; Ver Loren van Themaat, Emiel; Bartsch, Michael; Parker, Jane E

    2010-05-01

    Reactive oxygen species (ROS) have emerged as signals in the responses of plants to stress. Arabidopsis Enhanced Disease Susceptibility1 (EDS1) regulates defense and cell death against biotrophic pathogens and controls cell death propagation in response to chloroplast-derived ROS. Arabidopsis Nudix hydrolase7 (nudt7) mutants are sensitized to photo-oxidative stress and display EDS1-dependent enhanced resistance, salicylic acid (SA) accumulation and initiation of cell death. Here we explored the relationship between EDS1, EDS1-regulated SA and ROS by examining gene expression profiles, photo-oxidative stress and resistance phenotypes of nudt7 mutants in combination with eds1 and the SA-biosynthetic mutant, sid2. We establish that EDS1 controls steps downstream of chloroplast-derived O(2)(*-) that lead to SA-assisted H(2)O(2) accumulation as part of a mechanism limiting cell death. A combination of EDS1-regulated SA-antagonized and SA-promoted processes is necessary for resistance to host-adapted pathogens and for a balanced response to photo-oxidative stress. In contrast to SA, the apoplastic ROS-producing enzyme NADPH oxidase RbohD promotes initiation of cell death during photo-oxidative stress. Thus, chloroplastic O(2)(*-) signals are processed by EDS1 to produce counter-balancing activities of SA and RbohD in the control of cell death. Our data strengthen the idea that EDS1 responds to the status of O(2)(*-) or O(2)(*-)-generated molecules to coordinate cell death and defense outputs. This activity may enable the plant to respond flexibly to different biotic and abiotic stresses in the environment.

  17. Evaluation of the contribution of multiple DAMPs and DAMP receptors in cell death-induced sterile inflammatory responses.

    Science.gov (United States)

    Kataoka, Hiroshi; Kono, Hajime; Patel, Zubin; Kimura, Yoshitaka; Rock, Kenneth L

    2014-01-01

    When cells die by necrosis in vivo they stimulate an inflammatory response. It is thought that this response is triggered when the injured cells expose proinflammatory molecules, collectively referred to as damage associated molecular patterns (DAMPs), which are recognized by cells or soluble molecules of the innate or adaptive immune system. Several putative DAMPs and/or their receptors have been identified, but whether and how much they participate in responses in vivo is incompletely understood, and they have not previously been compared side-by-side in the same models. This study focuses on evaluating the contribution of multiple mechanisms that have been proposed to or potentially could participate in cell death-induced inflammation: The third component of complement (C3), ATP (and its receptor P2X7), antibodies, the C-type lectin receptor Mincle (Clec4e), and protease-activated receptor 2 (PAR2). We investigate the role of these factors in cell death-induced inflammation to dead cells in the peritoneum and acetaminophen-induced liver damage. We find that mice deficient in antibody, C3 or PAR2 have impaired inflammatory responses to dying cells. In contrast there was no reduction in inflammation to cell death in the peritoneum or liver of mice that genetically lack Mincle, the P2X7 receptor or that were treated with apyrase to deplete ATP. These results indicate that antibody, complement and PAR2 contribute to cell death-induced inflammation but that Mincle and ATP- P2X7 receptor are not required for this response in at least 2 different in vivo models.

  18. Evaluation of the contribution of multiple DAMPs and DAMP receptors in cell death-induced sterile inflammatory responses.

    Directory of Open Access Journals (Sweden)

    Hiroshi Kataoka

    Full Text Available When cells die by necrosis in vivo they stimulate an inflammatory response. It is thought that this response is triggered when the injured cells expose proinflammatory molecules, collectively referred to as damage associated molecular patterns (DAMPs, which are recognized by cells or soluble molecules of the innate or adaptive immune system. Several putative DAMPs and/or their receptors have been identified, but whether and how much they participate in responses in vivo is incompletely understood, and they have not previously been compared side-by-side in the same models. This study focuses on evaluating the contribution of multiple mechanisms that have been proposed to or potentially could participate in cell death-induced inflammation: The third component of complement (C3, ATP (and its receptor P2X7, antibodies, the C-type lectin receptor Mincle (Clec4e, and protease-activated receptor 2 (PAR2. We investigate the role of these factors in cell death-induced inflammation to dead cells in the peritoneum and acetaminophen-induced liver damage. We find that mice deficient in antibody, C3 or PAR2 have impaired inflammatory responses to dying cells. In contrast there was no reduction in inflammation to cell death in the peritoneum or liver of mice that genetically lack Mincle, the P2X7 receptor or that were treated with apyrase to deplete ATP. These results indicate that antibody, complement and PAR2 contribute to cell death-induced inflammation but that Mincle and ATP- P2X7 receptor are not required for this response in at least 2 different in vivo models.

  19. The Growing Complexity of Cancer Cell Response to DNA-Damaging Agents: Caspase 3 Mediates Cell Death or Survival?

    Science.gov (United States)

    Mirzayans, Razmik; Andrais, Bonnie; Kumar, Piyush; Murray, David

    2016-05-11

    It is widely stated that wild-type p53 either mediates the activation of cell cycle checkpoints to facilitate DNA repair and promote cell survival, or orchestrates apoptotic cell death following exposure to cancer therapeutic agents. This reigning paradigm has been challenged by numerous discoveries with different human cell types, including solid tumor-derived cell lines. Thus, activation of the p53 signaling pathway by ionizing radiation and other DNA-damaging agents hinders apoptosis and triggers growth arrest (e.g., through premature senescence) in some genetic backgrounds; such growth arrested cells remain viable, secrete growth-promoting factors, and give rise to progeny with stem cell-like properties. In addition, caspase 3, which is best known for its role in the execution phase of apoptosis, has been recently reported to facilitate (rather than suppress) DNA damage-induced genomic instability and carcinogenesis. This observation is consistent with an earlier report demonstrating that caspase 3 mediates secretion of the pro-survival factor prostaglandin E₂, which in turn promotes enrichment of tumor repopulating cells. In this article, we review these and related discoveries and point out novel cancer therapeutic strategies. One of our objectives is to demonstrate the growing complexity of the DNA damage response beyond the conventional "repair and survive, or die" hypothesis.

  20. Depletion of the cereblon gene activates the unfolded protein response and protects cells from ER stress-induced cell death.

    Science.gov (United States)

    Lee, Kwang Min; Yang, Seung-Joo; Park, Sojung; Choi, Yoo Duk; Shin, Hwa Kyoung; Pak, Jhang Ho; Park, Chul-Seung; Kim, Inki

    2015-02-27

    Previous studies showed that cereblon (CRBN) binds to various cellular target proteins, implying that CRBN regulates a wide range of cell responses. In this study, we found that deletion of the Crbn gene desensitized mouse embryonic fibroblast cells to various cell death-promoting stimuli, including endoplasmic reticulum stress inducers. Mechanistically, deletion of Crbn activates pathways involved in the unfolded protein response prior to ER stress induction. Loss of Crbn activated PKR-like ER kinase (PERK) with enhanced phosphorylation of eIF2α. Following ER stress induction, loss of Crbn delayed dephosphorylation of eIF2α, while reconstitution of Crbn reversed enhanced phosphorylation of PERK and eIF2α. Lastly, we found that activation of the PERK/eIF2α pathway following Crbn deletion is caused by activation of AMP-activated protein kinase (AMPK). We propose that CRBN plays a role in cellular stress signaling, including the unfolded protein response, by controlling the activity of AMPK.

  1. Defective high-affinity thiamine transporter leads to cell death in thiamine-responsive megaloblastic anemia syndrome fibroblasts

    OpenAIRE

    1999-01-01

    We have investigated the cellular pathology of the syndrome called thiamine-responsive megaloblastic anemia (TRMA) with diabetes and deafness. Cultured diploid fibroblasts were grown in thiamine-free medium and dialyzed serum. Normal fibroblasts survived indefinitely without supplemental thiamine, whereas patient cells died in 5–14 days (mean 9.5 days), and heterozygous cells survived for more than 30 days. TRMA fibroblasts were rescued from death with 10–30 nM thiamine (in the range of norma...

  2. Acrolein activates cell survival and apoptotic death responses involving the endoplasmic reticulum in A549 lung cells.

    Science.gov (United States)

    Tanel, André; Pallepati, Pragathi; Bettaieb, Ahmed; Morin, Patrick; Averill-Bates, Diana A

    2014-05-01

    Acrolein, a highly reactive α,β-unsaturated aldehyde, is a product of endogenous lipid peroxidation. It is a ubiquitous environmental pollutant that is generated mainly by smoke, overheated cooking oil and vehicle exhaust. Acrolein damages cellular proteins, which could lead to accumulation of aberrantly-folded proteins in the endoplasmic reticulum (ER). This study determines the mechanisms involved in acrolein-induced apoptosis mediated by the ER and possible links with the ER stress response in human A549 lung cells. The exposure of cells to acrolein (15-50μM) for shorter times of 15 to 30min activated several ER stress markers. These included the ER chaperone protein BiP and the three ER sensors: (i) the survival/rescue molecules protein kinase RNA (PKR)-like ER kinase (PERK) and eukaryotic initiation factor 2 alpha (eIF2α) were phosphorylated; (ii) cleavage of activating transcription factor 6 (ATF6) occurred, and (iii) inositol-requiring protein-1 alpha (IRE1α) was phosphorylated. Acrolein (25-50μM) caused apoptotic cell death mediated by the ER after 2h, which was characterised by the induction of CHOP and activation of ER proteases calpain and caspase-4. Calpain and caspase-7 were the initiating factors for caspase-4 activation in acrolein-induced apoptosis. These results increase our knowledge about cellular responses to acrolein in lung cells, which have implications for human health.

  3. Involvement of yeast HSP90 isoforms in response to stress and cell death induced by acetic acid.

    Science.gov (United States)

    Silva, Alexandra; Sampaio-Marques, Belém; Fernandes, Angela; Carreto, Laura; Rodrigues, Fernando; Holcik, Martin; Santos, Manuel A S; Ludovico, Paula

    2013-01-01

    Acetic acid-induced apoptosis in yeast is accompanied by an impairment of the general protein synthesis machinery, yet paradoxically also by the up-regulation of the two isoforms of the heat shock protein 90 (HSP90) chaperone family, Hsc82p and Hsp82p. Herein, we show that impairment of cap-dependent translation initiation induced by acetic acid is caused by the phosphorylation and inactivation of eIF2α by Gcn2p kinase. A microarray analysis of polysome-associated mRNAs engaged in translation in acetic acid challenged cells further revealed that HSP90 mRNAs are over-represented in this polysome fraction suggesting preferential translation of HSP90 upon acetic acid treatment. The relevance of HSP90 isoform translation during programmed cell death (PCD) was unveiled using genetic and pharmacological abrogation of HSP90, which suggests opposing roles for HSP90 isoforms in cell survival and death. Hsc82p appears to promote survival and its deletion leads to necrotic cell death, while Hsp82p is a pro-death molecule involved in acetic acid-induced apoptosis. Therefore, HSP90 isoforms have distinct roles in the control of cell fate during PCD and their selective translation regulates cellular response to acetic acid stress.

  4. Oxidative stress-dependent changes in immune responses and cell death in the substantia nigra after ozone exposure in rat

    Science.gov (United States)

    Rivas-Arancibia, Selva; Zimbrón, Luis Fernando Hernández; Rodríguez-Martínez, Erika; Maldonado, Perla D.; Borgonio Pérez, Gabino; Sepúlveda-Parada, María

    2015-01-01

    Parkinson's disease has been associated with the selective loss of neurons in the substantia nigra pars compacta. Increasing evidence suggests that oxidative stress plays a major role. The resulting increase in reactive oxygen species triggers a sequence of events that leads to cell damage, activation of microglia cells and neuroinflammatory responses. Our objective was to study whether chronic exposure to low doses of ozone, which produces oxidative stress itself, induces progressive cell death in conjunction with glial alterations in the substantia nigra. Animals were exposed to an ozone-free air stream (control) or to low doses of ozone for 7, 15, 30, 60, or 90 days. Each group underwent (1) spectrophotometric analysis for protein oxidation; (2) western blot testing for microglia reactivity and nuclear factor kappa B expression levels; and (3) immunohistochemistry for cytochrome c, GFAP, Iba-1, NFkB, and COX-2. Our results indicate that ozone induces an increase in protein oxidation levels, changes in activated astrocytes and microglia, and cell death. NFkB and cytochrome c showed an increase until 30 days of exposure, while cyclooxygenase 2 in the substantia nigra increased from 7 days up to 90 days of repetitive ozone exposure. These results suggest that oxidative stress caused by ozone exposure induces changes in inflammatory responses and progressive cell death in the substantia nigra in rats, which could also be occurring in Parkinson's disease. PMID:25999851

  5. Translational and posttranslational regulation of XIAP by eIF2α and ATF4 promotes ER stress-induced cell death during the unfolded protein response.

    Science.gov (United States)

    Hiramatsu, Nobuhiko; Messah, Carissa; Han, Jaeseok; LaVail, Matthew M; Kaufman, Randal J; Lin, Jonathan H

    2014-05-01

    Endoplasmic reticulum (ER) protein misfolding activates the unfolded protein response (UPR) to help cells cope with ER stress. If ER homeostasis is not restored, UPR promotes cell death. The mechanisms of UPR-mediated cell death are poorly understood. The PKR-like endoplasmic reticulum kinase (PERK) arm of the UPR is implicated in ER stress-induced cell death, in part through up-regulation of proapoptotic CCAAT/enhancer binding protein homologous protein (CHOP). Chop((-)/(-)) cells are partially resistant to ER stress-induced cell death, and CHOP overexpression alone does not induce cell death. These findings suggest that additional mechanisms regulate cell death downstream of PERK. Here we find dramatic suppression of antiapoptosis XIAP proteins in response to chronic ER stress. We find that PERK down-regulates XIAP synthesis through eIF2α and promotes XIAP degradation through ATF4. Of interest, PERK's down-regulation of XIAP occurs independently of CHOP activity. Loss of XIAP leads to increased cell death, whereas XIAP overexpression significantly enhances resistance to ER stress-induced cell death, even in the absence of CHOP. Our findings define a novel signaling circuit between PERK and XIAP that operates in parallel with PERK to CHOP induction to influence cell survival during ER stress. We propose a "two-hit" model of ER stress-induced cell death involving concomitant CHOP up-regulation and XIAP down-regulation both induced by PERK.

  6. 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.

  7. Toxin- and cadmium-induced cell death events in tomato suspension cells resemble features of hypersensitive response

    NARCIS (Netherlands)

    Iakimova, E.T.; Woltering, E.J.; Yordanova, Z.P.

    2007-01-01

    Elicitors of different origin (fumonisin B1, fungal toxin), camptothecin (alkaloid from Camptotheca acuminata), mastoparan (wasp venom) and the heavy metal (cadmium) were tested for their ability to induce programmed cell death (PCD) in a model system of tomato cell culture, line MsK8. By employing

  8. 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

  9. EdU induces DNA damage response and cell death in mESC in culture.

    Science.gov (United States)

    Kohlmeier, Fanni; Maya-Mendoza, Apolinar; Jackson, Dean A

    2013-03-01

    Recently, a novel DNA replication precursor analogue called 5-ethynyl-2'-deoxyuridine (EdU) has been widely used to monitor DNA synthesis as an alternative to bromodeoxyuridine. Use of EdU benefits from simplicity and reproducibility and the simple chemical detection systems allows excellent preservation of nuclear structure. However, the alkyne moiety is highly reactive, raising the possibility that incorporation might compromise genome stability. To assess the extent of possible DNA damage, we have analysed the effect of EdU incorporation into DNA during short- and long-term cell culture using a variety of cell lines. We show that EdU incorporation has no measurable impact on the rate of elongation of replication forks during synthesis. However, using different cell lines we find that during long-term cell culture variable responses to EdU incorporation are seen, which range from delayed cell cycle progression to complete cell cycle arrest. The most profound phenotypes were seen in mouse embryonic stem cells, which following incorporation of EdU accumulated in the G2/M-phase of the cell cycle before undergoing apoptosis. In long-term cell culture, EdU incorporation also triggered a DNA damage response in all cell types analysed. Our study shows that while EdU is extremely useful to tag sites of on-going replication, for long-term studies (i.e. beyond the cell cycle in which labelling is performed), a careful analysis of cell cycle perturbations must be performed in order to ensure that any conclusions made after EdU treatment are not a direct consequence of EdU-dependent activation of cell stress responses.

  10. Photoacoustic spectral analysis to sense programmed erythrocyte cell death (eryptosis) for monitoring cancer response to treatment

    Science.gov (United States)

    Fadhel, Muhannad N.; Kibria, Fayruz; Kolios, Michael C.

    2016-03-01

    Many types of cancer therapies target the tumor microenvironment, causing biochemical and morphological changes in tissues. In therapies using ultrasound activated microbubbles, vascular collapse is typically reported. Red blood cells (RBCs) that leak out of the vasculature become exposed to the ceramide that is released from damaged endothelial cells. Ceramide can induce programmed cell death in RBCs (eryptosis), and is characterized by cell shrinkage, membrane blebbing and scrambling. Since the effect of eryptotic cells on generated photoacoustics (PA) signals has not been reported, we investigated the potential PA may have for cancer treatment monitoring by using PA spectral analysis to sense eryptosis. To induce eryptosis, C2-ceramide was added to RBC suspensions and that were incubated for 24 hours at 37°C. A control and ceramide-induced sample was imaged in a vessel phantom using a high frequency PA system (VevoLAZR, 10 - 45 MHz bandwidth) irradiated with multiple wavelengths ranging from 680 to 900 nm. PA spectral parameters were measured and linked to changes in RBCs as it underwent eryptosis. These samples were examined using optical microscopy, a blood gas analyzer and an integrating sphere setup to measure optical properties (wavelengths 600 - 900 nm). The results of the experiment demonstrate how PA spectral analysis can be used to identify eryptosis at a depth of more than 1 cm into the phantom using ultrasound derived the y-intercept and mid bandfit (MBF) parameters at optical wavelengths of 800 - 900 nm. These parameters were correlated to the morphological and biochemical changes that eryptotic RBCs display. The results establish the potential of PA in cancer treatment monitoring through sensing treatment induced eryptosis.

  11. Toxin release in response to oxidative stress and programmed cell death in the cyanobacterium Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Cliff [Smithsonian Marine Station at Fort Pierce, 701 Seaway Drive, Ft. Pierce, FL 34949 (United States)]. E-mail: Ross@sms.si.edu; Santiago-Vazquez, Lory [Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (United States); Paul, Valerie [Smithsonian Marine Station at Fort Pierce, 701 Seaway Drive, Ft. Pierce, FL 34949 (United States)

    2006-06-10

    An unprecedented bloom of the cyanobacterium Microcystis aeruginosa Kuetz. occurred in the St. Lucie Estuary, FL in the summer of 2005. Samples were analyzed for toxicity by ELISA and by use of the polymerase chain reaction (PCR) with specific oligonucleotide primers for the mcyB gene that has previously been correlated with the biosynthesis of toxic microcystins. Despite the fact that secreted toxin levels were relatively low in dense natural assemblages (3.5 {mu}g l{sup -1}), detectable toxin levels increased by 90% when M. aeruginosa was stressed by an increase in salinity, physical injury, application of the chemical herbicide paraquat, or UV irradiation. The application of the same stressors caused a three-fold increase in the production of H{sub 2}O{sub 2} when compared to non-stressed cells. The application of micromolar concentrations of H{sub 2}O{sub 2} induced programmed cell death (PCD) as measured by a caspase protease assay. Catalase was capable of inhibiting PCD, implicating H{sub 2}O{sub 2} as the inducing oxidative species. Our results indicate that physical stressors induce oxidative stress, which results in PCD and a concomitant release of toxin into the surrounding media. Remediation strategies that induce cellular stress should be approached with caution since these protocols are capable of releasing elevated levels of microcystins into the environment.

  12. Strong innate immune response and cell death in chicken splenocytes infected with genotype VIId Newcastle disease virus

    Directory of Open Access Journals (Sweden)

    Hu Zenglei

    2012-09-01

    Full Text Available Abstract Background Genotype VIId Newcastle disease virus (NDV isolates induce more severe damage to lymphoid tissues, especially to the spleen, when compared to virulent viruses of other genotypes. However, the biological basis of the unusual pathological changes remains largely unknown. Methods Virus replication, cytokine gene expression profile and cell death response in chicken splenocytes infected with two genotype VIId NDV strains (JS5/05 and JS3/05, genotype IX NDV strain F48E8 and genotype IV NDV strain Herts/33 were evaluated. Statistical significance of differences between experimental groups was determined using the Independent-Samples T test. Results JS5/05 and JS3/05 caused hyperinduction of type I interferons (IFNs (IFN-α and -β during detection period compared to F48E8 and Herts/33. JS5/05 increased expression level of IFN-γ gene at 6 h post-inoculation (pi and JS3/05 initiated sustained activation of IFN-γ within 24 h pi, whereas transcriptional levels of IFN-γ remained unchanged at any of the time points during infection of F48E8 and Herts/33. In addition, compared to F48E8 and Herts/33, JS3/05 and JS5/05 significantly increased the amount of free nucleosomal DNA in splenocytes at 6 and 24 h pi respectively. Annexin-V and Proidium iodid (PI double staining of infected cells showed that cell death induced by JS3/05 and JS5/05 was characterized by marked necrosis compared to F48E8 and Herts/33 at 24 h pi. These results indicate that genotype VIId NDV strains JS3/05 and JS5/05 elicited stronger innate immune and cell death responses in chicken splenocytes than F48E8 and Herts/33. JS5/05 replicated at a significantly higher efficiency in splenocytes than F48E8 and Herts/33. Early excessive cell death induced by JS3/05 infection partially impaired virus replication. Conclusions Viral dysregulaiton of host response may be relevant to the severe pathological manifestation in the spleen following genotype VIId NDV infection.

  13. Role of ER stress response in photodynamic therapy: ROS generated in different subcellular compartments trigger diverse cell death pathways.

    Directory of Open Access Journals (Sweden)

    Irena Moserova

    Full Text Available We have analyzed the molecular mechanisms of photoinduced cell death using porphyrins with similar structure differing only in the position of the ethylene glycol (EG chain on the phenyl ring. Meta- and para-positioned EG chains targeted porphyrins to different subcellular compartments. After photoactivation, both types of derivatives induced death of tumor cells via reactive oxygen species (ROS. Para derivatives pTPP(EG4 and pTPPF(EG4 primarily accumulated in lysosomes activated the p38 MAP kinase cascade, which in turn induced the mitochondrial apoptotic pathway. In contrast, meta porphyrin derivative mTPP(EG4 localized in the endoplasmic reticulum (ER induced dramatic changes in Ca(2+ homeostasis manifested by Ca(2+ rise in the cytoplasm, activation of calpains and stress caspase-12 or caspase-4. ER stress developed into unfolded protein response. Immediately after irradiation the PERK pathway was activated through phosphorylation of PERK, eIF2α and induction of transcription factors ATF4 and CHOP, which regulate stress response genes. PERK knockdown and PERK deficiency protected cells against mTPP(EG4-mediated apoptosis, confirming the causative role of the PERK pathway.

  14. Downregulation of Noxa by RAF/MEK inhibition counteracts cell death response in mutant B-RAF melanoma cells.

    Science.gov (United States)

    Basile, Kevin J; Aplin, Andrew E

    2012-01-01

    FDA approval of new therapies in 2011 has greatly expanded the treatment options for metastatic melanoma. Patients with V600 mutant v-raf murine sarcoma viral oncogene homolog B1 (B-RAF) positive metastatic melanoma are now treated with the RAF inhibitor, vemurafenib (Zelboraf) as a first line therapy. Vemurafenib decreases tumor size by at least 30% in approximately 50% of patients and increases progression-free survival and overall patient survival compared to the previous standard-of-care, dacarbazine. However, some patients treated with vemurafenib fail to show significant tumor shrinkage, and most patients who initially respond to the drug eventually show disease progression. Therefore, there is a clinical need to improve efficacy and prevent resistance to vemurafenib. It has been previously shown that cell death resulting from RAF/mitogen-activated protein kinase kinase (MEK) inhibition is largely dependent on increased expression of pro-apoptotic, Bcl-2 homology domain (BH3)-only proteins, such as Bcl-2-like 11 (Bim-EL) and Bcl-2 modifying factor (Bmf). Here, we show that contrary to expression of Bim-EL and Bmf, the pro-apoptotic, BH3-only protein, phorbol-12-myristate-13-acetate-induced protein 1 (Noxa), is strongly downregulated after RAF/MEK inhibition. This downregulation occurs at both the protein and mRNA level of expression and is associated with the inhibition of cell cycle progression. Restoring expression of Noxa in combination with RAF/MEK inhibition enhances cell death. Co-expression of the pro-survival, B-cell CLL/lymphoma 2 (Bcl-2) family member, myeloid cell leukemia sequence 1 (Mcl-1), with Noxa fully mitigates the enhanced cell death associated with increased Noxa expression. These data indicate that manipulating the Noxa/Mcl-1 axis may enhance the efficacy of RAF/MEK inhibitors.

  15. 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.

  16. 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...

  17. Role of autophagy in disease resistance and hypersensitive response-associated cell death

    DEFF Research Database (Denmark)

    Hofius, Daniel; Munch, David; Bressendorff, Simon

    2011-01-01

    stress. At the same time, autophagy can contribute to cellular suicide. The concurrent engagement of autophagy in these processes during infection may sometimes mask its contribution to differing pro-survival and pro-death decisions. The importance of autophagy in innate immunity in mammals is well...

  18. Lazarus1, a DUF300 Protein, Contributes to Programmed Cell Death Associated with Arabidopsis acd11 and the Hypersensitive Response

    DEFF Research Database (Denmark)

    Malinovsky, F.G.; Brodersen, P.; Fiil, B.K.;

    2010-01-01

    associated with the HR, in addition to its role in acd11-related death. Furthermore, the similar topology of a plant and human DUF300 proteins suggests similar functions in PCD across the eukaryotic kingdoms, although a direct role for TMEM34 in cell death control remains to be established. Finally...

  19. The bioenergetic signature of isogenic colon cancer cells predicts the cell death response to treatment with 3-bromopyruvate, iodoacetate or 5-fluorouracil

    Directory of Open Access Journals (Sweden)

    Cuezva José M

    2011-02-01

    Full Text Available Abstract Background Metabolic reprogramming resulting in enhanced glycolysis is a phenotypic trait of cancer cells, which is imposed by the tumor microenvironment and is linked to the down-regulation of the catalytic subunit of the mitochondrial H+-ATPase (β-F1-ATPase. The bioenergetic signature is a protein ratio (β-F1-ATPase/GAPDH, which provides an estimate of glucose metabolism in tumors and serves as a prognostic indicator for cancer patients. Targeting energetic metabolism could be a viable alternative to conventional anticancer chemotherapies. Herein, we document that the bioenergetic signature of isogenic colon cancer cells provides a gauge to predict the cell-death response to the metabolic inhibitors, 3-bromopyruvate (3BrP and iodoacetate (IA, and the anti-metabolite, 5-fluorouracil (5-FU. Methods The bioenergetic signature of the cells was determined by western blotting. Aerobic glycolysis was determined from lactate production rates. The cell death was analyzed by fluorescence microscopy and flow cytometry. Cellular ATP concentrations were determined using bioluminiscence. Pearson's correlation coefficient was applied to assess the relationship between the bioenergetic signature and the cell death response. In vivo tumor regression activities of the compounds were assessed using a xenograft mouse model injected with the highly glycolytic HCT116 colocarcinoma cells. Results We demonstrate that the bioenergetic signature of isogenic HCT116 cancer cells inversely correlates with the potential to execute necrosis in response to 3BrP or IA treatment. Conversely, the bioenergetic signature directly correlates with the potential to execute apoptosis in response to 5-FU treatment in the same cells. However, despite the large differences observed in the in vitro cell-death responses associated with 3BrP, IA and 5-FU, the in vivo tumor regression activities of these agents were comparable. Conclusions Overall, we suggest that the

  20. 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.

  1. Transcriptomic analysis of host immune and cell death responses associated with the influenza A virus PB1-F2 protein.

    Directory of Open Access Journals (Sweden)

    Ronan Le Goffic

    2011-08-01

    Full Text Available Airway inflammation plays a major role in the pathogenesis of influenza viruses and can lead to a fatal outcome. One of the challenging objectives in the field of influenza research is the identification of the molecular bases associated to the immunopathological disorders developed during infection. While its precise function in the virus cycle is still unclear, the viral protein PB1-F2 is proposed to exert a deleterious activity within the infected host. Using an engineered recombinant virus unable to express PB1-F2 and its wild-type homolog, we analyzed and compared the pathogenicity and host response developed by the two viruses in a mouse model. We confirmed that the deletion of PB1-F2 renders the virus less virulent. The global transcriptomic analyses of the infected lungs revealed a potent impact of PB1-F2 on the response developed by the host. Thus, after two days post-infection, PB1-F2 invalidation severely decreased the number of genes activated by the host. PB1-F2 expression induced an increase in the number and level of expression of activated genes linked to cell death, inflammatory response and neutrophil chemotaxis. When generating interactive gene networks specific to PB1-F2, we identified IFN-γ as a central regulator of PB1-F2-regulated genes. The enhanced cell death of airway-recruited leukocytes was evidenced using an apoptosis assay, confirming the pro-apoptotic properties of PB1-F2. Using a NF-kB luciferase adenoviral vector, we were able to quantify in vivo the implication of NF-kB in the inflammation mediated by the influenza virus infection; we found that PB1-F2 expression intensifies the NF-kB activity. Finally, we quantified the neutrophil recruitment within the airways, and showed that this type of leukocyte is more abundant during the infection of the wild-type virus. Collectively, these data demonstrate that PB1-F2 strongly influences the early host response during IAV infection and provides new insights into the

  2. 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.

  3. Effects of the Cell Cycle Inhibitor Olomoucine on Inflammatory Response and Neuronal Cell Death after Spinal Cord Injury in Rats

    Institute of Scientific and Technical Information of China (English)

    TIAN Dai-shi; XIE Min-jie; YU Zhi-yuan; ZHANG Qiang; WANG Yi-hui; CHEN Bin; CHEN Chen; WANG Wei

    2007-01-01

    Objective:The influence of olomoucine on microglial proliferation with associated inflammatory response after spinal cord injury has been determined.Methods:Microglial proliferation and neuronal apoptosis were observed by immunofluorescence.Level of the proinflammatory cytokine interleukin-1β (IL-1β) expression in the injured cord was determined by Western blot analysis.Results:the cell cycle inhibitor olomoucine,administered at 1 h post injury,significantly suppressed microglial proliferation and produced a remarkable reduction of tissue edema formation.In the olomoucine-treated group,a significant reduction of activated and/or proliferated microglial induced IL-1β expression was observed 24 h after SCI.Moreover,olomoucine evidently attenuated the number of apoptotic neurons after SCI.Conclusion:Our findings suggest that modulation of microglial proliferation with associated proinflammatory cytokine expression may be a mechanism of cell cycle inhibition-mediated neuroprotections in the CNS trauma.

  4. Pleiotropic effects of spongean alkaloids on mechanisms of cell death, cell cycle progression and DNA damage response (DDR) of acute myeloid leukemia (AML) cells.

