Bcl-2 Blocks a Caspase-Dependent Pathway of Apoptosis Activated by Herpes Simplex Virus 1 Infection in HEp-2 Cells

PubMed Central

Galvan, Veronica; Brandimarti, Renato; Munger, Joshua; Roizman, Bernard

2000-01-01

Earlier reports have shown that herpes simplex virus 1 (HSV-1) mutants induce programmed cell death and that wild-type virus blocks the execution of the cell death program triggered by expression of viral genes, by the Fas and tumor necrosis factor pathways, or by nonspecific stress agents. In particular, an earlier report from this laboratory showed that the mutant virus d120 lacking the genes encoding infected cell protein 4 (ICP4), the major regulatory protein of the virus, induces a caspase-3-independent pathway of apoptosis in human SK-N-SH cells. Here we report that the pathway of apoptosis induced by the d120 mutant in human HEp-2 cells is caspase dependent. Specifically, in HEp-2 cells infected with d120, (i) a broad-range inhibitor of caspase activity, z-vad-FMK, efficiently blocked DNA fragmentation, (ii) cytochrome c was released into the cytoplasm, (iii) caspase-3 was activated inasmuch as poly(ADP-ribose) polymerase was cleaved, and (iv) chromatin condensation and fragmentation of cellular DNA were observed. In parallel studies, HEp-2 cells were transfected with a plasmid encoding human Bcl-2 and a clone (VAX-3) expressing high levels of Bcl-2 was selected. This report shows that Bcl-2 blocked all of the manifestations associated with programmed cell death caused by infection with the d120 mutant. Consistent with their resistance to programmed cell death, VAX-3 cells overproduced infected cell protein 0 (ICP0). An unexpected observation was that ICP0 encoded by the d120 mutant accumulated late in infection in small, quasi-uniform vesicle-like structures in all cell lines tested. Immunofluorescence-based colocalization studies indicated that these structures were not mitochondria or components of the endoplasmic reticulum or the late endosomal compartment. These studies affirm the conclusion that HSV can induce programmed cell death at multiple steps in the course of its replication, that the d120 mutant can induce both caspase-dependent and -independent pathways of programmed cell death, and that virus-induced stimuli of programmed cell death may differ with respect to the pathway that they activate. PMID:10644366

Scorched earth strategy

PubMed Central

Wrzaczek, Michael; Brosché, Mikael

2009-01-01

Programmed cell death is a common feature of developmental processes and responses to environmental cues in many multicellular organisms. Examples of programmed cell death in plants are leaf abscission in autumn and the hypersensitive response during pathogen attack. Reactive oxygen species (ROS) have been implicated in the regulation of various types of cell death.1,2 However, the precise mechanics of the involvement of ROS in the processes leading to initiation of cell death and subsequent containment are currently unknown. We recently showed the involvement of an Arabidopsis protein GRIM REAPER in the regulation of ROS-induced cell death under stress conditions.3 Our results indicated that the presence of a truncated protein primes plants for cell death in the presence of ROS leading to ozone sensitivity and increased resistance to hemibiotrophic pathogens. PMID:19820355

High stability of nuclear microsatellite loci during the early stages of somatic embryogenesis in Norway spruce.

PubMed

Helmersson, Andreas; von Arnold, Sara; Burg, Kornel; Bozhkov, Peter V

2004-10-01

Somatic embryos of Norway spruce (Picea abies (L.) Karst.) differentiate from proembryogenic masses (PEMs), which are subject to autodestruction through programmed cell death. In PEMs, somatic embryo formation and activation of programmed cell death are interrelated processes. We sought to determine if activation of programmed cell death in PEMs is caused by genetic aberrations during somatic embryogenesis. Based on the finding that withdrawal of auxin and cytokinin induces programmed cell death in PEMs, 1-week-old cell suspensions were cultured in medium either with or without auxin and cytokinin and then transferred to maturation medium containing abscisic acid. We analyzed the stability of three nuclear simple sequence repeat (SSR) microsatellite markers at successive stages of somatic embryogenesis in two cell lines. There were no mutations at the SSR loci at any of the successive developmental stages from PEMs to cotyledonary embryos, irrespective of whether or not the proliferation medium in which cell suspensions had been cultured contained auxin or cytokinin. The morphologies of plants regenerated from the cultures were similar, although withdrawal of auxin and cytokinin significantly stimulated the yield of both embryos and plants. We conclude, therefore, that the high genetic stability of somatic embryos in Norway spruce is unaffected by the induction of programmed cell death caused by withdrawal of auxin and cytokinin.

Death penalty for keratinocytes: apoptosis versus cornification.

PubMed

Lippens, S; Denecker, G; Ovaere, P; Vandenabeele, P; Declercq, W

2005-11-01

Homeostasis implies a balance between cell growth and cell death. This balance is essential for the development and maintenance of multicellular organisms. Homeostasis is controlled by several mechanisms including apoptosis, a process by which cells condemned to death are completely eliminated. However, in some cases, total destruction and removal of dead cells is not desirable, as when they fulfil a specific function such as formation of the skin barrier provided by corneocytes, also known as terminally differentiated keratinocytes. In this case, programmed cell death results in accumulation of functional cell corpses. Previously, this process has been associated with apoptotic cell death. In this overview, we discuss differences and similarities in the molecular regulation of epidermal programmed cell death and apoptosis. We conclude that despite earlier confusion, apoptosis and cornification occur through distinct molecular pathways, and that possibly antiapoptotic mechanisms are implicated in the terminal differentiation of keratinocytes.

Live to die another way: modes of programmed cell death and the signals emanating from dying cells

PubMed Central

Fuchs, Yaron; Steller, Hermann

2015-01-01

Preface All life ends in death, but perhaps one of life’s grander ironies is that it also depends on death. Cell-intrinsic suicide pathways, termed programmed cell death (PCD), are crucial for animal development, tissue homeostasis and pathogenesis. Originally, PCD was virtually synonymous with apoptosis, but recently, alternative PCD mechanisms have been reported. Here, we provide an overview of several distinct PCD mechanisms, namely apoptosis, autophagy and necroptosis. In addition, we discuss the complex signals emanating from dying cells, which can either fuel regeneration or instruct additional killing. Further advances in understanding the physiological role of multiple cell death mechanisms and associated signals will be important to selectively manipulate PCD for therapeutic purposes. PMID:25991373

Calcium regulates cell death in cancer: Roles of the mitochondria and mitochondria-associated membranes (MAMs).

PubMed

Danese, Alberto; Patergnani, Simone; Bonora, Massimo; Wieckowski, Mariusz R; Previati, Maurizio; Giorgi, Carlotta; Pinton, Paolo

2017-08-01

Until 1972, the term 'apoptosis' was used to differentiate the programmed cell death that naturally occurs in organismal development from the acute tissue death referred to as necrosis. Many studies on cell death and programmed cell death have been published and most are, at least to some degree, related to cancer. Some key proteins and molecular pathways implicated in cell death have been analyzed, whereas others are still being actively researched; therefore, an increasing number of cellular compartments and organelles are being implicated in cell death and cancer. Here, we discuss the mitochondria and subdomains of the endoplasmic reticulum (ER) that interact with mitochondria, the mitochondria-associated membranes (MAMs), which have been identified as critical hubs in the regulation of cell death and tumor growth. MAMs-dependent calcium (Ca 2+ ) release from the ER allows selective Ca 2+ uptake by the mitochondria. The perturbation of Ca 2+ homeostasis in cancer cells is correlated with sustained cell proliferation and the inhibition of cell death through the modulation of Ca 2+ signaling. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux. Copyright © 2017 Elsevier B.V. All rights reserved.

Senescence, apoptosis or autophagy? When a damaged cell must decide its path--a mini-review.

PubMed

Vicencio, José Miguel; Galluzzi, Lorenzo; Tajeddine, Nicolas; Ortiz, Carla; Criollo, Alfredo; Tasdemir, Ezgi; Morselli, Eugenia; Ben Younes, Amena; Maiuri, Maria Chiara; Lavandero, Sergio; Kroemer, Guido

2008-01-01

Many features of aging result from the incapacity of cells to adapt to stress conditions. When damage accumulates irreversibly, mitotic cells from renewable tissues rely on either of two mechanisms to avoid replication. They can permanently arrest the cell cycle (cellular senescence) or trigger cell death programs. Apoptosis (self-killing) is the best-described form of programmed cell death, but autophagy (self-eating), which is a lysosomal degradation pathway essential for homeostasis, reportedly contributes to cell death as well. Unlike mitotic cells, postmitotic cells like neurons or cardiomyocytes cannot become senescent since they are already terminally differentiated. The fate of these cells entirely depends on their ability to cope with stress. Autophagy then operates as a major homeostatic mechanism to eliminate damaged organelles, long-lived or aberrant proteins and superfluous portions of the cytoplasm. In this mini-review, we briefly summarize the molecular networks that allow damaged cells either to adapt to stress or to engage in programmed-cell-death pathways. (c) 2008 S. Karger AG, Basel.

Omega-3 docosahexaenoic acid induces pyroptosis cell death in triple-negative breast cancer cells.

PubMed

Pizato, Nathalia; Luzete, Beatriz Christina; Kiffer, Larissa Fernanda Melo Vasconcelos; Corrêa, Luís Henrique; de Oliveira Santos, Igor; Assumpção, José Antônio Fagundes; Ito, Marina Kiyomi; Magalhães, Kelly Grace

2018-01-31

The implication of inflammation in pathophysiology of several type of cancers has been under intense investigation. Omega-3 fatty acids can modulate inflammation and present anticancer effects, promoting cancer cell death. Pyroptosis is an inflammation related cell death and so far, the function of docosahexaenoic acid (DHA) in pyroptosis cell death has not been described. This study investigated the role of DHA in triggering pyroptosis activation in breast cancer cells. MDA-MB-231 breast cancer cells were supplemented with DHA and inflammation cell death was analyzed. DHA-treated breast cancer cells triggered increased caspase-1and gasdermin D activation, enhanced IL-1β secretion, translocated HMGB1 towards the cytoplasm, and membrane pore formation when compared to untreated cells, suggesting DHA induces pyroptosis programmed cell death in breast cancer cells. Moreover, caspase-1 inhibitor (YVAD) could protect breast cancer cells from DHA-induced pyroptotic cell death. In addition, membrane pore formation showed to be a lysosomal damage and ROS formation-depended event in breast cancer cells. DHA triggered pyroptosis cell death in MDA-MB-231by activating several pyroptosis markers in these cells. This is the first study that shows the effect of DHA triggering pyroptosis programmed cell death in breast cancer cells and it could improve the understanding of the omega-3 supplementation during breast cancer treatment.

Mouse embryonic stem cells undergo Charontosis, a novel programmed cell death pathway dependent upon cathepsins, p53, and EndoG, in response to etoposide treatment

PubMed Central

Tichy, Elisia D.; Stephan, Zachary A.; Osterburg, Andrew; Noel, Greg; Stambrook, Peter J.

2013-01-01

Embryonic stem cells (ESCs) are hypersensitive to many DNA damaging agents and can rapidly undergo cell death or cell differentiation following exposure. Treatment of mouse ESCs (mESCs) with etoposide (ETO), a topoisomerase II poison, followed by a recovery period resulted in massive cell death with characteristics of a programmed cell death pathway (PCD). While cell death was both caspase- and necroptosis-independent, it was partially dependent on the activity of lysosomal proteases. A role for autophagy in the cell death process was eliminated, suggesting that ETO induces a novel PCD pathway in mESCs. Inhibition of p53 either as a transcription factor by pifithrin α or in its mitochondrial role by pifithrin μ significantly reduced ESC death levels. Finally, EndoG was newly identified as a protease participating in the DNA fragmentation observed during ETO-induced PCD. We coined the term Charontosis after Charon, the ferryman of the dead in Greek mythology, to refer to the PCD signaling events induced by ETO in mESCs. PMID:23500643

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waters, Katrina M.; Sontag, Ryan L.; Weber, Thomas J., E-mail: Thomas.Weber@pnl.gov

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 programmore » 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.« less

Programmed cell death of tobacco BY-2 cells induced by still culture conditions is affected by the age of the culture under agitation.

PubMed

Hiraga, Asahi; Kaneta, Tsuyoshi; Sato, Yasushi; Sato, Seiichi

2010-01-25

Evans Blue staining indicated that actively growing tobacco BY-2 cells in the exponential phase died more rapidly than quiescent cells in the stationary phase when the cells cultured under agitation were placed under still conditions. Fifty percent cell death was induced at about 18, 26, 80 and 140 h for early, mid, late exponential- and stationary-phase cells, respectively. Actively growing cells became TUNEL (transferase-mediated dUTP nick end labelling)-positive more rapidly than quiescent cells, suggesting that the cell death evaluated by Evans Blue is accompanied by DNA cleavages. Electrophoresis of genomic DNA showed a typical 'DNA laddering' pattern formed by multiples of about 200 bp internucleosomal units. Chromatin condensation was first detected at least within 24 h by light microscopy, and then cell shrinkage followed. These findings suggest that the death of BY-2 cells induced by still conditions is PCD (programmed cell death).

Necroptosis: an alternative cell death program defending against cancer

PubMed Central

Chen, Dongshi; Yu, Jian; Zhang, Lin

2016-01-01

One of the hallmarks of cancer is resistance to programmed cell death, which maintains the survival of cells en route to oncogenic transformation and underlies therapeutic resistance. Recent studies demonstrate that programmed cell death is not confined to caspase-dependent apoptosis, but includes necroptosis, a form of necrotic death governed by Receptor-Interacting Protein 1 (RIP1), RIP3, and Mixed Lineage Kinase Domain-Like (MLKL). Necroptosis serves as a critical cell-killing mechanism in response to severe stress and blocked apoptosis, and can be induced by inflammatory cytokines or chemotherapeutic drugs. Genetic or epigenetic alterations of necroptosis regulators such as RIP3 and cylindromatosis (CYLD), are frequently found in human tumors. Unlike apoptosis, necroptosis elicits a more robust immune response that may function as a defensive mechanism by eliminating tumor-causing mutations and viruses. Furthermore, several classes of anticancer agents currently under clinical development, such as SMAC and BH3 mimetics, can promote necroptosis in addition to apoptosis. A more complete understanding of the interplay among necroptosis, apoptosis, and other cell death modalities is critical for developing new therapeutic strategies to enhance killing of tumor cells. PMID:26968619

Cancer’s Achilles’ Heel: Apoptosis and Necroptosis to the Rescue

PubMed Central

Dasgupta, Atreyi; Nomura, Motonari; Shuck, Ryan; Yustein, Jason

2016-01-01

Apoptosis, and the more recently discovered necroptosis, are two avenues of programmed cell death. Cancer cells survive by evading these two programs, driven by oncogenes and tumor suppressor genes. While traditional therapy using small molecular inhibitors and chemotherapy are continuously being utilized, a new and exciting approach is actively underway by identifying and using synergistic relationship between driver and rescue genes in a cancer cell. Through these synthetic lethal relationships, we are gaining tremendous insights into tumor vulnerabilities and specific molecular avenues for induction of programmed cell death. In this review, we briefly discuss the two cell death processes and cite examples of such synergistic manipulations for therapeutic purposes. PMID:28025559

Anti-CHMP5 single chain variable fragment antibody retrovirus infection induces programmed cell death of AML leukemic cells in vitro.

PubMed

Wang, Hai-rong; Xiao, Zhen-yu; Chen, Miao; Wang, Fei-long; Liu, Jia; Zhong, Hua; Zhong, Ji-hua; Ou-Yang, Ren-rong; Shen, Yan-lin; Pan, Shu-ming

2012-06-01

Over-expressed CHMP5 was found to act as oncogene that probably participated in leukemogenesis. In this study, we constructed the CHMP5 single chain variable fragment antibody (CHMP5-scFv) retrovirus and studied the changes of programmed cell death (PCD) of AML leukemic cells after infection by the retrovirus. The anti-CHMP5 KC14 hybridoma cell line was constructed to generate monoclonal antibody of CHMP5. The protein expression of CHMP5 was studied using immunofluorescence analysis. pMIG-CHMP5 scFv antibody expressible retroviral vector was constructed to prepare CHMP5-scFv retrovirus. AML leukemic U937 cells were infected with the retrovirus, and programmed cell death was studied using confocal microscope, FCM and Western blot. We obtained a monoclonal antibody of CHMP5, and found the expression of CHMP5 was up-regulated in the leukemic cells. After U937 cells were infected with CHMP5-scFv retrovirus, CHMP5 protein was neutralized. Moreover, the infection resulted in a significant increase in apoptosis and necrosis of U937 cells. In U937 cells infected with CHMP5-scFv retrovirus, apoptosis-inducing factor (AIF)-mediated caspase-independent necrotic PCD was activated, but autophagic programmed cell death was not observed. Neither the intrinsic nor extrinsic apoptotic PCD pathway was activated. The granzyme B/perforin-mediated caspase-dependent apoptotic PCD pathway was not activated. CHMP5-scFv retrovirus can neutralize the abnormally high levels of the CHMP5 protein in the cytosol of AML leukemic U937 cells, thereby inducing the programmed cell death of the leukemic cells via AIF-mediated caspase-independent necrosis and apoptosis.

THE ROLE OF APOPTOSIS IN NEUROTOXICOLOGY

EPA Science Inventory

Apoptosis, a form of programmed cell death, occurs in the nervous system throughout development, but with a preponderance of cell death occurring during the prenatal and perinatal periods. Aberrant periods of increased or decreased cell death, induced by toxicants in air, water,...

'Hints' in the killer protein gasdermin D: unveiling the secrets of gasdermins driving cell death.

PubMed

Qiu, Shiqiao; Liu, Jing; Xing, Feiyue

2017-04-01

Pyroptosis is a lytic form of cell death distinguished from apoptosis, ferroptosis, necrosis, necroptosis, NETosis, oncosis, pyronecrosis and autophagy. Proinflammatory caspases cleave a gasdermin D (GSDMD) protein to generate a 31 kDa N-terminal domain. The cleavage relieves the intramolecular inhibition on the gasdermin-N domain, which then moves to the plasma membrane to exhibit pore-forming activity. Thus, GSDMD acts as the final and direct executor of pyroptotic cell death. Owing to the selective targeting of the inner leaflet of the plasma membrane with the pore-forming that determines pyroptotic cell death, GSDMD could be a potential target to control cell death or extracellular bacterial infections. Intriguingly, other gasdermin family members also share similar N-terminal domains, but they present different cell death programs. Herein, we summarize features and functions of the novel player proteins in cell death, including GSDMD triggering pyroptosis, Gsdma3/GSDMA initiating autophagy/apoptosis and DFNA5 inducing apoptosis/secondary necrosis. The gasdermin N terminus appears to be a novel pore-forming protein. This provides novel insight into the underlying roles and mechanisms of lytic or nonlytic forms of programmed cell death, as well as their potential applications in inflammation-associated diseases.

NEMO Inhibits Programmed Necrosis in an NFκB-Independent Manner by Restraining RIP1

PubMed Central

Legarda, Diana; Ting, Adrian T.

2012-01-01

TNF can trigger two opposing responses: cell survival and cell death. TNFR1 activates caspases that orchestrate apoptosis but some cell types switch to a necrotic death when treated with caspase inhibitors. Several genes that are required to orchestrate cell death by programmed necrosis have been identified, such as the kinase RIP1, but very little is known about the inhibitory signals that keep this necrotic cell death pathway in check. We demonstrate that T cells lacking the regulatory subunit of IKK, NFκB essential modifier (NEMO), are hypersensitive to programmed necrosis when stimulated with TNF in the presence of caspase inhibitors. Surprisingly, this pro-survival activity of NEMO is independent of NFκB-mediated gene transcription. Instead, NEMO inhibits necrosis by binding to ubiquitinated RIP1 to restrain RIP1 from engaging the necrotic death pathway. In the absence of NEMO, or if ubiquitination of RIP1 is blocked, necrosis ensues when caspases are blocked. These results indicate that recruitment of NEMO to ubiquitinated RIP1 is a key step in the TNFR1 signaling pathway that determines whether RIP1 triggers a necrotic death response. PMID:22848449

Mouse embryonic stem cells undergo charontosis, a novel programmed cell death pathway dependent upon cathepsins, p53, and EndoG, in response to etoposide treatment.