    Science.gov (United States)

    Stuhldreier, Fabian; Kassel, Stefanie; Schumacher, Lena; Wesselborg, Sebastian; Proksch, Peter; Fritz, Gerhard

    2015-05-28

    We investigated cytotoxic mechanisms evoked by the spongean alkaloids aaptamine (Aa) and aeroplysinin-1 (Ap), applied alone and in combination with daunorubicin, employing acute myeloid leukemia (AML) cells. Aa and Ap reduced the viability of AML cells in a dose dependent manner with IC50 of 10-20 µM. Ap triggered apoptotic cell death more efficiently than Aa. Both alkaloids increased the protein level of S139-phosphorylated H2AX (γH2AX), which however was independent of the induction of DNA damage. Expression of the senescence markers p21 and p16 was increased, while the phosphorylation level of p-Chk-2 was reduced following Aa treatment. As a function of dose, Aa and Ap protected or sensitized AML cells against daunorubicin. Protection by Aa was paralleled by reduced formation of ROS and lower level of DNA damage. Both Aa and Ap attenuated daunorubicin-stimulated activation of the DNA damage response (DDR) as reflected on the levels of γH2AX, p-Kap-1 and p-Chk-1. Specifically Ap restored the decrease in S10 phosphorylation of histone H3 resulting from daunorubicin treatment. The cytoprotective effects of Aa and Ap were independent of daunorubicin import/export. Both Aa and Ap abrogated daunorubicin-induced accumulation of cells in S-phase. Inhibition of DNA synthesis was specific for Ap. The data show that Aa and Ap have both congruent and agent-specific pleiotropic effects that are preferential for anticancer drugs. Since Ap showed a broader spectrum of anticancer activities, this compound is suggested as novel lead compound for forthcoming in vivo studies elucidating the usefulness of spongean alkaloids in AML therapy.

  5. RNA-Seq-based transcriptomic and metabolomic analysis reveal stress responses and programmed cell death induced by acetic acid in Saccharomyces cerevisiae

    Science.gov (United States)

    Dong, Yachen; Hu, Jingjin; Fan, Linlin; Chen, Qihe

    2017-01-01

    As a typical harmful inhibitor in cellulosic hydrolyzates, acetic acid not only hinders bioethanol production, but also induces cell death in Saccharomyces cerevisiae. Herein, we conducted both transcriptomic and metabolomic analyses to investigate the global responses under acetic acid stress at different stages. There were 295 up-regulated and 427 down-regulated genes identified at more than two time points during acetic acid treatment (150 mM, pH 3.0). These differentially expressed genes (DEGs) were mainly involved in intracellular homeostasis, central metabolic pathway, transcription regulation, protein folding and stabilization, ubiquitin-dependent protein catabolic process, vesicle-mediated transport, protein synthesis, MAPK signaling pathways, cell cycle, programmed cell death, etc. The interaction network of all identified DEGs was constructed to speculate the potential regulatory genes and dominant pathways in response to acetic acid. The transcriptional changes were confirmed by metabolic profiles and phenotypic analysis. Acetic acid resulted in severe acidification in both cytosol and mitochondria, which was different from the effect of extracellular pH. Additionally, the imbalance of intracellular acetylation was shown to aggravate cell death under this stress. Overall, this work provides a novel and comprehensive understanding of stress responses and programmed cell death induced by acetic acid in yeast. PMID:28209995

  6. 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.

  7. 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.

  8. Induction of mitochondrial alternative oxidase in response to a cell signal pathway down-regulating the cytochrome pathway prevents programmed cell death.

    Science.gov (United States)

    Vanlerberghe, Greg C; Robson, Christine A; Yip, Justine Y H

    2002-08-01

    Treatment of tobacco (Nicotiana tabacum L. cv Petit Havana SR1) cells with cysteine (Cys) triggers a signal pathway culminating in a large loss of mitochondrial cytochrome (cyt) pathway capacity. This down-regulation of the cyt path likely requires events outside the mitochondrion and is effectively blocked by cantharidin or endothall, indicating that protein dephosphorylation is one critical process involved. Generation of reactive oxygen species, cytosolic protein synthesis, and Ca(2+) flux from organelles also appear to be involved. Accompanying the loss of cyt path is a large induction of alternative oxidase (AOX) protein and capacity. Induction of AOX allows the cells to maintain high rates of respiration, indicating that the lesion triggered by Cys is in the cyt path downstream of ubiquinone. Consistent with this, transgenic (AS8) cells unable to induce AOX (due to the presence of an antisense transgene) lose all respiratory capacity upon Cys treatment. This initiates in AS8 a programmed cell death pathway, as evidenced by the accumulation of oligonucleosomal fragments of DNA as the culture dies. Alternatively, wild-type cells remain viable and eventually recover their cyt path. Induction of AOX in response to a chemical inhibition of the cyt path (by antimycin A) is also dependent upon protein dephosphorylation and the generation of reactive oxygen species. Common events required for both down-regulation of the cyt path and induction of AOX may represent a mechanism to coordinate the biogenesis of these two electron transport paths. Such coordinate regulation may be necessary, not only to satisfy metabolic demands, but also to modulate the initiation of a programmed cell death pathway responsive to mitochondrial respiratory status.

  9. 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.

  10. 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.

  11. 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

  12. Targeting the Immune System’s Natural Response to Cell Death to Improve Therapeutic Response in Breast Cancers

    Science.gov (United States)

    2015-07-01

    coated Tran- swell filters (Figure 7H), as did recombi - nant TGF-β1 (2 pg/ml). Invasion through Trans- well filters in response to both efferocyto...Biosystems) and amplified using the murine cDNA-specific prim- ers (Integrated DNA Technologies) listed in Supplemental Methods, along with SYBR Green...genotyped by PCR of genomic DNA as previously described(30). Female virgin mice were randomized into 2 groups: (a) 1 group that remained virgin, and (b) 1

  13. 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,...

  14. GLYCINE-RICH RNA-BINDING PROTEIN1 interacts with RECEPTOR-LIKE CYTOPLASMIC PROTEIN KINASE1 and suppresses cell death and defense responses in pepper (Capsicum annuum).

    Science.gov (United States)

    Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

    2015-01-01

    Plants use a variety of innate immune regulators to trigger cell death and defense responses against pathogen attack. We identified pepper (Capsicum annuum) GLYCINE-RICH RNA-BINDING PROTEIN1 (CaGRP1) as a RECEPTOR-LIKE CYTOPLASMIC PROTEIN KINASE1 (CaPIK1)-interacting partner, based on bimolecular fluorescence complementation and coimmunoprecipitation analyses as well as gene silencing and transient expression analysis. CaGRP1 contains an N-terminal RNA recognition motif and a glycine-rich region at the C-terminus. The CaGRP1 protein had DNA- and RNA-binding activity in vitro. CaGRP1 interacted with CaPIK1 in planta. CaGRP1 and CaGRP1-CaPIK1 complexes were localized to the nucleus in plant cells. CaPIK1 phosphorylated CaGRP1 in vitro and in planta. Transient coexpression of CaGRP1 with CaPIK1 suppressed the CaPIK1-triggered cell death response, accompanied by a reduced CaPIK1-triggered reactive oxygen species (ROS) burst. The RNA recognition motif region of CaGRP1 was responsible for the nuclear localization of CaGRP1 as well as the suppression of the CaPIK1-triggered cell death response. CaGRP1 silencing in pepper conferred enhanced resistance to Xanthomonas campestris pv vesicatoria (Xcv) infection; however, CaPIK1-silenced plants were more susceptible to Xcv. CaGRP1 interacts with CaPIK1 and negatively regulates CaPIK1-triggered cell death and defense responses by suppressing ROS accumulation.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Hepatic Carcinoma—Associated Fibroblasts Promote an Adaptative Response in Colorectal Cancer Cells That Inhibit Proliferation and Apoptosis: Nonresistant Cells Die by Nonapoptotic Cell Death

    Directory of Open Access Journals (Sweden)

    Mireia Berdiel-Acer

    2011-10-01

    Full Text Available Carcinoma-associated fibroblasts (CAFs are important contributors of microenvironment in determining the tumor’s fate. This study aimed to compare the influence of liver microenvironment and primary tumor microenvironment on the behavior of colorectal carcinoma. Conditioned medium (CM from normal colonic fibroblasts (NCFs, CAFs from primary tumor (CAF-PT or liver metastasis (CAF-LM were obtained. We performed functional assays to test the influence of each CM on colorectal cell lines. Microarray and gene set enrichment analysis (GSEA were performed in DLD1 cells cultured in matched CM. In DLD1 cells, CAF-LM CM compared with CAF-PT CM and NCF led to a more aggressive phenotype, induced the features of an epithelial-to-mesenchymal transition more efficiently, and stimulated migration and invasion to a greater extent. Sustained stimulation with CAF-LM CM evoked a transient G2/M cell cycle arrest accompanied by a reduction of apoptosis, inhibition of proliferation, and decreased viability of SW1116, SW620, SW480, DLD1, HT-29, and Caco-2 cells and provoked nonapoptotic cell death in those cells carrying KRAS mutations. Cells resistant to CAF-LM CM completely changed their morphology in an extracellular signal-regulated protein kinase-dependent process and depicted an increased stemness capacity alongside the Wnt pathway stimulation. The transcriptomic profile of DLD1 cells treated with CAF-LM CM was associated with Wnt and mitogen-activated protein kinase pathways activation in GSEA. Therefore, the liver microenvironment induces more efficiently the aggressiveness of colorectal cancer cells than other matched microenvironments do but secondarily evokes cell death. Resistant cells displayed higher stemness capacity.

  20. Yeast Bax inhibitor, Bxi1p, is an ER-localized protein that links the unfolded protein response and programmed cell death in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    James Cebulski

    Full Text Available Bax inhibitor-1 (BI-1 is an anti-apoptotic gene whose expression is upregulated in a wide range of human cancers. Studies in both mammalian and plant cells suggest that the BI-1 protein resides in the endoplasmic reticulum and is involved in the unfolded protein response (UPR that is triggered by ER stress. It is thought to act via a mechanism involving altered calcium dynamics. In this paper, we provide evidence that the Saccharomyces cerevisiae protein encoded by the open reading frame, YNL305C, is a bona fide homolog for BI-1. First, we confirm that yeast cells from two different strain backgrounds lacking YNL305C, which we have renamed BXI1, are more sensitive to heat-shock induced cell death than wildtype controls even though they have indistinguishable growth rates at 30°C. They are also more susceptible both to ethanol-induced and to glucose-induced programmed cell death. Significantly, we show that Bxi1p-GFP colocalizes with the ER localized protein Sec63p-RFP. We have also discovered that Δbxi1 cells are not only more sensitive to drugs that induce ER stress, but also have a decreased unfolded protein response as measured with a UPRE-lacZ reporter. Finally, we have discovered that deleting BXI1 diminishes the calcium signaling response in response to the accumulation of unfolded proteins in the ER as measured by a calcineurin-dependent CDRE-lacZ reporter. In toto, our data suggests that the Bxi1p, like its metazoan homologs, is an ER-localized protein that links the unfolded protein response and programmed cell death.

  1. 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.

  2. 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....

  3. 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...

  4. 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.

  5. Towards elimination of maternal deaths: maternal deaths surveillance and response

    Directory of Open Access Journals (Sweden)

    Hounton Sennen

    2013-01-01

    Full Text Available Abstract Current methods for estimating maternal mortality lack precision, and are not suitable for monitoring progress in the short run. In addition, national maternal mortality ratios (MMRs alone do not provide useful information on where the greatest burden of mortality is located, who is concerned, what are the causes, and more importantly what sub-national variations occur. This paper discusses a maternal death surveillance and response (MDSR system. MDSR systems are not yet established in most countries and have potential added value for policy making and accountability and can build on existing efforts to conduct maternal death reviews, verbal autopsies and confidential enquiries. Accountability at national and sub-national levels cannot rely on global, regional and national retrospective estimates periodically generated from academia or United Nations organizations but on routine counting, investigation, sub national data analysis, long term investments in vital registration and national health information systems. Establishing effective maternal death surveillance and response will help achieve MDG 5, improve quality of maternity care and eliminate maternal mortality (MMR ≤ 30 per 100,000 by 2030.

  6. 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.

  7. Targeting Werner syndrome protein sensitizes U-2 OS osteosarcoma cells to selenium-induced DNA damage response and necrotic death

    DEFF Research Database (Denmark)

    Cheng, Wen-Hsing; Wu, Ryan T Y; Wu, Min;

    2012-01-01

    in mouse models of cancer. To test the hypothesis that targeting WRN can potentiate selenium toxicity in cancer cells, isogenic WRN small hairpin RNA (shRNA) and control shRNA U-2 OS osteosarcoma cells were treated with MSeA for 2d, followed by recovery for up to 7d. WRN deficiency sensitized U-2 OS cells......Mutations in the Werner syndrome protein (WRN), a caretaker of the genome, result in Werner syndrome, which is characterized by premature aging phenotypes and cancer predisposition. Methylseleninic acid (MSeA) can activate DNA damage responses and is a superior compound to suppress tumorigenesis......, but promoted recovery from the MSeA-induced DNA damage. Taken together, WRN protects U-2 OS osteosarcoma cells against MSeA-induced cytotoxicity, suggesting that oxidative DNA repair pathway is a promising target for improving the efficacy of selenium on tumor suppression....

  8. GmNAC30 and GmNAC81 integrate the endoplasmic reticulum stress- and osmotic stress-induced cell death responses through a vacuolar processing enzyme.

    Science.gov (United States)

    Mendes, Giselle C; Reis, Pedro A B; Calil, Iara P; Carvalho, Humberto H; Aragão, Francisco J L; Fontes, Elizabeth P B

    2013-11-26

    Prolonged endoplasmic reticulum and osmotic stress synergistically activate the stress-induced N-rich protein-mediated signaling that transduces a cell death signal by inducing GmNAC81 (GmNAC6) in soybean. To identify novel regulators of the stress-induced programmed cell death (PCD) response, we screened a two-hybrid library for partners of GmNAC81. We discovered another member of the NAC (NAM-ATAF1,2-CUC2) family, GmNAC30, which binds to GmNAC81 in the nucleus of plant cells to coordinately regulate common target promoters that harbor the core cis-regulatory element TGTG[TGC]. We found that GmNAC81 and GmNAC30 can function either as transcriptional repressors or activators and cooperate to enhance the transcriptional regulation of common target promoters, suggesting that heterodimerization may be required for the full regulation of gene expression. Accordingly, GmNAC81 and GmNAC30 display overlapping expression profiles in response to multiple environmental and developmental stimuli. Consistent with a role in PCD, GmNAC81 and GmNAC30 bind in vivo to and transactivate hydrolytic enzyme promoters in soybean protoplasts. A GmNAC81/GmNAC30 binding site is located in the promoter of the caspase-1-like vacuolar processing enzyme (VPE) gene, which is involved in PCD in plants. We demonstrated that the expression of GmNAC81 and GmNAC30 fully transactivates the VPE gene in soybean protoplasts and that this transactivation was associated with an increase in caspase-1-like activity. Collectively, our results indicate that the stress-induced GmNAC30 cooperates with GmNAC81 to activate PCD through the induction of the cell death executioner VPE.

  9. A novel transcription factor, ERD15 (Early Responsive to Dehydration 15), connects endoplasmic reticulum stress with an osmotic stress-induced cell death signal.

    Science.gov (United States)

    Alves, Murilo S; Reis, Pedro A B; Dadalto, Silvana P; Faria, Jerusa A Q A; Fontes, Elizabeth P B; Fietto, Luciano G

    2011-06-03

    As in all other eukaryotic organisms, endoplasmic reticulum (ER) stress triggers the evolutionarily conserved unfolded protein response in soybean, but it also communicates with other adaptive signaling responses, such as osmotic stress-induced and ER stress-induced programmed cell death. These two signaling pathways converge at the level of gene transcription to activate an integrated cascade that is mediated by N-rich proteins (NRPs). Here, we describe a novel transcription factor, GmERD15 (Glycine max Early Responsive to Dehydration 15), which is induced by ER stress and osmotic stress to activate the expression of NRP genes. GmERD15 was isolated because of its capacity to stably associate with the NRP-B promoter in yeast. It specifically binds to a 187-bp fragment of the NRP-B promoter in vitro and activates the transcription of a reporter gene in yeast. Furthermore, GmERD15 was found in both the cytoplasm and the nucleus, and a ChIP assay revealed that it binds to the NRP-B promoter in vivo. Expression of GmERD15 in soybean protoplasts activated the NRP-B promoter and induced expression of the NRP-B gene. Collectively, these results support the interpretation that GmERD15 functions as an upstream component of stress-induced NRP-B-mediated signaling to connect stress in the ER to an osmotic stress-induced cell death signal.

  10. Temporal pattern of neurodegeneration, programmed cell death, and neuroplastic responses in the thalamus after lateral fluid percussion brain injury in the rat.

    Science.gov (United States)

    Dolenec, Petra; Pilipović, Kristina; Rajič, Jelena; Župan, Gordana

    2015-06-01

    The effects of traumatic brain injury (TBI) on the thalamus are not well characterized. We analyzed neuronal degeneration and loss, apoptosis, programmed cell death-executing pathways, and neuroplastic responses in the rat thalamus during the first week after lateral fluid percussion injury (LFPI). The most prominent neurodegenerative and neuroplastic changes were observed in the region containing the posterior thalamic nuclear group and ventral posteromedial and posterolateral thalamic nuclei ipsilateral to the LFPI. There was progressive neurodegeneration in these regions, with maximal neuronal loss on Day 7. Increases in numbers of apoptotic cells were detected on Day 1 and were enhanced on Days 3 and 7 after TBI. There was unchanged expression of active caspase-3 at all postinjury time points, but there was increased expression of apoptosis-inducing factor (AIF) on Day 7. The AIF nuclear translocation was detected on Day 1 and was maximal on Day 7. Total thalamic synaptophysin expression was unchanged, but immunostaining intensities were increased at all time points after TBI. Decreased growth-associated protein-43 expression and signal intensity were observed on Day 1. Our results suggest that progressive neuronal damage and loss, AIF signaling pathway-dependent programmed cell death, and limited neuroplastic changes occur in the rat thalamus during the first week after LFPI induction.

  11. Tonsil-derived mesenchymal stem cells (T-MSCs) prevent Th17-mediated autoimmune response via regulation of the programmed death-1/programmed death ligand-1 (PD-1/PD-L1) pathway.

    Science.gov (United States)

    Kim, Ji-Yon; Park, Minhwa; Kim, Yu-Hee; Ryu, Kyung-Ha; Lee, Kyung Ho; Cho, Kyung-Ah; Woo, So-Youn

    2017-01-20

    Our knowledge of the immunomodulatory role of mesenchymal stem cells (MSCs) in both the innate and adaptive immune systems has dramatically expanded, providing great promise for treating various autoimmune diseases. However, the contribution of MSCs to Th17 dominant immune disease, such as psoriasis and its underlying mechanism remains elusive. In this study, we demonstrated that human palatine tonsil-derived MSCs (T-MSCs) constitutively express both the membrane-bound and soluble forms of programmed death-ligand 1 (PD-L1), which enables T-MSCs to be distinguished from MSCs originating from other organs (i.e., bone marrow or adipose tissue). We also found that T-MSC-derived PD-L1 effectively represses Th17 differentiation via both cell-to-cell contact and a paracrine effect. Further, T-MSCs increase PD-1 expression on T cells by secreting IFN-β, which may enhance engagement with PD-L1. Finally, transplantation of T-MSCs into imiquimod induced psoriatic skin inflammation in mice significantly abrogated disease symptoms, mainly by blunting the Th17 response in a PD-L1 dependent manner. This study suggests that T-MSCs might be a promising cell source to treat autoimmune diseases such as psoriasis, via its unique immunoregulatory features.

  12. Impaired inflammatory response to glial cell death in genetically metallothionein-I- and -II-deficient mice

    DEFF Research Database (Denmark)

    Penkowa, M; Giralt, M; Moos, T

    1999-01-01

    Metallothionein I+II (MT-I+II) are acute-phase proteins which are upregulated during pathological conditions in the brain. To elucidate the neuropathological importance of MT-I+II, we have examined MT-I+II-deficient mice following ip injection with 6-aminonicotinamide (6-AN). 6-AN is antimetabolic...... and toxic for bone marrow cells and grey matter astrocytes. In MT+/+ mice, injection with 6-AN resulted in breakdown of the blood-brain barrier (BBB) and absence of GFAP-positive astrocytes in specific grey matter areas of the brain stem. Reactive astrocytosis encircled the damaged grey matter areas, which...... and histochemically detectable zinc increased in the brain stem after 6-AN similarly in MT+/+ and MT-/- mice. Bone marrow myeloid monocytes and macrophages were increased as a reaction to 6-AN only in MT+/+ mice. The results demonstrate that the capability of MT-/- mice to mount a normal inflammatory response...

  13. 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.

  14. Arabidopsis RADICAL-INDUCED CELL DEATH1 belongs to the WWE protein-protein interaction domain protein family and modulates abscisic acid, ethylene, and methyl jasmonate responses.

    Science.gov (United States)

    Ahlfors, Reetta; Lång, Saara; Overmyer, Kirk; Jaspers, Pinja; Brosché, Mikael; Tauriainen, Airi; Kollist, Hannes; Tuominen, Hannele; Belles-Boix, Enric; Piippo, Mirva; Inzé, Dirk; Palva, E Tapio; Kangasjärvi, Jaakko

    2004-07-01

    Experiments with several Arabidopsis thaliana mutants have revealed a web of interactions between hormonal signaling. Here, we show that the Arabidopsis mutant radical-induced cell death1 (rcd1), although hypersensitive to apoplastic superoxide and ozone, is more resistant to chloroplastic superoxide formation, exhibits reduced sensitivity to abscisic acid, ethylene, and methyl jasmonate, and has altered expression of several hormonally regulated genes. Furthermore, rcd1 has higher stomatal conductance than the wild type. The rcd1-1 mutation was mapped to the gene At1g32230 where it disrupts an intron splice site resulting in a truncated protein. RCD1 belongs to the (ADP-ribosyl)transferase domain-containing subfamily of the WWE protein-protein interaction domain protein family. The results suggest that RCD1 could act as an integrative node in hormonal signaling and in the regulation of several stress-responsive genes.

  15. Effects of a novel carbocyclic analog of pyrrolo[2,3-d]pyrimidine nucleoside on pleiotropic induction of cell death in prostate cancer cells with different androgen responsiveness.

    Science.gov (United States)

    Suh, Hyewon; Choi, Ko-woon; Lee, Jongbok; Ryou, Chongsuk; Rhee, Hakjune; Lee, Chul-Hoon

    2016-02-15

    Prostate cancer is the most frequently diagnosed cancer and is one of the leading causes of male cancer death in the world. Recently, in the course of our screening for a novel anticancer compound, we synthesized carbocyclic analogs of pyrrolo[2,3-d]pyrimidine nucleoside; compounds 5, and 6. In the current study, we report the effects of compound 5 on pleiotropic induction of cell death via up-regulation of AR-associated p21(Cip1) protein in prostate cancer cells with different androgen responsiveness, such as LNCaP (androgen-dependent and -sensitive), LNCaP(C4-2) (androgen-independent and -sensitive; androgen-refractory), and DU145 (androgen-independent and -insensitive) cells. The treatment of LNCaP cells with 6 μM compound 5 for 24 h stimulated the androgen receptor (AR) activity and dramatically up-regulated transcription (56-fold) of p21(Cip1), which, in turn, induces typical apoptosis in the cells. However, induction of apoptosis through up-regulation (23-fold) of AR-associated p21(Cip1) achieved in LNCaP(C4-2) cells was possible by intensive cell treatment with compound 5 (9 μM, 48 h), because the cells are less sensitive and independent to androgen than LNCaP cells. Furthermore, 6 μM compound 5-treated DU145 cells, which exhibit extremely low AR activation due to no androgen responsiveness and dependency, showed neither up-regulation of p21(Cip1) nor apoptotic induction. Instead, a different type of cell death, autophagy-like death through the LC3B-associated autophagosome formation, was obviously induced in DU145 cells. Taken together, our results suggest that pleiotropic induction of prostate cancer cell death by compound 5 is determined by how efficiently and how abundantly androgen-dependent activation of the AR occurs, whereas compound 6 shows no induction of apoptosis in LNCaP cells.

  16. The Capsicum annuum class IV chitinase ChitIV interacts with receptor-like cytoplasmic protein kinase PIK1 to accelerate PIK1-triggered cell death and defence responses

    OpenAIRE

    2015-01-01

    The pepper receptor-like cytoplasmic protein kinase, CaPIK1, which mediates signalling of plant cell death and defence responses was previously identified. Here, the identification of a class IV chitinase, CaChitIV, from pepper plants (Capsicum annuum), which interacts with CaPIK1 and promotes CaPIK1-triggered cell death and defence responses, is reported. CaChitIV contains a signal peptide, chitin-binding domain, and glycol hydrolase domain. CaChitIV expression was up-regulated by Xanthomona...

  17. Reactive oxygen species and mitogen-activated protein kinase induce apoptotic death of SH-SY5Y cells in response to fipronil.

    Science.gov (United States)

    Ki, Yeo-Woon; Lee, Jeong Eun; Park, Jae Hyeon; Shin, In Chul; Koh, Hyun Chul

    2012-05-20

    There are multiple lines of evidence showing that environmental toxicants including pesticides may contribute to neuronal cell death. Fipronil (FPN) is a phenylpyrazole insecticide that acts on insect GABA receptors. Although the action of FPN is restricted to insect neuronal or muscular transmitter systems, a few studies have assessed the effects of this neurotoxicant on neuronal cell death distinct from an insect. To determine the mechanisms underlying FPN-induced neuronal cell death, we evaluated the ability of this chemical to induce oxidative stress and studied the involvement of mitogen activated protein kinases (MAPKs) in FPN-induced apoptosis stress in human neuroblastoma SH-SY5Y (SH-SY5Y) cells. Exposure of SH-SY5Y cells to FPN led to the production of reactive oxygen species (ROS) and apoptotic cell death via activation of caspase-9 and caspase-3. Interestingly, the antioxidant, N-acetyl-cysteine (NAC) attenuated apoptotic cell death and ROS production induced by FPN. These results indicated that oxidative stress plays a central role in FPN-induced cytotoxicity. Mitochondrial complex I activity was also inhibited by FPN treatment. These finding indicate that FPN triggers intrinsic apoptosis via the mitochondrial signaling pathway that is initiated by the generation of ROS. Furthermore, FPN treatment induced phosphorylation of MAPK members. Activation of these protein kinases by FPN was involved in the onset of apoptosis as inhibitors specific to these kinases protect against FPN-induced cell death as well as ROS generation. Our data indicate that FPN-induced apoptosis is mediated primarily by the generation of ROS and activation of MAPK members followed by activation of the intrinsic apoptotic pathway.

  18. Myeloid-derived suppressor cells express the death receptor Fas and apoptose in response to T cell-expressed FasL.

    Science.gov (United States)

    Sinha, Pratima; Chornoguz, Olesya; Clements, Virginia K; Artemenko, Konstantin A; Zubarev, Roman A; Ostrand-Rosenberg, Suzanne

    2011-05-19

    Myeloid-derived suppressor cells (MDSCs) inhibit adaptive and innate immunity and accumulate in the blood of persons with cancer, chronic inflammation, trauma, infection, and stress. Some of the factors inducing their accumulation are known; however, mechanisms regulating their turnover have not been identified. Mass spectrometry showed prominent expression of apoptosis pathway proteins, suggesting that MDSC turnover may be regulated by Fas-FasL-mediated apoptosis. This hypothesis was confirmed by showing that blood MDSCs induced by 3 mouse tumors were Fas(+) and apoptosed in response to Fas agonist in vitro and to activated FasL(+) T cells in vivo. FasL-deficient mice contained significantly more blood MDSCs than FasL(+/+) mice, and after removal of primary tumors MDSCs regressed in STAT6(-/-) and CD1(-/-) mice but not in STAT6(-/-)FasL(-/-) or CD1(-/-)FasL(-/-) mice. Fas(+) macrophages and dendritic cells did not apoptose in response to activated T cells, indicating that Fas-FasL regulation of myeloid cells was restricted to MDSCs. These results identify a new mechanism regulating MDSC levels in vivo and show a retaliatory relationship between T cells and MDSCs in that MDSCs suppress T-cell activation; however, once activated, T cells mediate MDSC apoptosis.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Neurotransmitters and neuronal apoptotic cell death of chronically aluminum intoxicated Nile catfish (Clarias gariepinus) in response to ascorbic acid supplementation.

    Science.gov (United States)

    Khalil, Samah R; Hussein, Mohamed M A

    2015-12-01

    Few studies have been carried out to assess the neurotoxic effect of aluminum (Al) on the aquatic creatures. This study aims to evaluate the neurotoxic effects of long term Al exposure on the Nile catfish (Clarias gariepinus) and the potential ameliorative influence of ascorbic acid (ASA) over a 180 days exposure period. Forty eight Nile catfish were divided into four groups: control group, placed in clean water, ASA exposed group (5mg/l), AlCl3 received group (28.96 μg/l; 1/20 LC50), and group received AlCl3 concomitantly with ASA. Brain tissue was examined by using flow cytometry to monitor the apoptotic cell population, HPLC analysis for the quantitative estimation of brain monoamine neurotransmitters [serotonin (5-HT), dopamine (DA), norepinephrine (NE)]. The amino acid neurotransmitters [serum taurine, glycine, aspartate and glutamine and brain gamma aminobutyric acid (GABA)] levels were assessed, plus changes in brain tissue structure using light microscopy. The concentration of Al in both brain tissue and serum was determined by using atomic absorption spectrophotometery. The Al content in serum and brain tissue were both elevated and Al exposure induced an increase in the number of apoptotic cells, a marked reduction of the monoamine and amino acids neurotransmitters levels and changes in tissue morphology. ASA supplementation partially abolished the effects of AL on the reduced neurotransmitter, the degree of apoptosis and restored the morphological changes to the brain. Overall, our results indicate that, ASA is a promising neuroprotective agent against for Al-induced neurotoxicity in the Nile catfish.

  4. The Impact of Autophagy on Cell Death Modalities

    Directory of Open Access Journals (Sweden)

    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.

  5. The Capsicum annuum class IV chitinase ChitIV interacts with receptor-like cytoplasmic protein kinase PIK1 to accelerate PIK1-triggered cell death and defence responses.

    Science.gov (United States)

    Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

    2015-04-01

    The pepper receptor-like cytoplasmic protein kinase, CaPIK1, which mediates signalling of plant cell death and defence responses was previously identified. Here, the identification of a class IV chitinase, CaChitIV, from pepper plants (Capsicum annuum), which interacts with CaPIK1 and promotes CaPIK1-triggered cell death and defence responses, is reported. CaChitIV contains a signal peptide, chitin-binding domain, and glycol hydrolase domain. CaChitIV expression was up-regulated by Xanthomonas campestris pv. vesicatoria (Xcv) infection. Notably, avirulent Xcv infection rapidly induced CaChitIV expression in pepper leaves. Bimolecular fluorescence complementation and co-immunoprecipitation revealed that CaPIK1 interacts with CaChitIV in planta, and that the CaPIK1-CaChitIV complex is localized mainly in the cytoplasm and plasma membrane. CaChitIV is also localized in the endoplasmic reticulum. Transient co-expression of CaChitIV with CaPIK1 enhanced CaPIK1-triggered cell death response and reactive oxygen species (ROS) and nitric oxide (NO) bursts. Co-silencing of both CaChitIV and CaPIK1 in pepper plants conferred enhanced susceptibility to Xcv infection, which was accompanied by a reduced induction of cell death response, ROS and NO bursts, and defence response genes. Ectopic expression of CaPIK1 in Arabidopsis enhanced basal resistance to Hyaloperonospora arabidopsidis infection. Together, the results suggest that CaChitIV positively regulates CaPIK1-triggered cell death and defence responses through its interaction with CaPIK1.