PubMed

Tichy, Elisia D; Stephan, Zachary A; Osterburg, Andrew; Noel, Greg; Stambrook, Peter J

2013-05-01

Embryonic stem cells (ESCs) are hypersensitive to many DNA damaging agents and can rapidly undergo cell death or cell differentiation following exposure. Treatment of mouse ESCs (mESCs) with etoposide (ETO), a topoisomerase II poison, followed by a recovery period resulted in massive cell death with characteristics of a programmed cell death pathway (PCD). While cell death was both caspase- and necroptosis-independent, it was partially dependent on the activity of lysosomal proteases. A role for autophagy in the cell death process was eliminated, suggesting that ETO induces a novel PCD pathway in mESCs. Inhibition of p53 either as a transcription factor by pifithrin α or in its mitochondrial role by pifithrin μ significantly reduced ESC death levels. Finally, EndoG was newly identified as a protease participating in the DNA fragmentation observed during ETO-induced PCD. We coined the term charontosis after Charon, the ferryman of the dead in Greek mythology, to refer to the PCD signaling events induced by ETO in mESCs. Copyright © 2013 Elsevier B.V. All rights reserved.

Regulatory role of calpain in neuronal death

PubMed Central

Cheng, Si-ying; Wang, Shu-chao; Lei, Ming; Wang, Zhen; Xiong, Kun

2018-01-01

Calpains are a group of calcium-dependent proteases that are over activated by increased intracellular calcium levels under pathological conditions. A wide range of substrates that regulate necrotic, apoptotic and autophagic pathways are affected by calpain. Calpain plays a very important role in neuronal death and various neurological disorders. This review introduces recent research progress related to the regulatory mechanisms of calpain in neuronal death. Various neuronal programmed death pathways including apoptosis, autophagy and regulated necrosis can be divided into receptor interacting protein-dependent necroptosis, mitochondrial permeability transition-dependent necrosis, pyroptosis and poly (ADP-ribose) polymerase 1-mediated parthanatos. Calpains cleave series of key substrates that may lead to cell death or participate in cell death. Regarding the investigation of calpain-mediated programed cell death, it is necessary to identify specific inhibitors that inhibit calpain mediated neuronal death and nervous system diseases. PMID:29623944

Necroptosis: an emerging type of cell death in liver diseases.

PubMed

Saeed, Waqar Khalid; Jun, Dae Won

2014-09-21

Cell death has been extensively evaluated for decades and it is well recognized that pharmacological interventions directed to inhibit cell death can prevent significant cell loss and can thus improve an organ's physiological function. For long, only apoptosis was considered as a sole form of programmed cell death. Recently necroptosis, a RIP1/RIP3-dependent programmed cell death, has been identified as an apoptotic backup cell death mechanism with necrotic morphology. The evidences of necroptosis and protective effects achieved by blocking necroptosis have been extensively reported in recent past. However, only a few studies reported the evidence of necroptosis and protective effects achieved by inhibiting necroptosis in liver related disease conditions. Although the number of necroptosis initiators is increasing; however, interestingly, it is still unclear that what actually triggers necroptosis in different liver diseases or if there is always a different necroptosis initiator in each specific disease condition followed by specific downstream signaling molecules. Understanding the precise mechanism of necroptosis as well as counteracting other cell death pathways in liver diseases could provide a useful insight towards achieving extensive therapeutic significance. By targeting necroptosis and/or other parallel death pathways, a significant cell loss and thus a decrement in an organ's physiological function can be prevented.

Apoptosis-Like Death in Bacteria Induced by HAMLET, a Human Milk Lipid-Protein Complex

PubMed Central

Hakansson, Anders P.; Roche-Hakansson, Hazeline; Mossberg, Ann-Kristin; Svanborg, Catharina

2011-01-01

Background Apoptosis is the primary means for eliminating unwanted cells in multicellular organisms in order to preserve tissue homeostasis and function. It is characterized by distinct changes in the morphology of the dying cell that are orchestrated by a series of discrete biochemical events. Although there is evidence of primitive forms of programmed cell death also in prokaryotes, no information is available to suggest that prokaryotic death displays mechanistic similarities to the highly regulated programmed death of eukaryotic cells. In this study we compared the characteristics of tumor and bacterial cell death induced by HAMLET, a human milk complex of alpha-lactalbumin and oleic acid. Methodology/Principal Findings We show that HAMLET-treated bacteria undergo cell death with mechanistic and morphologic similarities to apoptotic death of tumor cells. In Jurkat cells and Streptococcus pneumoniae death was accompanied by apoptosis-like morphology such as cell shrinkage, DNA condensation, and DNA degradation into high molecular weight fragments of similar sizes, detected by field inverse gel electrophoresis. HAMLET was internalized into tumor cells and associated with mitochondria, causing a rapid depolarization of the mitochondrial membrane and bound to and induced depolarization of the pneumococcal membrane with similar kinetic and magnitude as in mitochondria. Membrane depolarization in both systems required calcium transport, and both tumor cells and bacteria were found to require serine protease activity (but not caspase activity) to execute cell death. Conclusions/Significance Our results suggest that many of the morphological changes and biochemical responses associated with apoptosis are present in prokaryotes. Identifying the mechanisms of bacterial cell death has the potential to reveal novel targets for future antimicrobial therapy and to further our understanding of core activation mechanisms of cell death in eukaryote cells. PMID:21423701

Apoptosis-like death in bacteria induced by HAMLET, a human milk lipid-protein complex.

PubMed

Hakansson, Anders P; Roche-Hakansson, Hazeline; Mossberg, Ann-Kristin; Svanborg, Catharina

2011-03-10

Apoptosis is the primary means for eliminating unwanted cells in multicellular organisms in order to preserve tissue homeostasis and function. It is characterized by distinct changes in the morphology of the dying cell that are orchestrated by a series of discrete biochemical events. Although there is evidence of primitive forms of programmed cell death also in prokaryotes, no information is available to suggest that prokaryotic death displays mechanistic similarities to the highly regulated programmed death of eukaryotic cells. In this study we compared the characteristics of tumor and bacterial cell death induced by HAMLET, a human milk complex of alpha-lactalbumin and oleic acid. We show that HAMLET-treated bacteria undergo cell death with mechanistic and morphologic similarities to apoptotic death of tumor cells. In Jurkat cells and Streptococcus pneumoniae death was accompanied by apoptosis-like morphology such as cell shrinkage, DNA condensation, and DNA degradation into high molecular weight fragments of similar sizes, detected by field inverse gel electrophoresis. HAMLET was internalized into tumor cells and associated with mitochondria, causing a rapid depolarization of the mitochondrial membrane and bound to and induced depolarization of the pneumococcal membrane with similar kinetic and magnitude as in mitochondria. Membrane depolarization in both systems required calcium transport, and both tumor cells and bacteria were found to require serine protease activity (but not caspase activity) to execute cell death. Our results suggest that many of the morphological changes and biochemical responses associated with apoptosis are present in prokaryotes. Identifying the mechanisms of bacterial cell death has the potential to reveal novel targets for future antimicrobial therapy and to further our understanding of core activation mechanisms of cell death in eukaryote cells.

Long-term treatment of anterior pituitary cells with nitric oxide induces programmed cell death.

PubMed

Velardez, Miguel Omar; Poliandri, Ariel Hernán; Cabilla, Jimena Paula; Bodo, Cristian Carlos Armando; Machiavelli, Leticia Inés; Duvilanski, Beatriz Haydeé

2004-04-01

Nitric oxide (NO) plays a complex role in modulating programmed cell death. It can either protect the cell from apoptotic death or mediate apoptosis, depending on its concentration and the cell type and/or status. In this study, we demonstrate that long-term exposition to NO induces cell death of anterior pituitary cells from Wistar female rats. DETA NONOate (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate, 1 mm], a NO donor that releases NO for an extended period of time, decreased cellular viability and prolactin release from primary cultures of anterior pituitary cells. Morphological studies showed an increase in the number of cells with chromatin condensation and nuclear fragmentation at 24 and 48 h after DETA/NO exposure. DNA internucleosomal fragmentation was also observed at the same time. Reversibility of the NO effect on cellular viability and prolactin release was observed only when the cells were incubated with DETA/NO for less than 6 h. Most apoptotic cells were immunopositive for prolactin, suggesting a high susceptibility of lactotrophs to the effect of NO. The cytotoxic effect of NO is dependent of caspase-9 and caspase-3, but seems to be independent of oxidative stress or nitrosative stress. Our results show that the exposition of anterior pituitary cells to NO for long periods induces programmed cell death of anterior pituitary cells.

Programmed Cell Death-1/Programmed Death-ligand 1 Pathway: A New Target for Sepsis.

PubMed

Liu, Qiang; Li, Chun-Sheng

2017-04-20

Sepsis remains a leading cause of death in many Intensive Care Units worldwide. Immunosuppression has been a primary focus of sepsis research as a key pathophysiological mechanism. Given the important role of the negative costimulatory molecules programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1) in the occurrence of immunosuppression during sepsis, we reviewed literatures related to the PD-1/PD-L1 pathway to examine its potential as a new target for sepsis treatment. Studies of the association between PD-1/PD-L1 and sepsis published up to January 31, 2017, were obtained by searching the PubMed database. English language studies, including those based on animal models, clinical research, and reviews, with data related to PD-1/PD-L1 and sepsis, were evaluated. Immunomodulatory therapeutics could reverse the deactivation of immune cells caused by sepsis and restore immune cell activation and function. Blockade of the PD-1/PD-L1 pathway could reduce the exhaustion of T-cells and enhance the proliferation and activation of T-cells. The anti-PD-1/PD-L1 pathway shows promise as a new target for sepsis treatment. This review provides a basis for clinical trials and future studies aimed at revaluating the efficacy and safety of this targeted approach.

Non-apoptotic cell death in animal development.

PubMed

Kutscher, Lena M; Shaham, Shai

2017-08-01

Programmed cell death (PCD) is an important process in the development of multicellular organisms. Apoptosis, a form of PCD characterized morphologically by chromatin condensation, membrane blebbing, and cytoplasm compaction, and molecularly by the activation of caspase proteases, has been extensively investigated. Studies in Caenorhabditis elegans, Drosophila, mice, and the developing chick have revealed, however, that developmental PCD also occurs through other mechanisms, morphologically and molecularly distinct from apoptosis. Some non-apoptotic PCD pathways, including those regulating germ cell death in Drosophila, still appear to employ caspases. However, another prominent cell death program, linker cell-type death (LCD), is morphologically conserved, and independent of the key genes that drive apoptosis, functioning, at least in part, through the ubiquitin proteasome system. These non-apoptotic processes may serve as backup programs when caspases are inactivated or unavailable, or, more likely, as freestanding cell culling programs. Non-apoptotic PCD has been documented extensively in the developing nervous system, and during the formation of germline and somatic gonadal structures, suggesting that preservation of these mechanisms is likely under strong selective pressure. Here, we discuss our current understanding of non-apoptotic PCD in animal development, and explore possible roles for LCD and other non-apoptotic developmental pathways in vertebrates. We raise the possibility that during vertebrate development, apoptosis may not be the major PCD mechanism.

Necroptosis: an alternative cell death program defending against cancer.

PubMed

Chen, Dongshi; Yu, Jian; Zhang, Lin

2016-04-01

One of the hallmarks of cancer is resistance to programmed cell death, which maintains the survival of cells en route to oncogenic transformation and underlies therapeutic resistance. Recent studies demonstrate that programmed cell death is not confined to caspase-dependent apoptosis, but includes necroptosis, a form of necrotic death governed by Receptor-Interacting Protein 1 (RIP1), RIP3, and Mixed Lineage Kinase Domain-Like (MLKL) protein. Necroptosis serves as a critical cell-killing mechanism in response to severe stress and blocked apoptosis, and can be induced by inflammatory cytokines or chemotherapeutic drugs. Genetic or epigenetic alterations of necroptosis regulators such as RIP3 and cylindromatosis (CYLD), are frequently found in human tumors. Unlike apoptosis, necroptosis elicits a more robust immune response that may function as a defensive mechanism by eliminating tumor-causing mutations and viruses. Furthermore, several classes of anticancer agents currently under clinical development, such as SMAC and BH3 mimetics, can promote necroptosis in addition to apoptosis. A more complete understanding of the interplay among necroptosis, apoptosis, and other cell death modalities is critical for developing new therapeutic strategies to enhance killing of tumor cells. Copyright © 2016 Elsevier B.V. All rights reserved.

AtPDCD5 Plays a Role in Programmed Cell Death after UV-B Exposure in Arabidopsis1[OPEN

PubMed Central

Falcone Ferreyra, María Lorena; D’Andrea, Lucio; AbdElgawad, Hamada

2016-01-01

DNA damage responses have evolved to sense and react to DNA damage; the induction of DNA repair mechanisms can lead to genomic restoration or, if the damaged DNA cannot be adequately repaired, to the execution of a cell death program. In this work, we investigated the role of an Arabidopsis (Arabidopsis thaliana) protein, AtPDCD5, which is highly similar to the human PDCD5 protein; it is induced by ultraviolet (UV)-B radiation and participates in programmed cell death in the UV-B DNA damage response. Transgenic plants expressing AtPDCD5 fused to GREEN FLUORESCENT PROTEIN indicate that AtPDCD5 is localized both in the nucleus and the cytosol. By use of pdcd5 mutants, we here demonstrate that these plants have an altered antioxidant metabolism and accumulate higher levels of DNA damage after UV-B exposure, similar to levels in ham1ham2 RNA interference transgenic lines with decreased expression of acetyltransferases from the MYST family. By coimmunoprecipitation and pull-down assays, we provide evidence that AtPDCD5 interacts with HAM proteins, suggesting that both proteins participate in the same pathway of DNA damage responses. Plants overexpressing AtPDCD5 show less DNA damage but more cell death in root tips upon UV-B exposure. Finally, we here show that AtPDCD5 also participates in age-induced programmed cell death. Together, the data presented here demonstrate that AtPDCD5 plays an important role during DNA damage responses induced by UV-B radiation in Arabidopsis and also participates in programmed cell death programs. PMID:26884483

METACASPASE9 modulates autophagy to confine cell death to the target cells during Arabidopsis vascular xylem differentiation

PubMed Central

Escamez, Sacha; André, Domenique; Zhang, Bo; Bollhöner, Benjamin; Pesquet, Edouard; Tuominen, Hannele

2016-01-01

ABSTRACT We uncovered that the level of autophagy in plant cells undergoing programmed cell death determines the fate of the surrounding cells. Our approach consisted of using Arabidopsis thaliana cell cultures capable of differentiating into two different cell types: vascular tracheary elements (TEs) that undergo programmed cell death (PCD) and protoplast autolysis, and parenchymatic non-TEs that remain alive. The TE cell type displayed higher levels of autophagy when expression of the TE-specific METACASPASE9 (MC9) was reduced using RNAi (MC9-RNAi). Misregulation of autophagy in the MC9-RNAi TEs coincided with ectopic death of the non-TEs, implying the existence of an autophagy-dependent intercellular signalling from within the TEs towards the non-TEs. Viability of the non-TEs was restored when AUTOPHAGY2 (ATG2) was downregulated specifically in MC9-RNAi TEs, demonstrating the importance of autophagy in the spatial confinement of cell death. Our results suggest that other eukaryotic cells undergoing PCD might also need to tightly regulate their level of autophagy to avoid detrimental consequences for the surrounding cells. PMID:26740571

Oxidative Stress and Programmed Cell Death in Yeast

PubMed Central

Farrugia, Gianluca; Balzan, Rena

2012-01-01

Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. This review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed. PMID:22737670

TNF-induced necroptosis requires the plasma membrane localization of the MLKL protein | Center for Cancer Research

Cancer.gov

The cell signaling protein tumor necrosis factor (TNF), produced by white blood cells, promotes inflammation and immunity processes such as fever and is involved in tumorigenesis and apoptosis (programmed cell death). However, dysregulation of TNF can also lead to another form of programmed cell death called necroptosis, which is characterized by a rise in intracellular Ca2+,

‘Hints' in the killer protein gasdermin D: unveiling the secrets of gasdermins driving cell death

PubMed Central

Qiu, Shiqiao; Liu, Jing; Xing, Feiyue

2017-01-01

Pyroptosis is a lytic form of cell death distinguished from apoptosis, ferroptosis, necrosis, necroptosis, NETosis, oncosis, pyronecrosis and autophagy. Proinflammatory caspases cleave a gasdermin D (GSDMD) protein to generate a 31 kDa N-terminal domain. The cleavage relieves the intramolecular inhibition on the gasdermin-N domain, which then moves to the plasma membrane to exhibit pore-forming activity. Thus, GSDMD acts as the final and direct executor of pyroptotic cell death. Owing to the selective targeting of the inner leaflet of the plasma membrane with the pore-forming that determines pyroptotic cell death, GSDMD could be a potential target to control cell death or extracellular bacterial infections. Intriguingly, other gasdermin family members also share similar N-terminal domains, but they present different cell death programs. Herein, we summarize features and functions of the novel player proteins in cell death, including GSDMD triggering pyroptosis, Gsdma3/GSDMA initiating autophagy/apoptosis and DFNA5 inducing apoptosis/secondary necrosis. The gasdermin N terminus appears to be a novel pore-forming protein. This provides novel insight into the underlying roles and mechanisms of lytic or nonlytic forms of programmed cell death, as well as their potential applications in inflammation-associated diseases. PMID:28362726

Regulation of cell division cycle progression by bcl-2 expression: a potential mechanism for inhibition of programmed cell death

PubMed Central

1996-01-01

Expression of the bcl-2 gene has been shown to effectively confer resistance to programmed cell death under a variety of circumstances. However, despite a wealth of literature describing this phenomenon, very little is known about the mechanism of resistance. In the experiments described here, we show that bcl-2 gene expression can result in an inhibition of cell division cycle progression. These findings are based upon the analysis of cell cycle distribution, cell cycle kinetics, and relative phosphorylation of the retinoblastoma tumor suppressor protein, using primary tissues in vivo, ex vivo, and in vitro, as well as continuous cell lines. The effects of bcl-2 expression on cell cycle progression appear to be focused at the G1 to S phase transition, which is a critical control point in the decision between continued cell cycle progression or the induction programmed cell death. In all systems tested, bcl-2 expression resulted in a substantial 30-60% increase in the length of G1 phase; such an increase is very substantial in the context of other regulators of cell cycle progression. Based upon our findings, and the related findings of others, we propose a mechanism by which bcl-2 expression might exert its well known inhibition of programmed cell death by regulating the kinetics of cell cycle progression at a critical control point. PMID:8642331

Senescent cells re-engineered to express soluble programmed death receptor-1 for inhibiting programmed death receptor-1/programmed death ligand-1 as a vaccination approach against breast cancer.

PubMed

Chen, Zehong; Hu, Kang; Feng, Lieting; Su, Ruxiong; Lai, Nan; Yang, Zike; Kang, Shijun

2018-06-01

Various types of vaccines have been proposed as approaches for prevention or delay of the onset of cancer by boosting the endogenous immune system. We previously developed a senescent-cell-based vaccine, induced by radiation and veliparib, as a preventive and therapeutic tool against triple-negative breast cancer. However, the programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) pathway was found to play an important role in vaccine failure. Hence, we further developed soluble programmed death receptor-1 (sPD1)-expressing senescent cells to overcome PD-L1/PD-1-mediated immune suppression while vaccinating to promote dendritic cell (DC) maturity, thereby amplifying T-cell activation. In the present study, sPD1-expressing senescent cells showed a particularly active status characterized by growth arrest and modified immunostimulatory cytokine secretion in vitro. As expected, sPD1-expressing senescent tumor cell vaccine (STCV/sPD-1) treatment attracted more mature DC and fewer exhausted-PD1 + T cells in vivo. During the course of the vaccine studies, we observed greater safety and efficacy for STCV/sPD-1 than for control treatments. STCV/sPD-1 pre-injections provided complete protection from 4T1 tumor challenge in mice. Additionally, the in vivo therapeutic study of mice with s.c. 4T1 tumor showed that STCV/sPD-1 vaccination delayed tumorigenesis and suppressed tumor progression at early stages. These results showed that STCV/sPD-1 effectively induced a strong antitumor immune response against cancer and suggested that it might be a potential strategy for TNBC prevention. © 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Mastoparan-induced programmed cell death in the unicellular alga Chlamydomonas reinhardtii

PubMed Central

Yordanova, Zhenya P.; Woltering, Ernst J.; Kapchina-Toteva, Veneta M.; Iakimova, Elena T.

2013-01-01

Background and Aims Under stress-promoting conditions unicellular algae can undergo programmed cell death (PCD) but the mechanisms of algal cellular suicide are still poorly understood. In this work, the involvement of caspase-like proteases, DNA cleavage and the morphological occurrence of cell death in wasp venom mastoparan (MP)-treated Chlamydomonas reinhardtii were studied. Methods Algal cells were exposed to MP and cell death was analysed over time. Specific caspase inhibitors were employed to elucidate the possible role of caspase-like proteases. YVADase activity (presumably a vacuolar processing enzyme) was assayed by using a fluorogenic caspase-1 substrate. DNA breakdown was evaluated by DNA laddering and Comet analysis. Cellular morphology was examined by confocal laser scanning microscopy. Key Results MP-treated C. reinhardtii cells expressed several features of necrosis (protoplast shrinkage) and vacuolar cell death (lytic vesicles, vacuolization, empty cell-walled corpse-containing remains of digested protoplast) sometimes within one single cell and in different individual cells. Nucleus compaction and DNA fragmentation were detected. YVADase activity was rapidly stimulated in response to MP but the early cell death was not inhibited by caspase inhibitors. At later time points, however, the caspase inhibitors were effective in cell-death suppression. Conditioned medium from MP-treated cells offered protection against MP-induced cell death. Conclusions In C. reinhardtii MP triggered PCD of atypical phenotype comprising features of vacuolar and necrotic cell deaths, reminiscent of the modality of hypersensitive response. It was assumed that depending on the physiological state and sensitivity of the cells to MP, the early cell-death phase might be not mediated by caspase-like enzymes, whereas later cell death may involve caspase-like-dependent proteolysis. The findings substantiate the hypothesis that, depending on the mode of induction and sensitivity of the cells, algal PCD may take different forms and proceed through different pathways. PMID:23250917

The DNA Inflammasome in Human Myeloid Cells Is Initiated by a STING-Cell Death Program Upstream of NLRP3

PubMed Central

Gaidt, Moritz M.; Ebert, Thomas S.; Chauhan, Dhruv; Ramshorn, Katharina; Pinci, Francesca; Zuber, Sarah; O’Duill, Fionan; Schmid-Burgk, Jonathan L.; Hoss, Florian; Buhmann, Raymund; Wittmann, Georg; Latz, Eicke; Subklewe, Marion; Hornung, Veit

2018-01-01

Summary Detection of cytosolic DNA constitutes a central event in the context of numerous infectious and sterile inflammatory conditions. Recent studies have uncovered a bipartite mode of cytosolic DNA recognition, in which the cGAS-STING axis triggers antiviral immunity, whereas AIM2 triggers inflammasome activation. Here, we show that AIM2 is dispensable for DNA-mediated inflammasome activation in human myeloid cells. Instead, detection of cytosolic DNA by the cGAS-STING axis induces a cell death program initiating potassium efflux upstream of NLRP3. Forward genetics identified regulators of lysosomal trafficking to modulate this cell death program, and subsequent studies revealed that activated STING traffics to the lysosome, where it triggers membrane permeabilization and thus lysosomal cell death (LCD). Importantly, the cGAS-STING-NLRP3 pathway constitutes the default inflammasome response during viral and bacterial infections in human myeloid cells. We conclude that targeting the cGAS-STING-LCD-NLRP3 pathway will ameliorate pathology in inflammatory conditions that are associated with cytosolic DNA sensing. PMID:29033128

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

PubMed

Erental, Ariel; Sharon, Idith; Engelberg-Kulka, Hanna

2012-01-01

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.

Live or let die: manipulation of cellular suicide programs by murine cytomegalovirus.

PubMed

Handke, Wiebke; Krause, Eva; Brune, Wolfram

2012-11-01

Cytomegaloviruses (CMVs) are large double-stranded DNA viruses that replicate slowly and cause life-long persisting infections in their hosts. To achieve this, the CMVs had to evolve numerous countermeasures against innate and adaptive immune responses. Induction of programmed cell death is one important host defense mechanism against intracellular pathogens such as viruses. For a multicellular organism, it is advantageous to let infected cells die in order to thwart viral replication and dissemination. For a virus, by contrast, it is better to inhibit cell death and keep infected cells alive until the viral replication cycle has been completed. As a matter of fact, the CMVs encode a number of proteins devoted to interfering with different forms of programmed cell death: apoptosis and necroptosis. In this review, we summarize the known functions of the four best characterized cell death inhibitors of murine cytomegalovirus (MCMV), which are encoded by open reading frames, M36, m38.5, m41.1, and M45. The viral proteins interact with key molecules within different cell death pathways, namely caspase-8, Bax, Bak, and RIP1/RIP3. In addition, we discuss which events during MCMV infection might trigger apoptosis or necrosis and how MCMV's countermeasures compare to those of other herpesviruses. Since both, MCMV and its natural host, are amenable to genetic manipulation, the mouse model for CMV infection provides a particularly suitable system to study mechanisms of cell death induction and inhibition.

Time-course of programmed cell death during leaf senescence in Eucommia ulmoides.

PubMed

Cao, Jing; Jiang, Feng; Sodmergen; Cui, Keming

2003-02-01

Leaves of Eucommia ulmoidesOliv. harvested between April to November were examined for programmed cell death (PCD) during growth and senescence. Leaves developed in April, becoming fully expanded in late May, remaining unchanged until November when they started to dehisce. Falling leaves retained a green color. Our results showed that (1) mesophyll cells gradually reduced their nuclei from September to November, (2) positive TUNEL signals appeared on the nuclei from August, (3) ladder-like DNA fragmentation occurred in September and October, and (4) a 20-kDa Ca(2+)-dependent DNase appeared in these same months. In fallen leaves, intact mesophyll cell nuclei could not be detected, but a few cells around the vascular bundle had nuclei. Therefore, (1) programmed cell death (PCD) of leaf cells occurred in the leaves of E. ulmoides, (2) the progress of mesophyll cell PCD lasted for more than 2 months, and (3) PCD of leaf cells was asynchronous in natural senescing leaves.

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

PubMed Central

Mfouo-Tynga, Ivan; Abrahamse, Heidi

2015-01-01

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. PMID:25955645

24(S)-hydroxycholesterol induces neuronal cell death through necroptosis, a form of programmed necrosis.

PubMed

Yamanaka, Kazunori; Saito, Yoshiro; Yamamori, Tohru; Urano, Yasuomi; Noguchi, Noriko

2011-07-15

24(S)-Hydroxycholesterol (24S-OHC) produced by cholesterol 24-hydroxylase expressed mainly in neurons plays an important physiological role in the brain. Conversely, it has been reported that 24S-OHC possesses potent cytotoxicity. The molecular mechanisms of 24S-OHC-induced cell death have not yet been fully elucidated. In this study, using human neuroblastoma SH-SY5Y cells and primary cortical neuronal cells derived from rat embryo, we characterized the form of cell death induced by 24S-OHC. SH-SY5Y cells treated with 24S-OHC exhibited neither fragmentation of the nucleus nor caspase activation, which are the typical characteristics of apoptosis. 24S-OHC-treated cells showed necrosis-like morphological changes but did not induce ATP depletion, one of the features of necrosis. When cells were treated with necrostatin-1, an inhibitor of receptor-interacting serine/threonine kinase 1 (RIPK1) required for necroptosis, 24S-OHC-induced cell death was significantly suppressed. The knockdown of RIPK1 by transfection of small interfering RNA of RIPK1 effectively attenuated 24S-OHC-induced cell death. It was found that neither SH-SY5Y cells nor primary cortical neuronal cells expressed caspase-8, which was regulated for RIPK1-dependent apoptosis. Collectively, these results suggest that 24S-OHC induces neuronal cell death by necroptosis, a form of programmed necrosis.

24(S)-Hydroxycholesterol Induces Neuronal Cell Death through Necroptosis, a Form of Programmed Necrosis*

PubMed Central

Yamanaka, Kazunori; Saito, Yoshiro; Yamamori, Tohru; Urano, Yasuomi; Noguchi, Noriko

2011-01-01

24(S)-Hydroxycholesterol (24S-OHC) produced by cholesterol 24-hydroxylase expressed mainly in neurons plays an important physiological role in the brain. Conversely, it has been reported that 24S-OHC possesses potent cytotoxicity. The molecular mechanisms of 24S-OHC-induced cell death have not yet been fully elucidated. In this study, using human neuroblastoma SH-SY5Y cells and primary cortical neuronal cells derived from rat embryo, we characterized the form of cell death induced by 24S-OHC. SH-SY5Y cells treated with 24S-OHC exhibited neither fragmentation of the nucleus nor caspase activation, which are the typical characteristics of apoptosis. 24S-OHC-treated cells showed necrosis-like morphological changes but did not induce ATP depletion, one of the features of necrosis. When cells were treated with necrostatin-1, an inhibitor of receptor-interacting serine/threonine kinase 1 (RIPK1) required for necroptosis, 24S-OHC-induced cell death was significantly suppressed. The knockdown of RIPK1 by transfection of small interfering RNA of RIPK1 effectively attenuated 24S-OHC-induced cell death. It was found that neither SH-SY5Y cells nor primary cortical neuronal cells expressed caspase-8, which was regulated for RIPK1-dependent apoptosis. Collectively, these results suggest that 24S-OHC induces neuronal cell death by necroptosis, a form of programmed necrosis. PMID:21613228

Expression and clinical association of programmed cell death-1, programmed death-ligand-1 and CD8+ lymphocytes in primary sarcomas is subtype dependent

PubMed Central

van Erp, Anke E.M.; Versleijen-Jonkers, Yvonne M.H.; Hillebrandt-Roeffen, Melissa H.S.; van Houdt, Laurens; Gorris, Mark A.J.; van Dam, Laura S.; Mentzel, Thomas; Weidema, Marije E.; Savci-Heijink, C. Dilara; Desar, Ingrid M.E.; Merks, Hans H.M.; van Noesel, Max M.; Shipley, Janet; van der Graaf, Winette T.A.; Flucke, Uta E.; Meyer-Wentrup, Friederike A.G.

2017-01-01

In order to explore the potential of immune checkpoint blockade in sarcoma, we investigated expression and clinical relevance of programmed cell death-1 (PD-1), programmed death ligand-1 (PD-L1) and CD8 in tumors of 208 sarcoma patients. Primary untreated osteosarcoma (n = 46), Ewing sarcoma (n = 32), alveolar rhabdomyosarcoma (n = 20), embryonal rhabdomyosarcoma (n = 77), synovial sarcoma (n = 22) and desmoplastic small round cell tumors (DSRCT) (n = 11) were examined immunohistochemically. PD-L1 expression was predominantly detected in alveolar and embryonal rhabdomyosarcomas (15% and 16%, respectively). In the alveolar subtype PD-L1 expression was associated with better overall, event-free and metastases-free survival. PD-1 expression on lymphocytes was predominantly seen in synovial sarcomas (18%). High levels of CD8+ lymphocytes were predominantly detected in osteosarcomas (35%) and associated with worse event-free survival in synovial sarcomas. Ewing sarcoma and DSRCTs showed PD-1 on tumor cells instead of on tumor infiltrating lymphocytes. Overall, expression and clinical associations were found to be subtype dependent. For the first time PD-1 expression on Ewing sarcoma (19%) and DSRCT (82%) tumor cells was described. PMID:29050367

Expression and clinical association of programmed cell death-1, programmed death-ligand-1 and CD8+ lymphocytes in primary sarcomas is subtype dependent.

PubMed

van Erp, Anke E M; Versleijen-Jonkers, Yvonne M H; Hillebrandt-Roeffen, Melissa H S; van Houdt, Laurens; Gorris, Mark A J; van Dam, Laura S; Mentzel, Thomas; Weidema, Marije E; Savci-Heijink, C Dilara; Desar, Ingrid M E; Merks, Hans H M; van Noesel, Max M; Shipley, Janet; van der Graaf, Winette T A; Flucke, Uta E; Meyer-Wentrup, Friederike A G

2017-09-19

In order to explore the potential of immune checkpoint blockade in sarcoma, we investigated expression and clinical relevance of programmed cell death-1 (PD-1), programmed death ligand-1 (PD-L1) and CD8 in tumors of 208 sarcoma patients. Primary untreated osteosarcoma ( n = 46), Ewing sarcoma ( n = 32), alveolar rhabdomyosarcoma ( n = 20), embryonal rhabdomyosarcoma ( n = 77), synovial sarcoma ( n = 22) and desmoplastic small round cell tumors (DSRCT) ( n = 11) were examined immunohistochemically. PD-L1 expression was predominantly detected in alveolar and embryonal rhabdomyosarcomas (15% and 16%, respectively). In the alveolar subtype PD-L1 expression was associated with better overall, event-free and metastases-free survival. PD-1 expression on lymphocytes was predominantly seen in synovial sarcomas (18%). High levels of CD8+ lymphocytes were predominantly detected in osteosarcomas (35%) and associated with worse event-free survival in synovial sarcomas. Ewing sarcoma and DSRCTs showed PD-1 on tumor cells instead of on tumor infiltrating lymphocytes. Overall, expression and clinical associations were found to be subtype dependent. For the first time PD-1 expression on Ewing sarcoma (19%) and DSRCT (82%) tumor cells was described.

Role of the immune modulator programmed cell death-1 during development and apoptosis of mouse retinal ganglion cells

PubMed Central

Chen, Ling; Sham, Caroline W.; Chan, Ann M.; Francisco, Loise M.; Wu, Yin; Mareninov, Sergey; Sharpe, Arlene H.; Freeman, Gordon J.; Yang, Xian-Jie; Braun, Jonathan; Gordon, Lynn K.

2011-01-01

PURPOSE Mammalian programmed cell death-1 (PD-1) is a membrane-associated receptor regulating the balance between T cell activation, tolerance and immunopathology, however its role in neurons has not yet been defined. We investigate the hypothesis that PD-1 signaling actively promotes retinal ganglion cell (RGC) death within the developing mouse retina. METHODS Mature retinal cell types expressing PD-1 were identified by immunofluorescence staining of vertical retina sections; developmental expression was localized by immunostaining and quantified by Western analysis. PD-1 involvement in developmental RGC survival was assessed in vitro using retina explants and in vivo using PD-1 knockout mice. PD-1 ligand gene expression was detected by RT-PCR. RESULTS PD-1 is expressed in most adult RGCs, and undergoes dynamic upregulation during the early postnatal window of retinal cell maturation and physiological programmed cell death (PCD). In vitro blockade of PD-1 signaling during this time selectively increases survival of RGCs. Furthermore, PD-1 deficient mice show a selective increase in RGC number in the neonatal retina at the peak of developmental RGC death. Lastly, throughout postnatal retina maturation, we find gene expression of both immune PD-1 ligand genes, PD-L1 and PD-L2. CONCLUSIONS These findings collectively support a novel role for a PD-1-mediated signaling pathway in developmental PCD during postnatal RGC maturation. PMID:19420345

Increasing RpoS expression causes cell death in Borrelia burgdorferi.

PubMed

Chen, Linxu; Xu, Qilong; Tu, Jiagang; Ge, Yihe; Liu, Jun; Liang, Fang Ting

2013-01-01

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.

Multimodal immunogenic cancer cell death as a consequence of anticancer cytotoxic treatments

PubMed Central

Inoue, H; Tani, K

2014-01-01

Apoptotic cell death generally characterized by a morphologically homogenous entity has been considered to be essentially non-immunogenic. However, apoptotic cancer cell death, also known as type 1 programmed cell death (PCD), was recently found to be immunogenic after treatment with several chemotherapeutic agents and oncolytic viruses through the emission of various danger-associated molecular patterns (DAMPs). Extensive studies have revealed that two different types of immunogenic cell death (ICD) inducers, recently classified by their distinct actions in endoplasmic reticulum (ER) stress, can reinitiate immune responses suppressed by the tumor microenvironment. Indeed, recent clinical studies have shown that several immunotherapeutic modalities including therapeutic cancer vaccines and oncolytic viruses, but not conventional chemotherapies, culminate in beneficial outcomes, probably because of their different mechanisms of ICD induction. Furthermore, interests in PCD of cancer cells have shifted from its classical form to novel forms involving autophagic cell death (ACD), programmed necrotic cell death (necroptosis), and pyroptosis, some of which entail immunogenicity after anticancer treatments. In this review, we provide a brief outline of the well-characterized DAMPs such as calreticulin (CRT) exposure, high-mobility group protein B1 (HMGB1), and adenosine triphosphate (ATP) release, which are induced by the morphologically distinct types of cell death. In the latter part, our review focuses on how emerging oncolytic viruses induce different forms of cell death and the combinations of oncolytic virotherapies with further immunomodulation by cyclophosphamide and other immunotherapeutic modalities foster dendritic cell (DC)-mediated induction of antitumor immunity. Accordingly, it is increasingly important to fully understand how and which ICD inducers cause multimodal ICD, which should aid the design of reasonably multifaceted anticancer modalities to maximize ICD-triggered antitumor immunity and eliminate residual or metastasized tumors while sparing autoimmune diseases. PMID:23832118

Plasma membrane changes during programmed cell deaths

PubMed Central

Zhang, Yingying; Chen, Xin; Gueydan, Cyril; Han, Jiahuai

2018-01-01

Ruptured and intact plasma membranes are classically considered as hallmarks of necrotic and apoptotic cell death, respectively. As such, apoptosis is usually considered a non-inflammatory process while necrosis triggers inflammation. Recent studies on necroptosis and pyroptosis, two types of programmed necrosis, revealed that plasma membrane rupture is mediated by MLKL channels during necroptosis but depends on non-selective gasdermin D (GSDMD) pores during pyroptosis. Importantly, the morphology of dying cells executed by MLKL channels can be distinguished from that executed by GSDMD pores. Interestingly, it was found recently that secondary necrosis of apoptotic cells, a previously believed non-regulated form of cell lysis that occurs after apoptosis, can be programmed and executed by plasma membrane pore formation like that of pyroptosis. In addition, pyroptosis is associated with pyroptotic bodies, which have some similarities to apoptotic bodies. Therefore, different cell death programs induce distinctive reshuffling processes of the plasma membrane. Given the fact that the nature of released intracellular contents plays a crucial role in dying/dead cell-induced immunogenicity, not only membrane rupture or integrity but also the nature of plasma membrane breakdown would determine the fate of a cell as well as its ability to elicit an immune response. In this review, we will discuss recent advances in the field of apoptosis, necroptosis and pyroptosis, with an emphasis on the mechanisms underlying plasma membrane changes observed on dying cells and their implication in cell death-elicited immunogenicity. PMID:29076500

Bcl-2 proteins and autophagy regulate mitochondrial dynamics during programmed cell death in the Drosophila ovary.

PubMed

Tanner, Elizabeth A; Blute, Todd A; Brachmann, Carrie Baker; McCall, Kimberly

2011-01-01

The Bcl-2 family has been shown to regulate mitochondrial dynamics during cell death in mammals and C. elegans, but evidence for this in Drosophila has been elusive. Here, we investigate the regulation of mitochondrial dynamics during germline cell death in the Drosophila melanogaster ovary. We find that mitochondria undergo a series of events during the progression of cell death, with remodeling, cluster formation and uptake of clusters by somatic follicle cells. These mitochondrial dynamics are dependent on caspases, the Bcl-2 family, the mitochondrial fission and fusion machinery, and the autophagy machinery. Furthermore, Bcl-2 family mutants show a striking defect in cell death in the ovary. These data indicate that a mitochondrial pathway is a major mechanism for activation of cell death in Drosophila oogenesis.

Transglutaminase induction by various cell death and apoptosis pathways.

PubMed

Fesus, L; Madi, A; Balajthy, Z; Nemes, Z; Szondy, Z

1996-10-31

Clarification of the molecular details of forms of natural cell death, including apoptosis, has become one of the most challenging issues of contemporary biomedical sciences. One of the effector elements of various cell death pathways is the covalent cross-linking of cellular proteins by transglutaminases. This review will discuss the accumulating data related to the induction and regulation of these enzymes, particularly of tissue type transglutaminase, in the molecular program of cell death. A wide range of signalling pathways can lead to the parallel induction of apoptosis and transglutaminase, providing a handle for better understanding the exact molecular interactions responsible for the mechanism of regulated cell death.

Yeast as a model to study apoptosis?