  6. GOLPH3 Mediated Golgi Stress Response in Modulating N2A Cell Death upon Oxygen-Glucose Deprivation and Reoxygenation Injury.

    Science.gov (United States)

    Li, Ting; You, Hong; Mo, Xiaoye; He, Wenfang; Tang, Xiangqi; Jiang, Zheng; Chen, Shiyu; Chen, Yang; Zhang, Jie; Hu, Zhiping

    2016-03-01

    Increasing evidence implicating that the organelle-dependent initiation of cell death merits further research. The evidence also implicates Golgi as a sensor and common downstream-effector of stress signals in cell death pathways, and it undergoes disassembly and fragmentation during apoptosis in several neurological disorders. It has also been reported that during apoptotic cell death, there is a cross talk between ER, mitochondria, and Golgi. Thus, we hypothesized that Golgi might trigger death signals during oxidative stress through its own machinery. The current study found that GOLPH3, an outer membrane protein of the Golgi complex, was significantly upregulated in N2A cells upon oxygen-glucose deprivation and reoxygenation (OGD/R), positioning from the compact perinuclear ribbon to dispersed vesicle-like structures throughout the cytoplasm. Additionally, elevated GOLPH3 promoted a stress-induced conversion of the LC3 subunit I to II and reactive oxygen species (ROS) production in long-term OGD/R groups. The collective data indicated that GOLPH3 not only acted as a sensor of Golgi stress for its prompt upregulation during oxidative stress but also as an initiator that triggered and propagated specific Golgi stress signals to downstream effectors. This affected ROS production and stress-related autophagy and finally controlled the entry into apoptosis. The data also supported the hypothesis that the Golgi apparatus could be an ideal target for stroke, neurodegenerative diseases, or cancer therapy through its own functional proteins.

  7. 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.

  8. 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.

  9. 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

  10. Mitochondrial proteomics of the acetic acid – induced programmed cell death response in a highly tolerant Zygosaccharomyces bailii – derived hybrid strain

    Directory of Open Access Journals (Sweden)

    Joana F Guerreiro

    2016-01-01

    Full Text Available Very high concentrations of acetic acid at low pH induce programmed cell death (PCD in both the experimental model Saccharomyces cerevisiae and in Zygosaccharomyces bailii, the latter being considered the most problematic acidic food spoilage yeast due to its remarkable intrinsic resistance to this food preservative. However, while the mechanisms underlying S. cerevisiae PCD induced by acetic acid have been previously examined, the corresponding molecular players remain largely unknown in Z. bailii. Also, the reason why acetic acid concentrations known to be necrotic for S. cerevisiae induce PCD with an apoptotic phenotype in Z. bailii remains to be elucidated. In this study, a 2-DE-based expression mitochondrial proteomic analysis was explored to obtain new insights into the mechanisms involved in PCD in the Z. bailii derived hybrid strain ISA1307. This allowed the quantitative assessment of expression of protein species derived from each of the parental strains, with special emphasis on the processes taking place in the mitochondria known to play a key role in acetic acid – induced PCD. A marked decrease in the content of proteins involved in mitochondrial metabolism, in particular, in respiratory metabolism (Cor1, Rip1, Lpd1, Lat1 and Pdb1, with a concomitant increase in the abundance of proteins involved in fermentation (Pdc1, Ald4, Dld3 was registered. Other differentially expressed identified proteins also suggest the involvement of the oxidative stress response, protein translation, amino acid and nucleotide metabolism, among other processes, in the PCD response. Overall, the results strengthen the emerging concept of the importance of metabolic regulation of yeast PCD.

  11. Chk1 suppressed cell death

    Directory of Open Access Journals (Sweden)

    Meuth Mark

    2010-09-01

    Full Text Available Abstract The role of Chk1 in the cellular response to DNA replication stress is well established. However recent work indicates a novel role for Chk1 in the suppression of apoptosis following the disruption of DNA replication or DNA damage. This review will consider these findings in the context of known pathways of Chk1 signalling and potential applications of therapies that target Chk1.

  12. 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.

  13. 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.

  14. The pepper extracellular xyloglucan-specific endo-β-1,4-glucanase inhibitor protein gene, CaXEGIP1, is required for plant cell death and defense responses.

    Science.gov (United States)

    Choi, Hyong Woo; Kim, Nak Hyun; Lee, Yeon Kyeong; Hwang, Byung Kook

    2013-01-01

    Plants produce various proteinaceous inhibitors to protect themselves against microbial pathogen attack. A xyloglucan-specific endo-β-1,4-glucanase inhibitor1 gene, CaXEGIP1, was isolated and functionally characterized in pepper (Capsicum annuum) plants. CaXEGIP1 was rapidly and strongly induced in pepper leaves infected with avirulent Xanthomonas campestris pv vesicatoria, and purified CaXEGIP1 protein significantly inhibited the hydrolytic activity of the glycoside hydrolase74 family xyloglucan-specific endo-β-1,4-glucanase from Clostridium thermocellum. Soluble-modified green fluorescent protein-tagged CaXEGIP1 proteins were mainly localized to the apoplast of onion (Allium cepa) epidermal cells. Agrobacterium tumefaciens-mediated overexpression of CaXEGIP1 triggered pathogen-independent, spontaneous cell death in pepper and Nicotiana benthamiana leaves. CaXEGIP1 silencing in pepper conferred enhanced susceptibility to virulent and avirulent X. campestris pv vesicatoria, accompanied by a compromised hypersensitive response and lowered expression of defense-related genes. Overexpression of dexamethasone:CaXEGIP1 in Arabidopsis (Arabidopsis thaliana) enhanced resistance to Hyaloperonospora arabidopsidis infection. Comparative histochemical and proteomic analyses revealed that CaXEGIP1 overexpression induced a spontaneous cell death response and also increased the expression of some defense-related proteins in transgenic Arabidopsis leaves. This response was also accompanied by cell wall thickening and darkening. Together, these results suggest that pathogen-inducible CaXEGIP1 positively regulates cell death-mediated defense responses in plants.

  15. 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.

  16. Autophagic components contribute to hypersensitive cell death in Arabidopsis

    DEFF Research Database (Denmark)

    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....

  17. 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.

  18. 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.

  19. 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.

  20. Myeloid cell death associated with Toll-like receptor 7/8-mediated inflammatory response. Implication of ASK1, HIF-1 alpha, IL-1 beta and TNF-alpha.

    Science.gov (United States)

    Nicholas, Sally A; Oniku, Abraham E; Sumbayev, Vadim V

    2010-01-01

    Programmed cell death or apoptosis is an important part of the host innate immune defence, especially against ssRNA viruses (influenza virus, HIV-1, ebola virus, hepatitis C virus and many others). Viral ssRNA is recognised by endosomal Toll-like receptors 7 and 8 (TLR7/8) which induce further stages of immune defence against these pathogens. Some of the immune cells die because of inflammatory stress allowing for the selection of those cells which are resistant to stress-induced apoptosis and which are used in further stages of the host immune response. On the other hand, apoptosis could be used as an instrument to suppress the function of activated inflammatory cells. However, the mechanisms underlying death of the inflammatory cells associated with stress induced by ligands of TLR7/8 remain unclear. In this study we have found that programmed death of human myeloid cells from different cell lines associated with ligand-induced TLR7/8-mediated inflammatory stress depends on activation of apoptosis signal-regulating kinase 1 (ASK1). This enzyme is, however, not required for the production of pro-inflammatory cytokines - TNF-α and IL-1β. We have found that released IL-1β and TNF-α are involved in apoptosis of myeloid cells associated with TLR7/8-mediated inflammatory stress. The pro-apoptotic effect of released TNF-α in this case is much lower compared to that of IL-1β.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. The dose dependent in vitro responses of MCF-7 and MDA-MB-231 cell lines to extracts of Vatica diospyroides symington type SS fruit include effects on mode of cell death

    Science.gov (United States)

    Srisawat, Theera; Sukpondma, Yaowapa; Graidist, Potchanapond; Chimplee, Siriphon; Kanokwiroon, Kanyanatt

    2015-01-01

    Background: Vatica diospyroides type LS is a known source of valuable compounds for cancer treatment, however, in contrast little is known about therapeutic efficacy of type SS. Objective: This study focused on in vitro cytotoxicity of these fruit extracts, and the cell death mode they induce in breast cancer cells. Materials and Methods: Acetone extracts of fruit were tested for cytotoxicity against MCF-7 and MDA-MB-231 cell lines. The apoptosis and necrosis of these cells were quantified by fluorescence activated cell sorter (FACS) and western blot analyses. Results: After 72 h of treatment, the 50% growth inhibition concentrations (IC50) levels were 16.21 ± 0.13 µg/mL against MCF-7 and 30.0 ± 4.30 µg/mL against MDA-MB-231, indicating high and moderate cytotoxicity, respectively. From the FACS results, we estimate that the cotyledon extract at half IC50 produced 11.7% dead MCF-7 cells via apoptosis, whereas another concentrations both apoptosis and necrosis modes co-existed in a dose-dependent manner. In MDA-MB-231 cell line, only the apoptosis was induced by the pericarp extract in a dose-dependent manner. With the extracts at half IC50 concentration, in both cells, the expression of p21 decreased while that of Bax increased within 12–48 h of dosing, confirming apoptosis induced by time-dependent responses. Apoptosis dependent on p53 was found in MCF-7, whereas the mutant p53 of MDA-MB-231 cells was expressed. Conclusion: The results indicate that fruit extracts of V. diospyroides have cytotoxic effects against MCF-7 and MDA-MB-231 cells via apoptosis pathway in a dose-dependent manner. This suggests that the extracts could provide active ingredients for the development, targeting breast cancer therapy. PMID:26109760

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Intersex (ix) mutations of Drosophila melanogaster cause nonrandom cell death in genital disc and can induce tumours in genitals in response to decapentaplegic (dppdisk) mutations

    Indian Academy of Sciences (India)

    R. N. chatterjee; P. Chatterjee; S. Kuthe; M. Acharyya-Ari; R. Chatterjee

    2015-06-01

    In Drosophila melanogaster, the intersex (ix) is a terminally positioned gene in somatic sex determination hierarchy and function with the female specific product of double sex (DSXF) to implement female sexual differentiation. The null phenotype of ix is to transform diplo-X individuals into intersexes while leaving haplo-X animals unaffected. This study on the effect of different intersex mutations on genital disc development provides the following major results: (i) similar range of a characteristic array of morphological structures (from almost double sex terminalia to extreme reduction of terminal appendages) was displayed by the terminalia of XX ix1/ix1, XX ix2/ix2 and XX ix5/ix5 individuals; (ii) an increased number of apoptotic cells were found to occur in a localized manner in mature third instar larval genital discs of ix individuals; (iii) ix mutations can induce high frequency of neoplastic tumours in genitals in the presence of decapentaplegic (dppdisk) mutations; and (iv) heteroallelic combinations of dppdisk mutations can also induce tumours in intersex genitals with variable expressivity. On the basis of these findings, we suggest that: (i) loss of function of ix causes massive cell death in both male and female genital primordia of genital discs, resulting phenotype mimicking in male and female characteristics in genitals; and (ii) at the discs, the apoptotic cells persist as ‘undead’ cells that can induce oncogenic transformation in the neighbouring disc cells when dpp signalling is blocked or reduced by dppdisk mutations.

  16. 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.

  17. Necrosis is the dominant cell death pathway in uropathogenic Escherichia coli elicited epididymo-orchitis and is responsible for damage of rat testis.

    Directory of Open Access Journals (Sweden)

    Yongning Lu

    Full Text Available Male infertility is a frequent medical condition, compromising approximately one in twenty men, with infections of the reproductive tract constituting a major etiological factor. Bacterial epididymo-orchitis results in acute inflammation most often caused by ascending canalicular infections from the urethra via the continuous male excurrent ductal system. Uropathogenic Escherichia coli (UPEC represent a relevant pathogen in urogenital tract infections. To explore how bacteria can cause damage and cell loss and thus impair fertility, an in vivo epididymo-orchitis model was employed in rats by injecting UPEC strain CFT073 into the vas deference in close proximity to the epididymis. Seven days post infection bacteria were found predominantly in the testicular interstitial space. UPEC infection resulted in severe impairment of spermatogenesis by germ cell loss, damage of testicular somatic cells, a decrease in sperm numbers and a significant increase in TUNEL (+ cells. Activation of caspase-8 (extrinsic apoptotic pathway, caspase-3/-6 (intrinsic apoptotic pathway, caspase-1 (pyroptosis pathway and the presence of 180 bp DNA fragments, all of which serve as indicators of the classical apoptotic pathway, were not observed in infected testis. Notably, electron microscopical examination revealed degenerative features of Sertoli cells (SC in UPEC infected testis. Furthermore, the passive release of high mobility group protein B1 (HMGB1, as an indication of necrosis, was observed in vivo in infected testis. Thus, necrosis appears to be the dominant cell death pathway in UPEC infected testis. Substantial necrotic changes seen in Sertoli cells will contribute to impaired spermatogenesis by loss of function in supporting the dependent germ cells.

  18. Necrosis is the dominant cell death pathway in uropathogenic Escherichia coli elicited epididymo-orchitis and is responsible for damage of rat testis.

    Science.gov (United States)

    Lu, Yongning; Bhushan, Sudhanshu; Tchatalbachev, Svetlin; Marconi, Marcelo; Bergmann, Martin; Weidner, Wolfgang; Chakraborty, Trinad; Meinhardt, Andreas

    2013-01-01

    Male infertility is a frequent medical condition, compromising approximately one in twenty men, with infections of the reproductive tract constituting a major etiological factor. Bacterial epididymo-orchitis results in acute inflammation most often caused by ascending canalicular infections from the urethra via the continuous male excurrent ductal system. Uropathogenic Escherichia coli (UPEC) represent a relevant pathogen in urogenital tract infections. To explore how bacteria can cause damage and cell loss and thus impair fertility, an in vivo epididymo-orchitis model was employed in rats by injecting UPEC strain CFT073 into the vas deference in close proximity to the epididymis. Seven days post infection bacteria were found predominantly in the testicular interstitial space. UPEC infection resulted in severe impairment of spermatogenesis by germ cell loss, damage of testicular somatic cells, a decrease in sperm numbers and a significant increase in TUNEL (+) cells. Activation of caspase-8 (extrinsic apoptotic pathway), caspase-3/-6 (intrinsic apoptotic pathway), caspase-1 (pyroptosis pathway) and the presence of 180 bp DNA fragments, all of which serve as indicators of the classical apoptotic pathway, were not observed in infected testis. Notably, electron microscopical examination revealed degenerative features of Sertoli cells (SC) in UPEC infected testis. Furthermore, the passive release of high mobility group protein B1 (HMGB1), as an indication of necrosis, was observed in vivo in infected testis. Thus, necrosis appears to be the dominant cell death pathway in UPEC infected testis. Substantial necrotic changes seen in Sertoli cells will contribute to impaired spermatogenesis by loss of function in supporting the dependent germ cells.

  19. Triptolide induced cell death through apoptosis and autophagy in murine leukemia WEHI-3 cells in vitro and promoting immune responses in WEHI-3 generated leukemia mice in vivo.

    Science.gov (United States)

    Chan, Shih-Feng; Chen, Ya-Yin; Lin, Jen-Jyh; Liao, Ching-Lung; Ko, Yang-Ching; Tang, Nou-Ying; Kuo, Chao-Lin; Liu, Kuo-Ching; Chung, Jing-Gung

    2017-02-01

    Triptolide, a traditional Chinese medicine, obtained from Tripterygium wilfordii Hook F, has anti-inflammatory, antiproliferative, and proapoptotic properties. We investigated the potential efficacy of triptolide on murine leukemia by measuring the triptolide-induced cytotoxicity in murine leukemia WEHI-3 cells in vitro. Results indicated that triptolide induced cell morphological changes and induced cytotoxic effects through G0/G1 phase arrest, induction of apoptosis. Flow cytometric assays showed that triptolide increased the production of reactive oxygen species, Ca(2+) release and mitochondrial membrane potential (ΔΨm ), and activations of caspase-8, -9, and -3. Triptolide increased protein levels of Fas, Fas-L, Bax, cytochrome c, caspase-9, Endo G, Apaf-1, PARP, caspase-3 but reduced levels of AIF, ATF6α, ATF6β, and GRP78 in WEHI-3 cells. Triptolide stimulated autophagy based on an increase in acidic vacuoles, monodansylcadaverine staining for LC-3 expression and increased protein levels of ATG 5, ATG 7, and ATG 12. The in vitro data suggest that the cytotoxic effects of triptolide may involve cross-talk between cross-interaction of apoptosis and autophagy. Normal BALB/c mice were i.p. injected with WEHI-3 cells to generate leukemia and were oral treatment with triptolide at 0, 0.02, and 0.2 mg/kg for 3 weeks then animals were weighted and blood, liver, spleen samples were collected. Results indicated that triptolide did not significantly affect the weights of animal body, spleen and liver of leukemia mice, however, triptolide significant increased the cell populations of T cells (CD3), B cells (CD19), monocytes (CD11b), and macrophage (Mac-3). Furthermore, triptolide increased the phagocytosis of macrophage from peripheral blood mononuclear cells (PBMC) but not effects from peritoneum. Triptolide promoted T and B cell proliferation at 0.02 and 0.2 mg/kg treatment when cells were pretreated with Con A and LPS stimulation, respectively; however, triptolide

  20. 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.

  1. 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

  2. Bortezomib induces autophagic death in proliferating human endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    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. 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.

  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. Death by Numbers: A Response to Backer, Sarigianides, and Stillwaggon

    Science.gov (United States)

    Taubman, Peter

    2017-01-01

    In this response essay, Peter Taubman considers the relationship between melancholia and Freud's notion of a death drive. Taubman explores how audit culture sustains melancholia and intensifies the death drive, ultimately deadening our psyches by erasing memory, disparaging feelings, shutting down thought, and ignoring history. Taubman concludes…

  6. 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...

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. 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.

  14. 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.

  15. SK-N-MC cell death occurs by distinct molecular mechanisms in response to hydrogen peroxide and superoxide anions: involvements of JAK2-STAT3, JNK, and p38 MAP kinases pathways.

    Science.gov (United States)

    Moslehi, Maryam; Yazdanparast, Razieh

    2013-07-01

    Oxidative stress plays a vital role in the pathogenesis of neurodegenerative diseases. Nerve cells are incessantly exposed to environmental stresses leading to overproduction of some harmful species like reactive oxygen species (ROS). ROS including hydrogen peroxide and superoxide anion are potent inducers of various signaling pathways encompassing MAPKs and JAK-STAT pathways. In the current study, we scrutinized the effects of hydrogen peroxide and/or menadione (superoxide anion generator) on JNK/p38-MAPKs and JAK2-STAT3 pathways to elucidate the mechanism(s) by which each oxidant modulated the above-mentioned pathways leading to SK-N-MC cell death. Our results delineated that hydrogen peroxide and superoxide anion radical induced distinct responses as we showed that STAT3 and p38 were activated in response to hydrogen peroxide, but not superoxide anion radicals indicating the specificity in ROS-induced signaling pathways activations and behaviors. We also observed that menadione induced JNK-dependent p53 expression and apoptotic death in SK-N-MC cells while H2O2-induced JNK activation was p53 independent. Thus, we declare that ROS type has a key role in selective instigation of JNK/p38-MAPKs and JAK2-STAT3 pathways in SK-N-MC cells. Identifying these differential behaviors and mechanisms of hydrogen peroxide and superoxide anion functions illuminates the possible therapeutic targets in the prevention or treatment of ROS-induced neurodegenerative diseases such as Alzheimer's disease.

  16. 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.

  17. 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

  18. Methods for assessing autophagy and autophagic cell death.

    Science.gov (United States)

    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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  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. 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.

  6. 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.

  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. 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

  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. 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

  12. 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...

  13. 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

  14. Response to 'Fear of death and the symmetry argument'

    Directory of Open Access Journals (Sweden)

    Natalja Deng

    Full Text Available ABSTRACT This article is a response to 'Fear of death and the symmetry argument', in this issue. In that article, the author discusses the above Lucretian symmetry argument, and proposes a view that justifies the existing asymmetry in our attitudes towards birth and death. I begin by distinguishing this symmetry argument from a different one, also loosely inspired by Lucretius, which also plays a role in the article. I then describe what I take to be the author's solution to the original symmetry argument (i.e. the one above and explain why I am unpersuaded by it.

  15. 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.

  16. 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.

  17. Direct monitoring of paraquat induced cell death using quartz crystal sensor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Yun [School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo 192-0982 (Japan); Department of Electrical Engineering and NTRC, Dong-A University, 840 Hadan 2-dong, Saha-gu, Busan 604-714 (Korea, Republic of); Kang, Hyen-Wook, E-mail: nanokang@bs.teu.ac.j [School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo 192-0982 (Japan); Kaneko, Seiichi [School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo 192-0982 (Japan); Kwon, Young-Soo, E-mail: yskwon@dau.ac.k [Department of Electrical Engineering and NTRC, Dong-A University, 840 Hadan 2-dong, Saha-gu, Busan 604-714 (Korea, Republic of); Muramatsu, Hiroshi, E-mail: muramatu@bs.teu.ac.j [School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo 192-0982 (Japan)

    2009-11-30

    Paraquat, a nonselective herbicide and pesticide, has been implicated as an environmental toxicity which caused cell death. In order to investigate the influence of paraquat, we used a quartz crystal sensor with a micro CCD camera that measured morphology and resonance characteristics simultaneously. Human hepatoma cell line (HepG2) was cultured onto an indium tin oxide (ITO) surface of quartz crystal modified on a collagen film. After the growth of the cells, paraquat was injected to the chamber and the resonance responses of the quartz crystal were directly monitored with morphology. We analyzed changes of the cells by the resonance frequency (F) and the resonance resistance (R) responses (F-R diagram). With this analysis, we also observed the morphologies during cell culturing. From the data, we could know that paraquat caused the weakening and death of the cells. Namely, paraquat plays an important role in the free radicals production that led to apoptosis and cell death.

  18. Hepatitis B vaccine antibody response and the risk of clinical AIDS or death.

    Directory of Open Access Journals (Sweden)

    Michael L Landrum

    Full Text Available BACKGROUND: Whether seroresponse to a vaccine such as hepatitis B virus (HBV vaccine can provide a measure of the functional immune status of HIV-infected persons is unknown.This study evaluated the relationship between HBV vaccine seroresponses and progression to clinical AIDS or death. METHODS AND FINDINGS: From a large HIV cohort, we evaluated those who received HBV vaccine only after HIV diagnosis and had anti-HBs determination 1-12 months after the last vaccine dose. Non-response and positive response were defined as anti-HBs <10 and ≥ 10 IU/L, respectively. Participants were followed from date of last vaccination to clinical AIDS, death, or last visit. Univariate and multivariable risk of progression to clinical AIDS or death were evaluated with Cox regression models. A total of 795 participants vaccinated from 1986-2010 were included, of which 41% were responders. During 3,872 person-years of observation, 122 AIDS or death events occurred (53% after 1995. Twenty-two percent of non-responders experienced clinical AIDS or death compared with 5% of responders (p<0.001. Non-response to HBV vaccine was associated with a greater than 2-fold increased risk of clinical AIDS or death (HR 2.47; 95% CI, 1.38-4.43 compared with a positive response, after adjusting for CD4 count, HIV viral load, HAART use, and delayed type hypersensitivity skin test responses (an in vivo marker of cell-mediated immunity. This association remained evident among those with CD4 count ≥ 500 cells/mm³ (HR 3.40; 95% CI, 1.39-8.32. CONCLUSIONS: HBV vaccine responses may have utility in assessing functional immune status and risk stratificating HIV-infected individuals, including those with CD4 count ≥ 500 cells/mm³.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Cell response to surgery.

    LENUS (Irish Health Repository)

    Ni Choileain, Niamh

    2012-02-03

    OBJECTIVES: To describe the profound alterations in host immunity that are produced by major surgery as demonstrated by experimental and clinical studies, and to evaluate the benefits of therapeutic strategies aimed at attenuating perioperative immune dysfunction. DATA SOURCES: A review of the English-language literature was conducted, incorporating searches of the MEDLINE, EMBASE, and Cochrane collaboration databases to identify laboratory and clinical studies investigating the cellular response to surgery. STUDY SELECTION: Original articles and case reports describing immune dysfunction secondary to surgical trauma were included. DATA EXTRACTION: The results were compiled to show outcomes of different studies and were compared. DATA SYNTHESIS: Current evidence indicates that the early systemic inflammatory response syndrome observed after major surgery that is characterized by proinflammatory cytokine release, microcirculatory disturbance, and cell-mediated immune dysfunction is followed by a compensatory anti-inflammatory response syndrome, which predisposes the patient to opportunistic infection, multiple organ dysfunction syndrome, and death. Because there are currently no effective treatment options for multiple organ dysfunction syndrome, measures to prevent its onset should be initiated at an early stage. Accumulating experimental evidence suggests that targeted therapeutic strategies involving immunomodulatory agents such as interferon gamma, granulocyte colony-stimulating factor, the prostaglandin E(2) antagonist, indomethacin, and pentoxifylline may be used for the treatment of systemic inflammatory response syndrome to prevent the onset of multiple organ dysfunction syndrome. CONCLUSIONS: Surgical trauma produces profound immunological dysfunction. Therapeutic strategies directed at restoring immune homeostasis should aim to redress the physiological proinflammatory-anti-inflammatory cell imbalance associated with major surgery.

  11. 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.

  12. 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.

  13. Overexpression of Ref-1 Inhibits Lead-induced Endothelial Cell Death via the Upregulation of Catalase.

    Science.gov (United States)

    Lee, Kwon Ho; Lee, Sang Ki; Kim, Hyo Shin; Cho, Eun Jung; Joo, Hee Kyoung; Lee, Eun Ji; Lee, Ji Young; Park, Myoung Soo; Chang, Seok Jong; Cho, Chung-Hyun; Park, Jin Bong; Jeon, Byeong Hwa

    2009-12-01

    The role of apurinic/apyrimidinic endonuclease1/redox factor-1 (Ref-1) on the lead (Pb)-induced cellular response was investigated in the cultured endothelial cells. Pb caused progressive cellular death in endothelial cells, which occurred in a concentration- and time-dependent manner. However, Ref-1 overexpression with AdRef-1 significantly inhibited Pb-induced cell death in the endothelial cells. Also the overexpression of Ref-1 significantly suppressed Pb-induced superoxide and hydrogen peroxide elevation in the endothelial cells. Pb exposure induced the downregulation of catalase, it was inhibited by the Ref-1 overexpression in the endothelial cells. Taken together, our data suggests that the overexpression of Ref-1 inhibited Pb-induced cell death via the upregulation of catalase in the cultured endothelial cells.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. mTOR inhibition by everolimus in childhood acute lymphoblastic leukemia induces caspase-independent cell death.

    Directory of Open Access Journals (Sweden)

    Rana Baraz

    Full Text Available Increasingly, anti-cancer medications are being reported to induce cell death mechanisms other than apoptosis. Activating alternate death mechanisms introduces the potential to kill cells that have defects in their apoptotic machinery, as is commonly observed in cancer cells, including in hematological malignancies. We, and others, have previously reported that the mTOR inhibitor everolimus has pre-clinical efficacy and induces caspase-independent cell death in acute lymphoblastic leukemia cells. Furthermore, everolimus is currently in clinical trial for acute lymphoblastic leukemia. Here we characterize the death mechanism activated by everolimus in acute lymphoblastic leukemia cells. We find that cell death is caspase-independent and lacks the morphology associated with apoptosis. Although mitochondrial depolarization is an early event, permeabilization of the outer mitochondrial membrane only occurs after cell death has occurred. While morphological and biochemical evidence shows that autophagy is clearly present it is not responsible for the observed cell death. There are a number of features consistent with paraptosis including morphology, caspase-independence, and the requirement for new protein synthesis. However in contrast to some reports of paraptosis, the activation of JNK signaling was not required for everolimus-induced cell death. Overall in acute lymphoblastic leukemia cells everolimus induces a cell death that resembles paraptosis.

  9. Yokukansan inhibits neuronal death during ER stress by regulating the unfolded protein response.

    Directory of Open Access Journals (Sweden)

    Toru Hiratsuka

    Full Text Available BACKGROUND: Recently, several studies have reported Yokukansan (Tsumura TJ-54, a traditional Japanese medicine, as a potential new drug for the treatment of Alzheimer's disease (AD. Endoplasmic reticulum (ER stress is known to play an important role in the pathogenesis of AD, particularly in neuronal death. Therefore, we examined the effect of Yokukansan on ER stress-induced neurotoxicity and on familial AD-linked presenilin-1 mutation-associated cell death. METHODS: We employed the WST-1 assay and monitored morphological changes to evaluate cell viability following Yokukansan treatment or treatment with its components. Western blotting and PCR were used to observe the expression levels of GRP78/BiP, caspase-4 and C/EBP homologous protein. RESULTS: Yokukansan inhibited neuronal death during ER stress, with Cnidii Rhizoma (Senkyu, a component of Yokukansan, being particularly effective. We also showed that Yokukansan and Senkyu affect the unfolded protein response following ER stress and that these drugs inhibit the activation of caspase-4, resulting in the inhibition of ER stress-induced neuronal death. Furthermore, we found that the protective effect of Yokukansan and Senkyu against ER stress could be attributed to the ferulic acid content of these two drugs. CONCLUSIONS: Our results indicate that Yokukansan, Senkyu and ferulic acid are protective against ER stress-induced neuronal cell death and may provide a possible new treatment for AD.

  10. IL-1β but not programmed death-1 and programmed death-ligand pathway is critical for the human Th17 response to M. tuberculosis

    Directory of Open Access Journals (Sweden)

    Emmanuel Stephen-Victor

    2016-11-01

    Full Text Available The programmed death-1 (PD-1- programmed death ligand-1 (PD-L1 and PD-L2 co-inhibitory pathway has been implicated in the evasion strategies of Mycobacterium tuberculosis. Specifically, M. tuberculosis-induced PD-L1 orchestrates expansion of regulatory T cells (Tregs and suppression of Th1 response. However, the role of PD pathway in regulating Th17 response to M. tuberculosis has not been investigated. In the present report, we demonstrate that M. tuberculosis and M. tuberculosis-derived antigen fractions have differential abilities to mediate human monocyte and dendritic cell (DC-mediated Th17 response and were independent of expression of PD-L1 or PD-L2 on aforementioned antigen-presenting cells. Importantly, we observed that blockade of PD-L1 or PD-1 did not significantly modify either the frequencies of Th17 cells or the production of IL-17 from CD4+ T cells though IFN-γ response was significantly enhanced. On the contrary, IL-1β from monocytes and DCs were critical for the Th17 response to M. tuberculosis. Together, our results indicate that IL-1β but not members of the programmed death pathway is critical for human Th17 response to M. tuberculosis

  11. Metacaspase-8 Modulates Programmed Cell Death Induced by Ultraviolet Light and H2O2 in Arabidopsis

    NARCIS (Netherlands)

    He, R.; Drury, G.E.; Rotari, V.I.; Gordon, A.; Willer, M.; Farzaneh, T.; Woltering, E.J.; Gallois, P.

    2008-01-01

    Programmed cell death (PCD) is a genetically controlled cell death that is regulated during development and activated in response to environmental stresses or pathogen infection. The degree of conservation of PCD across kingdoms and phylum is not yet clear; however, whereas caspases are proteases th

  12. 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

  13. 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.