PubMed

Fleury, Christophe; Pampin, Mathieu; Tarze, Agathe; Mignotte, Bernard

2002-02-01

Programmed cell death (PCD) serves as a major mechanism for the precise regulation of cell numbers, and as a defense mechanism to remove unwanted and potentially dangerous cells. Despite the striking heterogeneity of cell death induction pathways, the execution of the death program is often associated with characteristic morphological and biochemical changes termed apoptosis. Although for a long time the absence of mitochondrial changes was considered as a hallmark of apoptosis, mitochondria appear today as the central executioner of programmed cell death. This crucial position of mitochondria in programmed cell death control is not due to a simple loss of function (deficit in energy supplying), but rather to an active process in the regulation of effector mechanisms. The large diversity of regulators of apoptosis in mammals and their numerous interactions complicate the analysis of their individual functions. Yeast, eukaryotic but unicellular organism, lack the main regulators of apoptosis (caspases, Bcl-2 family members, ...) found in mammals. This absence render them a powerful tool for heterologous expression, functional studies, and even cloning of new regulators of apoptosis. Great advances have thus been made in our understanding of the molecular mechanisms of Bcl-2 family members interactions with themselves and other cellular proteins, specially thanks to the two hybrid system and the easy manipulation of yeast (molecular biology and genetics). This review will focus on the use of yeast as a tool to identify new regulators and study function of mammalian apoptosis regulators.

Ferroptosis is Involved in Acetaminophen Induced Cell Death.

PubMed

Lőrincz, Tamás; Jemnitz, Katalin; Kardon, Tamás; Mandl, József; Szarka, András

2015-09-01

The recently described form of programmed cell death, ferroptosis can be induced by agents causing GSH depletion or the inhibition of GPX4. Ferroptosis clearly shows distinct morphologic, biochemical and genetic features from apoptosis, necrosis and autophagy. Since NAPQI the highly reactive metabolite of the widely applied analgesic and antipyretic, acetaminophen induces a cell death which can be characterized by GSH depletion, GPX inhibition and caspase independency the involvement of ferroptosis in acetaminophen induced cell death has been investigated. The specific ferroptosis inhibitor ferrostatin-1 failed to elevate the viability of acetaminophen treated HepG2 cells. It should be noticed that these cells do not form NAPQI due to the lack of phase I enzyme expression therefore GSH depletion cannot be observed. However in the case of acetaminophen treated primary mouse hepatocytes the significant elevation of cell viability could be observed upon ferrostatin-1 treatment. Similar to ferrostatin-1 treatment, the addition of the RIP1 kinase inhibitor necrostatin-1 could also elevate the viability of acetaminophen treated primary hepatocytes. Ferrostatin-1 has no influence on the expression of CYP2E1 or on the cellular GSH level which suggest that the protective effect of ferrostatin-1 in APAP induced cell death is not based on the reduced metabolism of APAP to NAPQI or on altered NAPQI conjugation by cellular GSH. Our results suggest that beyond necroptosis and apoptosis a third programmed cell death, ferroptosis is also involved in acetaminophen induced cell death in primary hepatocytes.

Characterization of mortality in children with sickle cell disease diagnosed through the Newborn Screening Program.

PubMed

Sabarense, Alessandra P; Lima, Gabriella O; Silva, Lívia M L; Viana, Marcos Borato

2015-01-01

To characterize the deaths of 193 children with sickle cell disease screened by a neonatal program from 1998 to 2012 and contrast the initial years with the final years. Deaths were identified by active surveillance of children absent to scheduled appointments in Blood Bank Clinical Centers (Hemominas). Clinical and epidemiological data came from death certificates, neonatal screening database, medical records, and family interviews. Between 1998 and 2012, 3,617,919 children were screened and 2,591 had sickle cell disease (1:1,400). There were 193 deaths (7.4%): 153 with SS/Sβ(0)-thalassemia, 34 SC and 6 Sβ(+)thalassemia; 76.7% were younger than five years; 78% died in the hospital and 21% at home or in transit. The main causes of death were infection (45%), indeterminate (28%), and acute splenic sequestration (14%). In 46% of death certificates, the term "sickle cell" was not recorded. Seven-year death rate for children born between 1998 and 2005 was 5.43% versus 5.12% for those born between 2005 and 2012 (p = 0.72). Medical care was provided to 75% of children; 24% were unassisted. Medical care was provided within 6 hours of symptom onset in only half of the interviewed cases. In 40.5% of cases, death occurred within the first 24 hours. Low family income was recorded in 90% of cases, and illiteracy in 5%. Although comprehensive and effective, neonatal screening for sickle cell disease was not sufficient to significantly reduce mortality in a newborn screening program. Economic and social development and increase of the knowledge on sickle cell disease among health professionals and family are needed to overcome excessive mortality. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

The retraction of the protoplast during PCD is an active, and interruptible, calcium-flux driven process.

PubMed

Kacprzyk, Joanna; Brogan, Niall P; Daly, Cara T; Doyle, Siamsa M; Diamond, Mark; Molony, Elizabeth M; McCabe, Paul F

2017-07-01

The protoplast retracts during apoptosis-like programmed cell death (AL-PCD) and, if this retraction is an active component of AL-PCD, it should be used as a defining feature for this type of programmed cell death. We used an array of pharmacological and genetic tools to test if the rates of protoplast retraction in cells undergoing AL-PCD can be modulated. Disturbing calcium flux signalling, ATP synthesis and mitochondrial permeability transition all inhibited protoplast retraction and often also the execution of the death programme. Protoplast retraction can precede loss of plasma membrane integrity and cell death can be interrupted after the protoplast retraction had already occurred. Blocking calcium influx inhibited the protoplast retraction, reduced DNA fragmentation and delayed death induced by AL-PCD associated stresses. At higher levels of stress, where cell death occurs without protoplast retraction, blocking calcium flux had no effect on the death process. The results therefore strongly suggest that retraction of the protoplast is an active biological process dependent on an early Ca 2+ -mediated trigger rather than cellular disintegration due to plasma membrane damage. Therefore this morphologically distinct cell type is a quantifiable feature, and consequently, reporter of AL-PCD. Copyright © 2017 Elsevier B.V. All rights reserved.

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

DTIC Science & Technology

2015-07-01

epithelial cells (MECs) are cleared from the mammary gland through efferocytosis, a process by which macrophages and other phagocytes recognize, bind to...chronic inflammatory lung disease. Chest. 2006;129(6):1673–1682. 48. deCathelineau AM, Henson PM. The final step in programmed cell death: phagocytes ...carry apoptotic cells to the grave. Essays Biochem. 2003;39:105–117. 49. Erwig LP, Henson PM. Clearance of apop- totic cells by phagocytes . Cell Death

Clinical evaluation of compounds targeting PD-1/PD-L1 pathway for cancer immunotherapy.

PubMed

Lu, Jing; Lee-Gabel, Linda; Nadeau, Michelle C; Ferencz, Thomas M; Soefje, Scott A

2015-12-01

Significant enthusiasm currently exists for new immunotherapeutic strategies: blocking the interaction between programmed death-1 receptor on T-cells and programmed death-ligand 1 on tumor cells to boost immune system stimulation to fight cancer. Immunomodulation with the antiprogrammed death-1/programmed death-ligand 1 monoclonal antibodies has shown to mediate tumor shrinkage and extend overall survival from several pivotal phase I/II studies in melanoma, renal cell carcinoma, and non-small cell lung cancer. This has prompted multiple large ongoing phase III trials with the expectation for fast-track FDA approvals to satisfy unmet medical needs. Compounds targeting the programmed death-1 pathway that are in clinical trials fall into two major categories, namely antiprogrammed death-1 antibodies: Nivolumab, MK-3475, and pidilizumab; and antiprogrammed death-ligand 1 antibodies: MPDL3280A, BMS-936559, MEDI4736, and MSB0010718C. We reviewed the clinical efficacy and safety of each compound based upon major registered clinical trials and published clinical data. Overall, response rate of more than 20% is consistently seen across all these trials, with maximal response of approximately 50% achieved by certain single antiprogrammed death-1 agents or when used in combination with cytotoxic T-lymphocyte antigen-4 blockade. The responses seen are early, durable, and have continued after treatment discontinuation. Immune-related adverse events are the most common side effects seen in these clinical trials. Overall, the skin and gastrointestinal tract are the most common organ systems affected by these compounds while hepatic, endocrine, and neurologic events are less frequent. These side effects are low grade, manageable, and typically resolve within a relatively short time frame with a predictable resolution pattern given proper management. We therefore propose detailed guidelines for management of major immune-related adverse events that are anticipated with antiprogrammed death-1/programmed death-ligand 1 therapies based on general experience with other monoclonal antibodies and the established management algorithms for immune-related adverse events for cytotoxic T-lymphocyte antigen-4 blockade with ipilimumab. We anticipate that the antiprogrammed death-1 strategy will become a viable and crucial clinical strategy for cancer therapy. © The Author(s) 2014.

The sweet taste of death: glucose triggers apoptosis during yeast chronological aging.

PubMed

Ruckenstuhl, Christoph; Carmona-Gutierrez, Didac; Madeo, Frank

2010-10-01

As time goes by, a postmitotic cell ages following a degeneration process ultimately ending in cell death. This phenomenon is evolutionary conserved and present in unicellular eukaryotes as well, making the yeast chronological aging system an appreciated model. Here, single cells die in a programmed fashion (both by apoptosis and necrosis) for the benefit of the whole population. Besides its meaning for aging and cell death research, age-induced programmed cell death represents the first experimental proof for the so-called group selection theory: Apoptotic genes became selected during evolution because of the benefits they might render to the whole cell culture and not to the individual cell. Many anti‐aging stimuli have been discovered in the yeast chronological aging system and have afterwards been confirmed in higher cells or organisms. New work from the Burhans group (this issue) now demonstrates that glucose signaling has a progeriatric effect on chronologically aged yeast cells: Glucose administration results in a diminished efficacy of cells to enter quiescence, finally causing superoxide‐mediated replication stress and apoptosis.

Collapsing Aged Culture of the Cyanobacterium Synechococcus elongatus Produces Compound(s) Toxic to Photosynthetic Organisms

PubMed Central

Cohen, Assaf; Sendersky, Eleonora; Carmeli, Shmuel; Schwarz, Rakefet

2014-01-01

Phytoplankton mortality allows effective nutrient cycling, and thus plays a pivotal role in driving biogeochemical cycles. A growing body of literature demonstrates the involvement of regulated death programs in the abrupt collapse of phytoplankton populations, and particularly implicates processes that exhibit characteristics of metazoan programmed cell death. Here, we report that the cell-free, extracellular fluid (conditioned medium) of a collapsing aged culture of the cyanobacterium Synechococcus elongatus is toxic to exponentially growing cells of this cyanobacterium, as well as to a large variety of photosynthetic organisms, but not to eubacteria. The toxic effect, which is light-dependent, involves oxidative stress, as suggested by damage alleviation by antioxidants, and the very high sensitivity of a catalase-mutant to the conditioned medium. At relatively high cell densities, S. elongatus cells survived the deleterious effect of conditioned medium in a process that required de novo protein synthesis. Application of conditioned medium from a collapsing culture caused severe pigment bleaching not only in S. elongatus cells, but also resulted in bleaching of pigments in a cell free extract. The latter observation indicates that the elicited damage is a direct effect that does not require an intact cell, and therefore, is mechanistically different from the metazoan-like programmed cell death described for phytoplankton. We suggest that S. elongatus in aged cultures are triggered to produce a toxic compound, and thus, this process may be envisaged as a novel regulated death program. PMID:24959874

Antigen-Specific Immune Modulation Targets mTORC1 Function To Drive Chemokine Receptor-Mediated T Cell Tolerance.

PubMed

Chen, Weirong; Wan, Xiaoxiao; Ukah, Tobechukwu K; Miller, Mindy M; Barik, Subhasis; Cattin-Roy, Alexis N; Zaghouani, Habib

2016-11-01

To contain autoimmunity, pathogenic T cells must be eliminated or diverted from reaching the target organ. Recently, we defined a novel form of T cell tolerance whereby treatment with Ag downregulates expression of the chemokine receptor CXCR3 and prevents diabetogenic Th1 cells from reaching the pancreas, leading to suppression of type 1 diabetes (T1D). This report defines the signaling events underlying Ag-induced chemokine receptor-mediated tolerance. Specifically, we show that the mammalian target of rapamycin complex 1 (mTORC1) is a major target for induction of CXCR3 downregulation and crippling of Th1 cells. Indeed, Ag administration induces upregulation of programmed death-ligand 1 on dendritic cells in a T cell-dependent manner. In return, programmed death-ligand 1 interacts with the constitutively expressed programmed death-1 on the target T cells and stimulates docking of Src homology 2 domain-containing tyrosine phosphatase 2 phosphatase to the cytoplasmic tail of programmed death-1. Active Src homology 2 domain-containing tyrosine phosphatase 2 impairs the signaling function of the PI3K/protein kinase B (AKT) pathway, leading to functional defect of mTORC1, downregulation of CXCR3 expression, and suppression of T1D. Thus, mTORC1 component of the metabolic pathway serves as a target for chemokine receptor-mediated T cell tolerance and suppression of T1D. Copyright © 2016 by The American Association of Immunologists, Inc.

Die Another Day: Inhibition of Cell Death Pathways by Cytomegalovirus.

PubMed

Brune, Wolfram; Andoniou, Christopher E

2017-09-02

Multicellular organisms have evolved multiple genetically programmed cell death pathways that are essential for homeostasis. The finding that many viruses encode cell death inhibitors suggested that cellular suicide also functions as a first line of defence against invading pathogens. This theory was confirmed by studying viral mutants that lack certain cell death inhibitors. Cytomegaloviruses, a family of species-specific viruses, have proved particularly useful in this respect. Cytomegaloviruses are known to encode multiple death inhibitors that are required for efficient viral replication. Here, we outline the mechanisms used by the host cell to detect cytomegalovirus infection and discuss the methods employed by the cytomegalovirus family to prevent death of the host cell. In addition to enhancing our understanding of cytomegalovirus pathogenesis we detail how this research has provided significant insights into the cross-talk that exists between the various cell death pathways.

A Conserved Core of Programmed Cell Death Indicator Genes Discriminates Developmentally and Environmentally Induced Programmed Cell Death in Plants.

PubMed

Olvera-Carrillo, Yadira; Van Bel, Michiel; Van Hautegem, Tom; Fendrych, Matyáš; Huysmans, Marlies; Simaskova, Maria; van Durme, Matthias; Buscaill, Pierre; Rivas, Susana; Coll, Nuria S.; Coppens, Frederik; Maere, Steven; Nowack, Moritz K.

2015-12-01

A plethora of diverse programmed cell death (PCD) processes has been described in living organisms. In animals and plants, different forms of PCD play crucial roles in development, immunity, and responses to the environment. While the molecular control of some animal PCD forms such as apoptosis is known in great detail, we still know comparatively little about the regulation of the diverse types of plant PCD. In part, this deficiency in molecular understanding is caused by the lack of reliable reporters to detect PCD processes. Here, we addressed this issue by using a combination of bioinformatics approaches to identify commonly regulated genes during diverse plant PCD processes in Arabidopsis (Arabidopsis thaliana). Our results indicate that the transcriptional signatures of developmentally controlled cell death are largely distinct from the ones associated with environmentally induced cell death. Moreover, different cases of developmental PCD share a set of cell death-associated genes. Most of these genes are evolutionary conserved within the green plant lineage, arguing for an evolutionary conserved core machinery of developmental PCD. Based on this information, we established an array of specific promoter-reporter lines for developmental PCD in Arabidopsis. These PCD indicators represent a powerful resource that can be used in addition to established morphological and biochemical methods to detect and analyze PCD processes in vivo and in planta. © 2015 American Society of Plant Biologists. All Rights Reserved.

Nonsmall Cell Lung Carcinoma with Giant Cell Features Expressing Programmed Death-Ligand 1: A Report of a Patient Successfully Treated with Pembrolizumab

PubMed Central

Nakayama, Shingo; Sasaki, Mamoru; Morinaga, Shojiroh

2018-01-01

Giant cell carcinoma, a rare variant of nonsmall cell lung carcinoma (NSCLC), is characterized by aggressive progression and poor response to conventional chemotherapy. This report is the first to describe a patient with NSCLC and giant cell features who was successfully treated with pembrolizumab, an antibody targeting programmed death-1 (PD-1). A 69-year-old woman was diagnosed with NSCLC with multiple brain metastases. Histological evaluation of lung biopsy specimens revealed proliferation of pleomorphic giant tumor cells with poor cohesiveness, findings consistent with giant cell carcinoma. Immunostaining showed that a high proportion of the tumor cells were positive for expression of programmed death-ligand 1 (PD-L1). The patient received stereotactic radiotherapy for the brain metastases, followed by administration of pembrolizumab. Treatment with pembrolizumab resulted in the rapid regression of the primary lung nodule, with the progression-free period maintained for at least four treatment cycles. Immunotherapy targeting PD-1/PD-L1 may be an option for patients with PD-L1-positive NSCLC with giant cell features. PMID:29736285

Nonsmall Cell Lung Carcinoma with Giant Cell Features Expressing Programmed Death-Ligand 1: A Report of a Patient Successfully Treated with Pembrolizumab.

PubMed

Nakayama, Shingo; Sasaki, Mamoru; Morinaga, Shojiroh; Minematsu, Naoto

2018-01-01

Giant cell carcinoma, a rare variant of nonsmall cell lung carcinoma (NSCLC), is characterized by aggressive progression and poor response to conventional chemotherapy. This report is the first to describe a patient with NSCLC and giant cell features who was successfully treated with pembrolizumab, an antibody targeting programmed death-1 (PD-1). A 69-year-old woman was diagnosed with NSCLC with multiple brain metastases. Histological evaluation of lung biopsy specimens revealed proliferation of pleomorphic giant tumor cells with poor cohesiveness, findings consistent with giant cell carcinoma. Immunostaining showed that a high proportion of the tumor cells were positive for expression of programmed death-ligand 1 (PD-L1). The patient received stereotactic radiotherapy for the brain metastases, followed by administration of pembrolizumab. Treatment with pembrolizumab resulted in the rapid regression of the primary lung nodule, with the progression-free period maintained for at least four treatment cycles. Immunotherapy targeting PD-1/PD-L1 may be an option for patients with PD-L1-positive NSCLC with giant cell features.

Ion channels involved in cell volume regulation: effects on migration, proliferation, and programmed cell death in non adherent EAT cells and adherent ELA cells.

PubMed

Hoffmann, Else Kay

2011-01-01

This mini review outlines studies of cell volume regulation in two closely related mammalian cell lines: nonadherent Ehrlich ascites tumour cells (EATC) and adherent Ehrlich Lettre ascites (ELA) cells. Focus is on the regulatory volume decrease (RVD) that occurs after cell swelling, the volume regulatory ion channels involved, and the mechanisms (cellular signalling pathways) that regulate these channels. Finally, I shall also briefly review current investigations in these two cell lines that focuses on how changes in cell volume can regulate cell functions such as cell migration, proliferation, and programmed cell death. Copyright © 2011 S. Karger AG, Basel.

BAX to basics: How the BCL2 gene family controls the death of retinal ganglion cells

PubMed Central

Maes, Margaret E.; Schlamp, Cassandra L.; Nickells, Robert W.

2017-01-01

Retinal ganglion cell (RGC) death is the principal consequence of injury to the optic nerve. For several decades, we have understood that the RGC death process was executed by apoptosis, suggesting that there may be ways to therapeutically intervene in this cell death program and provide a more direct treatment to the cells and tissues affected in diseases like glaucoma. A major part of this endeavor has been to elucidate the molecular biological pathways active in RGCs from the point of axonal injury to the point of irreversible cell death. A major component of this process is the complex interaction of members of the BCL2 gene family. Three distinct family members of proteins orchestrate the most critical junction in the apoptotic program of RGCs, culminating in the activation of pro-apoptotic BAX. Once active, BAX causes irreparable damage to mitochondria, while precipitating downstream events that finish off a dying ganglion cell. This review is divided into two major parts. First, we summarize the extent of knowledge of how BCL2 gene family proteins interact to facilitate the activation and function of BAX. This area of investigation has rapidly changed over the last few years and has yielded a dramatically different mechanistic understanding of how the intrinsic apoptotic program is run in mammalian cells. Second, we provided a comprehensive analysis of nearly two decades of investigation of the role of BAX in the process of RGC death, much of which has provided many important insights into the overall pathophysiology of diseases like glaucoma. PMID:28064040

BAX to basics: How the BCL2 gene family controls the death of retinal ganglion cells.

PubMed

Maes, Margaret E; Schlamp, Cassandra L; Nickells, Robert W

2017-03-01

Retinal ganglion cell (RGC) death is the principal consequence of injury to the optic nerve. For several decades, we have understood that the RGC death process was executed by apoptosis, suggesting that there may be ways to therapeutically intervene in this cell death program and provide a more direct treatment to the cells and tissues affected in diseases like glaucoma. A major part of this endeavor has been to elucidate the molecular biological pathways active in RGCs from the point of axonal injury to the point of irreversible cell death. A major component of this process is the complex interaction of members of the BCL2 gene family. Three distinct family members of proteins orchestrate the most critical junction in the apoptotic program of RGCs, culminating in the activation of pro-apoptotic BAX. Once active, BAX causes irreparable damage to mitochondria, while precipitating downstream events that finish off a dying ganglion cell. This review is divided into two major parts. First, we summarize the extent of knowledge of how BCL2 gene family proteins interact to facilitate the activation and function of BAX. This area of investigation has rapidly changed over the last few years and has yielded a dramatically different mechanistic understanding of how the intrinsic apoptotic program is run in mammalian cells. Second, we provided a comprehensive analysis of nearly two decades of investigation of the role of BAX in the process of RGC death, much of which has provided many important insights into the overall pathophysiology of diseases like glaucoma. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photoreceptor cell death and rescue in retinal detachment and degenerations

PubMed Central

Murakami, Yusuke; Notomi, Shoji; Hisatomi, Toshio; Nakazawa, Toru; Ishibashi, Tatsuro; Miller, Joan W.; Vavvas, Demetrios G.

2013-01-01

Photoreceptor cell death is the ultimate cause of vision loss in various retinal disorders, including retinal detachment (RD). Photoreceptor cell death has been thought to occur mainly through apoptosis, which is the most characterized form of programmed cell death. The caspase family of cysteine proteases plays a central role for inducing apoptosis, and in experimental models of RD, dying photoreceptor cells exhibit caspase activation; however, there is a paradox that caspase inhibition alone does not provide a sufficient protection against photoreceptor cell loss, suggesting that other mechanisms of cell death are involved. Recent accumulating evidence demonstrates that non-apoptotic forms of cell death, such as autophagy and necrosis, are also regulated by specific molecular machinery, such as those mediated by autophagy-related proteins and receptor-interacting protein kinases, respectively. Here we summarize the current knowledge of cell death signaling and its roles in photoreceptor cell death after RD and other retinal degenerative diseases. A body of studies indicate that not only apoptotic but also autophagic and necrotic signaling are involved in photoreceptor cell death, and that combined targeting of these pathways may be an effective neuroprotective strategy for retinal diseases associated with photoreceptor cell loss. PMID:23994436

Tomato 14-3-3 protein 7 (TFT7) positively regulates immunity-associated programmed cell death by enhancing accumulation and signaling ability of MAPKKKalpha

USDA-ARS?s Scientific Manuscript database

Programmed cell death (PCD) is triggered when Pto, a serine-threonine protein kinase recognizes either the AvrPto or AvrPtoB effector from Pseudomonas syringae pv. tomato. This PCD requires MAPKKKalpha as a positive regulator in tomato and Nicotiana benthamiana. To examine how PCD-eliciting activi...

Disruption of the vacuolar calcium-ATPases in arabidopsis results in the activation of a salicylic acid-dependent programmed cell death pathway

USDA-ARS?s Scientific Manuscript database

Calcium (Ca2+) signals regulate many aspects of plant development, including the Hypersensitive Response (HR) that triggers a programmed cell death response to protect a plant from a pathogen. A transient increase in cytosolic Ca2+ ([Ca2+]cyt ) results from Ca2+ entry from the apoplast or release fr...

Programmed cell death in vegetative development: apoptosis during the colonial life cycle of the ascidian Botryllus schlosseri.

PubMed

Tiozzo, S; Ballarin, L; Burighel, P; Zaniolo, G

2006-06-01

Programmed cell death (PCD) by apoptosis is a physiological mechanism by which cells are eliminated during embryonic and post-embryonic stages of animal life cycle. During asexual reproduction, the zooids of colonial ascidians originate from an assorted cell population instead of a single zygote, so that we assume that regulation of the equilibrium among proliferation, differentiation and cell death may follow different pathways in comparison to the embryonic development. Here we investigate the presence of apoptotic events throughout the blastogenetic life cycle of the colonial ascidian Botryllus schlosseri, by means of terminal deoxynucleotidyl transferase dUTP Nick End Labeling (TUNEL) coupled with histochemical and electron microscopy techniques. The occurrence of low levels of morphogenetic cell death suggests that, in contrast to what happens during sexual development (embryogenesis and metamorphosis), apoptosis does not play a pivotal role during asexual propagation in botryllid ascidian. Nevertheless, PCD emerges as a key force to regulate homeostasis in adult zooids and to shape and modulate the growth of the whole colony.

Morphodynamics of a growing microbial colony driven by cell death

NASA Astrophysics Data System (ADS)

Ghosh, Pushpita; Levine, Herbert

2017-11-01

Bacterial cells can often self-organize into multicellular structures with complex spatiotemporal morphology. In this work, we study the spatiotemporal dynamics of a growing microbial colony in the presence of cell death. We present an individual-based model of nonmotile bacterial cells which grow and proliferate by consuming diffusing nutrients on a semisolid two-dimensional surface. The colony spreads by growth forces and sliding motility of cells and undergoes cell death followed by subsequent disintegration of the dead cells in the medium. We model cell death by considering two possible situations: In one of the cases, cell death occurs in response to the limitation of local nutrients, while the other case corresponds to an active death process, known as apoptotic or programmed cell death. We demonstrate how the colony morphology is influenced by the presence of cell death. Our results show that cell death facilitates transitions from roughly circular to highly branched structures at the periphery of an expanding colony. Interestingly, our results also reveal that for the colonies which are growing in higher initial nutrient concentrations, cell death occurs much earlier compared to the colonies which are growing in lower initial nutrient concentrations. This work provides new insights into the branched patterning of growing bacterial colonies as a consequence of complex interplay among the biochemical and mechanical effects.

Spinosad induces programmed cell death involves mitochondrial dysfunction and cytochrome C release in Spodoptera frugiperda Sf9 cells.

PubMed

Yang, Mingjun; Wang, Bo; Gao, Jufang; Zhang, Yang; Xu, Wenping; Tao, Liming

2017-02-01

Spinosad, a reduced-risk insecticide, acts on the nicotinic acetylcholine receptors and the gamma-aminobutyric acid receptor in the nervous system of target insects. However, its mechanism of action in non-neural insect cells is unclear. This study aimed to evaluate mitochondrial functional changes associated with spinosad in Spodoptera frugiperda (Sf9) insect cells. Our results indicate that in Sf9 cells, spinosad induces programmed cell death and mitochondrial dysfunction through enhanced reactive oxygen species production, mitochondrial permeability transition pore (mPTP) opening, and mitochondrial membrane potential collapse, eventually leading to cytochrome C release and apoptosis. The cytochrome C release induced by spinosad treatment was partly inhibited by the mPTP inhibitors cyclosporin A and bongkrekic acid. Subsequently, we found that spinosad downregulated Bcl-2 expression and upregulated p53 and Bax expressions, activated caspase-9 and caspase-3, and triggered PARP cleavage in Sf9 cells. These findings suggested that spinosad-induced programmed cell death was modulated by mitochondrial dysfunction and cytochrome C release. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diabetes and renal tubular cell apoptosis

PubMed Central

Habib, Samy L

2013-01-01

Apoptosis contributes to the development of diabetic nephropathy, but the mechanism by which high glucose induces apoptosis is not fully understood. Apoptosis of tubular epithelial cells is a major feature of diabetic kidney disease, and hyperglycemia triggers the generation of free radicals and oxidant stress in tubular cells. Hyperglycemia and high glucose in vitro also lead to apoptosis, a form of programmed cell death. High glucose similar to those seen with hyperglycemia in people with diabetes mellitus, lead to accelerated apoptosis, a form of programmed cell death characterized by cell shrinkage, chromatin condensation and DNA fragmentation, in variety of cell types, including renal proximal tubular epithelial cells. PMID:23593533

Diabetes and renal tubular cell apoptosis.

PubMed

Habib, Samy L

2013-04-15

Apoptosis contributes to the development of diabetic nephropathy, but the mechanism by which high glucose induces apoptosis is not fully understood. Apoptosis of tubular epithelial cells is a major feature of diabetic kidney disease, and hyperglycemia triggers the generation of free radicals and oxidant stress in tubular cells. Hyperglycemia and high glucose in vitro also lead to apoptosis, a form of programmed cell death. High glucose similar to those seen with hyperglycemia in people with diabetes mellitus, lead to accelerated apoptosis, a form of programmed cell death characterized by cell shrinkage, chromatin condensation and DNA fragmentation, in variety of cell types, including renal proximal tubular epithelial cells.

Remodelling of lace plant leaves: antioxidants and ROS are key regulators of programmed cell death.

PubMed

Dauphinee, Adrian N; Fletcher, Jacob I; Denbigh, Georgia L; Lacroix, Christian R; Gunawardena, Arunika H L A N

2017-07-01

Antioxidants and reactive oxygen species are integral for programmed cell death signaling during perforation formation in the lace plant ( Aponogeton madagascariensis ). The lace plant is an excellent model system for studying developmentally regulated programmed cell death (PCD). During early lace plant leaf development, PCD systematically deletes cells resulting in a perforated leaf morphology that is unique in planta. A distinct feature in young lace plant leaves is an abundance of anthocyanins, which have antioxidant properties. The first sign of PCD induction is the loss of anthocyanin pigmentation in cells that are targeted for destruction, which results in a visible gradient of cell death. The cellular dynamics and time course of lace plant PCD are well documented; however, the signals involved in the pathway remain elusive. This study investigates the roles of antioxidants and ROS in developmental PCD signaling during lace plant perforation formation. The involvement of antioxidants and ROS in the pathway was determined using a variety of techniques including pharmacological whole plant experimentation, long-term live cell imaging, the 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid anti-radical activity assay, and western blot analysis. Results indicate that antioxidants and ROS are key regulators of PCD during the remodelling of lace plant leaves.

METHYLMERCURY BUT NOT MERCURIC CHLORIDE INDUCES APOPTOTIC CELL DEATH IN PC12 CELLS.

EPA Science Inventory

Normal development of the nervous system requires the process of apoptosis, a form of programmed cell death, to remove superfluous neurons. Abnormal patterns of apoptosis may be a consequence of exposure to environmental neurotoxicants leading to a disruption in the tightly regul...

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

PubMed

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.

The engulfment receptor Draper is required for autophagy during cell death.

PubMed

McPhee, Christina K; Baehrecke, Eric H

2010-11-01

Autophagy is a process to degrade and recycle cytoplasmic contents. Autophagy is required for survival in response to starvation, but has also been associated with cell death. How autophagy functions during cell survival in some contexts and cell death in others is unknown. Drosophila larval salivary glands undergo programmed cell death requiring autophagy genes, and are cleared in the absence of known phagocytosis. Recently, we demonstrated that Draper (Drpr), the Drosophila homolog of C. elegans engulfment receptor CED-1, is required for autophagy induction: during cell death, but not during cell survival. drpr mutants fail to clear salivary glands. drpr knockdown in salivary glands prevents the induction of autophagy, and Atg1 misexpression in drpr null mutants suppresses salivary gland persistence. Surprisingly, drpr knockdown cell-autonomously prevents autophagy induction in dying salivary gland cells, but not in larval fat body cells following starvation. This is the first engulfment factor shown to function in cellular self-clearance, and the first report of a cell-death-specific autophagy regulator.

The effector SPRYSEC-19 of Globodera rostochiensis suppresses CC-NB-LRR-mediated disease resistance in plants.

PubMed

Postma, Wiebe J; Slootweg, Erik J; Rehman, Sajid; Finkers-Tomczak, Anna; Tytgat, Tom O G; van Gelderen, Kasper; Lozano-Torres, Jose L; Roosien, Jan; Pomp, Rikus; van Schaik, Casper; Bakker, Jaap; Goverse, Aska; Smant, Geert

2012-10-01

The potato cyst nematode Globodera rostochiensis invades roots of host plants where it transforms cells near the vascular cylinder into a permanent feeding site. The host cell modifications are most likely induced by a complex mixture of proteins in the stylet secretions of the nematodes. Resistance to nematodes conferred by nucleotide-binding-leucine-rich repeat (NB-LRR) proteins usually results in a programmed cell death in and around the feeding site, and is most likely triggered by the recognition of effectors in stylet secretions. However, the actual role of these secretions in the activation and suppression of effector-triggered immunity is largely unknown. Here we demonstrate that the effector SPRYSEC-19 of G. rostochiensis physically associates in planta with the LRR domain of a member of the SW5 resistance gene cluster in tomato (Lycopersicon esculentum). Unexpectedly, this interaction did not trigger defense-related programmed cell death and resistance to G. rostochiensis. By contrast, agroinfiltration assays showed that the coexpression of SPRYSEC-19 in leaves of Nicotiana benthamiana suppresses programmed cell death mediated by several coiled-coil (CC)-NB-LRR immune receptors. Furthermore, SPRYSEC-19 abrogated resistance to Potato virus X mediated by the CC-NB-LRR resistance protein Rx1, and resistance to Verticillium dahliae mediated by an unidentified resistance in potato (Solanum tuberosum). The suppression of cell death and disease resistance did not require a physical association of SPRYSEC-19 and the LRR domains of the CC-NB-LRR resistance proteins. Altogether, our data demonstrated that potato cyst nematodes secrete effectors that enable the suppression of programmed cell death and disease resistance mediated by several CC-NB-LRR proteins in plants.

The Effector SPRYSEC-19 of Globodera rostochiensis Suppresses CC-NB-LRR-Mediated Disease Resistance in Plants1[C][W][OA

PubMed Central

Postma, Wiebe J.; Slootweg, Erik J.; Rehman, Sajid; Finkers-Tomczak, Anna; Tytgat, Tom O.G.; van Gelderen, Kasper; Lozano-Torres, Jose L.; Roosien, Jan; Pomp, Rikus; van Schaik, Casper; Bakker, Jaap; Goverse, Aska; Smant, Geert

2012-01-01

The potato cyst nematode Globodera rostochiensis invades roots of host plants where it transforms cells near the vascular cylinder into a permanent feeding site. The host cell modifications are most likely induced by a complex mixture of proteins in the stylet secretions of the nematodes. Resistance to nematodes conferred by nucleotide-binding-leucine-rich repeat (NB-LRR) proteins usually results in a programmed cell death in and around the feeding site, and is most likely triggered by the recognition of effectors in stylet secretions. However, the actual role of these secretions in the activation and suppression of effector-triggered immunity is largely unknown. Here we demonstrate that the effector SPRYSEC-19 of G. rostochiensis physically associates in planta with the LRR domain of a member of the SW5 resistance gene cluster in tomato (Lycopersicon esculentum). Unexpectedly, this interaction did not trigger defense-related programmed cell death and resistance to G. rostochiensis. By contrast, agroinfiltration assays showed that the coexpression of SPRYSEC-19 in leaves of Nicotiana benthamiana suppresses programmed cell death mediated by several coiled-coil (CC)-NB-LRR immune receptors. Furthermore, SPRYSEC-19 abrogated resistance to Potato virus X mediated by the CC-NB-LRR resistance protein Rx1, and resistance to Verticillium dahliae mediated by an unidentified resistance in potato (Solanum tuberosum). The suppression of cell death and disease resistance did not require a physical association of SPRYSEC-19 and the LRR domains of the CC-NB-LRR resistance proteins. Altogether, our data demonstrated that potato cyst nematodes secrete effectors that enable the suppression of programmed cell death and disease resistance mediated by several CC-NB-LRR proteins in plants. PMID:22904163

Combined fluorimetric caspase 3/7 assay and bradford protein determination for assessment of polycation-mediated cytotoxicity.

PubMed

Larsen, Anna K; Hall, Arnaldur; Lundsgart, Henrik; Moghimi, S Moein

2013-01-01

Cationic polyplexes and lipoplexes are widely used as artificial systems for nucleic acid delivery into the cells, but they can also induce cell death. Mechanistic understanding of cell toxicity and biological side effects of these cationic entities is essential for optimization strategies and design of safe and efficient nucleic acid delivery systems. Numerous methods are presently available to detect and delineate cytotoxicity and cell death-mediated signals in cell cultures. Activation of caspases is part of the classical apoptosis program and increased caspase activity is therefore a well-established hallmark of programmed cell death. Additional methods to monitor cell death-related signals must, however, also be carried out to fully define the type of cell toxicity in play. These may include methods that detect plasma membrane damage, loss of mitochondrial membrane potential, phosphatidylserine exposure, and cell morphological changes (e.g., membrane blebbing, nuclear changes, cytoplasmic swelling, cell rounding). Here we describe a 96-well format protocol for detection of capsase-3/7 activity in cell lysates, based on a fluorescent caspase-3 assay, combined with a method to simultaneously determine relative protein contents in the individual wells.

Silencing of Hsp27 and Hsp72 in glioma cells as a tool for programmed cell death induction upon temozolomide and quercetin treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jakubowicz-Gil, Joanna, E-mail: jjgil@poczta.umcs.lublin.pl; Langner, Ewa; Bądziul, Dorota

The aim of the present study was to investigate whether silencing of Hsp27 or Hsp72 expression in glioblastoma multiforme T98G and anaplastic astrocytoma MOGGCCM cells increases their sensitivity to programmed cell death induction upon temozolomide and/or quercetin treatment. Transfection with specific siRNA was performed for the Hsp gene silencing. As revealed by microscopic observation and flow cytometry, the inhibition of Hsp expression was correlated with severe apoptosis induction upon the drug treatment studied. No signs of autophagy were detected. This was correlated with a decreased mitochondrial membrane potential, increased level of cytochrome c in the cytoplasm, and activation of caspasemore » 3 and caspase 9. All these results suggest that the apoptotic signal was mediated by an internal pathway. Additionally, in a large percentage of cells treated with temozolomide, with or without quercetin, granules within the ER system were found, which was accompanied by an increased level of caspase 12 expression. This might be correlated with ER stress. Quercetin and temozolomide also changed the shape of nuclei from circular to “croissant like” in both transfected cell lines. Our results indicate that blocking of Hsp27 and Hsp72 expression makes T98G cells and MOGGCCM cells extremely vulnerable to apoptosis induction upon temozolomide and quercetin treatment and that programmed cell death is initiated by an internal signal. - Highlights: • Hsps gene silencing induced severe apoptosis upon temozolomide–quercetin treatment • Apoptosis in transfected glioma cells was initiated by internal signal • Programmed cell death was preceded by ER stress • Temozolomide–quercetin treatment changed nuclei shape in transfected glioma cells.« less

24(S)-Hydroxycholesterol induces RIPK1-dependent but MLKL-independent cell death in the absence of caspase-8.

PubMed

Vo, Diep-Khanh Ho; Urano, Yasuomi; Takabe, Wakako; Saito, Yoshiro; Noguchi, Noriko

2015-07-01

24(S)-Hydroxycholesterol (24S-OHC), which is enzymatically produced in the brain, is known to play an important role in maintaining brain cholesterol homeostasis. We have previously reported that 24S-OHC induces a type of non-apoptotic programmed necrosis in neuronal cells expressing little caspase-8. Necroptosis has been characterized as a type of programmed necrosis in which activation of receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like (MLKL) is involved in the signaling pathway. In the present study, we investigated the involvement of these three proteins in 24S-OHC-induced cell death. We found that RIPK1 but neither RIPK3 nor MLKL was expressed in human neuroblastoma SH-SY5Y cells, while all three proteins were expressed in human T lymphoma caspase-8-deficient Jurkat (Jurkat(Cas8-/-)) cells. In Jurkat(Cas8-/-) cells, tumor necrosis factor α (TNFα)-induced cell death was significantly suppressed by treatment with respective inhibitors of RIPK1, RIPK3, and MLKL. In contrast, only RIPK1 inhibitor showed significant suppression of 24S-OHC-induced cell death, and even this was less prominent than was observed in TNFα-induced cell death. In Jurkat(Cas8-/-) cells, knockdown of either RIPK1 or RIPK3 caused moderate but significant suppression of 24S-OHC-induced cell death, but no such effect was observed as a result of knockdown of MLKL. Collectively, these results suggest that, for both SH-SY5Y cells and Jurkat(Cas8-/-) cells, 24S-OHC-induced cell death is dependent on RIPK1 but not on MLKL. We therefore conclude that, in the absence of caspase-8 activity, 24S-OHC induces a necroptosis-like cell death which is RIPK1-dependent but MLKL-independent. Copyright © 2015 Elsevier Inc. All rights reserved.

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

PubMed

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Correlation of 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced apoptotic cell death in the embryonic vasculature with embryotoxicity

USGS Publications Warehouse

Cantrell, Susannah M.; Joy-Schlezinger, Jennifer; Stegeman, John J.; Tillitt, Donald E.; Hannington, Mark D.