  14. Mutants for Drosophila Isocitrate Dehydrogenase 3b Are Defective in Mitochondrial Function and Larval Cell Death

    Science.gov (United States)

    Duncan, Dianne M.; Kiefel, Paula; Duncan, Ian

    2017-01-01

    The death of larval salivary gland cells during metamorphosis in Drosophila melanogaster has been a key system for studying steroid controlled programmed cell death. This death is induced by a pulse of the steroid hormone ecdysone that takes place at the end of the prepupal period. For many years, it has been thought that the ecdysone direct response gene Eip93F (E93) plays a critical role in initiating salivary gland cell death. This conclusion was based largely on the finding that the three “type” alleles of E93 cause a near-complete block in salivary gland cell death. Here, we show that these three mutations are in fact allelic to Idh3b, a nearby gene that encodes the β subunit of isocitrate dehydrogenase 3, a mitochondrial enzyme of the tricarboxylic acid (TCA) cycle. The strongest of the Idh3b alleles appears to cause a near-complete block in oxidative phosphorylation, as mitochondria are depolarized in mutant larvae, and development arrests early during cleavage in embryos from homozygous-mutant germline mothers. Idh3b-mutant larval salivary gland cells fail to undergo mitochondrial fragmentation, which normally precedes the death of these cells, and do not initiate autophagy, an early step in the cell death program. These observations suggest a close relationship between the TCA cycle and the initiation of larval cell death. In normal development, tagged Idh3b is released from salivary gland mitochondria during their fragmentation, suggesting that Idh3b may be an apoptogenic factor that functions much like released cytochrome c in mammalian cells. PMID:28104670

  15. 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.

  16. Cell Death Inducing Microbial Protein Phosphatase Inhibitors—Mechanisms of Action

    Directory of Open Access Journals (Sweden)

    Rune Kleppe

    2015-10-01

    Full Text Available Okadaic acid (OA and microcystin (MC as well as several other microbial toxins like nodularin and calyculinA are known as tumor promoters as well as inducers of apoptotic cell death. Their intracellular targets are the major serine/threonine protein phosphatases. This review summarizes mechanisms believed to be responsible for the death induction and tumor promotion with focus on the interdependent production of reactive oxygen species (ROS and activation of Ca2+/calmodulin kinase II (CaM-KII. New data are presented using inhibitors of specific ROS producing enzymes to curb nodularin/MC-induced liver cell (hepatocyte death. They indicate that enzymes of the arachidonic acid pathway, notably phospholipase A2, 5-lipoxygenase, and cyclooxygenases, may be required for nodularin/MC-induced (and presumably OA-induced cell death, suggesting new ways to overcome at least some aspects of OA and MC toxicity.

  17. Apoptosis-like death, an extreme SOS response in Escherichia coli.

    Science.gov (United States)

    Erental, Ariel; Kalderon, Ziva; Saada, Ann; Smith, Yoav; Engelberg-Kulka, Hanna

    2014-07-15

    In bacteria, SOS is a global response to DNA damage, mediated by the recA-lexA genes, resulting in cell cycle arrest, DNA repair, and mutagenesis. Previously, we reported that Escherichia coli responds to DNA damage via another recA-lexA-mediated pathway resulting in programmed cell death (PCD). We called it apoptosis-like death (ALD) because it is characterized by membrane depolarization and DNA fragmentation, which are hallmarks of eukaryotic mitochondrial apoptosis. Here, we show that ALD is an extreme SOS response that occurs only under conditions of severe DNA damage. Furthermore, we found that ALD is characterized by additional hallmarks of eukaryotic mitochondrial apoptosis, including (i) rRNA degradation by the endoribonuclease YbeY, (ii) upregulation of a unique set of genes that we called extensive-damage-induced (Edin) genes, (iii) a decrease in the activities of complexes I and II of the electron transport chain, and (iv) the formation of high levels of OH˙ through the Fenton reaction, eventually resulting in cell death. Our genetic and molecular studies on ALD provide additional insight for the evolution of mitochondria and the apoptotic pathway in eukaryotes. Importance: The SOS response is the first described and the most studied bacterial response to DNA damage. It is mediated by a set of two genes, recA-lexA, and it results in DNA repair and thereby in the survival of the bacterial culture. We have shown that Escherichia coli responds to DNA damage by an additional recA-lexA-mediated pathway resulting in an apoptosis-like death (ALD). Apoptosis is a mode of cell death that has previously been reported only in eukaryotes. We found that E. coli ALD is characterized by several hallmarks of eukaryotic mitochondrial apoptosis. Altogether, our results revealed that recA-lexA is a DNA damage response coordinator that permits two opposite responses: life, mediated by the SOS, and death, mediated by the ALD. The choice seems to be a function of the degree

  18. Bar represses dPax2 and decapentaplegic to regulate cell fate and morphogenetic cell death in Drosophila eye.

    Directory of Open Access Journals (Sweden)

    Jongkyun Kang

    Full Text Available The coordinated regulation of cell fate and cell survival is crucial for normal pattern formation in developing organisms. In Drosophila compound eye development, crystalline arrays of hexagonal ommatidia are established by precise assembly of diverse cell types, including the photoreceptor cells, cone cells and interommatidial (IOM pigment cells. The molecular basis for controlling the number of cone and IOM pigment cells during ommatidial pattern formation is not well understood. Here we present evidence that BarH1 and BarH2 homeobox genes are essential for eye patterning by inhibiting excess cone cell differentiation and promoting programmed death of IOM cells. Specifically, we show that loss of Bar from the undifferentiated retinal precursor cells leads to ectopic expression of Prospero and dPax2, two transcription factors essential for cone cell specification, resulting in excess cone cell differentiation. We also show that loss of Bar causes ectopic expression of the TGFβ homolog Decapentaplegic (Dpp posterior to the morphogenetic furrow in the larval eye imaginal disc. The ectopic Dpp expression is not responsible for the formation of excess cone cells in Bar loss-of-function mutant eyes. Instead, it causes reduction in IOM cell death in the pupal stage by antagonizing the function of pro-apoptotic gene reaper. Taken together, this study suggests a novel regulatory mechanism in the control of developmental cell death in which the repression of Dpp by Bar in larval eye disc is essential for IOM cell death in pupal retina.

  19. 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.

  20. 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.

  1. A shift to organismal stress resistance in programmed cell death mutants.

    Directory of Open Access Journals (Sweden)

    Meredith E Judy

    Full Text Available Animals have many ways of protecting themselves against stress; for example, they can induce animal-wide, stress-protective pathways and they can kill damaged cells via apoptosis. We have discovered an unexpected regulatory relationship between these two types of stress responses. We find that C. elegans mutations blocking the normal course of programmed cell death and clearance confer animal-wide resistance to a specific set of environmental stressors; namely, ER, heat and osmotic stress. Remarkably, this pattern of stress resistance is induced by mutations that affect cell death in different ways, including ced-3 (cell death defective mutations, which block programmed cell death, ced-1 and ced-2 mutations, which prevent the engulfment of dying cells, and progranulin (pgrn-1 mutations, which accelerate the clearance of apoptotic cells. Stress resistance conferred by ced and pgrn-1 mutations is not additive and these mutants share altered patterns of gene expression, suggesting that they may act within the same pathway to achieve stress resistance. Together, our findings demonstrate that programmed cell death effectors influence the degree to which C. elegans tolerates environmental stress. While the mechanism is not entirely clear, it is intriguing that animals lacking the ability to efficiently and correctly remove dying cells should switch to a more global animal-wide system of stress resistance.

  2. Programmed Death-Ligand 1 Expression and Response to the Anti-Programmed Death 1 Antibody Pembrolizumab in Melanoma.

    Science.gov (United States)

    Daud, Adil I; Wolchok, Jedd D; Robert, Caroline; Hwu, Wen-Jen; Weber, Jeffrey S; Ribas, Antoni; Hodi, F Stephen; Joshua, Anthony M; Kefford, Richard; Hersey, Peter; Joseph, Richard; Gangadhar, Tara C; Dronca, Roxana; Patnaik, Amita; Zarour, Hassane; Roach, Charlotte; Toland, Grant; Lunceford, Jared K; Li, Xiaoyun Nicole; Emancipator, Kenneth; Dolled-Filhart, Marisa; Kang, S Peter; Ebbinghaus, Scot; Hamid, Omid

    2016-12-01

    Purpose Expression of programmed death-ligand 1 (PD-L1) is a potential predictive marker for response and outcome after treatment with anti-programmed death 1 (PD-1). This study explored the relationship between anti-PD-1 activity and PD-L1 expression in patients with advanced melanoma who were treated with pembrolizumab in the phase Ib KEYNOTE-001 study (clinical trial information: NCT01295827). Patients and Methods Six hundred fifty-five patients received pembrolizumab10 mg/kg once every 2 weeks or once every 3 weeks, or 2 mg/kg once every 3 weeks. Tumor response was assessed every 12 weeks per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 by independent central review. Primary outcome was objective response rate. Secondary outcomes included progression-free survival (PFS) and overall survival (OS). Membranous PD-L1 expression in tumor and tumor-associated immune cells was assessed by a clinical trial immunohistochemistry assay (22C3 antibody) and scored on a unique melanoma (MEL) scale of 0 to 5 by one of three pathologists who were blinded to clinical outcome; a score ≥ 2 (membranous staining in ≥ 1% of cells) was considered positive. Results Of 451 patients with evaluable PD-L1 expression, 344 (76%) had PD-L1-positive tumors. Demographic and staging variables were equally distributed among PD-L1-positive and -negative patients. An association between higher MEL score and higher response rate and longer PFS (hazard ratio, 0.76; 95% CI, 0.71 to 0.82) and OS (hazard ratio, 0.76; 95% CI, 0.69 to 0.83) was observed ( P < .001 for each). Objective response rate was 8%, 12%, 22%, 43%, 57%, and 53% for MEL 0, 1, 2, 3, 4, and 5, respectively. Conclusion PD-L1 expression in pretreatment tumor biopsy samples was correlated with response rate, PFS, and OS; however, patients with PD-L1-negative tumors may also achieve durable responses.

  3. Interaction of CSR1 with XIAP reverses inhibition of caspases and accelerates cell death.

    Science.gov (United States)

    Zheng, Zhong-Liang; Tan, Lang-Zhu; Yu, Yan P; Michalopoulos, George; Luo, Jian-Hua

    2012-08-01

    Cellular Stress Response 1 (CSR1) is a tumor suppressor gene that is located at 8p21, a region that is frequently deleted in prostate cancer as well as a variety of human malignancies. Previous studies have indicated that the expression of CSR1 induces cell death. In this study, we found that CSR1 interacts with X-linked Inhibitor of Apoptosis Protein (XIAP), using yeast two-hybrid screening analyses. XIAP overexpression has been found in many human cancers, and forced expression of XIAP blocks apoptosis. Both in vitro and in vivo analyses indicated that the C-terminus of CSR1 binds XIAP with high affinity. Through a series of in vitro recombinant protein-binding analyses, the XIAP-binding motif in CSR1 was determined to include amino acids 513 to 572. Targeted knock-down of XIAP enhanced CSR1-induced cell death, while overexpression of XIAP antagonized CSR1 activity. The binding of CSR1 with XIAP enhanced caspase-9 and caspase-3 protease activities, and CSR1-induced cell death was dramatically reduced on expression of a mutant CSR1 that does not bind XIAP. However, a XIAP mutant that does not interact with caspase-9 had no impact on CSR1-induced cell death. These results suggest that cell death is induced when CSR1 binds XIAP, preventing the interaction of XIAP with caspases. Thus, this study may have elucidated a novel mechanism by which tumor suppressors induce cell death.

  4. Hepatic leukemia factor promotes resistance to cell death: Implications for therapeutics and chronotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Waters, Katrina M. [Computational Biology and Bioinformatics, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Sontag, Ryan L. [Systems Toxicology Groups, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Weber, Thomas J., E-mail: Thomas.Weber@pnl.gov [Systems Toxicology Groups, Pacific Northwest National Laboratory, Richland, WA 99354 (United States)

    2013-04-15

    Physiological variation related to circadian rhythms and aberrant gene expression patterns are believed to modulate therapeutic efficacy, but the precise molecular determinants remain unclear. Here we examine the regulation of cell death by hepatic leukemia factor (HLF), which is an output regulator of circadian rhythms and is aberrantly expressed in human cancers, using an ectopic expression strategy in JB6 mouse epidermal cells and human keratinocytes. Ectopic HLF expression inhibited cell death in both JB6 cells and human keratinocytes, as induced by serum-starvation, tumor necrosis factor alpha and ionizing radiation. Microarray analysis indicates that HLF regulates a complex multi-gene transcriptional program encompassing upregulation of anti-apoptotic genes, downregulation of pro-apoptotic genes, and many additional changes that are consistent with an anti-death program. Collectively, our results demonstrate that ectopic expression of HLF, an established transcription factor that cycles with circadian rhythms, can recapitulate many features associated with circadian-dependent physiological variation. - Highlights: ► Circadian-dependent physiological variation impacts therapeutic efficacy. ► Hepatic leukemia factor inhibits cell death and is a candidate circadian factor. ► Hepatic leukemia factor anti-death program is conserved in murine and human cells. ► Transcriptomics indicates the anti-death program results from a systems response.

  5. 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...

  6. A Response to the Legitimacy of Brain Death in Islam.

    Science.gov (United States)

    Rady, Mohamed Y; Verheijde, Joseph L

    2016-08-01

    Brain death is a novel construct of death for the procurement of transplantable organs. Many authoritative Islamic organizations and governments have endorsed brain death as true death for organ donation. Many commentators have reiterated the misconception that the Quranic text does not define death. We respond by clarifying: (1) the Quran does define death as biologic disintegration and clearly distinguishes it from the dying process, (2) brain death belongs scientifically within the spectrum of neurologic disorders of consciousness and should not be confused with death, and (3) religious and legal discord about brain death has grown in jurisdictions worldwide. We urge for public transparency and truthfulness about brain death and the accommodation and respect of religious objection to the determination of death by neurologic criteria.

  7. 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.

  8. 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.

  9. Two modes of cell death caused by exposure to nanosecond pulsed electric field.

    Directory of Open Access Journals (Sweden)

    Olga N Pakhomova

    Full Text Available High-amplitude electric pulses of nanosecond duration, also known as nanosecond pulsed electric field (nsPEF, are a novel modality with promising applications for cell stimulation and tissue ablation. However, key mechanisms responsible for the cytotoxicity of nsPEF have not been established. We show that the principal cause of cell death induced by 60- or 300-ns pulses in U937 cells is the loss of the plasma membrane integrity ("nanoelectroporation", leading to water uptake, cell swelling, and eventual membrane rupture. Most of this early necrotic death occurs within 1-2 hr after nsPEF exposure. The uptake of water is driven by the presence of pore-impermeable solutes inside the cell, and can be counterbalanced by the presence of a pore-impermeable solute such as sucrose in the medium. Sucrose blocks swelling and prevents the early necrotic death; however the long-term cell survival (24 and 48 hr does not significantly change. Cells protected with sucrose demonstrate higher incidence of the delayed death (6-24 hr post nsPEF. These cells are more often positive for the uptake of an early apoptotic marker dye YO-PRO-1 while remaining impermeable to propidium iodide. Instead of swelling, these cells often develop apoptotic fragmentation of the cytoplasm. Caspase 3/7 activity increases already in 1 hr after nsPEF and poly-ADP ribose polymerase (PARP cleavage is detected in 2 hr. Staurosporin-treated positive control cells develop these apoptotic signs only in 3 and 4 hr, respectively. We conclude that nsPEF exposure triggers both necrotic and apoptotic pathways. The early necrotic death prevails under standard cell culture conditions, but cells rescued from the necrosis nonetheless die later on by apoptosis. The balance between the two modes of cell death can be controlled by enabling or blocking cell swelling.

  10. Two modes of cell death caused by exposure to nanosecond pulsed electric field.

    Science.gov (United States)

    Pakhomova, Olga N; Gregory, Betsy W; Semenov, Iurii; Pakhomov, Andrei G

    2013-01-01

    High-amplitude electric pulses of nanosecond duration, also known as nanosecond pulsed electric field (nsPEF), are a novel modality with promising applications for cell stimulation and tissue ablation. However, key mechanisms responsible for the cytotoxicity of nsPEF have not been established. We show that the principal cause of cell death induced by 60- or 300-ns pulses in U937 cells is the loss of the plasma membrane integrity ("nanoelectroporation"), leading to water uptake, cell swelling, and eventual membrane rupture. Most of this early necrotic death occurs within 1-2 hr after nsPEF exposure. The uptake of water is driven by the presence of pore-impermeable solutes inside the cell, and can be counterbalanced by the presence of a pore-impermeable solute such as sucrose in the medium. Sucrose blocks swelling and prevents the early necrotic death; however the long-term cell survival (24 and 48 hr) does not significantly change. Cells protected with sucrose demonstrate higher incidence of the delayed death (6-24 hr post nsPEF). These cells are more often positive for the uptake of an early apoptotic marker dye YO-PRO-1 while remaining impermeable to propidium iodide. Instead of swelling, these cells often develop apoptotic fragmentation of the cytoplasm. Caspase 3/7 activity increases already in 1 hr after nsPEF and poly-ADP ribose polymerase (PARP) cleavage is detected in 2 hr. Staurosporin-treated positive control cells develop these apoptotic signs only in 3 and 4 hr, respectively. We conclude that nsPEF exposure triggers both necrotic and apoptotic pathways. The early necrotic death prevails under standard cell culture conditions, but cells rescued from the necrosis nonetheless die later on by apoptosis. The balance between the two modes of cell death can be controlled by enabling or blocking cell swelling.

  11. Oxytocin Protects against Stress-Induced Cell Death in Murine Pancreatic β-Cells

    Science.gov (United States)

    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

  12. 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

  13. When Supply Does Not Meet Demand-ER Stress and Plant Programmed Cell Death

    Directory of Open Access Journals (Sweden)

    Brett eWilliams

    2014-06-01

    Full Text Available The endoplasmic reticulum (ER is the central organelle in the eukaryotic secretory pathway. The ER functions in protein synthesis and maturation and is crucial for proper maintenance of cellular homeostasis and adaptation to adverse environments. Acting as a cellular sentinel, the ER is exquisitely sensitive to changing environments principally via the ER quality control machinery. When perturbed, ER-stress triggers a tightly regulated and highly conserved, signal transduction pathway known as the unfolded protein response (UPR that prevents the dangerous accumulation of unfolded/misfolded proteins. In situations where excessive UPR activity surpasses threshold levels, cells deteriorate and eventually trigger programmed cell death (PCD as a way for the organism to cope with dysfunctional or toxic signals. The programmed cell death that results from excessive ER stress in mammalian systems contributes to several important diseases including hypoxia, neurodegeneration and diabetes. Importantly, hallmark features and markers of cell death that are associated with ER stress in mammals are also found in plants. In particular, there is a common, conserved set of chaperones that modulate ER cell death signalling. Here we review the elements of plant cell death responses to ER stress and note that an increasing number of plant-pathogen interactions are being identified in which the host ER is targeted by plant pathogens to establish compatibility.

  14. Cell cycle arrest and biochemical changes accompanying cell death in harmful dinoflagellates following exposure to bacterial algicide IRI-160AA

    Science.gov (United States)

    Pokrzywinski, Kaytee L.; Tilney, Charles L.; Warner, Mark E.; Coyne, Kathryn J.

    2017-03-01

    Bacteria may play a role in regulating harmful algal blooms, but little is known about the biochemical and physiological changes associated with cell death induced by algicidal bacteria. Previous work characterized an algicidal exudate (IRI-160AA) produced by Shewanella sp. IRI-160 that is effective against dinoflagellates, while having little to no effect on other phytoplankton species in laboratory culture experiments. The objective of this study was to evaluate biochemical changes associated with cell death and impacts on the cell cycle in three dinoflagellate species (Prorocentrum minimum, Karlodinium veneficum and Gyrodinium instriatum) after exposure to IRI-160AA. In this study, IRI-160AA induced cell cycle arrest in all dinoflagellates examined. Several indicators for programmed cell death (PCD) that are often observed in phytoplankton in response to a variety of stressors were also evaluated. Cell death was accompanied by significant increases in DNA degradation, intra- and extracellular ROS concentrations and DEVDase (caspase-3 like) protease activity, which have been associated with PCD in other phytoplankton species. Overall, results of this investigation provide strong evidence that treatment with the bacterial algicide, IRI-160AA results in cell cycle arrest and induces biochemical changes consistent with stress-related cell death responses observed in other phytoplankton.

  15. 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.

  16. 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.

  17. Ethylene initiates ROS generation and results in necrotic cell death during Tm-22 response to ToMV%乙烯在Tm-22抗ToMV反应中激发ROS发生并导致细胞死亡

    Institute of Scientific and Technical Information of China (English)

    姜国勇; 杨仁崔

    2004-01-01

    Tomato Tm-22 resistance gene confers durable resistance against tobamoviruses. The fact that Tm-22 gene can functionally expressed in Nicotiana tabaccum allows us through this system to get insight in the resistant mechanism of ROS during Tm-22 resistant response to ToMV. In our observation, ROS generation could be induced through exogenous ethylene application and ACC combination. Ethylene-sustainable stimulation and high concentration ACC application could cause necrotic cell death accompanied by ROS generation on transient expression.%番茄的抗病基因Tm-22对Tobamoviruses属病毒有持续抗性.鉴于Tm-22基因在烟草(Nicotiana tabaccum)上能够功能表达,我们可以应用这一体系来了解Tm-22抗ToMV反应中氧离子自由基(ROS)的产生机制.瞬间表达的研究结果表明,ROS能够被外源的乙烯和ACC诱导,持续的乙烯刺激和应用高浓度的ACC能够导致细胞坏死并伴随着ROS的产生.

  18. Neisseria gonorrhoeae Modulates Cell Death in Human Endocervical Epithelial Cells through Export of Exosome-Associated cIAP2.

    Science.gov (United States)

    Nudel, Kathleen; Massari, Paola; Genco, Caroline A

    2015-09-01

    Several bacterial pathogens persist and survive in the host by modulating host cell death pathways. We previously demonstrated that Neisseria gonorrhoeae, a Gram-negative pathogen responsible for the sexually transmitted infection gonorrhea, protects against exogenous induction of apoptosis in human cervical epithelial cells. However, induction of cell death by N. gonorrhoeae has also been reported in other cell types. The mechanisms by which N. gonorrhoeae modulates cell death are not clear, although a role for the inhibitor of apoptosis-2 (cIAP2) has been proposed. In this study, we confirmed that N. gonorrhoeae induces production of cIAP2 in human cervical epithelial cells. High levels of intracellular cIAP2 were detected early after N. gonorrhoeae stimulation, which was followed by a marked decrease at 24 h. At this time point, we observed increased levels of extracellular cIAP2 associated with exosomes and an overall increase in production of exosomes. Inhibition of cIAP2 in N. gonorrhoeae-stimulated epithelial cells resulted in increased cell death and interleukin-1β (IL-1β) production. Collectively these results indicate that N. gonorrhoeae stimulation of human endocervical epithelial cells induces the release of cIAP2, an essential regulator of cell death and immune signaling.

  19. 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.

  20. 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.

  1. 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.

  2. Low-frequency quantitative ultrasound imaging of cell death in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J. [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Papanicolau, Naum; Tadayyon, Hadi [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Lee, Justin [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Zubovits, Judit [Department of Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Sadeghian, Alireza [Department of Computer Science, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Karshafian, Raffi [Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Al-Mahrouki, Azza; Giles, Anoja [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Kolios, Michael C. [Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5, Canada and Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada)

    2013-08-15

    Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicated significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r{sup 2}= 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant frequency

  3. 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.

  4. Cell wall dynamics modulate acetic acid-induced apoptotic cell death of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    António Rego

    2014-08-01

    Full Text Available Acetic acid triggers apoptotic cell death in Saccharomyces cerevisiae, similar to mammalian apoptosis. To uncover novel regulators of this process, we analyzed whether impairing MAPK signaling affected acetic acid-induced apoptosis and found the mating-pheromone response and, especially, the cell wall integrity pathways were the major mediators, especially the latter, which we characterized further. Screening downstream effectors of this pathway, namely targets of the transcription factor Rlm1p, highlighted decreased cell wall remodeling as particularly important for acetic acid resistance. Modulation of cell surface dynamics therefore emerges as a powerful strategy to increase acetic acid resistance, with potential application in industrial fermentations using yeast, and in biomedicine to exploit the higher sensitivity of colorectal carcinoma cells to apoptosis induced by acetate produced by intestinal propionibacteria.

  5. 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...

  6. Transient and sustained neural responses to death-related linguistic cues.

    Science.gov (United States)

    Shi, Zhenhao; Han, Shihui

    2013-06-01

    Recent research showed that perception of death-related vs death-unrelated linguistic cues produced increased frontoparietal activity but decreased insular activity. This study investigated (i) whether the increased frontoparietal and decreased insular activities are, respectively, associated with transient trial-specific processes of death-related linguistic cues and sustained death-related thought during death-relevance judgments on linguistic cues and (ii) whether the neural activity underlying death-related thought can predict individuals' dispositional death anxiety. Participants were presented with death-related/unrelated words, life-related/unrelated words, and negative-valence/neutral words in separate sessions. Participants were scanned using functional magnetic resonance imaging while performing death-relevance, life-relevance, and valence judgments on the words, respectively. The contrast of death-related vs death-unrelated words during death-relevance judgments revealed transient increased activity in the left inferior parietal lobule, the right frontal eye field, and the right superior parietal lobule. The contrast of death-relevance judgments vs life-relevance/valence judgments showed decreased activity in the bilateral insula. The sustained insular activity was correlated with dispositional death anxiety, but only in those with weak transient frontoparietal responses to death-related words. Our results dissociate the transient and sustained neural responses to death-related linguistic cues and suggest that the combination of the transient and sustained neural activities can predict dispositional death anxiety.

  7. 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.

  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. In Vitro Brucella suis Infection Prevents the Programmed Cell Death of Human Monocytic Cells

    Science.gov (United States)

    Gross, Antoine; Terraza, Annie; Ouahrani-Bettache, Safia; Liautard, Jean-Pierre; Dornand, Jacques

    2000-01-01

    During the complex interaction between an infectious agent and a host organism, the pathogen can interfere with the host cell's programmed death to its own benefit. Induction or prevention of host cell apoptosis appears to be a critical step for determining the infection outcome. Members of the gram-negative bacterial genus Brucella are intracellular pathogens which preferentially invade monocytic cells and develop within these cells. We investigated the effect of Brucella suis infection on apoptosis of human monocytic phagocytes. The present study provides evidence that Brucella infection inhibited spontaneously occurring apoptosis in human monocytes. Prevention of monocyte apoptosis was not mediated by Brucella lipopolysaccharide and required bacterial survival within infected cells. Both invaded and noninvaded cells were protected, indicating that soluble mediators released during infection were involved in the phenomenon. Analysis of Brucella-infected monocytes revealed specific overexpression of the A1 gene, a member of the bcl-2 family implicated in the survival of hematopoietic cells. Brucella infection also rendered macrophage-like cells resistant to Fas ligand- or gamma interferon-induced apoptosis, suggesting that Brucella infection protected host cells from several cytotoxic processes occurring at different steps of the immune response. The present data clearly show that Brucella suis modulated the monocyte/macrophage's apoptotic response to the advantage of the pathogen, thus preventing host cell elimination. This might represent a strategy for Brucella development in infected hosts. PMID:10603407

  10. The Influence of Programmed Cell Death in Myeloid Cells on Host Resilience to Infection with Legionella pneumophila or Streptococcus pyogenes

    Science.gov (United States)

    Gamradt, Pia; Xu, Yun; Gratz, Nina; Duncan, Kellyanne; Kobzik, Lester; Högler, Sandra; Decker, Thomas

    2016-01-01

    Pathogen clearance and host resilience/tolerance to infection are both important factors in surviving an infection. Cells of the myeloid lineage play important roles in both of these processes. Neutrophils, monocytes, macrophages, and dendritic cells all have important roles in initiation of the immune response and clearance of bacterial pathogens. If these cells are not properly regulated they can result in excessive inflammation and immunopathology leading to decreased host resilience. Programmed cell death (PCD) is one possible mechanism that myeloid cells may use to prevent excessive inflammation. Myeloid cell subsets play roles in tissue repair, immune response resolution, and maintenance of homeostasis, so excessive PCD may also influence host resilience in this way. In addition, myeloid cell death is one mechanism used to control pathogen replication and dissemination. Many of these functions for PCD have been well defined in vitro, but the role in vivo is less well understood. We created a mouse that constitutively expresses the pro-survival B-cell lymphoma (bcl)-2 protein in myeloid cells (CD68(bcl2tg), thus decreasing PCD specifically in myeloid cells. Using this mouse model we explored the impact that decreased cell death of these cells has on infection with two different bacterial pathogens, Legionella pneumophila and Streptococcus pyogenes. Both of these pathogens target multiple cell death pathways in myeloid cells, and the expression of bcl2 resulted in decreased PCD after infection. We examined both pathogen clearance and host resilience and found that myeloid cell death was crucial for host resilience. Surprisingly, the decreased myeloid PCD had minimal impact on pathogen clearance. These data indicate that the most important role of PCD during infection with these bacteria is to minimize inflammation and increase host resilience, not to aid in the clearance or prevent the spread of the pathogen. PMID:27973535

  11. 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...

  12. Induction of morphological changes in death-induced cancer cells monitored by holographic microscopy.

    Science.gov (United States)

    El-Schich, Zahra; Mölder, Anna; Tassidis, Helena; Härkönen, Pirkko; Falck Miniotis, Maria; Gjörloff Wingren, Anette

    2015-03-01

    We are using the label-free technique of holographic microscopy to analyze cellular parameters including cell number, confluence, cellular volume and area directly in the cell culture environment. We show that death-induced cells can be distinguished from untreated counterparts by the use of holographic microscopy, and we demonstrate its capability for cell death assessment. Morphological analysis of two representative cell lines (L929 and DU145) was performed in the culture flasks without any prior cell detachment. The two cell lines were treated with the anti-tumour agent etoposide for 1-3days. Measurements by holographic microscopy showed significant differences in average cell number, confluence, volume and area when comparing etoposide-treated with untreated cells. The cell volume of the treated cell lines was initially increased at early time-points. By time, cells decreased in volume, especially when treated with high doses of etoposide. In conclusion, we have shown that holographic microscopy allows label-free and completely non-invasive morphological measurements of cell growth, viability and death. Future applications could include real-time monitoring of these holographic microscopy parameters in cells in response to clinically relevant compounds.

  13. From nature to bedside: pro-survival and cell death mechanisms as therapeutic targets in cancer treatment.

    Science.gov (United States)

    Cerella, Claudia; Teiten, Marie-Hélène; Radogna, Flavia; Dicato, Mario; Diederich, Marc

    2014-11-01

    Cell death is an important physiological regulator during development, tissue homeostasis and stress response but it is also a protective tumor suppressive mechanism. Tumor cells almost universally acquire the ability to evade cell death pathways that in normal cells act as a protective mechanism to remove damaged cells. As a result, a population of death-resistant cells with accumulating genetic and epigenetic abnormalities contributes to malignant transformation. Any alteration of the homeostatic balance between survival and death is therefore a critical factor in carcinogenesis. Several forms of cell death exist and cross talk among them is emerging; however, we still miss many molecular details. It becomes essential to revisit the role of each type of cell death to understand interconnections existing between different cell death pathways as well as the network of their mediators to eventually develop new effective strategies to kill cancer cells. More specifically, new therapies based on compounds selectively triggering apoptosis, necrosis or autophagy recently became both appealing and challenging. Despite the rather clear classification of the different cell death modalities according to morphological criteria and the attempt to describe them with distinct signaling pathways, the reality reveals a complex interplay between apoptosis, regulated necrosis and autophagy involving a heterogeneous mix of molecular mediators. Nature, presenting an almost endless plenitude of bioactive scaffolds, can efficiently contribute compounds that allow deciphering the intricate pathways of cell death pathways and thus eventually contribute to selectively target cancer-type specific pathways in an attempt to personalize cancer patient treatment depending on cancer death pathway specificities. The aim of this review is to provide first an overview of molecular cell death specificities and to highlight how compounds of natural origins, with or without hemisynthetic

  14. Parasitic worms stimulate host NADPH oxidases to produce reactive oxygen species that limit plant cell death and promote infection.