1998-01-01

Vertebrate embryos are particularly sensitive to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Identification of tissues that are susceptible to the adverse effects of TCDD is requisite for understanding the embryo toxic effects of TCDD. The objective of the present study was to quantitate the temporal appearance of and dose dependence of apoptosis in TCDD-exposed medaka embryos (Oryzias latipes). A fluorescent-based DNA end-labeling assay provided a sensitive method for detection of TCDD-induced apoptosis in tissue sections of medaka embryos. Apoptotic cells were readily apparent in the medial yolk vein at all observed embryonic stages in TCDD-exposed embryos. Slope-comparison analysis indicated that TCDD-induced programmed cell death in the embryonic medial yolk vein was mechanistically linked to embryo mortality. These data are consistent with the hypothesis that vascular damage contributes to the acute embryo toxic effects of TCDD. However, as sublethal concentrations of dioxin-like compounds are more typical of environmental exposures, tissue damage was also assessed in medaka fry that were exposed to low doses of TCDD during embryonic development. Cell death was detected in gill and digestive tissues in visibly healthy medaka fry that had been exposed to low doses of TCDD during embryonic development. Increased expression of cytochrome P450 1A is a major biochemical consequence of TCDD exposure and is often used as a biomarker for exposure to dioxin-like compounds. Therefore, we compared the tissue distribution of TCDD-induced P450 1A expression and TCDD-induced programmed cell death. TCDD-induced programmed cell death co-localized with TCDD-induced P450 1A expression in both embryos and in visibly healthy post-hatch fry. Our results suggest that aberrant programmed cell death may be a suitable marker for exposure of feral organisms to dioxin-like compounds.

THE PROS AND CONS OF APOPTOSIS ASSAYS FOR USE IN THE STUDY OF CELLS, TISSUES AND ORGANS

EPA Science Inventory

Abstract
Programmed cell death or apoptosis occurs in many tissues during normal development and in the normal homeostasis of adult tissues. Apoptosis also plays a significant role in abnormal development and disease. Increased interest in apoptosis and cell death in general...

What cell death does in development.

PubMed

Zakeri, Zahra; Penaloza, Carlos G; Smith, Kyle; Ye, Yixia; Lockshin, Richard A

2015-01-01

Cell death is prominent in gametogenesis and shapes and sculpts embryos. In non-mammalian embryos one sees little or no cell death prior to the maternal-zygotic transition, but, in mammalian embryos, characteristic deaths of one or two cells occur at the end of compaction and are apparently necessary for the separation of the trophoblast from the inner cell mass. Considerable sculpting of the embryo occurs by cell deaths during organogenesis, and appropriate cell numbers, especially in the CNS and in the immune system, are generated by massive overproduction of cells and selection of a few, with death of the rest. The timing, identity, and genetic control of specific cells that die have been well documented in Caenorhabditis, but in other embryos the stochastic nature of the deaths limit our ability to do more than identify the regions in which cells will die. Complete disruption of the cell death machinery can be lethal, but many mutations of the regulatory machinery yield only modest or no phenotypes, indicating substantial redundancy and compensation of regulatory mechanisms. Most of the deaths are apoptotic and are identified by techniques used to recognize apoptosis, but techniques identifying lysosomes (whether in dying or involuting cells or in the phagocytes that invade the tissue) also reveal patterns of cell death. Aberrant cell deaths that produce known phenotypes are typically localized, indicating that the mechanism of activating a programmed death in a specific region, rather than the mechanism of death, is aberrant. These results lead us to conclude that we need to know much more about the conversations among cells that lead cells to commit suicide.

Programming stress-induced altruistic death in engineered bacteria

PubMed Central

Tanouchi, Yu; Pai, Anand; Buchler, Nicolas E; You, Lingchong

2012-01-01

Programmed death is often associated with a bacterial stress response. This behavior appears paradoxical, as it offers no benefit to the individual. This paradox can be explained if the death is ‘altruistic': the killing of some cells can benefit the survivors through release of ‘public goods'. However, the conditions where bacterial programmed death becomes advantageous have not been unambiguously demonstrated experimentally. Here, we determined such conditions by engineering tunable, stress-induced altruistic death in the bacterium Escherichia coli. Using a mathematical model, we predicted the existence of an optimal programmed death rate that maximizes population growth under stress. We further predicted that altruistic death could generate the ‘Eagle effect', a counter-intuitive phenomenon where bacteria appear to grow better when treated with higher antibiotic concentrations. In support of these modeling insights, we experimentally demonstrated both the optimality in programmed death rate and the Eagle effect using our engineered system. Our findings fill a critical conceptual gap in the analysis of the evolution of bacterial programmed death, and have implications for a design of antibiotic treatment. PMID:23169002

Different ways to die: cell death modes of the unicellular chlorophyte Dunaliella viridis exposed to various environmental stresses are mediated by the caspase-like activity DEVDase.

PubMed

Jiménez, Carlos; Capasso, Juan M; Edelstein, Charles L; Rivard, Christopher J; Lucia, Scott; Breusegem, Sophia; Berl, Tomás; Segovia, María

2009-01-01

Programmed cell death is necessary for homeostasis in multicellular organisms and it is also widely recognized to occur in unicellular organisms. However, the mechanisms through which it occurs in unicells, and the enzymes involved within the final response is still the subject of heated debate. It is shown here that exposure of the unicellular microalga Dunaliella viridis to several environmental stresses, induced different cell death morphotypes, depending on the stimulus received. Senescent cells demonstrated classical and unambiguous apoptotic-like characteristics such as chromatin condensation, DNA fragmentation, intact organelles, and blebbing of the cell membrane. Acute heat shock caused general swelling and altered plasma membrane, but the presence of chromatin clusters and DNA strand breaks suggested a necrotic-like event. UV irradiated cells presented changes typical for necrosis, together with apoptotic characteristics resembling an intermediate cell-death phenotype termed aponecrosis-like. Cells subjected to hyperosmotic shock revealed chromatin spotting without DNA fragmentation, and extensive cytoplasmic swelling and vacuolization, comparable to a paraptotic-like cell death phenotype. Nitrogen-starved cells showed pyknosis, blebbing, and cytoplasmic consumption, indicating a similarity to autophagic/vacuolar-like cell death. The caspase-like activity DEVDase was measured by using the fluorescent substrate Ac-DEVD-AMC and antibodies against the human caspase-3 active enzyme cross-reacted with bands, the intensity of which paralleled the activity. All the environmental stresses tested produced a substantial increase in both DEVDase activity and protein levels. The irreversible caspase-3 inhibitor Z-DEVD-FMK completely inhibited the enzymatic activity whereas serine and aspartyl proteases inhibitors did not. These results show that cell death in D. viridis does not conform to a single pattern and that environmental stimuli may produce different types of cell death depending on the type and intensity of the stimulus, all of which help to understand the cell death-dependent and cell death-independent functions of caspase-like proteins. Hence, these data support the theory that alternative, non-apoptotic programmed cell death (PCDs), exist either in parallel or in an independent manner with apoptosis and were already present in single-celled organisms that evolved some 1.2-1.6 billion years ago.

Different ways to die: cell death modes of the unicellular chlorophyte Dunaliella viridis exposed to various environmental stresses are mediated by the caspase-like activity DEVDase

PubMed Central

Jiménez, Carlos; Capasso, Juan M.; Edelstein, Charles L.; Rivard, Christopher J.; Lucia, Scott; Breusegem, Sophia; Berl, Tomás; Segovia, María

2009-01-01

Programmed cell death is necessary for homeostasis in multicellular organisms and it is also widely recognized to occur in unicellular organisms. However, the mechanisms through which it occurs in unicells, and the enzymes involved within the final response is still the subject of heated debate. It is shown here that exposure of the unicellular microalga Dunaliella viridis to several environmental stresses, induced different cell death morphotypes, depending on the stimulus received. Senescent cells demonstrated classical and unambiguous apoptotic-like characteristics such as chromatin condensation, DNA fragmentation, intact organelles, and blebbing of the cell membrane. Acute heat shock caused general swelling and altered plasma membrane, but the presence of chromatin clusters and DNA strand breaks suggested a necrotic-like event. UV irradiated cells presented changes typical for necrosis, together with apoptotic characteristics resembling an intermediate cell-death phenotype termed aponecrosis-like. Cells subjected to hyperosmotic shock revealed chromatin spotting without DNA fragmentation, and extensive cytoplasmic swelling and vacuolization, comparable to a paraptotic-like cell death phenotype. Nitrogen-starved cells showed pyknosis, blebbing, and cytoplasmic consumption, indicating a similarity to autophagic/vacuolar-like cell death. The caspase-like activity DEVDase was measured by using the fluorescent substrate Ac-DEVD-AMC and antibodies against the human caspase-3 active enzyme cross-reacted with bands, the intensity of which paralleled the activity. All the environmental stresses tested produced a substantial increase in both DEVDase activity and protein levels. The irreversible caspase-3 inhibitor Z-DEVD-FMK completely inhibited the enzymatic activity whereas serine and aspartyl proteases inhibitors did not. These results show that cell death in D. viridis does not conform to a single pattern and that environmental stimuli may produce different types of cell death depending on the type and intensity of the stimulus, all of which help to understand the cell death-dependent and cell death-independent functions of caspase-like proteins. Hence, these data support the theory that alternative, non-apoptotic programmed cell death (PCDs), exist either in parallel or in an independent manner with apoptosis and were already present in single-celled organisms that evolved some 1.2-1.6 billion years ago. PMID:19251986

Essential role of grim-led programmed cell death for the establishment of corazonin-producing peptidergic nervous system during embryogenesis and metamorphosis in Drosophila melanogaster.

PubMed

Lee, Gyunghee; Sehgal, Ritika; Wang, Zixing; Nair, Sudershana; Kikuno, Keiko; Chen, Chun-Hong; Hay, Bruce; Park, Jae H

2013-03-15

In Drosophila melanogaster, combinatorial activities of four death genes, head involution defective (hid), reaper (rpr), grim, and sickle (skl), have been known to play crucial roles in the developmentally regulated programmed cell death (PCD) of various tissues. However, different expression patterns of the death genes also suggest distinct functions played by each. During early metamorphosis, a great number of larval neurons unfit for adult life style are removed by PCD. Among them are eight pairs of corazonin-expressing larval peptidergic neurons in the ventral nerve cord (vCrz). To reveal death genes responsible for the PCD of vCrz neurons, we examined extant and recently available mutations as well as RNA interference that disrupt functions of single or multiple death genes. We found grim as a chief proapoptotic gene and skl and rpr as minor ones. The function of grim is also required for PCD of the mitotic sibling cells of the vCrz neuronal precursors (EW3-sib) during embryonic neurogenesis. An intergenic region between grim and rpr, which, it has been suggested, may enhance expression of three death genes in embryonic neuroblasts, appears to play a role for the vCrz PCD, but not for the EW3-sib cell death. The death of vCrz neurons and EW3-sib is triggered by ecdysone and the Notch signaling pathway, respectively, suggesting distinct regulatory mechanisms of grim expression in a cell- and developmental stage-specific manner.

Human-specific bacterial pore-forming toxins induce programmed necrosis in erythrocytes.

PubMed

LaRocca, Timothy J; Stivison, Elizabeth A; Hod, Eldad A; Spitalnik, Steven L; Cowan, Peter J; Randis, Tara M; Ratner, Adam J

2014-08-26

A subgroup of the cholesterol-dependent cytolysin (CDC) family of pore-forming toxins (PFTs) has an unusually narrow host range due to a requirement for binding to human CD59 (hCD59), a glycosylphosphatidylinositol (GPI)-linked complement regulatory molecule. hCD59-specific CDCs are produced by several organisms that inhabit human mucosal surfaces and can act as pathogens, including Gardnerella vaginalis and Streptococcus intermedius. The consequences and potential selective advantages of such PFT host limitation have remained unknown. Here, we demonstrate that, in addition to species restriction, PFT ligation of hCD59 triggers a previously unrecognized pathway for programmed necrosis in primary erythrocytes (red blood cells [RBCs]) from humans and transgenic mice expressing hCD59. Because they lack nuclei and mitochondria, RBCs have typically been thought to possess limited capacity to undergo programmed cell death. RBC programmed necrosis shares key molecular factors with nucleated cell necroptosis, including dependence on Fas/FasL signaling and RIP1 phosphorylation, necrosome assembly, and restriction by caspase-8. Death due to programmed necrosis in RBCs is executed by acid sphingomyelinase-dependent ceramide formation, NADPH oxidase- and iron-dependent reactive oxygen species formation, and glycolytic formation of advanced glycation end products. Bacterial PFTs that are hCD59 independent do not induce RBC programmed necrosis. RBC programmed necrosis is biochemically distinct from eryptosis, the only other known programmed cell death pathway in mature RBCs. Importantly, RBC programmed necrosis enhances the growth of PFT-producing pathogens during exposure to primary RBCs, consistent with a role for such signaling in microbial growth and pathogenesis. In this work, we provide the first description of a new form of programmed cell death in erythrocytes (RBCs) that occurs as a consequence of cellular attack by human-specific bacterial toxins. By defining a new RBC death pathway that shares important components with necroptosis, a programmed necrosis module that occurs in nucleated cells, these findings expand our understanding of RBC biology and RBC-pathogen interactions. In addition, our work provides a link between cholesterol-dependent cytolysin (CDC) host restriction and promotion of bacterial growth in the presence of RBCs, which may provide a selective advantage to human-associated bacterial strains that elaborate such toxins and a potential explanation for the narrowing of host range observed in this toxin family. Copyright © 2014 LaRocca et al.

Influence of PD-L1 cross-linking on cell death in PD-L1-expressing cell lines and bovine lymphocytes

PubMed Central

Ikebuchi, Ryoyo; Konnai, Satoru; Okagawa, Tomohiro; Yokoyama, Kazumasa; Nakajima, Chie; Suzuki, Yasuhiko; Murata, Shiro; Ohashi, Kazuhiko

2014-01-01

Programmed death-ligand 1 (PD-L1) blockade is accepted as a novel strategy for the reactivation of exhausted T cells that express programmed death-1 (PD-1). However, the mechanism of PD-L1-mediated inhibitory signalling after PD-L1 cross-linking by anti-PD-L1 monoclonal antibody (mAb) or PD-1–immunogloblin fusion protein (PD-1-Ig) is still unknown, although it may induce cell death of PD-L1+ cells required for regular immune reactions. In this study, PD-1-Ig or anti-PD-L1 mAb treatment was tested in cell lines that expressed PD-L1 and bovine lymphocytes to investigate whether the treatment induces immune reactivation or PD-L1-mediated cell death. PD-L1 cross-linking by PD-1-Ig or anti-PD-L1 mAb primarily increased the number of dead cells in PD-L1high cells, but not in PD-L1low cells; these cells were prepared from Cos-7 cells in which bovine PD-L1 expression was induced by transfection. The PD-L1-mediated cell death also occurred in Cos-7 and HeLa cells transfected with vectors only encoding the extracellular region of PD-L1. In bovine lymphocytes, the anti-PD-L1 mAb treatment up-regulated interferon-γ (IFN-γ) production, whereas PD-1-Ig treatment decreased this cytokine production and cell proliferation. The IFN-γ production in B-cell-depleted peripheral blood mononuclear cells was not reduced by PD-1-Ig treatment and the percentages of dead cells in PD-L1+ B cells were increased by PD-1-Ig treatment, indicating that PD-1-Ig-induced immunosuppression in bovine lymphocytes could be caused by PD-L1-mediated B-cell death. This study provides novel information for the understanding of signalling through PD-L1. PMID:24405267

Targeting Programmed Cell Death Using Small-Molecule Compounds to Improve Potential Cancer Therapy.

PubMed

Ke, Bowen; Tian, Mao; Li, Jingjing; Liu, Bo; He, Gu

2016-11-01

Evasion of cell death is one of the hallmarks of cancer cells, beginning with long-established apoptosis and extending to other new forms of cell death. An elaboration of cell death pathways thus will contribute to a better understanding of cancer pathogenesis and therapeutics. With the recent substantial biochemical and genetic explorations of cell death subroutines, their classification has switched from primarily morphological to more molecular definitions. According to their measurable biochemical features and intricate mechanisms, cell death subroutines can be divided into apoptosis, autophagic cell death, mitotic catastrophe, necroptosis, parthanatos, ferroptosis, pyroptosis, pyronecrosis, anoikis, cornification, entosis, and NETosis. Supportive evidence has gradually revealed the prime molecular mechanisms of each subroutine and thus providing series of possible targets in cancer therapy, while the intricate relationships between different cell death subroutines still remain to be clarified. Over the past decades, cancer drug discovery has significantly benefited from the use of small-molecule compounds to target classical modalities of cell death such as apoptosis, while newly identified cell death subroutines has also emerging their potential for cancer drug discovery in recent years. In this review, we comprehensively focus on summarizing 12 cell death subroutines and discussing their corresponding small-molecule compounds in potential cancer therapy. Together, these inspiring findings may provide more evidence to fill in the gaps between cell death subroutines and small-molecule compounds to better develop novel cancer therapeutic strategies. © 2016 Wiley Periodicals, Inc.

Understanding cell cycle and cell death regulation provides novel weapons against human diseases.

PubMed

Wiman, K G; Zhivotovsky, B

2017-05-01

Cell division, cell differentiation and cell death are the three principal physiological processes that regulate tissue homoeostasis in multicellular organisms. The growth and survival of cells as well as the integrity of the genome are regulated by a complex network of pathways, in which cell cycle checkpoints, DNA repair and programmed cell death have critical roles. Disruption of genomic integrity and impaired regulation of cell death may both lead to uncontrolled cell growth. Compromised cell death can also favour genomic instability. It is becoming increasingly clear that dysregulation of cell cycle and cell death processes plays an important role in the development of major disorders such as cancer, cardiovascular disease, infection, inflammation and neurodegenerative diseases. Research achievements in these fields have led to the development of novel approaches for treatment of various conditions associated with abnormalities in the regulation of cell cycle progression or cell death. A better understanding of how cellular life-and-death processes are regulated is essential for this development. To highlight these important advances, the Third Nobel Conference entitled 'The Cell Cycle and Cell Death in Disease' was organized at Karolinska Institutet in 2016. In this review we will summarize current understanding of cell cycle progression and cell death and discuss some of the recent advances in therapeutic applications in pathological conditions such as cancer, neurological disorders and inflammation. © 2017 The Association for the Publication of the Journal of Internal Medicine.

Necroptosis and Cancer.

PubMed

Najafov, Ayaz; Chen, Hongbo; Yuan, Junying

2017-04-01

Necroptosis is a programmed lytic cell death pathway, deregulation of which is linked to various inflammatory disorders. Escape from programmed cell death and inflammation play a significant role in cancer, and therefore, investigating the role of necroptosis in cancer has been of high interest. Necroptosis has been shown to promote cancer metastasis and T cells death. Escape from necroptosis via loss of RIPK3 expression is a feature of some cancers. While necroptosis is a promising novel target for cancer therapies, further investigation into its biological role in carcinogenesis is warranted. In this article, we review the recently-identified interplay points between necroptosis and cancer, and outline major biological questions that require further inquiry on the road to targeting this pathway in cancer.

PD-1-PD-L1 immune-checkpoint blockade in malignant lymphomas.

PubMed

Wang, Yi; Wu, Ling; Tian, Chen; Zhang, Yizhuo

2018-02-01

Tumor cells can evade immune surveillance through overexpressing the ligands of checkpoint receptors on tumor cells or adjacent cells, leading T cells to anergy or exhaustion. Growing evidence of the interaction between tumor cells and microenvironment promoted the emergence of immune-checkpoint blockade. By targeting programmed cell death-1 (PD-1) pathway, cytotoxic activity of T cell is enhanced significantly and tumor cell lysis is induced subsequently. Currently, various antibodies against PD-1 and programmed death-ligand 1 (PD-L1) are under clinical studies in lymphomas. In this review, we outline the rationale for investigation of PD-1-PD-L1 immune-checkpoint blockade in lymphomas and discuss their prospect of applications in clinical treatment.

α-blockade, apoptosis, and prostate shrinkage: how are they related?