    Science.gov (United States)

    Siddique, Shahid; Matera, Christiane; Radakovic, Zoran S; Hasan, M Shamim; Gutbrod, Philipp; Rozanska, Elzbieta; Sobczak, Miroslaw; Torres, Miguel Angel; Grundler, Florian M W

    2014-04-08

    Plants and animals produce reactive oxygen species (ROS) in response to infection. In plants, ROS not only activate defense responses and promote cell death to limit the spread of pathogens but also restrict the amount of cell death in response to pathogen recognition. Plants also use hormones, such as salicylic acid, to mediate immune responses to infection. However, there are long-lasting biotrophic plant-pathogen interactions, such as the interaction between parasitic nematodes and plant roots during which defense responses are suppressed and root cells are reorganized to specific nurse cell systems. In plants, ROS are primarily generated by plasma membrane-localized NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidases, and loss of NADPH oxidase activity compromises immune responses and cell death. We found that infection of Arabidopsis thaliana by the parasitic nematode Heterodera schachtii activated the NADPH oxidases RbohD and RbohF to produce ROS, which was necessary to restrict infected plant cell death and promote nurse cell formation. RbohD- and RbohF-deficient plants exhibited larger regions of cell death in response to nematode infection, and nurse cell formation was greatly reduced. Genetic disruption of SID2, which is required for salicylic acid accumulation and immune activation in nematode-infected plants, led to the increased size of nematodes in RbohD- and RbohF-deficient plants, but did not decrease plant cell death. Thus, by stimulating NADPH oxidase-generated ROS, parasitic nematodes fine-tune the pattern of plant cell death during the destructive root invasion and may antagonize salicylic acid-induced defense responses during biotrophic life stages.

  15. DCD – a novel plant specific domain in proteins involved in development and programmed cell death

    Directory of Open Access Journals (Sweden)

    Doerks Tobias

    2005-07-01

    Full Text Available Abstract Background Recognition of microbial pathogens by plants triggers the hypersensitive reaction, a common form of programmed cell death in plants. These dying cells generate signals that activate the plant immune system and alarm the neighboring cells as well as the whole plant to activate defense responses to limit the spread of the pathogen. The molecular mechanisms behind the hypersensitive reaction are largely unknown except for the recognition process of pathogens. We delineate the NRP-gene in soybean, which is specifically induced during this programmed cell death and contains a novel protein domain, which is commonly found in different plant proteins. Results The sequence analysis of the protein, encoded by the NRP-gene from soybean, led to the identification of a novel domain, which we named DCD, because it is found in plant proteins involved in development and cell death. The domain is shared by several proteins in the Arabidopsis and the rice genomes, which otherwise show a different protein architecture. Biological studies indicate a role of these proteins in phytohormone response, embryo development and programmed cell by pathogens or ozone. Conclusion It is tempting to speculate, that the DCD domain mediates signaling in plant development and programmed cell death and could thus be used to identify interacting proteins to gain further molecular insights into these processes.

  16. 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.

  17. 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.

  18. 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.

  19. Cell death following thermal neutron exposure

    Energy Technology Data Exchange (ETDEWEB)

    Paterson, L.C. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Atanackovic, J. [Ontario Power Generation, Toronto, Ontario (Canada); Boyer, C. [Canadian Neutron Beam Centre, Chalk River, Ontario (Canada); El-Jaby, S.; Priest, N.D. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Seymour, C.B.; Boreham, D.R. [McMaster Univ., Hamilton, Ontario (Canada); Richardson, R.B. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2014-07-01

    When individuals are exposed to unknown external ionizing radiation, it is desirable to have the means to assess both the absorbed dose received (Gy) and the radiation quality. Yet, conventional biodosimetry techniques, specifically the dicentric chromosome assay, cannot differentiate between the damage caused by high- and low-linear energy transfer (LET) exposures. Frequencies of apoptosis and necrosis, may provide an alternative method that assesses both the absorbed dose and radiation quality after unknown exposures. For this preliminary study, human lymphocytes were irradiated with {sup 60}Co gamma rays and thermal neutrons. Both apoptosis and necrosis increased with increasing gamma dose. In contrast, no dose-response was observed following thermal neutron exposure at doses up to 2.61 Gy. (author)

  20. 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

  1. Cytoprotective effects of fisetin against hypoxia-induced cell death in PC12 cells.

    Science.gov (United States)

    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.

  2. Seasonal variations of group-specific phytoplankton cell death in Xiamen Bay, China

    Science.gov (United States)

    Huang, Xiaozhou; Liu, Xin; Chen, Jixin; Xiao, Wupeng; Cao, Zhen; Huang, Bangqin

    2017-03-01

    The importance of phytoplankton cell death is being increasingly recognized, however, there are still no published reports on this in Xiamen Bay. In this study, the proportion of dead phytoplankton cells associated with environmental factors was assessed at a station in Xiamen Bay from December 2012 to December 2013, using a cell digestion assay, which is an effective method to analyze dead/ living cells in complex natural phytoplankton communities. The percentages of dead cells (% DC) in the total phytoplankton in summer (16%±6%) were lower than those in winter (27%±16%). Six groups of phytoplankton (G1-G6) were categorized by flow cytometry. These phytoplankton communities with diverse seasonal variations in % DC had different responses to environmental constraints. The main factors affecting mortality were temperature and salinity, while nutrient concentration showed little influence on phytoplankton death. Additionally, our results provide evidence that chlorophyll a concentrations had an inverse relationship with total phytoplankton % DC and viable cell abundance was more meaningful than total cells to explain variations in environmental parameters (such as Chl a). Moreover, the lowest mean % DC in total phytoplankton was 16%±6% at our sample site, which is in a subtropical area with high water temperatures, full solar radiation, and rich nutrients. This indicates that phytoplankton cell death is a process that cannot be ignored. In summary, phytoplankton cell death is important in understanding the dynamics of phytoplankton communities and the functioning of subtropical ecosystems.

  3. Molecular characterization of propolis-induced cell death in Saccharomyces cerevisiae.

    Science.gov (United States)

    de Castro, Patrícia Alves; Savoldi, Marcela; Bonatto, Diego; Barros, Mário Henrique; Goldman, Maria Helena S; Berretta, Andresa A; Goldman, Gustavo Henrique

    2011-03-01

    Propolis, a natural product of plant resins, is used by the bees to seal holes in their honeycombs and protect the hive entrance. However, propolis has also been used in folk medicine for centuries. Here, we apply the power of Saccharomyces cerevisiae as a model organism for studies of genetics, cell biology, and genomics to determine how propolis affects fungi at the cellular level. Propolis is able to induce an apoptosis cell death response. However, increased exposure to propolis provides a corresponding increase in the necrosis response. We showed that cytochrome c but not endonuclease G (Nuc1p) is involved in propolis-mediated cell death in S. cerevisiae. We also observed that the metacaspase YCA1 gene is important for propolis-mediated cell death. To elucidate the gene functions that may be required for propolis sensitivity in eukaryotes, the full collection of about 4,800 haploid S. cerevisiae deletion strains was screened for propolis sensitivity. We were able to identify 138 deletion strains that have different degrees of propolis sensitivity compared to the corresponding wild-type strains. Systems biology revealed enrichment for genes involved in the mitochondrial electron transport chain, vacuolar acidification, negative regulation of transcription from RNA polymerase II promoter, regulation of macroautophagy associated with protein targeting to vacuoles, and cellular response to starvation. Validation studies indicated that propolis sensitivity is dependent on the mitochondrial function and that vacuolar acidification and autophagy are important for yeast cell death caused by propolis.

  4. Chloroplasts activity and PAP-signaling regulate programmed cell death in Arabidopsis

    KAUST Repository

    Bruggeman, Quentin

    2016-01-09

    Programmed cell death (PCD) is a crucial process both for plant development and responses to biotic and abiotic stress. There is accumulating evidence that chloroplasts may play a central role during plant PCD as for mitochondria in animal cells, but it is still unclear whether they participate in PCD onset, execution, or both. To tackle this question, we have analyzed the contribution of chloroplast function to the cell death phenotype of the myoinositol phosphate synthase1 (mips1) mutant that forms spontaneous lesions in a light-dependent manner. We show that photosynthetically active chloroplasts are required for PCD to occur in mips1, but this process is independent of the redox state of the chloroplast. Systematic genetic analyses with retrograde signaling mutants reveal that 3’-phosphoadenosine 5’-phosphate, a chloroplast retrograde signal that modulates nuclear gene expression in response to stress, can inhibit cell death and compromises plant innate immunity via inhibition of the RNA-processing 5’-3’ exoribonucleases. Our results provide evidence for the role of chloroplast-derived signal and RNA metabolism in the control of cell death and biotic stress response. © 2016 American Society of Plant Biologists. All Rights Reserved.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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...

  10. 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.

  11. A unifying mechanism for cancer cell death through ion channel activation by HAMLET.

    Science.gov (United States)

    Storm, Petter; Klausen, Thomas Kjaer; Trulsson, Maria; Ho C S, James; Dosnon, Marion; Westergren, Tomas; Chao, Yinxia; Rydström, Anna; Yang, Henry; Pedersen, Stine Falsig; Svanborg, Catharina

    2013-01-01

    Ion channels and ion fluxes control many aspects of tissue homeostasis. During oncogenic transformation, critical ion channel functions may be perturbed but conserved tumor specific ion fluxes remain to be defined. Here we used the tumoricidal protein-lipid complex HAMLET as a probe to identify ion fluxes involved in tumor cell death. We show that HAMLET activates a non-selective cation current, which reached a magnitude of 2.74±0.88 nA within 1.43±0.13 min from HAMLET application. Rapid ion fluxes were essential for HAMLET-induced carcinoma cell death as inhibitors (amiloride, BaCl2), preventing the changes in free cellular Na(+) and K(+) concentrations also prevented essential steps accompanying carcinoma cell death, including changes in morphology, uptake, global transcription, and MAP kinase activation. Through global transcriptional analysis and phosphorylation arrays, a strong ion flux dependent p38 MAPK response was detected and inhibition of p38 signaling delayed HAMLET-induced death. Healthy, differentiated cells were resistant to HAMLET challenge, which was accompanied by innate immunity rather than p38-activation. The results suggest, for the first time, a unifying mechanism for the initiation of HAMLET's broad and rapid lethal effect on tumor cells. These findings are particularly significant in view of HAMLET's documented therapeutic efficacy in human studies and animal models. The results also suggest that HAMLET offers a two-tiered therapeutic approach, killing cancer cells while stimulating an innate immune response in surrounding healthy tissues.

  12. Role of apoptosis and necrosis in cell death induced by nanoparticle-mediated photothermal therapy

    Energy Technology Data Exchange (ETDEWEB)

    Pattani, Varun P., E-mail: varun.pattani@utexas.edu; Shah, Jay; Atalis, Alexandra; Sharma, Anirudh; Tunnell, James W. [The University of Texas at Austin, Department of Biomedical Engineering (United States)

    2015-01-15

    Current cancer therapies can cause significant collateral damage due to a lack of specificity and sensitivity. Therefore, we explored the cell death pathway response to gold nanorod (GNR)-mediated photothermal therapy as a highly specific cancer therapeutic to understand the role of apoptosis and necrosis during intense localized heating. By developing this, we can optimize photothermal therapy to induce a maximum of ‘clean’ cell death pathways, namely apoptosis, thereby reducing external damage. GNRs were targeted to several subcellular localizations within colorectal tumor cells in vitro, and the cell death pathways were quantitatively analyzed after photothermal therapy using flow cytometry. In this study, we found that the cell death response to photothermal therapy was dependent on the GNR localization. Furthermore, we demonstrated that nanorods targeted to the perinuclear region irradiated at 37.5 W/cm{sup 2} laser fluence rate led to maximum cell destruction with the ‘cleaner’ method of apoptosis, at similar percentages as other anti-cancer targeted therapies. We believe that this indicates the therapeutic potential for GNR-mediated photothermal therapy to treat cancer effectively without causing damage to surrounding tissue.

  13. Increased anion channel activity is an unavoidable event in ozone-induced programmed cell death.

    Directory of Open Access Journals (Sweden)

    Takashi Kadono

    Full Text Available BACKGROUND: Ozone is a major secondary air pollutant often reaching high concentrations in urban areas under strong daylight, high temperature and stagnant high-pressure systems. Ozone in the troposphere is a pollutant that is harmful to the plant. PRINCIPAL FINDINGS: By exposing cells to a strong pulse of ozonized air, an acute cell death was observed in suspension cells of Arabidopsis thaliana used as a model. We demonstrated that O(3 treatment induced the activation of a plasma membrane anion channel that is an early prerequisite of O(3-induced cell death in A. thaliana. Our data further suggest interplay of anion channel activation with well known plant responses to O(3, Ca(2+ influx and NADPH-oxidase generated reactive oxygen species (ROS in mediating the oxidative cell death. This interplay might be fuelled by several mechanisms in addition to the direct ROS generation by O(3; namely, H(2O(2 generation by salicylic and abscisic acids. Anion channel activation was also shown to promote the accumulation of transcripts encoding vacuolar processing enzymes, a family of proteases previously reported to contribute to the disruption of vacuole integrity observed during programmed cell death. SIGNIFICANCE: Collectively, our data indicate that anion efflux is an early key component of morphological and biochemical events leading to O(3-induced programmed cell death. Because ion channels and more specifically anion channels assume a crucial position in cells, an understanding about the underlying role(s for ion channels in the signalling pathway leading to programmed cell death is a subject that warrants future investigation.

  14. 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, ...

  15. 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

  16. Cell-to-Cell Transmission of HIV-1 Is Required to Trigger Pyroptotic Death of Lymphoid-Tissue-Derived CD4 T Cells.

    Science.gov (United States)

    Galloway, Nicole L K; Doitsh, Gilad; Monroe, Kathryn M; Yang, Zhiyuan; Muñoz-Arias, Isa; Levy, David N; Greene, Warner C

    2015-09-01

    The progressive depletion of CD4 T cells underlies clinical progression to AIDS in untreated HIV-infected subjects. Most dying CD4 T cells correspond to resting nonpermissive cells residing in lymphoid tissues. Death is due to an innate immune response against the incomplete cytosolic viral DNA intermediates accumulating in these cells. The viral DNA is detected by the IFI16 sensor, leading to inflammasome assembly, caspase-1 activation, and the induction of pyroptosis, a highly inflammatory form of programmed cell death. We now show that cell-to-cell transmission of HIV is obligatorily required for activation of this death pathway. Cell-free HIV-1 virions, even when added in large quantities, fail to activate pyroptosis. These findings underscore the infected CD4 T cells as the major killing units promoting progression to AIDS and highlight a previously unappreciated role for the virological synapse in HIV pathogenesis.

  17. Silencer of death domains controls cell death through tumour necrosis factor-receptor 1 and caspase-10 in acute lymphoblastic leukemia.

    Directory of Open Access Journals (Sweden)

    Adam Cisterne

    Full Text Available Resistance to apoptosis remains a significant problem in drug resistance and treatment failure in malignant disease. NO-aspirin is a novel drug that has efficacy against a number of solid tumours, and can inhibit Wnt signaling, and although we have shown Wnt signaling to be important for acute lymphoblastic leukemia (ALL cell proliferation and survival inhibition of Wnt signaling does not appear to be involved in the induction of ALL cell death. Treatment of B lineage ALL cell lines and patient ALL cells with NO-aspirin induced rapid apoptotic cell death mediated via the extrinsic death pathway. Apoptosis was dependent on caspase-10 in association with the formation of the death-inducing signaling complex (DISC incorporating pro-caspase-10 and tumor necrosis factor receptor 1 (TNF-R1. There was no measurable increase in TNF-R1 or TNF-α in response to NO-aspirin, suggesting that the process was ligand-independent. Consistent with this, expression of silencer of death domain (SODD was reduced following NO-aspirin exposure and lentiviral mediated shRNA knockdown of SODD suppressed expansion of transduced cells confirming the importance of SODD for ALL cell survival. Considering that SODD and caspase-10 are frequently over-expressed in ALL, interfering with these proteins may provide a new strategy for the treatment of this and potentially other cancers.

  18. A comparison between nuclear dismantling during plant and animal programmed cell death.

    Science.gov (United States)

    Domínguez, Fernando; Cejudo, Francisco Javier

    2012-12-01

    Programmed cell death (PCD) is a process of organized destruction of cells, essential for the development and maintenance of cellular homeostasis of multicellular organisms. Cells undergoing PCD begin a degenerative process in response to internal or external signals, whereby the nucleus becomes one of the targets. The process of nuclear dismantling includes events affecting the nuclear envelope, such as formation of lobes at the nuclear surface, selective proteolysis of nucleoporins and nuclear pore complex clustering. In addition, chromatin condensation increases in coordination with DNA fragmentation. These processes have been largely studied in animals, but remain poorly understood in plants. The overall process of cell death has different morphological and biochemical features in plants and animals. However, recent advances suggest that nuclear dismantling in plant cells progresses with morphological and biochemical characteristics similar to those in apoptotic animal cells. In this review, we summarize nuclear dismantling in plant PCD, focusing on the similarities and differences with their animal counterparts.

  19. 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.

  20. Untangling the Roles of Anti-Apoptosis in Regulating Programmed Cell Death using Humanized Yeast Cells.

    Science.gov (United States)

    Clapp, Caitlin; Portt, Liam; Khoury, Chamel; Sheibani, Sara; Eid, Rawan; Greenwood, Matthew; Vali, Hojatollah; Mandato, Craig A; Greenwood, Michael T

    2012-01-01

    Genetically programmed cell death (PCD) mechanisms, including apoptosis, are important for the survival of metazoans since it allows, among things, the removal of damaged cells that interfere with normal function. Cell death due to PCD is observed in normal processes such as aging and in a number of pathophysiologies including hypoxia (common causes of heart attacks and strokes) and subsequent tissue reperfusion. Conversely, the loss of normal apoptotic responses is associated with the development of tumors. So far, limited success in preventing unwanted PCD has been reported with current therapeutic approaches despite the fact that inhibitors of key apoptotic inducers such as caspases have been developed. Alternative approaches have focused on mimicking anti-apoptotic processes observed in cells displaying increased resistance to apoptotic stimuli. Hormesis and pre-conditioning are commonly observed cellular strategies where sub-lethal levels of pro-apoptotic stimuli lead to increased resistance to higher or lethal levels of stress. Increased expression of anti-apoptotic sequences is a common mechanism mediating these protective effects. The relevance of the latter observation is exemplified by the observation that transgenic mice overexpressing anti-apoptotic genes show significant reductions in tissue damage following ischemia. Thus strategies aimed at increasing the levels of anti-apoptotic proteins, using gene therapy or cell penetrating recombinant proteins are being evaluated as novel therapeutics to decrease cell death following acute periods of cell death inducing stress. In spite of its functional and therapeutic importance, more is known regarding the processes involved in apoptosis than anti-apoptosis. The genetically tractable yeast Saccharomyces cerevisiae has emerged as an exceptional model to study multiple aspects of PCD including the mitochondrial mediated apoptosis observed in metazoans. To increase our knowledge of the process of anti

  1. 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.

  2. PARP-1 cleavage fragments: signatures of cell-death proteases in neurodegeneration

    Directory of Open Access Journals (Sweden)

    Alexander Jonathan S

    2010-12-01

    Full Text Available Abstract The normal function of poly (ADP-ribose polymerase-1 (PARP-1 is the routine repair of DNA damage by adding poly (ADP ribose polymers in response to a variety of cellular stresses. Recently, it has become widely appreciated that PARP-1 also participates in diverse physiological and pathological functions from cell survival to several forms of cell death and has been implicated in gene transcription, immune responses, inflammation, learning, memory, synaptic functions, angiogenesis and aging. In the CNS, PARP inhibition attenuates injury in pathologies like cerebral ischemia, trauma and excitotoxicity demonstrating a central role of PARP-1 in these pathologies. PARP-1 is also a preferred substrate for several 'suicidal' proteases and the proteolytic action of suicidal proteases (caspases, calpains, cathepsins, granzymes and matrix metalloproteinases (MMPs on PARP-1 produces several specific proteolytic cleavage fragments with different molecular weights. These PARP-1 signature fragments are recognized biomarkers for specific patterns of protease activity in unique cell death programs. This review focuses on specific suicidal proteases active towards PARP-1 to generate signature PARP-1 fragments that can identify key proteases and particular forms of cell death involved in pathophysiology. The roles played by some of the PARP-1 fragments and their associated binding partners in the control of different forms of cell death are also discussed.

  3. 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.

  4. 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.

  5. Monocytes regulate the mechanism of T-cell death by inducing Fas-mediated apoptosis during bacterial infection.

    Directory of Open Access Journals (Sweden)

    Marc Daigneault

    Full Text Available Monocytes and T-cells are critical to the host response to acute bacterial infection but monocytes are primarily viewed as amplifying the inflammatory signal. The mechanisms of cell death regulating T-cell numbers at sites of infection are incompletely characterized. T-cell death in cultures of peripheral blood mononuclear cells (PBMC showed 'classic' features of apoptosis following exposure to pneumococci. Conversely, purified CD3(+ T-cells cultured with pneumococci demonstrated necrosis with membrane permeabilization. The death of purified CD3(+ T-cells was not inhibited by necrostatin, but required the bacterial toxin pneumolysin. Apoptosis of CD3(+ T-cells in PBMC cultures required 'classical' CD14(+ monocytes, which enhanced T-cell activation. CD3(+ T-cell death was enhanced in HIV-seropositive individuals. Monocyte-mediated CD3(+ T-cell apoptotic death was Fas-dependent both in vitro and in vivo. In the early stages of the T-cell dependent host response to pneumococci reduced Fas ligand mediated T-cell apoptosis was associated with decreased bacterial clearance in the lung and increased bacteremia. In summary monocytes converted pathogen-associated necrosis into Fas-dependent apoptosis and regulated levels of activated T-cells at sites of acute bacterial infection. These changes were associated with enhanced bacterial clearance in the lung and reduced levels of invasive pneumococcal disease.

  6. 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

  7. The Enemy Within: Innate Surveillance-mediated Cell Death, the common mechanism of neurodegenerative disease

    Directory of Open Access Journals (Sweden)

    Robert Ian Richards

    2016-05-01

    Full Text Available Neurodegenerative diseases comprise an array of progressive neurological disorders all characterized by the selective death of neurons in the central nervous system. Although rare (familial and common (sporadic forms can occur for the same disease, it is unclear whether this reflects several distinct pathogenic pathways or the convergence of different causes into a common form of nerve cell death. Remarkably, neurodegenerative diseases are increasingly found to be accompanied by activation of the innate immune surveillance system normally associated with pathogen recognition and response. Innate surveillance is the cell’s quality control system for the purpose of detecting such danger signals and responding in an appropriate manner. Innate surveillance is an ‘intelligent system’, in that the manner of response is relevant to the magnitude and duration of the threat. If possible, the threat is dealt with within the cell in which it is detected, by degrading the danger signal(s and restoring homeostasis. If this is not successful then an inflammatory response is instigated that is aimed at restricting the spread of the threat by elevating degradative pathways, sensitizing neighboring cells, and recruiting specialized cell types to the site. If the danger signal persists, then the ultimate response can include not only the programmed cell death of the original cell, but the contents of this dead cell can also bring about the death of adjacent sensitized cells. These responses are clearly aimed at destroying the ability of the detected pathogen to propagate and spread. Innate surveillance comprises intracellular, extracellular, non-cell autonomous and systemic processes. Recent studies have revealed how multiple steps in these processes involve proteins that, through their mutation, have been linked to many familial forms of neurodegenerative disease. This suggests that individuals harboring these mutations may have an amplified response to

  8. The modulatory effects of connexin 43 on cell death/survival beyond cell coupling.

    Science.gov (United States)

    Rodríguez-Sinovas, Antonio; Cabestrero, Alberto; López, Diego; Torre, Iratxe; Morente, Miriam; Abellán, Arancha; Miró, Elisabet; Ruiz-Meana, Marisol; García-Dorado, David

    2007-01-01

    Connexins form a diverse and ubiquitous family of integral membrane proteins. Characteristically, connexins are assembled into intercellular channels that aggregate into discrete cell-cell contact areas termed gap junctions (GJ), allowing intercellular chemical communication, and are essential for propagation of electrical impulses in excitable tissues, including, prominently, myocardium, where connexin 43 (Cx43) is the most important isoform. Previous studies have shown that GJ-mediated communication has an important role in the cellular response to stress or ischemia. However, recent evidence suggests that connexins, and in particular Cx43, may have additional effects that may be important in cell death and survival by mechanisms independent of cell to cell communication. Connexin hemichannels, located at the plasma membrane, may be important in paracrine signaling that could influence intracellular calcium and cell survival by releasing intracellular mediators as ATP, NAD(+), or glutamate. In addition, recent studies have shown the presence of connexins in cell structures other than the plasma membrane, including the cell nucleus, where it has been suggested that Cx43 influences cell growth and differentiation. In addition, translocation of Cx43 to mitochondria appears to be important for certain forms of cardioprotection. These findings open a new field of research of previously unsuspected roles of Cx43 intracellular signaling.

  9. 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.

  10. [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

  11. 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.

  12. 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.

  13. Cancer resistance in the blind mole rat is mediated by concerted necrotic cell death mechanism.

    Science.gov (United States)

    Gorbunova, Vera; Hine, Christopher; Tian, Xiao; Ablaeva, Julia; Gudkov, Andrei V; Nevo, Eviatar; Seluanov, Andrei

    2012-11-20

    Blind mole rats Spalax (BMR) are small subterranean rodents common in the Middle East. BMR is distinguished by its adaptations to life underground, remarkable longevity (with a maximum documented lifespan of 21 y), and resistance to cancer. Spontaneous tumors have never been observed in spalacids. To understand the mechanisms responsible for this resistance, we examined the growth of BMR fibroblasts in vitro of the species Spalax judaei and Spalax golani. BMR cells proliferated actively for 7-20 population doublings, after which the cells began secreting IFN-β, and the cultures underwent massive necrotic cell death within 3 d. The necrotic cell death phenomenon was independent of culture conditions or telomere shortening. Interestingly, this cell behavior was distinct from that observed in another long-lived and cancer-resistant African mole rat, Heterocephalus glaber, the naked mole rat in which cells display hypersensitivity to contact inhibition. Sequestration of p53 and Rb proteins using SV40 large T antigen completely rescued necrotic cell death. Our results suggest that cancer resistance of BMR is conferred by massive necrotic response to overproliferation mediated by p53 and Rb pathways, and triggered by the release of IFN-β. Thus, we have identified a unique mechanism that contributes to cancer resistance of this subterranean mammal extremely adapted to life underground.

  14. Peroxiredoxin I and II inhibit H2O2-induced cell death in MCF-7 cell lines.

    Science.gov (United States)

    Bae, Ji-Yeon; Ahn, Soo-Jung; Han, Wonshik; Noh, Dong-Young

    2007-07-01

    Apoptosis is known to be induced by direct oxidative damage due to oxygen-free radicals or hydrogen peroxide or by their generation in cells by the actions of injurious agents. Together with glutathione peroxidase and catalase, peroxiredoxin (Prx) enzymes play an important role in eliminating peroxides generated during metabolism. We investigated the role of Prx enzymes during cellular response to oxidative stress. Using Prx isoforms-specific antibodies, we investigated the presence of Prx isoforms by immunoblot analysis in cell lysates of the MCF-7 breast cancer cell line. Treatment of MCF-7 with hydrogen peroxide (H2O2) resulted in the dose-dependent expressions of Prx I and II at the protein and mRNA levels. To investigate the physiologic relevance of the Prx I and II expressions induced by H2O2, we compared the survivals of MCF10A normal breast cell line and MCF-7 breast cancer cell line following exposure to H2O2. The treatment of MCF10A with H2O2 resulted in rapid cell death, whereas MCF-7 was resistant to H2O2. In addition, we found that Prx I and II transfection enabled MCF10A cells to resist H2O2-induced cell death. These findings suggest that Prx I and II have important functions as inhibitors of cell death during cellular response to oxidative stress.

  15. Glucose starvation-mediated inhibition of salinomycin induced autophagy amplifies cancer cell specific cell death.

    Science.gov (United States)

    Jangamreddy, Jaganmohan R; Jain, Mayur V; Hallbeck, Anna-Lotta; Roberg, Karin; Lotfi, Kourosh; Łos, Marek J

    2015-04-30

    Salinomycin has been used as treatment for malignant tumors in a small number of humans, causing far less side effects than standard chemotherapy. Several studies show that Salinomycin targets cancer-initiating cells (cancer stem cells, or CSC) resistant to conventional therapies. Numerous studies show that Salinomycin not only reduces tumor volume, but also decreases tumor recurrence when used as an adjuvant to standard treatments. In this study we show that starvation triggered different stress responses in cancer cells and primary normal cells, which further improved the preferential targeting of cancer cells by Salinomycin. Our in vitro studies further demonstrate that the combined use of 2-Fluoro 2-deoxy D-glucose, or 2-deoxy D-glucose with Salinomycin is lethal in cancer cells while the use of Oxamate does not improve cell death-inducing properties of Salinomycin. Furthermore, we show that treatment of cancer cells with Salinomycin under starvation conditions not only increases the apoptotic caspase activity, but also diminishes the protective autophagy normally triggered by the treatment with Salinomycin alone. Thus, this study underlines the potential use of Salinomycin as a cancer treatment, possibly in combination with short-term starvation or starvation-mimicking pharmacologic intervention.

  16. Stem cells decreased neuronal cell death after hypoxic stress in primary fetal rat neurons in vitro.

    Science.gov (United States)

    Sakai, Tetsuro; Xu, Yan

    2012-01-01

    To explore stem cell-mediated neuronal protection through extracellular signaling pathways by transplanted stem cells, we sought to identify potential candidate molecules responsible for neuronal protection using an in vitro coculture system. Primary fetal rat hippocampal neurons underwent hypoxia (≤1% oxygen) for 96 h nad then were returned to a normoxic condition. The study group then received rat umbilical cord matrix-derived stem cells, while the control group received fresh media only. The experimental group showed decreased neuronal apoptosis compared to the control group [44.5 ± 1.6% vs. 71.0 ± 4.2% (mean ± SD, p = 0.0005) on day 5] and higher neuronal survival (4.9 ± 1.2 cells/100× field vs. 2.2 ± 0.3, p = 0.02 on day 5). Among 90 proteins evaluated using a protein array, stem cell coculture media showed increased protein secretion of TIMP-1 (5.61-fold), TIMP-2 (4.88), CNTF-Rα (3.42), activin A (2.20), fractalkine (2.04), CCR4 (2.02), and decreased secretion in MIP-2 (0.30-fold), AMPK α1 (0.43), TROY (0.48), and TIMP-3 (0.50). This study demonstrated that coculturing stem cells with primary neurons in vitro decreased neuronal cell death after hypoxia with significantly altered protein secretion. The results suggest that stem cells may offer neuronal protection through extracellular signaling.