PubMed

Chłosta, Piotr; Drewa, Tomasz; Kaplan, Steven

2013-01-01

The α1-adrenoreceptor antagonists, such as terazosin and doxazosin, induce prostate programmed cell death (apoptosis) within prostate epithelial and stromal cells in vitro. This treatment should cause prostate volume decrease, However, this has never been observed in clinical conditions. The aim of this paper is to review the disconnect between these two processes. PubMed and DOAJ were searched for papers related to prostate, apoptosis, and stem cell death. The following key words were used: prostate, benign prostate hyperplasia, programmed cell death, apoptosis, cell death, α1-adrenoreceptor antagonist, α-blockade, prostate epithelium, prostate stroma, stem cells, progenitors, and in vitro models. We have shown how discoveries related to stem cells can influence our understanding of α-blockade treatment for BPH patients. Prostate epithelial and mesenchymal compartments have stem (progenitors) and differentiating cells. These compartments are described in relation to experimental in vitro and in vivo settings. Apoptosis is observed within prostate tissue, but this effect has no clinical significance and cannot lead to prostate shrinkage. In part, this is due to stem cells that are responsible for prostate tissue regeneration and are resistant to apoptosis triggered by α1-receptor antagonists.

Autophagy promotes caspase-dependent cell death during Drosophila development.

PubMed

Mohseni, Nilufar; McMillan, Stephanie C; Chaudhary, Roopali; Mok, Jane; Reed, Bruce H

2009-04-01

The relationship between autophagic cell death and apoptosis is a poorly understood aspect of programmed cell death (PCD). We have examined this relationship by studying the elimination of an extra-embryonic tissue, known as the amnioserosa (AS), during Drosophila development. The AS becomes autophagic during the final stages of embryogenesis; ultimately, however, the elimination of the AS involves caspase-dependent nuclear fragmentation, tissue dissociation and engulfment by phagocytic macrophages. Mutants that are defective in the activation or execution of caspase-dependent PCD fail to degrade and eliminate the AS but show no abatement in AS autophagy. Sustained autophagy does not, therefore, necessarily result in cell death. Surprisingly, the downregulation of autophagy also results in a persistent AS phenotype and reduced cell death. Conversely, upregulation of autophagy results in caspase-dependent premature AS dissociation. These observations are consistent with the interpretation that autophagy is a prerequisite for caspase-dependent cell death in the AS.

Necroptosis in neurodegenerative diseases: a potential therapeutic target

PubMed Central

Zhang, Shuo; Tang, Mi-bo; Luo, Hai-yang; Shi, Chang-he; Xu, Yu-ming

2017-01-01

Neurodegenerative diseases are a group of chronic progressive disorders characterized by neuronal loss. Necroptosis, a recently discovered form of programmed cell death, is a cell death mechanism that has necrosis-like morphological characteristics. Necroptosis activation relies on the receptor-interacting protein (RIP) homology interaction motif (RHIM). A variety of RHIM-containing proteins transduce necroptotic signals from the cell trigger to the cell death mediators RIP3 and mixed lineage kinase domain-like protein (MLKL). RIP1 plays a particularly important and complex role in necroptotic cell death regulation ranging from cell death activation to inhibition, and these functions are often cell type and context dependent. Increasing evidence suggests that necroptosis plays an important role in the pathogenesis of neurodegenerative diseases. Moreover, small molecules such as necrostatin-1 are thought inhibit necroptotic signaling pathway. Understanding the precise mechanisms underlying necroptosis and its interactions with other cell death pathways in neurodegenerative diseases could provide significant therapeutic insights. The present review is aimed at summarizing the molecular mechanisms of necroptosis and highlighting the emerging evidence on necroptosis as a major driver of neuron cell death in neurodegenerative diseases. PMID:28661482

Boron Nutrition of Tobacco BY-2 Cells. V. Oxidative Damage is the Major Cause of Cell Death Induced by Boron Deprivation

PubMed Central

Koshiba, Taichi; Kobayashi, Masaru; Matoh, Toru

2009-01-01

Boron (B) is an essential micronutrient for vascular plants. However, it remains unclear how B deficiency leads to various metabolic disorders and cell death. To understand this mechanism, we analyzed the physiological changes in suspension-cultured tobacco (Nicotiana tabacum) BY-2 cells upon B deprivation. When 3-day-old cells were transferred to B-free medium, cell death was detectable as early as 12 h after treatment. The B-deprived cells accumulated more reactive oxygen species and lipid peroxides than control cells, and showed a slight but significant decrease in the cellular ascorbate pool. Supplementing the media with lipophilic antioxidants effectively suppressed the death of B-deprived cells, suggesting that the oxidative damage is the immediate and major cause of cell death under B deficiency. Dead cells in B-free culture exhibited a characteristic morphology with a shrunken cytoplasm, which is often seen in cells undergoing programmed cell death (PCD). However, they did not display other hallmarks of PCD such as internucleosomal DNA fragmentation, decreased ascorbate peroxidase expression and protection from death by cycloheximide. These results suggest that the death of tobacco cells induced by B deprivation is not likely to be a typical PCD. PMID:19054807

Tumor Necrosis Factor-α (TNFα)-induced Ceramide Generation via Ceramide Synthases Regulates Loss of Focal Adhesion Kinase (FAK) and Programmed Cell Death.

PubMed

Hernández-Corbacho, María José; Canals, Daniel; Adada, Mohamad M; Liu, Mengling; Senkal, Can E; Yi, Jae Kyo; Mao, Cungui; Luberto, Chiara; Hannun, Yusuf A; Obeid, Lina M

2015-10-16

Ceramide synthases (CerS1-CerS6), which catalyze the N-acylation of the (dihydro)sphingosine backbone to produce (dihydro)ceramide in both the de novo and the salvage or recycling pathway of ceramide generation, have been implicated in the control of programmed cell death. However, the regulation of the de novo pathway compared with the salvage pathway is not fully understood. In the current study, we have found that late accumulation of multiple ceramide and dihydroceramide species in MCF-7 cells treated with TNFα occurred by up-regulation of both pathways of ceramide synthesis. Nevertheless, fumonisin B1 but not myriocin was able to protect from TNFα-induced cell death, suggesting that ceramide synthase activity is crucial for the progression of cell death and that the pool of ceramide involved derives from the salvage pathway rather than de novo biosynthesis. Furthermore, compared with control cells, TNFα-treated cells exhibited reduced focal adhesion kinase and subsequent plasma membrane permeabilization, which was blocked exclusively by fumonisin B1. In addition, exogenously added C6-ceramide mimicked the effects of TNFα that lead to cell death, which were inhibited by fumonisin B1. Knockdown of individual ceramide synthases identified CerS6 and its product C16-ceramide as the ceramide synthase isoform essential for the regulation of cell death. In summary, our data suggest a novel role for CerS6/C16-ceramide as an upstream effector of the loss of focal adhesion protein and plasma membrane permeabilization, via the activation of caspase-7, and identify the salvage pathway as the critical mechanism of ceramide generation that controls cell death. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

S-Adenosyl-L-methionine protects the probiotic yeast, Saccharomyces boulardii, from acid-induced cell death.

PubMed

Cascio, Vincent; Gittings, Daniel; Merloni, Kristen; Hurton, Matthew; Laprade, David; Austriaco, Nicanor

2013-02-13

Saccharomyces boulardii is a probiotic yeast routinely used to prevent and to treat gastrointestinal disorders, including the antibiotic-associated diarrhea caused by Clostridium difficile infections. However, only 1-3% of the yeast administered orally is recovered alive in the feces suggesting that this yeast is unable to survive the acidic environment of the gastrointestinal tract. We provide evidence that suggests that S. boulardii undergoes programmed cell death (PCD) in acidic environments, which is accompanied by the generation of reactive oxygen species and the appearance of caspase-like activity. To better understand the mechanism of cell death at the molecular level, we generated microarray gene expression profiles of S. boulardii cells cultured in an acidic environment. Significantly, functional annotation revealed that the up-regulated genes were significantly over-represented in cell death pathways Finally, we show that S-adenosyl-L-methionine (AdoMet), a commercially available, FDA-approved dietary supplement, enhances the viability of S. boulardii in acidic environments, most likely by preventing programmed cell death. In toto, given the observation that many of the proven health benefits of S. boulardii are dependent on cell viability, our data suggests that taking S. boulardii and AdoMet together may be a more effective treatment for gastrointestinal disorders than taking the probiotic yeast alone.

S-Adenosyl-L-Methionine protects the probiotic yeast, Saccharomyces boulardii, from acid-induced cell death

PubMed Central

2013-01-01

Background Saccharomyces boulardii is a probiotic yeast routinely used to prevent and to treat gastrointestinal disorders, including the antibiotic-associated diarrhea caused by Clostridium difficile infections. However, only 1-3% of the yeast administered orally is recovered alive in the feces suggesting that this yeast is unable to survive the acidic environment of the gastrointestinal tract. Results We provide evidence that suggests that S. boulardii undergoes programmed cell death (PCD) in acidic environments, which is accompanied by the generation of reactive oxygen species and the appearance of caspase-like activity. To better understand the mechanism of cell death at the molecular level, we generated microarray gene expression profiles of S. boulardii cells cultured in an acidic environment. Significantly, functional annotation revealed that the up-regulated genes were significantly over-represented in cell death pathways Finally, we show that S-adenosyl-L-methionine (AdoMet), a commercially available, FDA-approved dietary supplement, enhances the viability of S. boulardii in acidic environments, most likely by preventing programmed cell death. Conclusions In toto, given the observation that many of the proven health benefits of S. boulardii are dependent on cell viability, our data suggests that taking S. boulardii and AdoMet together may be a more effective treatment for gastrointestinal disorders than taking the probiotic yeast alone. PMID:23402325

Apoptosis and Vocal Fold Disease: Clinically Relevant Implications of Epithelial Cell Death

ERIC Educational Resources Information Center

Novaleski, Carolyn K.; Carter, Bruce D.; Sivasankar, M. Preeti; Ridner, Sheila H.; Dietrich, Mary S.; Rousseau, Bernard

2017-01-01

Purpose: Vocal fold diseases affecting the epithelium have a detrimental impact on vocal function. This review article provides an overview of apoptosis, the most commonly studied type of programmed cell death. Because apoptosis can damage epithelial cells, this article examines the implications of apoptosis on diseases affecting the vocal fold…

Mitochondrial membrane permeabilization and cell death during myocardial infarction: roles of calcium and reactive oxygen species

PubMed Central

Webster, Keith A

2013-01-01

Excess generation of reactive oxygen species (ROS) and cytosolic calcium accumulation play major roles in the initiation of programmed cell death during acute myocardial infarction. Cell death may include necrosis, apoptosis and autophagy, and combinations thereof. During ischemia, calcium handling between the sarcoplasmic reticulum and myofilament is disrupted and calcium is diverted to the mitochondria causing swelling. Reperfusion, while essential for survival, reactivates energy transduction and contractility and causes the release of ROS and additional ionic imbalance. During acute ischemia–reperfusion, the principal death pathways are programmed necrosis and apoptosis through the intrinsic pathway, initiated by the opening of the mitochondrial permeability transition pore and outer mitochondrial membrane permeabilization, respectively. Despite intense investigation, the mechanisms of action and modes of regulation of mitochondrial membrane permeabilization are incompletely understood. Extrinsic apoptosis, necroptosis and autophagy may also contribute to ischemia–reperfusion injury. In this review, the roles of dysregulated calcium and ROS and the contributions of Bcl-2 proteins, as well as mitochondrial morphology in promoting mitochondrial membrane permeability change and the ensuing cell death during myocardial infarction are discussed. PMID:23176689

Ozone-Induced Cell Death in Tobacco Cultivar Bel W3 Plants. The Role of Programmed Cell Death in Lesion Formation

PubMed Central

Pasqualini, Stefania; Piccioni, Claudia; Reale, Lara; Ederli, Luisa; Della Torre, Guido; Ferranti, Francesco

2003-01-01

Treatment of the ozone-sensitive tobacco (Nicotiana tabacum L. cv Bel W3) with an ozone pulse (150 nL L–1 for 5 h) induced visible injury, which manifested 48 to 72 h from onset of ozone fumigation. The “classical” ozone symptoms in tobacco cv Bel W3 plants occur as sharply defined, dot-like lesions on the adaxial side of the leaf and result from the death of groups of palisade cells. We investigated whether this reaction had the features of a hypersensitive response like that which results from the incompatible plant-pathogen interaction. We detected an oxidative burst, the result of H2O2 accumulation at 12 h from the starting of fumigation. Ozone treatment induced deposition of autofluorescent compounds and callose 24 h from the start of treatment. Total phenolic content was also strongly stimulated at the 10th and 72nd h from starting fumigation, concomitant with an enhancement in phenylalanine ammonia-lyase a and phenylalanine ammonia-lyase b expression, as evaluated by reverse transcriptase-polymerase chain reaction. There was also a marked, but transient, increase in the mRNA level of pathogenesis-related-1a, a typical hypersensitive response marker. Overall, these results are evidence that ozone triggers a hypersensitive response in tobacco cv Bel W3 plants. We adopted four criteria for detecting programmed cell death in ozonated tobacco cv Bel W3 leaves: (a) early release of cytochrome c from mitochondria; (b) activation of protease; (c) DNA fragmentation by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling of DNA 3′-OH groups; and (d) ultrastructural changes characteristic of programmed cell death, including chromatin condensation and blebbing of plasma membrane. We, therefore, provide evidence that ozone-induced oxidative stress triggers a cell death program in tobacco cv Bel W3. PMID:14612586

Identification of factors that function in Drosophila salivary gland cell death during development using proteomics

PubMed Central

McPhee, C K; Balgley, B M; Nelson, C; Hill, J H; Batlevi, Y; Fang, X; Lee, C S; Baehrecke, E H

2013-01-01

Proteasome inhibitors induce cell death and are used in cancer therapy, but little is known about the relationship between proteasome impairment and cell death under normal physiological conditions. Here, we investigate the relationship between proteasome function and larval salivary gland cell death during development in Drosophila. Drosophila larval salivary gland cells undergo synchronized programmed cell death requiring both caspases and autophagy (Atg) genes during development. Here, we show that ubiquitin proteasome system (UPS) function is reduced during normal salivary gland cell death, and that ectopic proteasome impairment in salivary gland cells leads to early DNA fragmentation and salivary gland condensation in vivo. Shotgun proteomic analyses of purified dying salivary glands identified the UPS as the top category of proteins enriched, suggesting a possible compensatory induction of these factors to maintain proteolysis during cell death. We compared the proteome following ectopic proteasome impairment to the proteome during developmental cell death in salivary gland cells. Proteins that were enriched in both populations of cells were screened for their function in salivary gland degradation using RNAi knockdown. We identified several factors, including trol, a novel gene CG11880, and the cop9 signalsome component cop9 signalsome 6, as required for Drosophila larval salivary gland degradation. PMID:22935612

Caspases and Kinases in a Death Grip

PubMed Central

Kurokawa, Manabu; Kornbluth, Sally

2011-01-01

The complex process of apoptosis is orchestrated by caspases, a family of cysteine proteases with unique substrate specificities. Accumulating evidence suggests that cell death pathways are finely tuned by multiple signaling events, including direct phosphorylation of caspases, whereas kinases are often substrates of active caspases. Importantly, caspase-mediated cleavage of kinases can terminate prosurvival signaling or generate proapoptotic peptide fragments that help to execute the death program and facilitate packaging of the dying cells. Here, we review caspases as kinase substrates and kinases as caspase substrates and discuss how the balance between cell survival and cell death can be shifted through crosstalk between these two enzyme families. PMID:19737514

Anthranilate Fluorescence Marks a Calcium-Propagated Necrotic Wave That Promotes Organismal Death in C. elegans

PubMed Central

Coburn, Cassandra; Allman, Erik; Mahanti, Parag; Benedetto, Alexandre; Cabreiro, Filipe; Pincus, Zachary; Matthijssens, Filip; Araiz, Caroline; Mandel, Abraham; Vlachos, Manolis; Edwards, Sally-Anne; Fischer, Grahame; Davidson, Alexander; Pryor, Rosina E.; Stevens, Ailsa; Slack, Frank J.; Tavernarakis, Nektarios; Braeckman, Bart P.; Schroeder, Frank C.; Nehrke, Keith; Gems, David

2013-01-01

For cells the passage from life to death can involve a regulated, programmed transition. In contrast to cell death, the mechanisms of systemic collapse underlying organismal death remain poorly understood. Here we present evidence of a cascade of cell death involving the calpain-cathepsin necrosis pathway that can drive organismal death in Caenorhabditis elegans. We report that organismal death is accompanied by a burst of intense blue fluorescence, generated within intestinal cells by the necrotic cell death pathway. Such death fluorescence marks an anterior to posterior wave of intestinal cell death that is accompanied by cytosolic acidosis. This wave is propagated via the innexin INX-16, likely by calcium influx. Notably, inhibition of systemic necrosis can delay stress-induced death. We also identify the source of the blue fluorescence, initially present in intestinal lysosome-related organelles (gut granules), as anthranilic acid glucosyl esters—not, as previously surmised, the damage product lipofuscin. Anthranilic acid is derived from tryptophan by action of the kynurenine pathway. These findings reveal a central mechanism of organismal death in C. elegans that is related to necrotic propagation in mammals—e.g., in excitotoxicity and ischemia-induced neurodegeneration. Endogenous anthranilate fluorescence renders visible the spatio-temporal dynamics of C. elegans organismal death. PMID:23935448

Neural crest apoptosis and the establishment of craniofacial pattern: an honorable death.

PubMed

Graham, A; Koentges, G; Lumsden, A

1996-01-01

During development of the vertebrate head neural crest cells emigrate from the hindbrain and populate the branchial arches, giving rise to distinct skeletal elements and muscle connective tissues in each arch. The production of neural crest from the hindbrain is discontinuous and crest cells destined for different arches, carrying different positional cues, are separated by regions of apoptosis centered on rhombomeres (r) 3 and r5. This cell death program is under the interactive control of the neighboring hindbrain segments. Both r3 and r5 produce large numbers of crest cells when freed from their flanking rhombomere, but when conjoined with their neighbor the cell death program is restored. Two key components of this program are Bmp 4 and msx-2, both of which are expressed in the apoptotic foci of r3 and r5 and which are also regulated by neighbor interactions. Importantly, the addition of recombinant Bmp 4 to isolated cultures of r3 and r5 induces the expression of Bmp 4 and msx-2 and restores the cell death program. This early neural crest segregation is maintained during development and it has profound effects upon the final craniofacial pattern. Even though crest cells from different axial origins will contribute to compound skeletal elements, these distinct populations do not intermingle. Furthermore head muscle connective tissues are exclusively anchored to skeletal domains arising from neural crest from the same axial level. Thus the discontinuous production of neural crest sculpts the crest into nonmixing streams and consequently ensures the fidelity of patterning.

Calcein+/PI- as an early apoptotic feature in Leishmania.

PubMed

Basmaciyan, Louise; Azas, Nadine; Casanova, Magali

2017-01-01

Although leishmaniases are responsible for high morbidity and mortality all over the world, no really satisfying treatment exists. Furthermore, the corresponding parasite Leishmania undergoes a very characteristic form of programmed cell death. Indeed, different stimuli can induce morphological and biochemical apoptotic-like features. However, the key proteins involved in mammal apoptosis, such as caspases and death receptors, are not encoded in the genome of this parasite. Currently, little is known about Leishmania apoptosis, notably owing to the lack of specific tools for programmed cell death analysis in these parasites. Furthermore, there is a need for a better understanding of Leishmania programmed cell death in order (i) to better understand the role of apoptosis in unicellular organisms, (ii) to better understand apoptosis in general through the study of an ancestral eukaryote, and (iii) to identify new therapeutic targets against leishmaniases. To advance understanding of apoptosis in Leishmania, in this study we developed a new tool based on the quantification of calcein and propidium iodide by flow cytometry. This double labeling can be employed to distinguish early apoptosis, late apoptosis and necrosis in Leishmania live cells with a very simple and rapid assay. This paper should, therefore, be of interest for people working on Leishmania and related parasites.

Programmed cell death in seeds of angiosperms.

PubMed

López-Fernández, María Paula; Maldonado, Sara

2015-12-01

During the diversification of angiosperms, seeds have evolved structural, chemical, molecular and physiologically developing changes that specially affect the nucellus and endosperm. All through seed evolution, programmed cell death (PCD) has played a fundamental role. However, examples of PCD during seed development are limited. The present review examines PCD in integuments, nucellus, suspensor and endosperm in those representative examples of seeds studied to date. © 2015 Institute of Botany, Chinese Academy of Sciences.