  17. 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...

  18. 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...

  19. Red wine triggers cell death and thioredoxin reductase inhibition: effects beyond resveratrol and SIRT1.

    Science.gov (United States)

    Wallenborg, Karolina; Vlachos, Pinelopi; Eriksson, Sofi; Huijbregts, Lukas; Arnér, Elias S J; Joseph, Bertrand; Hermanson, Ola

    2009-05-01

    Red wine contains antioxidants and is at moderate amounts believed to exert certain positive health effects. Resveratrol is one of the most studied antioxidants in red wine and has been suggested to activate the longevity- and metabolism-associated histone deacetylase SIRT1. Here we show that relatively low concentrations of resveratrol (0.5-3 microM) specifically inhibited neuronal differentiation of neural stem cells in a SIRT1-dependent manner whereas higher concentrations of resveratrol (> or =10 microM) induced a SIRT1-independent cell death. Surprisingly, using a cell based assay, we found that small amounts of red wine (1-5% v/v)--but not white wine--induced a massive and rapid cell death of various cell types, including neural stem cells and several cancer cell lines. This red wine-induced cell death was ethanol-, SIRT1- and resveratrol-independent but associated with increased oxidative stress and inhibition of thioredoxin reductase (TrxR) activity. The TrxR inhibition correlated with the red color (absorbance at 520 nm) of the wines demonstrating that pigment components of red wine can exert profound cellular effects. Our results unveil important roles for SIRT1 and TrxR in resveratrol and red wine-mediated effects on progenitor and cancer cells, and demonstrate that cellular responses to red wine may be more complex than generally appreciated.

  20. The influence of the surface chemistry of silver nanoparticles on cell death.

    Science.gov (United States)

    Sur, Ilknur; Altunbek, Mine; Kahraman, Mehmet; Culha, Mustafa

    2012-09-21

    The influence of the surface chemistry of silver nanoparticles (AgNPs) on p53 mediated cell death was evaluated using human dermal fibroblast (HDF) and lung cancer (A549) cells. The citrate reduced AgNPs (C-AgNPs) were modified with either lactose (L-AgNPs) or a 12-base long oligonucleotide (O-AgNPs). Both unmodified and modified AgNPs showed increased concentration and time dependent cytotoxicity and genotoxicity causing an increased p53 up-regulation within 6 h and led to apoptotic or necrotic cell deaths. The C-AgNPs induced more cytotoxicity and cellular DNA damage than the surface modified AgNPs. Modifying the C-AgNPs with lactose or the oligonucleotide reduced both necrotic and apoptotic cell deaths in the HDF cells. The C-AgNPs caused an insignificant necrosis in A549 cells whereas the modified AgNPs caused necrosis and apoptosis in both cell types. Compared to the O-AgNPs, the L-AgNPs triggered more cellular DNA damage, which led to up-regulation of p53 gene inducing apoptosis in A549 cells compared to HDF cells. This suggests that the different surface chemistries of the AgNPs cause different cellular responses that may be important not only for their use in medicine but also for reducing their toxicity.

  1. The influence of the surface chemistry of silver nanoparticles on cell death

    Science.gov (United States)

    Sur, Ilknur; Altunbek, Mine; Kahraman, Mehmet; Culha, Mustafa

    2012-09-01

    The influence of the surface chemistry of silver nanoparticles (AgNPs) on p53 mediated cell death was evaluated using human dermal fibroblast (HDF) and lung cancer (A549) cells. The citrate reduced AgNPs (C-AgNPs) were modified with either lactose (L-AgNPs) or a 12-base long oligonucleotide (O-AgNPs). Both unmodified and modified AgNPs showed increased concentration and time dependent cytotoxicity and genotoxicity causing an increased p53 up-regulation within 6 h and led to apoptotic or necrotic cell deaths. The C-AgNPs induced more cytotoxicity and cellular DNA damage than the surface modified AgNPs. Modifying the C-AgNPs with lactose or the oligonucleotide reduced both necrotic and apoptotic cell deaths in the HDF cells. The C-AgNPs caused an insignificant necrosis in A549 cells whereas the modified AgNPs caused necrosis and apoptosis in both cell types. Compared to the O-AgNPs, the L-AgNPs triggered more cellular DNA damage, which led to up-regulation of p53 gene inducing apoptosis in A549 cells compared to HDF cells. This suggests that the different surface chemistries of the AgNPs cause different cellular responses that may be important not only for their use in medicine but also for reducing their toxicity.

  2. Key players of singlet oxygen-induced cell death in plants

    Science.gov (United States)

    Laloi, Christophe; Havaux, Michel

    2015-01-01

    The production of reactive oxygen species (ROS) is an unavoidable consequence of oxygenic photosynthesis. Singlet oxygen (1O2) is a highly reactive species to which has been attributed a major destructive role during the execution of ROS-induced cell death in photosynthetic tissues exposed to excess light. The study of the specific biological activity of 1O2 in plants has been hindered by its high reactivity and short lifetime, the concurrent production of other ROS under photooxidative stress, and limited in vivo detection methods. However, during the last 15 years, the isolation and characterization of two 1O2-overproducing mutants in Arabidopsis thaliana, flu and ch1, has allowed the identification of genetically controlled 1O2 cell death pathways and a 1O2 acclimation pathway that are triggered at sub-cytotoxic concentrations of 1O2. The study of flu has revealed the control of cell death by the plastid proteins EXECUTER (EX)1 and EX2. In ch1, oxidized derivatives of β-carotene, such as β-cyclocitral and dihydroactinidiolide, have been identified as important upstream messengers in the 1O2 signaling pathway that leads to stress acclimation. In both the flu and ch1 mutants, phytohormones act as important promoters or inhibitors of cell death. In particular, jasmonate has emerged as a key player in the decision between acclimation and cell death in response to 1O2. Although the flu and ch1 mutants show many similarities, especially regarding their gene expression profiles, key differences, such as EXECUTER-independent cell death in ch1, have also been observed and will need further investigation to be fully understood. PMID:25699067

  3. 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.

  4. 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.

  5. Nanosecond pulsed electric fields induce poly(ADP-ribose) formation and non-apoptotic cell death in HeLa S3 cells.

    Science.gov (United States)

    Morotomi-Yano, Keiko; Akiyama, Hidenori; Yano, Ken-ichi

    2013-08-30

    Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs.

  6. A mathematical model of radiation carcinogenesis with induction of genomic instability and cell death.

    Science.gov (United States)

    Ohtaki, M; Niwa, O

    2001-11-01

    We developed a mathematical model of carcinogenesis that incorporates genomic instability, a feature characterized by long-term destabilization of the genome in irradiated cells that leads to an increase in cancer risk in the exposed individuals at the cancer-prone age. This model also considers the induction of cell death, another important effect of radiation on cells. It is assumed that cell killing by radiation may occur at all stages of the carcinogenic process. The resulting model can explain not only the paradoxical relationship between low mutation rates and high cancer incidence but also the low-order dose-response relationship of cancer risk.

  7. Cell death pathways in astrocytes with a modified model of oxygen-glucose deprivation.

    Directory of Open Access Journals (Sweden)

    Qiaoying Huang

    Full Text Available Traditional oxygen-glucose deprivation (OGD models do not produce sufficiently stable and continuous deprivation to induce cell death in the ischemic core. Therefore, we modified the OGD model to mimic the observed damage in the ischemic core following stroke and utilized this new model to study cell death pathways in astrocytes. The PO2 and pH levels in the astrocyte culture medium were compared between a physical OGD group, a chemical OGD group and a mixed OGD group. The mixed OGD group was able to maintain anaerobic conditions in astrocyte culture medium for 6 h, while the physical and the chemical groups failed to maintain such conditions. Astrocyte viability decreased and LDH release into in the medium increased as a function of exposure to OGD. Compared to the control group, the expression of active caspase-3 in the mixed OGD group increased within 2 h after OGD, but decreased after 2 h of OGD. Additionally, porimin mRNA levels did not significantly increase during the first 2 h of OGD, while bcl-2 mRNA levels decreased at 1 h. However, both porimin and bcl-2 mRNA levels increased after 2 h of OGD; interestingly, they both suddenly decreased at 4 h of OGD. Taken together, these results indicate that apoptosis and oncosis are the two cell death pathways responsible for astrocyte death in the ischemic core. However, the main death pathway varies depending on the OGD period.

  8. Methylglyoxal Causes Cell Death in Neural Progenitor Cells and Impairs Adult Hippocampal Neurogenesis.

    Science.gov (United States)

    Chun, Hye Jeong; Lee, Yujeong; Kim, Ah Hyun; Lee, Jaewon

    2016-04-01

    Methylglyoxal (MG) is formed during normal metabolism by processes like glycolysis, lipid peroxidation, and threonine catabolism, and its accumulation is associated with various degenerative diseases, such as diabetes and arterial atherogenesis. Furthermore, MG has also been reported to have toxic effects on hippocampal neurons. However, these effects have not been studied in the context of neurogenesis. Here, we report that MG adversely affects hippocampal neurogenesis and induces neural progenitor cell (NPC) death. MG significantly reduced C17.2 NPC proliferation, and high concentration of MG (500 μM) induced cell death and elevated oxidative stress. Further, MG was found to activate the ERK signaling pathway, indicating elevated stress response. To determine the effects of MG in vivo, mice were administrated with vehicle or MG (0.5 or 1 % in drinking water) for 4 weeks. The numbers of BrdU-positive cells in hippocampi were significantly lower in MG-treated mice, indicating impaired neurogenesis, but MG did not induce neuronal damage or glial activations. Interestingly, MG reduced memory retention when administered to mice at 1 % but not at 0.5 %. In addition, the levels of hippocampal BDNF and synaptophysin were significantly lower in the hippocampi of mice treated with MG at 1 %. Collectively, our findings suggest MG could be harmful to NPCs and to hippocampal neurogenesis.

  9. Involvement of PACAP/ADNP signaling in the resistance to cell death in malignant peripheral nerve sheath tumor (MPNST) cells.

    Science.gov (United States)

    Castorina, Alessandro; Giunta, Salvatore; Scuderi, Soraya; D'Agata, Velia

    2012-11-01

    Malignant peripheral nerve sheath tumors (MPNSTs) are sarcomas able to grow under conditions of metabolic stress caused by insufficient nutrients or oxygen. Both pituitary adenylate cyclase-activating polypeptide (PACAP) and activity-dependent neuroprotective protein (ADNP) have glioprotective potential. However, whether PACAP/ADNP signaling is involved in the resistance to cell death in MPNST cells remains to be clarified. Here, we investigated the involvement of this signaling system in the survival response of MPNST cells against hydrogen peroxide (H(2)O(2))-evoked death both in the presence of normal serum (NS) and in serum-starved (SS) cells. Results showed that ADNP levels increased time-dependently (6-48 h) in SS cells. Treatment with PACAP38 (10(-9) to 10(-5) M) dose-dependently increased ADNP levels in NS but not in SS cells. PAC(1)/VPAC receptor antagonists completely suppressed PACAP-stimulated ADNP increase and partially reduced ADNP expression in SS cells. NS-cultured cells exposed to H(2)O(2) showed significantly reduced cell viability (~50 %), increased p53 and caspase-3, and DNA fragmentation, without affecting ADNP expression. Serum starvation significantly reduced H(2)O(2)-induced detrimental effects in MPNST cells, which were not further ameliorated by PACAP38. Altogether, these finding provide evidence for the involvement of an endogenous PACAP-mediated ADNP signaling system that increases MPNST cell resistance to H(2)O(2)-induced death upon serum starvation.

  10. PCM1 Depletion Inhibits Glioblastoma Cell Ciliogenesis and Increases Cell Death and Sensitivity to Temozolomide

    Directory of Open Access Journals (Sweden)

    Lan B. Hoang-Minh

    2016-10-01

    Full Text Available A better understanding of the molecules implicated in the growth and survival of glioblastoma (GBM cells and their response to temozolomide (TMZ, the standard-of-care chemotherapeutic agent, is necessary for the development of new therapies that would improve the outcome of current GBM treatments. In this study, we characterize the role of pericentriolar material 1 (PCM1, a component of centriolar satellites surrounding centrosomes, in GBM cell proliferation and sensitivity to genotoxic agents such as TMZ. We show that PCM1 is expressed around centrioles and ciliary basal bodies in patient GBM biopsies and derived cell lines and that its localization is dynamic throughout the cell cycle. To test whether PCM1 mediates GBM cell proliferation and/or response to TMZ, we used CRISPR/Cas9 genome editing to generate primary GBM cell lines depleted of PCM1. These PCM1-depleted cells displayed reduced AZI1 satellite protein localization and significantly decreased proliferation, which was attributable to increased apoptotic cell death. Furthermore, PCM1-depleted lines were more sensitive to TMZ toxicity than control lines. The increase in TMZ sensitivity may be partly due to the reduced ability of PCM1-depleted cells to form primary cilia, as depletion of KIF3A also ablated GBM cells' ciliogenesis and increased their sensitivity to TMZ while preserving PCM1 localization. In addition, the co-depletion of KIF3A and PCM1 did not have any additive effect on TMZ sensitivity. Together, our data suggest that PCM1 plays multiple roles in GBM pathogenesis and that associated pathways could be targeted to augment current or future anti-GBM therapies.

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    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. Loss of Atrx sensitizes cells to DNA damaging agents through p53-mediated death pathways.

    Directory of Open Access Journals (Sweden)

    Damiano Conte

    Full Text Available Prevalent cell death in forebrain- and Sertoli cell-specific Atrx knockout mice suggest that Atrx is important for cell survival. However, conditional ablation in other tissues is not associated with increased death indicating that diverse cell types respond differently to the loss of this chromatin remodeling protein. Here, primary macrophages isolated from Atrx(f/f mice were infected with adenovirus expressing Cre recombinase or β-galactosidase, and assayed for cell survival under different experimental conditions. Macrophages survive without Atrx but undergo rapid apoptosis upon lipopolysaccharide (LPS activation suggesting that chromatin reorganization in response to external stimuli is compromised. Using this system we next tested the effect of different apoptotic stimuli on cell survival. We observed that survival of Atrx-null cells were similar to wild type cells in response to serum withdrawal, anti-Fas antibody, C2 ceramide or dexamethasone treatment but were more sensitive to 5-fluorouracil (5-FU. Cell survival could be rescued by re-introducing Atrx or by removal of p53 demonstrating the cell autonomous nature of the effect and its p53-dependence. Finally, we demonstrate that multiple primary cell types (myoblasts, embryonic fibroblasts and neurospheres were sensitive to 5-FU, cisplatin, and UV light treatment. Together, our results suggest that cells lacking Atrx are more sensitive to DNA damaging agents and that this may result in enhanced death during development when cells are at their proliferative peak. Moreover, it identifies potential treatment options for cancers associated with ATRX mutations, including glioblastoma and pancreatic neuroendocrine tumors.

  14. Loss of Atrx sensitizes cells to DNA damaging agents through p53-mediated death pathways.

    Science.gov (United States)

    Conte, Damiano; Huh, Michael; Goodall, Emma; Delorme, Marilyne; Parks, Robin J; Picketts, David J

    2012-01-01

    Prevalent cell death in forebrain- and Sertoli cell-specific Atrx knockout mice suggest that Atrx is important for cell survival. However, conditional ablation in other tissues is not associated with increased death indicating that diverse cell types respond differently to the loss of this chromatin remodeling protein. Here, primary macrophages isolated from Atrx(f/f) mice were infected with adenovirus expressing Cre recombinase or β-galactosidase, and assayed for cell survival under different experimental conditions. Macrophages survive without Atrx but undergo rapid apoptosis upon lipopolysaccharide (LPS) activation suggesting that chromatin reorganization in response to external stimuli is compromised. Using this system we next tested the effect of different apoptotic stimuli on cell survival. We observed that survival of Atrx-null cells were similar to wild type cells in response to serum withdrawal, anti-Fas antibody, C2 ceramide or dexamethasone treatment but were more sensitive to 5-fluorouracil (5-FU). Cell survival could be rescued by re-introducing Atrx or by removal of p53 demonstrating the cell autonomous nature of the effect and its p53-dependence. Finally, we demonstrate that multiple primary cell types (myoblasts, embryonic fibroblasts and neurospheres) were sensitive to 5-FU, cisplatin, and UV light treatment. Together, our results suggest that cells lacking Atrx are more sensitive to DNA damaging agents and that this may result in enhanced death during development when cells are at their proliferative peak. Moreover, it identifies potential treatment options for cancers associated with ATRX mutations, including glioblastoma and pancreatic neuroendocrine tumors.

  15. From plants to animals; the role of plant cell death in ruminant herbivores.

    Science.gov (United States)

    Kingston-Smith, Alison H; Davies, Teri E; Edwards, Joan E; Theodorou, Michael K

    2008-01-01

    Plant cell death occurring as a result of adverse environmental conditions is known to limit crop production. It is less well recognized that plant cell death processes can also contribute to the poor environmental footprint of ruminant livestock production. Although the forage cells ingested by grazing ruminant herbivores will ultimately die, the lack of oxygen, elevated temperature, and challenge by microflora experienced in the rumen induce regulated plant stress responses resulting in DNA fragmentation and autolytic protein breakdown during the cell death process. Excessive ruminal proteolysis contributes to the inefficient conversion of plant to microbial and animal protein which results in up to 70% of the ingested nitrogen being returned to the land as the nitrogenous pollutants ammonia and urea. This constitutes a significant challenge for sustainable livestock production. As it is estimated that 25% of cultivated land worldwide is assigned to livestock production, it is clear that understanding the fundamental biology underlying cell death in ingested forage will have a highly significant role in minimizing the impact of human activities. This review examines our current understanding of plant metabolism in the rumen and explores opportunities for exploitation of plant genetics to advance sustainable land use.

  16. 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.

  17. Coping with Life after Death: The Counselor's Response Ability.

    Science.gov (United States)

    Hartley, Maurice P.

    1980-01-01

    Physicians, nurses, social workers, and counselors often fail to relate effectively to the dying and the bereaved. They must first come to terms with their own feelings about death in order to respond to others. (Author/JAC)

  18. 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 ...

  19. 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.

  20. Necrosis is an active and controlled form of programmed cell death.

    Science.gov (United States)

    Proskuryakov, S Ya; Gabai, V L; Konoplyannikov, A G

    2002-04-01

    In all studies on programmed cell death (PCD) and apoptosis as its most showy form, this process was considered to be a paradigmatic antithesis to necrotic cell death. On one hand, a concept on necrosis as a cellular cataclysm, an uncontrolled and passive phenomenon, had been provoked by an enormous bulk of experimental data on its inducibility by superphysiological exposures. On the other hand, much attention was attracted to a rapidly expanding (from nematodes) field of genetic studies on PCD. However, the findings accumulated which suggested a likeness rather than the opposition of the necrotic and apoptotic forms of elimination of "unwanted" cells. 1. Very diverse pathophysiological exposures (stimuli, stresses), such as heat, ionizing radiation, pathogens, cytokines cause both forms of cell death in the same cell population. 2. Anti-apoptotic mechanisms (e.g., Bcl-2) can protect cells from both necrotic and apoptotic destruction. 3. Biochemical interventions (e.g., with inhibitors of poly-(ADP-riboso)-polymerase) into the signal and executive mechanisms of PCD can change the choice of the cell death form. 4. During both necrosis and epigenetic programs of apoptotic cell death that need no macromolecular synthesis (e.g., the CD95-dependent death), the nucleus plays a passive role. Therefore, necrosis, similarly to apoptosis, is suggested to be a form of the programmed cell death. However, for the whole body the physiological consequences of apoptosis and necrosis are quite different. In the case of apoptosis, all constituents of the nucleus and cytoplasm are isolated by an undamaged membrane and then by phagocytes together with the membrane-bound "eat me" markers (phosphatidylserine, etc.). In other words, the elimination of the cell which has realized its apoptotic program remains virtually unnoticed by the body. In the case of necrosis, the cytoplasmic content released into the intercellular space provokes an inflammatory response, i.e., an activation of

  1. 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...

  2. 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

  3. Inhibition of TNF-alpha induced cell death in human umbilical vein endothelial cells and Jurkat cells by protocatechuic acid.

    Science.gov (United States)

    Zhou-Stache, J; Buettner, R; Artmann, G; Mittermayer, C; Bosserhoff, A K

    2002-11-01

    The Chinese herb radix Salviae miltiorrhizae (RSM) is used in traditional Chinese medicine as a treatment for cardiovascular and cerebrovascular diseases. Several components of the plant extract from salvia mitorrhiza bunge have been determined previously, one of which is protocatechuic acid (PAC). It has been found, in the study, that PAC inhibited TNF-alpha-induced cell death of human umbilical vein endothelial cells (HUVECs) and Jurkat cells in a concentration of 100 microM when applied 2 h prior to TNF-alpha exposure. Molecular studies revealed that PAC activated NF-kappaB with a maximum effect after 30 min of treatment. Inhibition of NF-kappaB action by MG132 and NF-kappaB inhibitory peptide suppressed the cell-protective effect of PAC. Further, degradation of IkBalpha occurred in response to PAC treatment. The results provide evidence that activation of NF-kappaB plays an important role in mediating the cell-protecting effect of PAC on HUVECs and Jurkat cells. Further studies are required to test whether PAC, a component of radix salviae miltiorrhizae, could be useful in preventing in vivo cell death resulting from cardiovascular or cerebrovascular diseases.

  4. EDR2 negatively regulates salicylic acid-based defenses and cell death during powdery mildew infections of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Nishimura Marc

    2007-07-01

    Full Text Available Abstract Background The hypersensitive necrosis response (HR of resistant plants to avirulent pathogens is a form of programmed cell death in which the plant sacrifices a few cells under attack, restricting pathogen growth into adjacent healthy tissues. In spite of the importance of this defense response, relatively little is known about the plant components that execute the cell death program or about its regulation in response to pathogen attack. Results We isolated the edr2-6 mutant, an allele of the previously described edr2 mutants. We found that edr2-6 exhibited an exaggerated chlorosis and necrosis response to attack by three pathogens, two powdery mildew and one downy mildew species, but not in response to abiotic stresses or attack by the bacterial leaf speck pathogen. The chlorosis and necrosis did not spread beyond inoculated sites suggesting that EDR2 limits the initiation of cell death rather than its spread. The pathogen-induced chlorosis and necrosis of edr2-6 was correlated with a stimulation of the salicylic acid defense pathway and was suppressed in mutants deficient in salicylic acid signaling. EDR2 encodes a novel protein with a pleckstrin homology and a StAR transfer (START domain as well as a plant-specific domain of unknown function, DUF1336. The pleckstrin homology domain binds to phosphatidylinositol-4-phosphate in vitro and an EDR2:HA:GFP protein localizes to endoplasmic reticulum, plasma membrane and endosomes. Conclusion EDR2 acts as a negative regulator of cell death, specifically the cell death elicited by pathogen attack and mediated by the salicylic acid defense pathway. Phosphatidylinositol-4-phosphate may have a role in limiting cell death via its effect on EDR2. This role in cell death may be indirect, by helping to target EDR2 to the appropriate membrane, or it may play a more direct role.

  5. Serratia marcescens induces apoptotic cell death in host immune cells via a lipopolysaccharide- and flagella-dependent mechanism.

    Science.gov (United States)

    Ishii, Kenichi; Adachi, Tatsuo; Imamura, Katsutoshi; Takano, Shinya; Usui, Kimihito; Suzuki, Kazushi; Hamamoto, Hiroshi; Watanabe, Takeshi; Sekimizu, Kazuhisa

    2012-10-19

    Injection of Serratia marcescens into the blood (hemolymph) of the silkworm, Bombyx mori, induced the activation of c-Jun NH(2)-terminal kinase (JNK), followed by caspase activation and apoptosis of blood cells (hemocytes). This process impaired the innate immune response in which pathogen cell wall components, such as glucan, stimulate hemocytes, leading to the activation of insect cytokine paralytic peptide. S. marcescens induced apoptotic cell death of silkworm hemocytes and mouse peritoneal macrophages in vitro. We searched for S. marcescens transposon mutants with attenuated ability to induce apoptosis of silkworm hemocytes. Among the genes identified, disruption mutants of wecA (a gene involved in lipopolysaccharide O-antigen synthesis), and flhD and fliR (essential genes in flagella synthesis) showed reduced motility and impaired induction of mouse macrophage cell death. These findings suggest that S. marcescens induces apoptosis of host immune cells via lipopolysaccharide- and flagella-dependent motility, leading to the suppression of host innate immunity.

  6. 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....

  7. Dopaminergic cell death induced by MPP(+), oxidant and specific neurotoxicants shares the common molecular mechanism.

    Science.gov (United States)

    Chun, H S; Gibson, G E; DeGiorgio, L A; Zhang, H; Kidd, V J; Son, J H

    2001-02-01

    Recent etiological study in twins (Tanner et al. 1999) strongly suggests that environmental factors play an important role in typical, non-familial Parkinson's disease (PD), beginning after age 50. Epidemiological risk factor analyses of typical PD cases have identified several neurotoxicants, including MPP(+) (the active metabolite of MPTP), paraquat, dieldrin, manganese and salsolinol. Here, we tested the hypothesis that these neurotoxic agents might induce cell death in our nigral dopaminergic cell line, SN4741 (Son et al. 1999) through a common molecular mechanism. Our initial experiments revealed that treatment with both MPP(+) and the other PD-related neurotoxicants induced apoptotic cell death in SN4741 cells, following initial increases of H(2)O(2)-related ROS activity and subsequent activation of JNK1/2 MAP kinases. Moreover, we have demonstrated that during dopaminergic cell death cascades, MPP(+), the neurotoxicants and an oxidant, H(2)O(2) equally induce the ROS-dependent events. Remarkably, the oxidant treatment alone induced similar sequential molecular events: ROS increase, activation of JNK MAP kinases, activation of the PITSLRE kinase, p110, by both Caspase-1 and Caspase-3-like activities and apoptotic cell death. Pharmacological intervention using the combination of the antioxidant Trolox and a pan-caspase inhibitor Boc-(Asp)-fmk (BAF) exerted significant neuroprotection against ROS-induced dopaminergic cell death. Finally, the high throughput cDNA microarray screening using the current model identified downstream response genes, such as heme oxygenase-1, a constituent of Lewy bodies, that can be the useful biomarkers to monitor the pathological conditions of dopaminergic neurons under neurotoxic insult.

  8. Intrahepatic infiltrating NK and CD8 T cells cause liver cell death in different phases of dengue virus infection.

    Science.gov (United States)

    Sung, Jui-Min; Lee, Chien-Kuo; Wu-Hsieh, Betty A

    2012-01-01

    Elevated liver enzyme level is an outstanding feature in patients with dengue. However, the pathogenic mechanism of liver injury has not been clearly demonstrated. In this study, employing a mouse model we aimed to investigate the immunopathogenic mechanism of dengue liver injury. Immunocompetent C57BL/6 mice were infected intravenously with dengue virus strain 16681. Infected mice had transient viremia, detectable viral capsid gene and cleaved caspase 3 in the liver. In the mean time, NK cell and T cell infiltrations peaked at days 1 and 5, respectively. Neutralizing CXCL10 or depletion of Asialo GM1(+) cells reduced cleaved caspase 3 and TUNEL(+) cells in the liver at day 1 after infection. CD8(+) T cells infiltrated into the liver at later time point and at which time intrahepatic leukocytes (IHL) exhibited cytotoxicity against DENV-infected targets. Cleaved caspase 3 and TUNEL(+) cells were diminished in mice with TCRβ deficiency and in those depleted of CD8(+) T cells, respectively, at day 5 after infection. Moreover, intrahepatic CD8(+) T cells were like their splenic counterparts recognized DENV NS4B(99-107) peptide. Together, these results show that infiltrating NK and CD8(+) T cells cause liver cell death. While NK cells were responsible for cell death at early time point of infection, CD8(+) T cells were for later. CD8(+) T cells that recognize NS4B(99-107) constitute at least one of the major intrahepatic cytotoxic CD8(+) T cell populations.

  9. Intrahepatic infiltrating NK and CD8 T cells cause liver cell death in different phases of dengue virus infection.

    Directory of Open Access Journals (Sweden)

    Jui-Min Sung

    Full Text Available Elevated liver enzyme level is an outstanding feature in patients with dengue. However, the pathogenic mechanism of liver injury has not been clearly demonstrated. In this study, employing a mouse model we aimed to investigate the immunopathogenic mechanism of dengue liver injury. Immunocompetent C57BL/6 mice were infected intravenously with dengue virus strain 16681. Infected mice had transient viremia, detectable viral capsid gene and cleaved caspase 3 in the liver. In the mean time, NK cell and T cell infiltrations peaked at days 1 and 5, respectively. Neutralizing CXCL10 or depletion of Asialo GM1(+ cells reduced cleaved caspase 3 and TUNEL(+ cells in the liver at day 1 after infection. CD8(+ T cells infiltrated into the liver at later time point and at which time intrahepatic leukocytes (IHL exhibited cytotoxicity against DENV-infected targets. Cleaved caspase 3 and TUNEL(+ cells were diminished in mice with TCRβ deficiency and in those depleted of CD8(+ T cells, respectively, at day 5 after infection. Moreover, intrahepatic CD8(+ T cells were like their splenic counterparts recognized DENV NS4B(99-107 peptide. Together, these results show that infiltrating NK and CD8(+ T cells cause liver cell death. While NK cells were responsible for cell death at early time point of infection, CD8(+ T cells were for later. CD8(+ T cells that recognize NS4B(99-107 constitute at least one of the major intrahepatic cytotoxic CD8(+ T cell populations.

  10. Cytosolic guanine nucledotide binding deficient form of transglutaminase 2 (R580a potentiates cell death in oxygen glucose deprivation.

    Directory of Open Access Journals (Sweden)

    Gozde Colak

    Full Text Available Transglutaminase 2 (TG2 is a hypoxia-responsive protein that is a calcium-activated transamidating enzyme, a GTPase and a scaffolding/linker protein. Upon activation TG2 undergoes a large conformational change, which likely affects not only its enzymatic activities but its non-catalytic functions as well. The focus of this study was on the role of transamidating activity, conformation and localization of TG2 in ischemic cell death. Cells expressing a GTP binding deficient form of TG2 (TG2-R580A with high basal transamidation activity and a more extended conformation showed significantly increased cell death in response to oxygen-glucose deprivation; however, targeting TG2-R580A to the nucleus abrogated its detrimental role in oxygen-glucose deprivation. Treatment of cells expressing wild type TG2, TG2-C277S (a transamidating inactive mutant and TG2-R580A with Cp4d, a reversible TG2 inhibitor, did not affect cell death in response to oxygen-glucose deprivation. These findings indicate that the pro-cell death effects of TG2 are dependent on its localization to the cytosol and independent of its transamidation activity. Further, the conformational state of TG2 is likely an important determinant in cell survival and the prominent function of TG2 in ischemic cell death is as a scaffold to modulate cellular processes.

  11. 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.

  12. Chemical chaperones reduce ionizing radiation-induced endoplasmic reticulum stress and cell death in IEC-6 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Sang; Lee, Hae-June; Lee, Yoon-Jin [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Jeong, Jae-Hoon [Division of Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Kang, Seongman [Division of Life Sciences, Korea University, Seoul 136-701 (Korea, Republic of); Lim, Young-Bin, E-mail: yblim@kirams.re.kr [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of)

    2014-07-25

    Highlights: • UPR activation precedes caspase activation in irradiated IEC-6 cells. • Chemical ER stress inducers radiosensitize IEC-6 cells. • siRNAs that targeted ER stress responses ameliorate IR-induced cell death. • Chemical chaperons prevent cell death in irradiated IEC-6 cells. - Abstract: Radiotherapy, which is one of the most effective approaches to the treatment of various cancers, plays an important role in malignant cell eradication in the pelvic area and abdomen. However, it also generates some degree of intestinal injury. Apoptosis in the intestinal epithelium is the primary pathological factor that initiates radiation-induced intestinal injury, but the mechanism by which ionizing radiation (IR) induces apoptosis in the intestinal epithelium is not clearly understood. Recently, IR has been shown to induce endoplasmic reticulum (ER) stress, thereby activating the unfolded protein response (UPR) signaling pathway in intestinal epithelial cells. However, the consequences of the IR-induced activation of the UPR signaling pathway on radiosensitivity in intestinal epithelial cells remain to be determined. In this study, we investigated the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhanced IR-induced caspase 3 activation and DNA fragmentation in intestinal epithelial cells. Knockdown of Xbp1 or Atf6 with small interfering RNA inhibited IR-induced caspase 3 activation. Treatment with chemical chaperones prevented ER stress and subsequent apoptosis in IR-exposed intestinal epithelial cells. Our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Furthermore, inhibiting ER stress may be an effective strategy to prevent IR-induced intestinal injury.

  13. Cold Atmospheric Plasma Induces a Predominantly Necrotic Cell Death via the Microenvironment.

    Directory of Open Access Journals (Sweden)

    François Virard

    Full Text Available Cold plasma is a partially ionized gas generated by an electric field at atmospheric pressure that was initially used in medicine for decontamination and sterilization of inert surfaces. There is currently growing interest in using cold plasma for more direct medical applications, mainly due to the possibility of tuning it to obtain selective biological effects in absence of toxicity for surrounding normal tissues,. While the therapeutic potential of cold plasma in chronic wound, blood coagulation, and cancer treatment is beginning to be documented, information on plasma/cell interaction is so far limited and controversial.Using normal primary human fibroblast cultures isolated from oral tissue, we sought to decipher the effects on cell behavior of a proprietary cold plasma device generating guided ionization waves carried by helium. In this model, cold plasma treatment induces a predominantly necrotic cell death. Interestingly, death is not triggered by a direct interaction of the cold plasma with cells, but rather via a transient modification in the microenvironment. We show that modification of the microenvironment redox status suppresses treatment toxicity and protects cells from death. Moreover, necrosis is not accidental and seems to be an active response to an environmental cue, as its execution can be inhibited to rescue cells.These observations will need to be taken into account when studying in vitro plasma/cell interaction and may have implications for the design and future evaluation of the efficacy and safety of this new treatment strategy.

  14. Lafora disease proteins laforin and malin negatively regulate the HIPK2-p53 cell death pathway.

    Science.gov (United States)

    Upadhyay, Mamta; Gupta, Smriti; Bhadauriya, Pratibha; Ganesh, Subramaniam

    2015-08-14

    Lafora disease (LD) is an autosomal recessive, progressive, and fatal form of a neurodegenerative disorder characterized by the presence of Lafora polyglucosan bodies. LD is caused by defects in either the laforin protein phosphatase or the malin E3 ubiquitin ligase. Laforin and malin were shown play key roles in proteolytic processes, unfolded stress response, and glycogen metabolism. Therefore, the LD proteins laforin and malin are thought to function as pro-survival factors and their loss thus could result in neurodegeneration. To understand the molecular pathway leading to the cell death in LD, in the present study, we investigated the possible role of LD proteins in the p53-mediated cell death pathway. We show that loss of laforin or malin results in the increased level and activity of p53, both in cellular and animal models of LD, and that this is primarily due to the increased levels of Hipk2, a proapoptotic activator of p53. Overexpression of laforin or malin confers protection against Hipk2-mediated cell death by targeting the Hipk2 to the cytoplasmic compartment. Taken together, our study strengthens the notion that laforin and malin are pro-survival factors, and that the activation of Hipk2-p53 cell death pathway might underlie neurodegeneration in LD.

  15. 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.

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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...

  2. Role of RecA and the SOS response in thymineless death in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Natalie C Fonville

    2010-03-01

    Full Text Available Thymineless death (TLD is a classic and enigmatic phenomenon, documented in bacterial, yeast, and human cells, whereby cells lose viability rapidly when deprived of thymine. Despite its being the essential mode of action of important chemotherapeutic agents, and despite having been studied extensively for decades, the basic mechanisms of TLD have remained elusive. In Escherichia coli, several proteins involved in homologous recombination (HR are required for TLD, however, surprisingly, RecA, the central HR protein and activator of the SOS DNA-damage response was reported not to be. We demonstrate that RecA and the SOS response are required for a substantial fraction of TLD. We show that some of the Rec proteins implicated previously promote TLD via facilitating activation of the SOS response and that, of the roughly 40 proteins upregulated by SOS, SulA, an SOS-inducible inhibitor of cell division, accounts for most or all of how SOS causes TLD. The data imply that much of TLD results from an irreversible cell-cycle checkpoint due to blocked cell division. FISH analyses of the DNA in cells undergoing TLD reveal blocked replication and apparent DNA loss with the region near the replication origin underrepresented initially and the region near the terminus lost later. Models implicating formation of single-strand DNA at blocked replication forks, a SulA-blocked cell cycle, and RecQ/RecJ-catalyzed DNA degradation and HR are discussed. The data predict the importance of DNA damage-response and HR networks to TLD and chemotherapy resistance in humans.

  3. Assessment of caregiver responsibility in unintentional child injury deaths: challenges for injury prevention.

    Science.gov (United States)

    Schnitzer, Patricia G; Covington, Theresa M; Kruse, Robin L

    2011-02-01

    Most unintentional injury deaths among young children result from inadequate supervision or failure by caregivers to protect the child from potential hazards. Determining whether inadequate supervision or failure to protect could be classified as child neglect is a component of child death review (CDR) in most states. However, establishing that an unintentional injury death was neglect related can be challenging as differing definitions, lack of standards regarding supervision, and changing norms make consensus difficult. The purpose of this study was to assess CDR team members' categorisation of the extent to which unintentional injury deaths were neglect related. CDR team members were surveyed and asked to classify 20 vignettes-presented in 10 pairs-that described the circumstances of unintentional injury deaths among children. Vignette pairs differed by an attribute that might affect classification, such as poverty or intent. Categories for classifying vignettes were: (1) caregiver not responsible/not neglect related; (2) some caregiver responsibility/somewhat neglect related; (3) caregiver responsible /definitely neglect related. CDR team members from five states (287) completed surveys. Respondents assigned the child's caregiver at least some responsibility for the death in 18 vignettes (90%). A majority of respondents classified the caregiver as definitely responsible for the child's death in eight vignettes (40%). This study documents attributes that influence CDR team members' decisions when assessing caregiver responsibility in unintentional injury deaths, including supervision, intent, failure to use safety devices, and a pattern of previous neglectful behaviour. The findings offer insight for incorporating injury prevention into CDR more effectively.

  4. 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.

  5. 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.

  6. 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.

  7. p53 family members - important messengers in cell death signaling in photodynamic therapy of cancer?

    Science.gov (United States)

    Acedo, Pilar; Zawacka-Pankau, Joanna

    2015-08-01

    TP53 is one of the genes most frequently inactivated in cancers. Mutations in TP53 gene are linked to worse prognosis and shorter overall survival of cancer patients. TP53 encodes a critical tumor suppressor, which dictates cell fate decisions upon stress stimuli. As a sensor of cellular stress, p53 is a relevant messenger of cell death signaling in ROS-driven photodynamic therapy (PDT) of cancer. The significant role of p53 in response to PDT has been reported for several clinically approved photosensitizers. Multiple reports described that wild-type p53 contributes to cell killing upon photodynamic therapy with clinically approved photosensitizers but the mechanism is still not fully understood. This work outlines the diverse functions of p53 family members in cancer cells' susceptibility and resistance to PDT. In summary p53 and p53 family members are emerging as important mediators of cell death signaling in photodynamic therapy of cancer, however the mechanism of cell death provoked during PDT might differ depending on the tissue type and the photosensitizer applied.

  8. 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.

  9. Modeling the role of p53 pulses in DNA damage- induced cell death decision

    Directory of Open Access Journals (Sweden)

    Cui Jun

    2009-06-01

    Full Text Available Abstract Background The tumor suppressor p53 plays pivotal roles in tumorigenesis suppression. Although oscillations of p53 have been extensively studied, the mechanism of p53 pulses and their physiological roles in DNA damage response remain unclear. Results To address these questions we presented an integrated model in which Ataxia-Telangiectasia Mutated (ATM activation and p53 oscillation were incorporated with downstream apoptotic events, particularly the interplays between Bcl-2 family proteins. We first reproduced digital oscillation of p53 as the response of normal cells to DNA damage. Subsequent modeling in mutant cells showed that high basal DNA damage is a plausible cause for sustained p53 pulses observed in tumor cells. Further computational analyses indicated that p53-dependent PUMA accumulation and the PUMA-controlled Bax activation switch might play pivotal roles to count p53 pulses and thus decide the cell fate. Conclusion The high levels of basal DNA damage are responsible for generating sustained pulses of p53 in the tumor cells. Meanwhile, the Bax activation switch can count p53 pulses through PUMA accumulation and transfer it into death signal. Our modeling provides a plausible mechanism about how cells generate and orchestrate p53 pulses to tip the balance between survival and death.

  10. 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.

  11. 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...

  12. 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.

  13. Regulatory T cells and human myeloid dendritic cells promote tolerance via programmed death ligand-1.

    Directory of Open Access Journals (Sweden)

    Shoba Amarnath

    2010-02-01

    Full Text Available Immunotherapy using regulatory T cells (Treg has been proposed, yet cellular and molecular mechanisms of human Tregs remain incompletely characterized. Here, we demonstrate that human Tregs promote the generation of myeloid dendritic cells (DC with reduced capacity to stimulate effector T cell responses. In a model of xenogeneic graft-versus-host disease (GVHD, allogeneic human DC conditioned with Tregs suppressed human T cell activation and completely abrogated posttransplant lethality. Tregs induced programmed death ligand-1 (PD-L1 expression on Treg-conditioned DC; subsequently, Treg-conditioned DC induced PD-L1 expression in vivo on effector T cells. PD-L1 blockade reversed Treg-conditioned DC function in vitro and in vivo, thereby demonstrating that human Tregs can promote immune suppression via DC modulation through PD-L1 up-regulation. This identification of a human Treg downstream cellular effector (DC and molecular mechanism (PD-L1 will facilitate the rational design of clinical trials to modulate alloreactivity.

  14. A unifying mechanism for cancer cell death through ion channel activation by HAMLET.

    Directory of Open Access Journals (Sweden)

    Petter Storm

    Full Text Available Ion channels and ion fluxes control many aspects of tissue homeostasis. During oncogenic transformation, critical ion channel functions may be perturbed but conserved tumor specific ion fluxes remain to be defined. Here we used the tumoricidal protein-lipid complex HAMLET as a probe to identify ion fluxes involved in tumor cell death. We show that HAMLET activates a non-selective cation current, which reached a magnitude of 2.74±0.88 nA within 1.43±0.13 min from HAMLET application. Rapid ion fluxes were essential for HAMLET-induced carcinoma cell death as inhibitors (amiloride, BaCl2, preventing the changes in free cellular Na(+ and K(+ concentrations also prevented essential steps accompanying carcinoma cell death, including changes in morphology, uptake, global transcription, and MAP kinase activation. Through global transcriptional analysis and phosphorylation arrays, a strong ion flux dependent p38 MAPK response was detected and inhibition of p38 signaling delayed HAMLET-induced death. Healthy, differentiated cells were resistant to HAMLET challenge, which was accompanied by innate immunity rather than p38-activation. The results suggest, for the first time, a unifying mechanism for the initiation of HAMLET's broad and rapid lethal effect on tumor cells. These findings are particularly significant in view of HAMLET's documented therapeutic efficacy in human studies and animal models. The results also suggest that HAMLET offers a two-tiered therapeutic approach, killing cancer cells while stimulating an innate immune response in surrounding healthy tissues.

  15. 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

  16. 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...

  17. 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.

  18. 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.

  19. A Novel Function for Arabidopsis CYCLASE1 in Programmed Cell Death Revealed by Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) Analysis of Extracellular Matrix Proteins.

    Science.gov (United States)

    Smith, Sarah J; Kroon, Johan T M; Simon, William J; Slabas, Antoni R; Chivasa, Stephen

    2015-06-01

    Programmed cell death is essential for plant development and stress adaptation. A detailed understanding of the signal transduction pathways that regulate plant programmed cell death requires identification of the underpinning protein networks. Here, we have used a protagonist and antagonist of programmed cell death triggered by fumonisin B1 as probes to identify key cell death regulatory proteins in Arabidopsis. Our hypothesis was that changes in the abundance of cell death-regulatory proteins induced by the protagonist should be blocked or attenuated by concurrent treatment with the antagonist. We focused on proteins present in the mobile phase of the extracellular matrix on the basis that they are important for cell-cell communications during growth and stress-adaptive responses. Salicylic acid, a plant hormone that promotes programmed cell death, and exogenous ATP, which can block fumonisin B1-induced cell death, were used to treat Arabidopsis cell suspension cultures prior to isobaric-tagged relative and absolute quantitation analysis of secreted proteins. A total of 33 proteins, whose response to salicylic acid was suppressed by ATP, were identified as putative cell death-regulatory proteins. Among these was CYCLASE1, which was selected for further analysis using reverse genetics. Plants in which CYCLASE1 gene expression was knocked out by insertion of a transfer-DNA sequence manifested dramatically increased cell death when exposed to fumonisin B1 or a bacterial pathogen that triggers the defensive hypersensitive cell death. Although pathogen inoculation altered CYCLASE1 gene expression, multiplication of bacterial pathogens was indistinguishable between wild type and CYCLASE1 knockout plants. However, remarkably severe chlorosis symptoms developed on gene knockout plants in response to inoculation with either a virulent bacterial pathogen or a disabled mutant that is incapable of causing disease in wild type plants. These results show that CYCLASE1, which

  20. Thymineless death is inhibited by CsrA in Escherichia coli lacking the SOS response.

    Science.gov (United States)

    Hamilton, Holly M; Wilson, Ray; Blythe, Martin; Nehring, Ralf B; Fonville, Natalie C; Louis, Edward J; Rosenberg, Susan M

    2013-11-01

    Thymineless death (TLD) is the rapid loss of colony-forming ability in bacterial, yeast and human cells starved for thymine, and is the mechanism of action of common chemotherapeutic drugs. In Escherichia coli, significant loss of viability during TLD requires the SOS replication-stress/DNA-damage response, specifically its role in inducing the inhibitor of cell division, SulA. An independent RecQ- and RecJ-dependent TLD pathway accounts for a similarly large additional component of TLD, and a third SOS- and RecQ/J-independent TLD pathway has also been observed. Although two groups have implicated the SOS-response in TLD, an SOS-deficient mutant strain from an earlier study was found to be sensitive to thymine deprivation. We performed whole-genome resequencing on that SOS-deficient strain and find that, compared with the SOS-proficient control strain, it contains five mutations in addition to the SOS-blocking lexA(Ind(-)) mutation. One of the additional mutations, csrA, confers TLD sensitivity specifically in SOS-defective strains. We find that CsrA, a carbon storage regulator, reduces TLD in SOS- or SulA-defective cells, and that the increased TLD that occurs in csrA(-) SOS-defective cells is dependent on RecQ. We consider a hypothesis in which the modulation of nucleotide pools by CsrA might inhibit TLD specifically in SOS-deficient (SulA-deficient) cells.

  1. Transcriptional activity around bacterial cell death reveals molecular biomarkers for cell viability

    Directory of Open Access Journals (Sweden)

    Schuren Frank H

    2008-12-01

    Full Text Available Abstract Background In bacteriology, the ability to grow in selective media and to form colonies on nutrient agar plates is routinely used as a retrospective criterion for the detection of living bacteria. However, the utilization of indicators for bacterial viability-such as the presence of specific transcripts or membrane integrity-would overcome bias introduced by cultivation and reduces the time span of analysis from initiation to read out. Therefore, we investigated the correlation between transcriptional activity, membrane integrity and cultivation-based viability in the Gram-positive model bacterium Bacillus subtilis. Results We present microbiological, cytological and molecular analyses of the physiological response to lethal heat stress under accurately defined conditions through systematic sampling of bacteria from a single culture exposed to gradually increasing temperatures. We identified a coherent transcriptional program including known heat shock responses as well as the rapid expression of a small number of sporulation and competence genes, the latter only known to be active in the stationary growth phase. Conclusion The observed coordinated gene expression continued even after cell death, in other words after all bacteria permanently lost their ability to reproduce. Transcription of a very limited number of genes correlated with cell viability under the applied killing regime. The transcripts of the expressed genes in living bacteria – but silent in dead bacteria-include those of essential genes encoding chaperones of the protein folding machinery and can serve as molecular biomarkers for bacterial cell viability.

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

    Science.gov (United States)

    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.

  3. 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...

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

    Directory of Open Access Journals (Sweden)

    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

  5. 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.

  6. 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.

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

    Science.gov (United States)

    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.

  8. 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

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

    Science.gov (United States)

    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.

  10. 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.

  11. 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.

  12. Distinct effects of rotenone, 1-methyl-4-phenylpyridinium and 6-hydroxydopamine on cellular bioenergetics and cell death.

    Directory of Open Access Journals (Sweden)

    Samantha Giordano

    Full Text Available Parkinson's disease is characterized by dopaminergic neurodegeneration and is associated with mitochondrial dysfunction. The bioenergetic susceptibility of dopaminergic neurons to toxins which induce Parkinson's like syndromes in animal models is then of particular interest. For example, rotenone, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP and its active metabolite 1-methyl-4-phenylpyridinium (MPP(+, and 6-hydroxydopamine (6-OHDA, have been shown to induce dopaminergic cell death in vivo and in vitro. Exposure of animals to these compounds induce a range of responses characteristics of Parkinson's disease, including dopaminergic cell death, and Reactive Oxygen Species (ROS production. Here we test the hypothesis that cellular bioenergetic dysfunction caused by these compounds correlates with induction of cell death in differentiated dopaminergic neuroblastoma SH-SY5Y cells. At increasing doses, rotenone induced significant cell death accompanied with caspase 3 activation. At these concentrations, rotenone had an immediate inhibition of mitochondrial basal oxygen consumption rate (OCR concomitant with a decrease of ATP-linked OCR and reserve capacity, as well as a stimulation of glycolysis. MPP(+ exhibited a different behavior with less pronounced cell death at doses that nearly eliminated basal and ATP-linked OCR. Interestingly, MPP(+, unlike rotenone, stimulated bioenergetic reserve capacity. The effects of 6-OHDA on bioenergetic function was markedly less than the effects of rotenone or MPP(+ at cytotoxic doses, suggesting a mechanism largely independent of bioenergetic dysfunction. These studies suggest that these dopaminergic neurotoxins induce cell death through distinct mechanisms and differential effects on cellular bioenergetics.

  13. Taurolidine and povidone-iodine induce different types of cell death in malignant pleural mesothelioma.

    Science.gov (United States)

    Opitz, I; Sigrist, B; Hillinger, S; Lardinois, D; Stahel, R; Weder, W; Hopkins-Donaldson, S

    2007-06-01

    Taurolidine and povidone-iodine (PVP-I) are used in every day clinical practice, taurolidine as a broad spectrum antibiotic, and PVP-I as an antiseptic. The type of cell death induced in malignant pleural mesothelioma (MPM) cell lines by these agents was compared, and their ability to sensitize to chemotherapy assessed. Both taurolidine and PVP-I inhibited MPM cell growth after 7.5min incubation, but taurolidine was more effective at later time points and was more specific towards tumour cells than PVP-I. Taurolidine induced death by caspase-dependent and independent mechanisms, whereas in contrast, PVP-I induced a necrotic phenotype that was not caspase-dependent. Interestingly, both taurolidine and PVP-I induced the production of reactive oxygen intermediates and decreased mitochondrial membrane permeability, and cell death was inhibited by the oxygen scavenger N-acetyl cysteine. Taurolidine but not PVP-I treatment resulted in p53 activation in 2/3 MPM cell lines and a decrease in the protein levels of survivin, Bcl-2 and Mcl-1. Survivin also decreased in response to PVP-I whereas Bcl-xL remained unaffected by both treatments. Targeting of Bcl-xL with siRNA sensitized MPM cells to taurolidine and taurolidine treatment sensitized MPM cells to cisplatin-induced apoptosis. In conclusion, taurolidine and PVP-I are both cytotoxic to human MPM cells at early and late time points and induce reactive oxygen intermediate production. Taurolidine induces apoptosis and necrosis, activates p53 and sensitizes cells to cisplatin, whereas PVP-I inhibits cell growth via necrosis. Both agents are promising candidates for use in local treatment within multimodality concepts for MPM.

  14. 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.``

  15. Mechanism and efficiency of cell death of type II photosensitizers: effect of zinc chelation.

    Science.gov (United States)

    Pavani, Christiane; Iamamoto, Yassuko; Baptista, Maurício S

    2012-01-01

    A series of meso-substituted tetra-cationic porphyrins, which have methyl and octyl substituents, was studied in order to understand the effect of zinc chelation and photosensitizer subcellular localization in the mechanism of cell death. Zinc chelation does not change the photophysical properties of the photosensitizers (all molecules studied are type II photosensitizers) but affects considerably the interaction of the porphyrins with membranes, reducing mitochondrial accumulation. The total amount of intracellular reactive species induced by treating cells with photosensitizer and light is similar for zinc-chelated and free-base porphyrins that have the same alkyl substituent. Zinc-chelated porphyrins, which are poorly accumulated in mitochondria, show higher efficiency of cell death with features of apoptosis (higher MTT response compared with trypan blue staining, specific acridine orange/ethidium bromide staining, loss of mitochondrial transmembrane potential, stronger cytochrome c release and larger sub-G1 cell population), whereas nonchelated porphyrins, which are considerably more concentrated in mitochondria, triggered mainly necrotic cell death. We hypothesized that zinc-chelation protects the photoinduced properties of the porphyrins in the mitochondrial environment.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Molecular mechanisms of methylmercury-induced cell death in human HepG2 cells.

    Science.gov (United States)

    Cuello, Susana; Goya, Luis; Madrid, Yolanda; Campuzano, Susana; Pedrero, Maria; Bravo, Laura; Cámara, Carmen; Ramos, Sonia

    2010-05-01

    Methylmercury (MeHg) has been suggested to exert cytotoxicity through multiple mechanisms, but the precise biochemical machinery has not been fully defined. This study was aimed at investigating the time-course (0-24h) effect of 2mg/L MeHg on cell death in human HepG2 cells. MeHg decreased cell viability in a time-dependent manner, which was concomitant with increased LDH leakage, reduced GSH levels, CAT activity and altered activity of the antioxidant enzymes GPx and GR at the longest times of incubation (16 and 24h). Activity of the detoxifying enzyme GST was also early enhanced (2h). Caspase-3 activity reached a maximum value at 8h and continued increased up to 24h. This feature was preceded by an enhancement in the caspase-9 activity (2h), whereas caspase-8 activity remained unchanged. MeHg early diminished Bcl-x(L)/Bcl-x(S) ratio and increased levels of the pro-apoptotic Bax and Bad. Moreover, MeHg-induced cytotoxicity was completely inhibited by the antioxidants (GSH and NAC) and notably by the mitochondrial complex I inhibitor rotenone, but not by the NADH oxidase inhibitor DPI. In summary, MeHg induced an oxidative stress responsible for apoptosis in HepG2 cells through direct activation of the caspase cascade and altered the cellular antioxidant and detoxificant enzymatic system to later provoke necrosis at later stages.

  4. Programmed cell death activated by Rose Bengal in Arabidopsis thaliana cell suspension cultures requires functional chloroplasts.

    Science.gov (United States)

    Gutiérrez, Jorge; González-Pérez, Sergio; García-García, Francisco; Daly, Cara T; Lorenzo, Oscar; Revuelta, José L; McCabe, Paul F; Arellano, Juan B

    2014-07-01

    Light-grown Arabidopsis thaliana cell suspension culture (ACSC) were subjected to mild photooxidative damage with Rose Bengal (RB) with the aim of gaining a better understanding of singlet oxygen-mediated defence responses in plants. Additionally, ACSC were treated with H2O2 at concentrations that induced comparable levels of protein oxidation damage. Under low to medium light conditions, both RB and H2O2 treatments activated transcriptional defence responses and inhibited photosynthetic activity, but they differed in that programmed cell death (PCD) was only observed in cells treated with RB. When dark-grown ACSC were subjected to RB in the light, PCD was suppressed, indicating that the singlet oxygen-mediated signalling pathway in ACSC requires functional chloroplasts. Analysis of up-regulated transcripts in light-grown ACSC, treated with RB in the light, showed that both singlet oxygen-responsive transcripts and transcripts with a key role in hormone-activated PCD (i.e. ethylene and jasmonic acid) were present. A co-regulation analysis proved that ACSC treated with RB exhibited higher correlation with the conditional fluorescence (flu) mutant than with other singlet oxygen-producing mutants or wild-type plants subjected to high light. However, there was no evidence for the up-regulation of EDS1, suggesting that activation of PCD was not associated with the EXECUTER- and EDS1-dependent signalling pathway described in the flu mutant. Indigo Carmine and Methylene Violet, two photosensitizers unable to enter chloroplasts, did not activate transcriptional defence responses in ACSC; however, whether this was due to their location or to their inherently low singlet oxygen quantum efficiencies was not determined.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. A novel approach for studying programmed cell death in living plant tissues

    DEFF Research Database (Denmark)

    Mark, Christina

    Programmed cell death (PCD) is a highly regulated process in which cells are killed as part of developmental programmes or as defence mechanisms against pathogens, but the process is less well understood in plant cells compared to animal cells. Reactive oxygen species (ROS) are involved in PCD...... and quality of crops and thus contribute to solving the increasing food demands of the planet. Examples of this could be the development of cultivars with enhanced and/or faster response to pathogen attacks, or cultivars with increased grain filling and hence increased starch content through delayed cell...... that each analysis is performed on a different pool of samples, as each tissue sample or population of cells can only be analysed at a single time point. This is of great importance for studies of time-dependent processes such as PCD, as time course experiments can be affected by biological and experimental...

  7. Inflammatory cytokines protect retinal pigment epithelial cells from oxidative stress-induced death

    DEFF Research Database (Denmark)

    Juel, Helene B; Faber, Carsten; Svendsen, Signe Goul

    2013-01-01

    -mediated induction of the anti-oxidative stress response, upregulating protective anti-oxidant pathway(s). These findings suggest caution for the clinical use of anti-inflammatory agents in the management of immune-associated eye diseases such as age-related macular degeneration.......PURPOSE: To investigate the effects of inflammatory factors and oxidative stress on cell survival of the human retinal pigment epithelial (RPE) cell line, ARPE-19. METHODS: Confluent RPE cells were treated with peripheral blood mononuclear cells-conditioned medium (PCM), H2O2, NaIO3, interferon...... (IFN)-γ, tumor necrosis factor (TNF)-α, or combinations of these. Cell viability was determined by viability assays and by light microscopy. Effector molecules of cell death were investigated by immunofluorescence microscopy and flow cytometry. Microarrays were performed to screen for differential...

  8. 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...

  9. 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.

  10. 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.

  11. Mechanisms of pre-apoptotic calreticulin exposure in immunogenic cell death.

    Science.gov (United States)

    Panaretakis, Theocharis; Kepp, Oliver; Brockmeier, Ulf; Tesniere, Antoine; Bjorklund, Ann-Charlotte; Chapman, Daniel C; Durchschlag, Michael; Joza, Nicholas; Pierron, Gérard; van Endert, Peter; Yuan, Junying; Zitvogel, Laurence; Madeo, Frank; Williams, David B; Kroemer, Guido

    2009-03-04

    Dying tumour cells can elicit a potent anticancer immune response by exposing the calreticulin (CRT)/ERp57 complex on the cell surface before the cells manifest any signs of apoptosis. Here, we enumerate elements of the pathway that mediates pre-apoptotic CRT/ERp57 exposure in response to several immunogenic anticancer agents. Early activation of the endoplasmic reticulum (ER)-sessile kinase PERK leads to phosphorylation of the translation initiation factor eIF2alpha, followed by partial activation of caspase-8 (but not caspase-3), caspase-8-mediated cleavage of the ER protein BAP31 and conformational activation of Bax and Bak. Finally, a pool of CRT that has transited the Golgi apparatus is secreted by SNARE-dependent exocytosis. Knock-in mutation of eIF2alpha (to make it non-phosphorylatable) or BAP31 (to render it uncleavable), depletion of PERK, caspase-8, BAP31, Bax, Bak or SNAREs abolished CRT/ERp57 exposure induced by anthracyclines, oxaliplatin and ultraviolet C light. Depletion of PERK, caspase-8 or SNAREs had no effect on cell death induced by anthracyclines, yet abolished the immunogenicity of cell death, which could be restored by absorbing recombinant CRT to the cell surface.

  12. Proline dehydrogenase is a positive regulator of cell death in different kingdoms.

    Science.gov (United States)

    Cecchini, Nicolás M; Monteoliva, Mariela I; Alvarez, María E

    2011-08-01

    Proline dehydrogenase (ProDH) catalyzes the flavin-dependent oxidation of Pro into Δ1-pyrroline-5-carboxylate (P5C). This is the first of the two enzymatic reactions that convert proline (Pro) into glutamic acid (Glu). The P5C thus produced is non-enzymatically transformed into glutamate semialdehyde (GSA), which acts as a substrate of P5C dehydrogenase (P5CDH) to generate Glu. Activation of ProDH can generate different effects depending on the behaviour of other enzymes of this metabolism. Under different conditions it can generate toxic levels of P5C, alter the cellular redox homeostasis and even produce reactive oxygen species (ROS). Recent studies indicate that in Arabidopsis, the enzyme potentiates the oxidative burst and cell death associated to the Hypersensitive Responses (HR). Interestingly, activation of ProDH can also produce harmful effects in other organisms, suggesting that the enzyme may play a conserved role in the control of cell death.

  13. The modulation of radiation-induced cell death by genistein in K562 cells:Activation of thymidine kinase 1

    Institute of Scientific and Technical Information of China (English)

    Min Ho JEONG; Young Hee JIN; Eun Young KANG; Wol Soon JO; Hwan Tae PARK; Jae Dong LEE; Yeo Jin YOO; Soo Jin JEONG

    2004-01-01

    Ionizing radiation is one of the most effective tools in cancer therapy. In a previous study, we reported that protein tyrosine kinase (PTK) inhibitors modulate the radiation responses in the human chronic myelogenous leukemia (CML)cell line K562. The receptor tyrosine kinase inhibitor, genistein, delayed radiation-induced cell death, while non-recepter tyrosine kinase inhibitor, herbimycin A (HMA) enhances radiation-induced apoptosis. In this study, we focused on the modulation of radiation-induced cell death by genistein and performed PCR-select suppression subtractive hybridization(SSH) to understand its molecular mechanism. We identified human thymidine kinase 1 (TK1), which is cell cycle regulatory gene and confirmed expression of TK1 mRNA by Northern blot analysis. Expression of TK1 mRNA and TK 1enzymatic activity were parallel in their increase and decrease. TK1 is involved in G1-S phase transition of cell cycle progression. In cell cycle analysis, we showed that radiation induced G2 arrest in K562 cells but it was not able to sustain. However, the addition of genistein to irradiated cells sustained a prolonged G2 arrest up to 120 h. In addition,the expression of cell cycle-related proteins, cyclin A and cyclin B 1, provided the evidences of G1/S progression and G2-arrest, and their relationship with TK1 in cells treated with radiation and genistein. These results suggest that the activation of TK1 may be critical to modulate the radiation-induced cell death and cell cycle progression in irradiated K562 cells.

  14. Slow and sustained nitric oxide releasing compounds inhibit multipotent vascular stem cell proliferation and differentiation without causing cell death

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Brandon M.; Leix, Kyle Alexander [Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859 (United States); Ji, Yajing [Department of Biomedical Science and Medicine, Michigan State University, East Lansing, MI 48824 (United States); Glaves, Richard Samuel Elliot [Department of Biology, Central Michigan University, Mount Pleasant, MI 48859 (United States); Ash, David E. [Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859 (United States); Mohanty, Dillip K., E-mail: Mohan1dk@cmich.edu [Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859 (United States)

    2014-07-18

    Highlights: • Multipotent vascular stem cells (MVSCs) proliferate and differentiate. • Nitric oxide inhibits proliferation of MVSCs. • Nitric oxide inhibits MVSC differentiation to mesenchymal-like stem cells (MSCs). • Smooth muscle cells (SMCs) neither de-differentiate nor proliferate. - Abstract: Atherosclerosis is the leading cause of cerebral and myocardial infarction. It is believed that neointimal growth common in the later stages of atherosclerosis is a result of vascular smooth muscle cell (SMC) de-differentiation in response to endothelial injury. However, the claims of the SMC de-differentiation theory have not been substantiated by monitoring the fate of mature SMCs in response to such injuries. A recent study suggests that atherosclerosis is a consequence of multipotent vascular stem cell (MVSC) differentiation. Nitric oxide (NO) is a well-known mediator against atherosclerosis, in part because of its inhibitory effect on SMC proliferation. Using three different NO-donors, we have investigated the effects of NO on MVSC proliferation. Results indicate that NO inhibits MVSC proliferation in a concentration dependent manner. A slow and sustained delivery of NO proved to inhibit proliferation without causing cell death. On the other hand, larger, single-burst NO concentrations, inhibits proliferation, with concurrent significant cell death. Furthermore, our results indicate that endogenously produced NO inhibits MVSC differentiation to mesenchymal-like stem cells (MSCs) and subsequently to SMC as well.

  15. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Hypoxia-induced cell death and changes in hypoxia-inducible factor-1 activity in PC12 cells upon exposure to nerve growth factor.

    Science.gov (United States)

    Charlier, Nico; Leclere, Norbert; Felderhoff, Ursula; Heldt, Julia; Kietzmann, Thomas; Obladen, Michael; Gross, Johann

    2002-07-15

    The transcription factor hypoxia-inducible factor-1 (HIF-1) strongly contributes to the expression of adaptive genes under hypoxic conditions. In addition, HIF-1 has been implicated in the regulation of delayed neuronal cell death. Suspension-grown and adherent PC12 cells treated with NGF were used as an experimental model for studying the relationship between hypoxia-induced cell death and activation of HIF-1. Cell damage was assessed by flow cytometry of double-stained (Annexin V and propidiumiodide) cells, and by analysis of the overall death parameters LDH and mitochondrial dehydrogenase. In parallel, cells were transfected with a control and a three-hypoxia-responsive-elements (HRE)-containing vector and HIF-1-driven luciferase activity was determined. Exposure of NGF-treated PC12 cells to hypoxia resulted in a higher cell death rate when compared to untreated controls. PC12 cells exposed for 2 days to NGF exhibited a decrease of HIF-1 activity up to a factor of ten. This decrease may contribute to the enhanced hypoxia-induced cell death via reduced expression of HIF-1alpha-regulated genes responsible for adaptation to hypoxia, like those for glucose transport proteins and enzymes of the glycolytic chain. The decrease in HIF-1 activity and the increase in hypoxia sensitivity may suggest that NGF act as an hierarchically organized signaling molecule.

  19. Up-regulation of K{sub ir}2.1 by ER stress facilitates cell death of brain capillary endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Kito, Hiroaki [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Yamazaki, Daiju [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Department of Biological Chemistry, Kyoto University, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Ohya, Susumu; Yamamura, Hisao [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Imaizumi, Yuji, E-mail: yimaizum@phar.nagoya-cu.ac.jp [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan)

    2011-07-29

    Highlights: {yields} We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. {yields} The ER stress facilitated the expression of inward rectifier K{sup +} channel (K{sub ir}2.1) and induced sustained membrane hyperpolarization. {yields} The membrane hyperpolarization induced sustained Ca{sup 2+} entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. {yields} The K{sub ir}2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K{sup +} channel (K{sub ir}2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K{sub ir} channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca{sup 2+} concentration due to Ca{sup 2+} influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K{sub ir}2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

  20. 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.

  1. 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.

  2. 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.

  3. XIAP Restricts TNF- and RIP3-Dependent Cell Death and Inflammasome Activation

    DEFF Research Database (Denmark)

    Yabal, Monica; Müller, Nicole; Adler, Heiko;

    2014-01-01

    X-linked inhibitor of apoptosis protein (XIAP) has been identified as a potent regulator of innate immune responses, and loss-of-function mutations in XIAP cause the development of the X-linked lymphoproliferative syndrome type 2 (XLP-2) in humans. Using gene-targeted mice, we show that loss...... but proceeds independently of caspase-1/caspase-11 or caspase-8 function. Loss of XIAP results in aberrantly elevated ubiquitylation of RIP1 outside of TNFR complex I. Virally infected Xiap(-/-) mice present with symptoms reminiscent of XLP-2. Our data show that XIAP controls RIP3-dependent cell death and IL-1...... of XIAP or deletion of its RING domain lead to excessive cell death and IL-1β secretion from dendritic cells triggered by diverse Toll-like receptor stimuli. Aberrant IL-1β secretion is TNF dependent and requires RIP3 but is independent of cIAP1/cIAP2. The observed cell death also requires TNF and RIP3...

  4. Interplay among nitric oxide and reactive oxygen species: a complex network determining cell survival or death.

    Science.gov (United States)

    Zhao, Jian

    2007-11-01

    Programmed cell death (PCD) is an integrated cellular process occurring in plant growth, development, and defense responses to facilitate normal growth and development and better survival against various stresses as a whole. As universal toxic chemicals in plant and animal cells, reactive oxygen or nitrogen species (ROS or RNS), mainly superoxide anion (O(2) (-*)), hydrogen peroxide (H(2)O(2)) or nitric oxide ((*)NO), have been studied extensively for their roles in PCD induction. Physiological and genetic studies have convincingly shown their essential roles. However, the details and mechanisms by which ROS and (*)NO interplay and induce PCD are not well understood. Our recent study on Cupressus lusitanica culture cell death revealed the elicitor-induced co-accumulation of ROS and (*)NO and interactions between (*)NO and H(2)O(2) or O(2)-(*) in different ways to regulate cell death. (*)NO and H(2)O(2) reciprocally enhanced the production of each other whereas (*)NO and O(2) (-*) showed reciprocal suppression on each other's production. It was the interaction between (*)NO and O(2)-(*) but not between (*)NO and H(2)O(2) that induced PCD, probably through peroxynitrite (ONOO(-)). In this addendum, some unsolved issues in the study were discussed based on recent studies on the complex network of ROS and (*)NO leading to PCD in animals and plants.

  5. Interferon-γ increases neuronal death in response to amyloid-β1-42

    Directory of Open Access Journals (Sweden)

    Williams Alun

    2006-03-01

    Full Text Available Abstract Background Alzheimer's disease is a neurodegenerative disorder characterized by a progressive cognitive impairment, the consequence of neuronal dysfunction and ultimately the death of neurons. The amyloid hypothesis proposes that neuronal damage results from the accumulation of insoluble, hydrophobic, fibrillar peptides such as amyloid-β1-42. These peptides activate enzymes resulting in a cascade of second messengers including prostaglandins and platelet-activating factor. Apoptosis of neurons is thought to follow as a consequence of the uncontrolled release of second messengers. Biochemical, histopathological and genetic studies suggest that pro-inflammatory cytokines play a role in neurodegeneration during Alzheimer's disease. In the current study we examined the effects of interferon (IFN-γ, tumour necrosis factor (TNFα, interleukin (IL-1β and IL-6 on neurons. Methods Primary murine cortical or cerebellar neurons, or human SH-SY5Y neuroblastoma cells, were grown in vitro. Neurons were treated with cytokines prior to incubation with different neuronal insults. Cell survival, caspase-3 activity (a measure of apoptosis and prostaglandin production were measured. Immunoblots were used to determine the effects of cytokines on the levels of cytoplasmic phospholipase A2 or phospholipase C γ-1. Results While none of the cytokines tested were directly neurotoxic, pre-treatment with IFN-γ sensitised neurons to the toxic effects of amyloid-β1-42 or HuPrP82-146 (a neurotoxic peptide found in prion diseases. The effects of IFN-γ were seen on cortical and cerebellar neurons, and on SH-SY5Y neuroblastoma cells. However, pre-treatment with IFN-γ did not affect the sensitivity to neurons treated with staurosporine or hydrogen peroxide. Pre-treatment with IFN-γ increased the levels of cytoplasmic phospholipase A2 in SH-SY5Y cells and increased prostaglandin E2 production in response to amyloid-β1-42. Conclusion Treatment of neuronal cells

  6. alpha-Amylase and programmed cell death in aleurone of ripening wheat grains.

    Science.gov (United States)

    Mrva, Kolumbina; Wallwork, Meredith; Mares, Daryl J

    2006-01-01

    associated with cell death, providing further evidence for the involvement of gibberellin in the LMA response.

  7. 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.

  8. 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.

  9. 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.

  10. Clinical implications of the involvement of tPA in neuronal cell death.

    Science.gov (United States)

    Tsirka, S E

    1997-05-01

    Tissue plasminogen activator (tPA), the serine protease that converts inactive plasminogen to the protease plasmin, was recently shown to mediate neurodegeneration in the mouse hippocampus. Mice deficient in tissue plasminogen activator (tPA) display a dramatic resistance to a paradigm of excitotoxic neuronal death that involves intrahippocampal injection of the excitotoxin. This model is thought to reproduce the mechanism of neuronal death observed during acute (such as ischemic stroke) and degenerative (such as amyotrophic lateral sclerosis) diseases of the nervous system. The requirement for the proteolytic activity of tPA to mediate neuronal death is acute in the adult mouse. Serine protease inhibitors, specific for tPA or the tPA/plasmin proteolytic cascade, are effective in conferring extensive neuroprotection following the excitotoxic injection. These findings suggest possible new ways for interfering with the neuronal death observed in the hippocampus as a result of excitotoxicity. In addition, tPA is produced in the hippocampus primarily by microglial cells, which become activated in response to the neuronal injury. Blocking microglial activation has been shown in other injury paradigms to protect against neuronal death, therefore suggesting another way to retard neurodegeneration in the CNS. Furthermore, after the insult has been inflicted and in the presence of a compromised blood-brain barrier macrophages (cells deriving from the same lineage as microglia) migrate into the brain, where they are thought to contribute to the neuronal cell loss by secreting neurotoxic molecules. If these macrophages/microglia expressed, however, a tPA inhibitor, rather than the possibly neurotoxic tPA, they might be able to protect the neurons from dying.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. 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.

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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.

  16. Protein Kinase D Regulates Cell Death Pathways in Experimental Pancreatitis

    OpenAIRE

    Yuan, Jingzhen; Liu, Yannan; Tan, Tanya; Guha, Sushovan; Gukovsky, Ilya; Gukovskaya, Anna; Pandol, Stephen J.

    2012-01-01

    Inflammation and acinar cell necrosis are two major pathological responses of acute pancreatitis, a serious disorder with no current therapies directed to its molecular pathogenesis. Serine/threonine protein kinase D family, which includes PKD/PKD1, PKD2, and PKD3, has been increasingly implicated in the regulation of multiple physiological and pathophysiological effects. We recently reported that PKD/PKD1, the predominant PKD isoform expressed in rat pancreatic acinar cells, mediates early e...

  17. The fusarium mycotoxin deoxynivalenol can inhibit plant apoptosis-like programmed cell death.

    Directory of Open Access Journals (Sweden)

    Mark Diamond

    Full Text Available The Fusarium genus of fungi is responsible for commercially devastating crop diseases and the contamination of cereals with harmful mycotoxins. Fusarium mycotoxins aid infection, establishment, and spread of the fungus within the host plant. We investigated the effects of the Fusarium mycotoxin deoxynivalenol (DON on the viability of Arabidopsis cells. Although it is known to trigger apoptosis in animal cells, DON treatment at low concentrations surprisingly did not kill these cells. On the contrary, we found that DON inhibited apoptosis-like programmed cell death (PCD in Arabidopsis cells subjected to abiotic stress treatment in a manner independent of mitochondrial cytochrome c release. This suggested that Fusarium may utilise mycotoxins to suppress plant apoptosis-like PCD. To test this, we infected Arabidopsis cells with a wild type and a DON-minus mutant strain of F. graminearum and found that only the DON producing strain could inhibit death induced by heat treatment. These results indicate that mycotoxins may be capable of disarming plant apoptosis-like PCD and thereby suggest a novel way that some fungi can influence plant cell fate.

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

    Directory of Open Access Journals (Sweden)

    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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Plasma membrane ubiquinone controls ceramide production and prevents cell death induced by serum withdrawal.

    Science.gov (United States)

    Barroso, M P; Gómez-Díaz, C; Villalba, J M; Burón, M I; López-Lluch, G; Navas, P

    1997-06-01

    Serum provides cultured cells with survival factors required to maintain growth. Its withdrawal induces the development of programmed cell death. HL-60 cells were sensitive to serum removal, and an increase of lipid peroxidation and apoptosis was observed. Long-term treatment with ethidium bromide induced the mitochondria-deficient rho(o)HL-60 cell line. These cells were surprisingly more resistant to serum removal, displaying fewer apoptotic cells and lower lipid peroxidation. HL-60 cells contained less ubiquinone at the plasma membrane than rho(o)HL-60 cells. Both cell types increased plasma membrane ubiquinone in response to serum removal, although this increase was much higher in rho(o) cells. Addition of ubiquinone to both cell cultures in the absence of serum improved cell survival with decreasing lipid peroxidation and apoptosis. Ceramide was accumulated after serum removal in HL-60 but not in rho(o)HL-60 cells, and exogenous ubiquinone reduced this accumulation. These results demonstrate a relationship between ubiquinone levels in the plasma membrane and the induction of serum withdrawal-induced apoptosis, and ceramide accumulation. Thus, ubiquinone, which is a central component of the plasma membrane electron transport system, can represent a first level of protection against oxidative damage caused by serum withdrawal.

  4. 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.

  5. 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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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.

  9. Down-regulation of phosphoglucomutase 3 mediates sulforaphane-induced cell death in LNCaP prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Lee Hyo-Jeong

    2010-12-01

    Full Text Available Abstract Background Sulforaphane (SFN is an isothiocyanate found in cruciferous vegetables that exerts anti-oxidant, anti-inflammatory, anti-cancer and radio-sensitizing activities. Nonetheless, the mechanism responsible for SFN-induced cell death is not fully understood. In the present study, anti-cancer mechanism of SFN was elucidated in LNCaP prostate cancer cells. Results SFN exerted cytotoxicity and increased TUNEL positive cells in a concentration-dependent manner in LNCaP cells. Proteomics study revealed that levels of nine proteins including tubulin β-2, phosphoglucomutase-3 (PGM3, melanoma-derived leucine zipper containing extra-nuclear factor, activin A type I receptor precursor, smoothelin-A, KIA0073, hypothetical protein LOC57691 and two unnamed proteins were changed over 8 folds in SFN treated LNCaP cells compared to untreated control. We have further confirmed that SFN reduced PGM3 expression with western blotting and showed that PGM3 siRNA enhanced cytotoxicity demonstrated by cell morphology and TUNEL assays in LNCaP cells. Conclusion Taken together, these findings suggest that PGM3 plays a role in mediating SFN-induced cell death in LNCaP cells, and is a potential molecular therapeutic target for prostate cancer.

  10. 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...

  11. The disease resistance signaling components EDS1 and PAD4 are essential regulators of the cell death pathway controlled by LSD1 in Arabidopsis.

    Science.gov (United States)

    Rustérucci, C; Aviv, D H; Holt, B F; Dangl, J L; Parker, J E

    2001-10-01

    Specific recognition of pathogens is mediated by plant disease resistance (R) genes and translated into a successful defense response. The extent of associated hypersensitive cell death varies from none to an area encompassing cells surrounding an infection site, depending on the R gene activated. We constructed double mutants in Arabidopsis between positive regulators of R function and a negative regulator of cell death, LSD1, to address whether genes required for normal R function also regulate the runaway cell death observed in lsd1 mutants. We report here that EDS1 and PAD4, two signaling genes that mediate some but not all R responses, also are required for runaway cell death in the lsd1 mutant. Importantly, this novel function of EDS1 and PAD4 is operative when runaway cell death in lsd1 is initiated through an R gene that does not require EDS1 or PAD4 for disease resistance. NDR1, another component of R signaling, also contributes to the control of plant cell death. The roles of EDS1 and PAD4 in regulating lsd1 runaway cell death are related to the interpretation of reactive oxygen intermediate-derived signals at infection sites. We further demonstrate that the fate of superoxide at infection sites is different from that observed at the leading margins of runaway cell death lesions in lsd1 mutants.

  12. 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

  13. Fine-Tuned Expression of Programmed Death 1 Ligands in Mature Dendritic Cells Stimulated by CD40 Ligand is Critical for the Induction of an Efficient Tumor Specific Immune Response

    Institute of Scientific and Technical Information of China (English)

    Tao Gu; Yong Huang; Yuhua Qiu; Xueguang Zhang; Yibei Zhu; Cheng Chen; Min Li; Yongjing Chen; Gehua Yu; Yan Ge; Shiyong Zhou; Huan Zhou

    2008-01-01

    During maturation, murine myeloid dendritic cells(DCs)upregulated the expressions of CD11c, CD25, CD40, CD80, CD86.MHc II and programmed death 1 ligands 1 and 2(PD-L1 and PD-L2).Differential expression patterns of PD-L1 and PD. L2 were found when DCs were triggered by CD40 ligand and TNF-α.PD-L1 expression-was repressed and PD. L2 expression remained unchanged in mature CD40-ligated DCs, whereas TNF-αstimulted DCs kept high expression of PD. L1 and significantly enhanced PD-L2 expression on DCs. Proliferations of T lymphocytes stimulated by immature DCs were enhanced by blockade of the PD-1 and PD-1 ligand interaction. But inhibiitive effects were found in T lymphocytes stimulated by CD40-ligated DCs. With the tine-tuned expressions of the PD-L1 and PD-L2, CD40-ligated DCs could sustain a longer activation period and elicit a more efficient T lymphocyte activation. Cellular & Molecular Immunology. 2008;5(1):33-39.

  14. 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

  15. Involvement of ERK-Nrf-2 signaling in ionizing radiation induced cell death in normal and tumor cells.

    Directory of Open Access Journals (Sweden)

    Raghavendra S Patwardhan

    Full Text Available Prolonged oxidative stress favors tumorigenic environment and inflammation. Oxidative stress may trigger redox adaptation mechanism(s in tumor cells but not normal cells. This may increase levels of intracellular antioxidants and establish a new redox homeostasis. Nrf-2, a master regulator of battery of antioxidant genes is constitutively activated in many tumor cells. Here we show that, murine T cell lymphoma EL-4 cells show constitutive and inducible radioresistance via activation of Nrf-2/ERK pathway. EL-4 cells contained lower levels of ROS than their normal counterpart murine splenic lymphocytes. In response to radiation, the thiol redox circuits, GSH and thioredoxin were modified in EL-4 cells. Pharmacological inhibitors of ERK and Nrf-2 significantly enhanced radiosensitivity and reduced clonogenic potential of EL-4 cells. Unirradiated lymphoma cells showed nuclear accumulation of Nrf-2, upregulation of its dependent genes and protein levels. Interestingly, MEK inhibitor abrogated its nuclear translocation suggesting role of ERK in basal and radiation induced Nrf-2 activation in tumor cells. Double knockdown of ERK and Nrf-2 resulted in higher sensitivity to radiation induced cell death as compared to individual knockdown cells. Importantly, NF-kB which is reported to be constitutively active in many tumors was not present at basal levels in EL-4 cells and its inhibition did not influence radiosensitivity of EL-4 cells. Thus our results reveal that, tumor cells which are subjected to heightened oxidative stress employ master regulator cellular redox homeostasis Nrf-2 for prevention of radiation induced cell death. Our study reveals the molecular basis of tumor radioresistance and highlights role of Nrf-2 and ERK.

  16. Cytoplasmic p21 induced by p65 prevents doxorubicin-induced cell death in pancreatic carcinoma cell line

    Directory of Open Access Journals (Sweden)

    Zhou YingQi

    2012-02-01

    Full Text Available Abstract Background Studies have shown the existence of p21 induction in a p53-dependent and -independent pathway. Our previous study indicates that DOX-induced p65 is able to bind the p21 promoter to activate its transactivation in the cells. Methods Over-expression and knock-down experiments were performed in Human Pancreatic Carcinoma (PANC1 cells. Cell cycle and cell death related proteins were assessed by Western Blotting. Cytotoxicity assay was checked by CCK-8 kit. Cell growth was analyzed by flow cytometers. Results Here we showed that over-expression of p65 decreased the cytotoxic effect of DOX on PANC1 cells, correlating with increased induction of cytoplasmic p21. We observed that pro-caspase-3 physically associated with cytoplasmic p21, which may be contribution to prevent p21 translocation into the nucleus. Our data also suggested that no clear elevation of nuclear p21 by p65 provides a survival advantage by progression cell cycle after treatment of DOX. Likewise, down-regulation of p65 expression enhanced the cytotoxic effect of DOX, due to a significant decrease of mRNA levels of anti-apoptotic genes, such as the cellular inhibitor of apoptosis-1 (c-IAP1, and the long isoform of B cell leukemia/lymphoma-2 (Bcl-2, leading to efficient induction of caspase-3 cleavage in the cells. More, we present evidence that over-expression of p53 or p53/p65 in the PANC1 cells were more sensitive to DOX treatment, correlated with activation of caspase-3 and clear elevation of nuclear p21 level. Our previous data suggested that expression of p21 increases Gefitinib-induced cell death by blocking the cell cycle at the G1 and G2 phases. The present findings here reinforced this idea by showing p21's ability of potentiality of DOX-induced cell death correlated with its inhibition of cell cycle progression after over-expression of p53 or p53/p65. Conclusion Our data suggested p65 could increase p53-mediated cell death in response to DOX in PANC1 cells

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Involvement of Arabidopsis Hexokinase1 in Cell Death Mediated by Myo -Inositol Accumulation

    KAUST Repository

    Bruggeman, Quentin

    2015-06-05

    Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. We recently identified the mips1 mutant of Arabidopsis thaliana, which is deficient for the enzyme catalyzing the limiting step of myo-inositol (MI) synthesis. One of the most striking features of mips1 is the light-dependent formation of lesions on leaves due to salicylic acid (SA)-dependent PCD. Here, we identified a suppressor of PCD by screening for mutations that abolish the mips1 cell death phenotype. Our screen identified the hxk1 mutant, mutated in the gene encoding the hexokinase1 (HXK1) enzyme that catalyzes sugar phosphorylation and acts as a genuine glucose sensor. We show that HXK1 is required for lesion formation in mips1 due to alterations in MI content, via SA-dependant signaling. Using two catalytically inactive HXK1 mutants, we also show that hexokinase catalytic activity is necessary for the establishment of lesions in mips1. Gas chromatography-mass spectrometry analyses revealed a restoration of the MI content in mips1 hxk1 that it is due to the activity of the MIPS2 isoform, while MIPS3 is not involved. Our work defines a pathway of HXK1-mediated cell death in plants and demonstrates that two MIPS enzymes act cooperatively under a particular metabolic status, highlighting a novel checkpoint of MI homeostasis in plants. © 2015 American Society of Plant Biologists. All rights reserved.

  4. Oxidative Stress Impairs Cell Death by Repressing the Nuclease Activity of Mitochondrial Endonuclease G

    Directory of Open Access Journals (Sweden)

    Jason L.J. Lin

    2016-07-01

    Full Text Available Endonuclease G (EndoG is a mitochondrial protein that is released from mitochondria and relocated into the nucleus to promote chromosomal DNA fragmentation during apoptosis. Here, we show that oxidative stress causes cell-death defects in C. elegans through an EndoG-mediated cell-death pathway. In response to high reactive oxygen species (ROS levels, homodimeric CPS-6—the C. elegans homolog of EndoG—is dissociated into monomers with diminished nuclease activity. Conversely, the nuclease activity of CPS-6 is enhanced, and its dimeric structure is stabilized by its interaction with the worm AIF homolog, WAH-1, which shifts to disulfide cross-linked dimers under high ROS levels. CPS-6 thus acts as a ROS sensor to regulate the life and death of cells. Modulation of the EndoG dimer conformation could present an avenue for prevention and treatment of diseases resulting from oxidative stress.

  5. 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.

  6. 3-Bromopyruvate induces rapid human prostate cancer cell death by affecting cell energy metabolism, GSH pool and the glyoxalase system.

    Science.gov (United States)

    Valenti, Daniela; Vacca, Rosa A; de Bari, Lidia

    2015-12-01

    3-bromopyruvate (3-BP) is an anti-tumour drug effective on hepatocellular carcinoma and other tumour cell types, which affects both glycolytic and mitochondrial targets, depleting cellular ATP pool. Here we tested 3-BP on human prostate cancer cells showing, differently from other tumour types, efficient ATP production and functional mitochondrial metabolism. We found that 3-BP rapidly induced cultured androgen-insensitive (PC-3) and androgen-responsive (LNCaP) prostate cancer cell death at low concentrations (IC(50) values of 50 and 70 μM, respectively) with a multimodal mechanism of action. In particular, 3-BP-treated PC-3 cells showed a selective, strong reduction of glyceraldeide 3-phosphate dehydrogenase activity, due to the direct interaction of the drug with the enzyme. Moreover, 3-BP strongly impaired both glutamate/malate- and succinate-dependent mitochondrial respiration, membrane potential generation and ATP synthesis, concomitant with the inhibition of respiratory chain complex I, II and ATP synthase activities. The drastic reduction of cellular ATP levels and depletion of GSH pool, associated with significant increase in cell oxidative stress, were found after 3-BP treatment of PC-3 cells. Interestingly, the activity of both glyoxalase I and II, devoted to the elimination of the cytotoxic methylglyoxal, was strongly inhibited by 3-BP. Both N-acetylcysteine and aminoguanidine, GSH precursor and methylglyoxal scavenger, respectively, prevented 3-BP-induced PC-3 cell death, showing that impaired cell antioxidant and detoxifying capacities are crucial events leading to cell death. The provided information on the multi-target cytotoxic action of 3-BP, finally leading to PC-3 cell necrosis, might be useful for future development of 3-BP as a therapeutic option for prostate cancer treatment.

  7. Oxidative stress activates the TRPM2-Ca(2+)-CaMKII-ROS signaling loop to induce cell death in cancer cells.

    Science.gov (United States)

    Wang, Qian; Huang, Lihong; Yue, Jianbo

    2016-12-20

    High intracellular levels of reactive oxygen species (ROS) cause oxidative stress that results in numerous pathologies, including cell death. Transient potential receptor melastatin-2 (TRPM2), a Ca(2+)-permeable cation channel, is mainly activated by intracellular adenosine diphosphate ribose (ADPR) in response to oxidative stress. Here we studied the role and mechanisms of TRPM2-mediated Ca(2+) influx on oxidative stress-induced cell death in cancer cells. We found that oxidative stress activated the TRPM2-Ca(2+)-CaMKII cascade to inhibit early autophagy induction, which ultimately led to cell death in TRPM2 expressing cancer cells. On the other hand, TRPM2 knockdown switched cells from cell death to autophagy for survival in response to oxidative stress. Moreover, we found that oxidative stress activated the TRPM2-CaMKII cascade to further induce intracellular ROS production, which led to mitochondria fragmentation and loss of mitochondrial membrane potential. In summary, our data demonstrated that oxidative stress activates the TRPM2-Ca(2+)-CaMKII-ROS signal loop to inhibit autophagy and induce cell death.

  8. 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

  9. Role of BH3-only molecules Bim and Puma in β-cell death in Pdx1 deficiency.

    Science.gov (United States)

    Ren, Decheng; Sun, Juan; Wang, Changzheng; Ye, Honggang; Mao, Liqun; Cheng, Emily H; Bell, Graeme I; Polonsky, Kenneth S

    2014-08-01

    Mutations in pancreatic duodenal homeobox-1 (PDX1) are associated with diabetes in humans. Pdx1-haploinsufficient mice develop diabetes due to an increase in β-cell death leading to reduced β-cell mass. For definition of the molecular link between Pdx1 deficiency and β-cell death, Pdx1-haploinsufficient mice in which the genes for the BH3-only molecules Bim and Puma had been ablated were studied on a high-fat diet. Compared with Pdx1(+/-) mice, animals haploinsufficient for both Pdx1 and Bim or Puma genes showed improved glucose tolerance, enhanced β-cell mass, and reduction in the number of TUNEL-positive cells in islets. These results suggest that Bim and Puma ablation improves β-cell survival in Pdx1(+/-) mice. For exploration of the mechanisms responsible for these findings, Pdx1 gene expression was knocked down in mouse MIN6 insulinoma cells resulting in apoptotic cell death that was found to be associated with increased expression of BH3-only molecules Bim and Puma. If the upregulation of Bim and Puma that occurs during Pdx1 suppression was prevented, apoptotic β-cell death was reduced in vitro. These results suggest that Bim and Puma play an important role in β-cell apoptosis in Pdx1-deficient diabetes.

  10. Vav-1 expression correlates with NFkappaB activation and CD40-mediated cell death in diffuse large B-cell lymphoma cell lines

    DEFF Research Database (Denmark)

    Hollmann, Annette; Aloyz, Raquel; Baker, Kristi;

    2010-01-01

    Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy with a variable response to therapy. We have previously shown that DLBCL cell lines differ in their susceptibility to CD40-mediated cell death, and that resistance to CD40-targeted antibodies correlated with increased expression...... of markers of immature B-cell and absence of Vav-1 mRNA. We used gene expression profiling to investigate the mechanism of CD40 resistance in these cell lines, and found that resistance correlated with lack of Vav-1 and inability to activate NFkappaB upon CD40 ligation. Analysis of tissue microarrays of 213...

  11. p53 Activation following Rift Valley fever virus infection contributes to cell death and viral production.

    Directory of Open Access Journals (Sweden)

    Dana Austin

    Full Text Available Rift Valley fever virus (RVFV is an emerging viral zoonosis that is responsible for devastating outbreaks among livestock and is capable of causing potentially fatal disease in humans. Studies have shown that upon infection, certain viruses have the capability of utilizing particular cellular signaling pathways to propagate viral infection. Activation of p53 is important for the DNA damage signaling cascade, initiation of apoptosis, cell cycle arrest and transcriptional regulation of multiple genes. The current study focuses on the role of p53 signaling in RVFV infection and viral replication. These results show an up-regulation of p53 phosphorylation at several serine sites after RVFV MP-12 infection that is highly dependent on the viral protein NSs. qRT-PCR data showed a transcriptional up-regulation of several p53 targeted genes involved in cell cycle and apoptos