Essential role of grim-led programmed cell death for the establishment of corazonin-producing peptidergic nervous system during embryogenesis and metamorphosis in Drosophila melanogaster

PubMed Central

Lee, Gyunghee; Sehgal, Ritika; Wang, Zixing; Nair, Sudershana; Kikuno, Keiko; Chen, Chun-Hong; Hay, Bruce; Park, Jae H.

2013-01-01

Summary In Drosophila melanogaster, combinatorial activities of four death genes, head involution defective (hid), reaper (rpr), grim, and sickle (skl), have been known to play crucial roles in the developmentally regulated programmed cell death (PCD) of various tissues. However, different expression patterns of the death genes also suggest distinct functions played by each. During early metamorphosis, a great number of larval neurons unfit for adult life style are removed by PCD. Among them are eight pairs of corazonin-expressing larval peptidergic neurons in the ventral nerve cord (vCrz). To reveal death genes responsible for the PCD of vCrz neurons, we examined extant and recently available mutations as well as RNA interference that disrupt functions of single or multiple death genes. We found grim as a chief proapoptotic gene and skl and rpr as minor ones. The function of grim is also required for PCD of the mitotic sibling cells of the vCrz neuronal precursors (EW3-sib) during embryonic neurogenesis. An intergenic region between grim and rpr, which, it has been suggested, may enhance expression of three death genes in embryonic neuroblasts, appears to play a role for the vCrz PCD, but not for the EW3-sib cell death. The death of vCrz neurons and EW3-sib is triggered by ecdysone and the Notch signaling pathway, respectively, suggesting distinct regulatory mechanisms of grim expression in a cell- and developmental stage-specific manner. PMID:23519152

Markers of Developmentally Regulated Programmed Cell Death and Their Analysis in Cereal Seeds.

PubMed

Domínguez, Fernando; Cejudo, Francisco Javier

2018-01-01

Programmed cell death (PCD) is a key process for the development and differentiation of multicellular organisms, which is characterized by well-defined morphological and biochemical features. These include chromatin condensation, DNA degradation and nuclear fragmentation, with nucleases and proteases playing a relevant function in these processes. In this chapter we describe methods routinely used for the analysis of hallmarks of developmentally regulated PCD in cereal seed tissues, which are based on agarose and polyacrylamide gel electrophoresis, in situ staining of DNA fragmentation, and cell-free assays of relevant enzymatic activities.

Novel function of STAT1beta in B cells: induction of cell death by a mechanism different from that of STAT1alpha.

PubMed

Najjar, Imen; Schischmanoff, Pierre Olivier; Baran-Marszak, Fanny; Deglesne, Pierre-Antoine; Youlyouz-Marfak, Ibtissam; Pampin, Mathieu; Feuillard, Jean; Bornkamm, Georg W; Chelbi-Alix, Mounira K; Fagard, Remi

2008-12-01

Alternate splicing of STAT1 produces two isoforms: alpha, known as the active form, and beta, previously shown to act as a dominant-negative factor. Most studies have dealt with STAT1alpha, showing its involvement in cell growth control and cell death. To examine the specific function of either isoform in cell death, a naturally STAT1-deficient human B cell line was transfected to express STAT1alpha or STAT1beta. STAT1alpha, expressed alone, enhanced cell death, potentiated the fludarabine-induced apoptosis, and enhanced the nuclear location, the phosphorylation, and the transcriptional activity of p53. Unexpectedly, STAT1beta, expressed alone, induced cell death through a mechanism that was independent of the nuclear function of p53. Indeed, in STAT1beta-expressing B cells, p53 was strictly cytoplasmic where it formed clusters, and there was no induction of the transcriptional activity of p53. These data reveal a novel role of STAT1beta in programmed cell death, which is independent of p53.

Bim controls IL-15 availability and limits engagement of multiple BH3-only proteins

PubMed Central

Kurtulus, S; Sholl, A; Toe, J; Tripathi, P; Raynor, J; Li, K-P; Pellegrini, M; Hildeman, D A

2015-01-01

During the effector CD8+ T-cell response, transcriptional differentiation programs are engaged that promote effector T cells with varying memory potential. Although these differentiation programs have been used to explain which cells die as effectors and which cells survive and become memory cells, it is unclear if the lack of cell death enhances memory. Here, we investigated effector CD8+ T-cell fate in mice whose death program has been largely disabled because of the loss of Bim. Interestingly, the absence of Bim resulted in a significant enhancement of effector CD8+ T cells with more memory potential. Bim-driven control of memory T-cell development required T-cell-specific, but not dendritic cell-specific, expression of Bim. Both total and T-cell-specific loss of Bim promoted skewing toward memory precursors, by enhancing the survival of memory precursors, and limiting the availability of IL-15. Decreased IL-15 availability in Bim-deficient mice facilitated the elimination of cells with less memory potential via the additional pro-apoptotic molecules Noxa and Puma. Combined, these data show that Bim controls memory development by limiting the survival of pre-memory effector cells. Further, by preventing the consumption of IL-15, Bim limits the role of Noxa and Puma in causing the death of effector cells with less memory potential. PMID:25124553

Bim controls IL-15 availability and limits engagement of multiple BH3-only proteins.

PubMed

Kurtulus, S; Sholl, A; Toe, J; Tripathi, P; Raynor, J; Li, K-P; Pellegrini, M; Hildeman, D A

2015-01-01

During the effector CD8+ T-cell response, transcriptional differentiation programs are engaged that promote effector T cells with varying memory potential. Although these differentiation programs have been used to explain which cells die as effectors and which cells survive and become memory cells, it is unclear if the lack of cell death enhances memory. Here, we investigated effector CD8+ T-cell fate in mice whose death program has been largely disabled because of the loss of Bim. Interestingly, the absence of Bim resulted in a significant enhancement of effector CD8+ T cells with more memory potential. Bim-driven control of memory T-cell development required T-cell-specific, but not dendritic cell-specific, expression of Bim. Both total and T-cell-specific loss of Bim promoted skewing toward memory precursors, by enhancing the survival of memory precursors, and limiting the availability of IL-15. Decreased IL-15 availability in Bim-deficient mice facilitated the elimination of cells with less memory potential via the additional pro-apoptotic molecules Noxa and Puma. Combined, these data show that Bim controls memory development by limiting the survival of pre-memory effector cells. Further, by preventing the consumption of IL-15, Bim limits the role of Noxa and Puma in causing the death of effector cells with less memory potential.

Gasdermin: A new player to the inflammasome game.

PubMed

Ramos-Junior, Erivan S; Morandini, Ana Carolina

2017-12-01

Pyroptosis is a lytic type of programmed cell death that was traditionally associated with the involvement of inflammatory caspases, such as caspase-1. These inflammatory caspases are activated within multi-protein complexes called inflammasomes that are assembled in response to invading pathogens and/or danger signals. Pyroptotic cell death was suggested to evolve via the formation of pores in the plasma membrane, but the exact mechanism underlying the formation of these pores remained unclear. Recently, gasdermin D, a member of the gasdermin protein family was identified as a caspase substrate and essential effector of pyroptosis, being identified as the protagonist of membrane pore formation. Gasdermins have emerged as a family of new class of cell death inducers, but many questions remain unanswered. Here, we present an overview of recent work being done in the area of programmed cell death and the latest evidence regarding the role and participation of gasdermin D as an effector of pyroptosis. Copyright © 2017 Chang Gung University. Published by Elsevier B.V. All rights reserved.

Programmed cell death during development of cowpea (Vigna unguiculata (L.) Walp.) seed coat.

PubMed

Lima, Nathália Bastos; Trindade, Fernanda Gomes; da Cunha, Maura; Oliveira, Antônia Elenir Amâncio; Topping, Jennifer; Lindsey, Keith; Fernandes, Kátia Valevski Sales

2015-04-01

The seed coat develops primarily from maternal tissues and comprises multiple cell layers at maturity, providing a metabolically dynamic interface between the developing embryo and the environment during embryogenesis, dormancy and germination of seeds. Seed coat development involves dramatic cellular changes, and the aim of this research was to investigate the role of programmed cell death (PCD) events during the development of seed coats of cowpea [Vigna unguiculata (L.) Walp.]. We demonstrate that cells of the developing cowpea seed coats undergo a programme of autolytic cell death, detected as cellular morphological changes in nuclei, mitochondria, chloroplasts and vacuoles, DNA fragmentation and oligonucleosome accumulation in the cytoplasm, and loss of membrane viability. We show for the first time that classes 6 and 8 caspase-like enzymes are active during seed coat development, and that these activities may be compartmentalized by translocation between vacuoles and cytoplasm during PCD events. © 2014 John Wiley & Sons Ltd.

Necroptosis and Cancer

PubMed Central

Najafov, Ayaz; Chen, Hongbo; Yuan, Junying

2017-01-01

Necroptosis is a programmed lytic cell death pathway, deregulation of which is linked to various inflammatory disorders. Escape from programmed cell death and inflammation play a significant role in cancer, and therefore, investigating the role of necroptosis in cancer has been of high interest. Necroptosis has been shown to promote cancer metastasis and T cells death. Escape from necroptosis via loss of RIPK3 expression is a feature of some cancers. While necroptosis is a promising novel target for cancer therapies, further investigation into its biological role in carcinogenesis is warranted. In this article, we review the recently-identified interplay points between necroptosis and cancer, and outline major biological questions that require further inquiry on the road to targeting this pathway in cancer. PMID:28451648

The role of necroptosis in pulmonary diseases.

PubMed

Mizumura, Kenji; Maruoka, Shuichiro; Gon, Yasuhiro; Choi, Augustine M K; Hashimoto, Shu

2016-11-01

By regulating the cell number and eliminating harmful cells, programmed cell death plays a critical role in development, homeostasis, and disease. While apoptosis is a recognized form of programmed cell death, necrosis was considered a type of uncontrolled cell death induced by extreme physical or chemical stress. However, recent studies have revealed the existence of a genetically programmed and regulated form of necrosis, termed necroptosis. Necroptosis is defined as necrotic cell death that is dependent on receptor-interacting protein kinase 3 (RIPK3). RIPK3, receptor-interacting protein kinase 1 (RIPK1), and a mixed-lineage kinase domain-like protein (MLKL) form a multiprotein complex called a necrosome. Although necroptosis generally provides a cell-autonomous host defense, on the other hand, cell rupture caused by necroptosis induces inflammation through the release of damage-associated molecular patterns, such as mitochondrial DNA, HMGB1, and IL-1. Previously, necroptosis was considered an alternative to apoptosis, but it is becoming increasingly clear that necroptosis itself is relevant to clinical disease, independent of apoptosis. According to some recent studies, autophagy, a cellular process for organelle and protein turnover, regulates necroptosis. This review outlines the principal components of necroptosis and provides an overview of the emerging importance of necroptosis in the pathogenesis of pulmonary disease, including chronic obstructive pulmonary disease, lung cancer, infection, and sepsis. We also discuss the molecular relationship between necroptosis and autophagy. Strategies targeting necroptosis may yield novel therapies for pulmonary diseases. Copyright © 2016 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

Regulation of Tumor Progression by Programmed Necrosis

PubMed Central

Jeon, Hyun Min; Jeong, Eui Kyong; Lee, Yig Ji; Kim, Cho Hee; Park, Hye Gyeong

2018-01-01

Rapidly growing malignant tumors frequently encounter hypoxia and nutrient (e.g., glucose) deprivation, which occurs because of insufficient blood supply. This results in necrotic cell death in the core region of solid tumors. Necrotic cells release their cellular cytoplasmic contents into the extracellular space, such as high mobility group box 1 (HMGB1), which is a nonhistone nuclear protein, but acts as a proinflammatory and tumor-promoting cytokine when released by necrotic cells. These released molecules recruit immune and inflammatory cells, which exert tumor-promoting activity by inducing angiogenesis, proliferation, and invasion. Development of a necrotic core in cancer patients is also associated with poor prognosis. Conventionally, necrosis has been thought of as an unregulated process, unlike programmed cell death processes like apoptosis and autophagy. Recently, necrosis has been recognized as a programmed cell death, encompassing processes such as oncosis, necroptosis, and others. Metabolic stress-induced necrosis and its regulatory mechanisms have been poorly investigated until recently. Snail and Dlx-2, EMT-inducing transcription factors, are responsible for metabolic stress-induced necrosis in tumors. Snail and Dlx-2 contribute to tumor progression by promoting necrosis and inducing EMT and oncogenic metabolism. Oncogenic metabolism has been shown to play a role(s) in initiating necrosis. Here, we discuss the molecular mechanisms underlying metabolic stress-induced programmed necrosis that promote tumor progression and aggressiveness. PMID:29636841

Live morphological analysis of taxol-induced cytoplasmic vacuolization [corrected] in human lung adenocarcinoma cells.

PubMed

Wang, Xiao-Ping; Chen, Tong-Sheng; Sun, Lei; Cai, Ji-Ye; Wu, Ming-Qian; Mok, Martin

2008-12-01

Taxol (paclitaxel), one of the most active cancer chemotherapeutic agents, can cause programmed cell death (PCD) and cytoplasmic vacuolization. The objective of this study was to analyze the morphological characteristics induced by taxol. Human lung adenocarcinoma (ASTC-a-1) cells were exposed to various concentration of taxol. CCK-8 was used to assay the cell viability. Atomic force microscopy (AFM), plasmid transfection and confocal fluorescence microscopy were performed to image the cells morphological change induced by taxol. Fluorescence resonance energy transfer (FRET) was used to monitor the caspase-3 activation in living cells during taxol-induced cell death. Cells treated with taxol exhibited significant swelling and cytoplasmic vacuolization which may be due to endoplasmic reticulum (ER) vacuolization. Caspase-3 was not activated during taxol-induced cytoplasmic vacuolization and cell death. These findings suggest that taxol induces caspase-3-independent cytoplasmic vacuolization, cell swelling and cell death through ER vacuolization.

E-Cigarette Aerosol Exposure Induces Reactive Oxygen Species, DNA Damage, and Cell Death in Vascular Endothelial Cells.

PubMed

Anderson, Chastain; Majeste, Andrew; Hanus, Jakub; Wang, Shusheng

2016-12-01

Cigarette smoking remains one of the leading causes of preventable death worldwide. Vascular cell death and dysfunction is a central or exacerbating component in the majority of cigarette smoking related pathologies. The recent development of the electronic nicotine delivery systems known as e-cigarettes provides an alternative to conventional cigarette smoking; however, the potential vascular health risks of e-cigarette use remain unclear. This study evaluates the effects of e-cigarette aerosol extract (EAE) and conventional cigarette smoke extract (CSE) on human umbilical vein endothelial cells (HUVECs). A laboratory apparatus was designed to produce extracts from e-cigarettes and conventional cigarettes according to established protocols for cigarette smoking. EAE or conventional CSE was applied to human vascular endothelial cells for 4-72 h, dependent on the assay. Treated cells were assayed for reactive oxygen species, DNA damage, cell viability, and markers of programmed cell death pathways. Additionally, the anti-oxidants α-tocopherol and n-acetyl-l-cysteine were used to attempt to rescue e-cigarette induced cell death. Our results indicate that e-cigarette aerosol is capable of inducing reactive oxygen species, causing DNA damage, and significantly reducing cell viability in a concentration dependent fashion. Immunofluorescent and flow cytometry analysis indicate that both the apoptosis and programmed necrosis pathways are triggered by e-cigarette aerosol treatment. Additionally, anti-oxidant treatment provides a partial rescue of the induced cell death, indicating that reactive oxygen species play a causal role in e-cigarette induced cytotoxicity. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The serine protease inhibitor TLCK attenuates intrinsic death pathways in neurons upstream of mitochondrial demise.

PubMed

Reuther, C; Ganjam, G K; Dolga, A M; Culmsee, C

2014-11-01

It is well-established that activation of proteases, such as caspases, calpains and cathepsins are essential components in signaling pathways of programmed cell death (PCD). Although these proteases have also been linked to mechanisms of neuronal cell death, they are dispensable in paradigms of intrinsic death pathways, e.g. induced by oxidative stress. However, emerging evidence implicated a particular role for serine proteases in mechanisms of PCD in neurons. Here, we investigated the role of trypsin-like serine proteases in a model of glutamate toxicity in HT-22 cells. In these cells glutamate induces oxytosis, a form of caspase-independent cell death that involves activation of the pro-apoptotic protein BH3 interacting-domain death agonist (Bid), leading to mitochondrial demise and ensuing cell death. In this model system, the trypsin-like serine protease inhibitor Nα-tosyl-l-lysine chloromethyl ketone hydrochloride (TLCK) inhibited mitochondrial damage and cell death. Mitochondrial morphology alterations, the impairment of the mitochondrial membrane potential and ATP depletion were prevented and, moreover, lipid peroxidation induced by glutamate was completely abolished. Strikingly, truncated Bid-induced cell death was not affected by TLCK, suggesting a detrimental activity of serine proteases upstream of Bid activation and mitochondrial demise. In summary, this study demonstrates the protective effect of serine protease inhibition by TLCK against oxytosis-induced mitochondrial damage and cell death. These findings indicate that TLCK-sensitive serine proteases play a crucial role in cell death mechanisms upstream of mitochondrial demise and thus, may serve as therapeutic targets in diseases, where oxidative stress and intrinsic pathways of PCD mediate neuronal cell death.

PROGRAMMED CELL DEATH IN EXTRAOCULAR MUSCLE TENDON/SCLERA PRECURSORS

EPA Science Inventory

Abstract

Purpose: 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...

Prior irradiation results in elevated programmed cell death protein 1 (PD-1) in T cells.

PubMed

Li, Deguan; Chen, Renxiang; Wang, Yi-Wen; Fornace, Albert J; Li, Heng-Hong

2018-05-01

In this study we addressed the question whether radiation-induced adverse effects on T cell activation are associated with alterations of T cell checkpoint receptors. Expression levels of checkpoint receptors on T cell subpopulations were analyzed at multiple post-radiation time points ranging from one to four weeks in mice receiving a single fraction of 1 or 4 Gy of γ-ray. T cell activation associated metabolic changes were assessed. Our results showed that prior irradiation resulted in significant elevated expression of programmed cell death protein 1 (PD-1) in both CD4+ and CD8+ populations, at all three post-radiation time points. T cells with elevated PD-1 mostly were either central memory or naïve cells. In addition, the feedback induction of PD-1 expression in activated T cells declined after radiation. Taken together, the elevated PD-1 level observed at weeks after radiation exposure is connected to T cell dysfunction. Recent preclinical and clinical studies have showed that a combination of radiotherapy and T cell checkpoint blockade immunotherapy including targeting the programmed death-ligand 1 (PD-L1)/PD-1 axis may potentiate the antitumor response. Understanding the dynamic changes in PD-1 levels in T cells after radiation should help in the development of a more effective therapeutic strategy.

Nitric oxide production is not required for dihydrosphingosine-induced cell death in tobacco BY-2 cells.

PubMed

Da Silva, Daniel; Lachaud, Christophe; Cotelle, Valérie; Brière, Christian; Grat, Sabine; Mazars, Christian; Thuleau, Patrice

2011-05-01

Sphinganine or dihydrosphingosine (d18:0, DHS), one of the most abundant free sphingoid Long Chain Base (LCB) in plants, is known to induce a calcium dependent programmed cell death (PCD) in tobacco BY-2 cells. In addition, we have recently shown that DHS triggers a production of H2O2, via the activation of NADPH oxidase(s). However, this production of H2O2 is not correlated with the DHS-induced cell death but would rather be associated with basal cell defense mechanisms. In the present study, we extend our current knowledge of the DHS signaling pathway, by demonstrating that DHS also promotes a production of nitric oxide (NO) in tobacco BY-2 cells. As for H2O2, this NO production is not necessary for cell death induction. 

Arabidopsis ACCELERATED CELL DEATH2 Modulates Programmed Cell DeathW⃞

PubMed Central

Yao, Nan; Greenberg, Jean T.

2006-01-01

The Arabidopsis thaliana chloroplast protein ACCELERATED CELL DEATH2 (ACD2) modulates the amount of programmed cell death (PCD) triggered by Pseudomonas syringae and protoporphyrin IX (PPIX) treatment. In vitro, ACD2 can reduce red chlorophyll catabolite, a chlorophyll derivative. We find that ACD2 shields root protoplasts that lack chlorophyll from light- and PPIX-induced PCD. Thus, chlorophyll catabolism is not obligatory for ACD2 anti-PCD function. Upon P. syringae infection, ACD2 levels and localization change in cells undergoing PCD and in their close neighbors. Thus, ACD2 shifts from being largely in chloroplasts to partitioning to chloroplasts, mitochondria, and, to a small extent, cytosol. ACD2 protects cells from PCD that requires the early mitochondrial oxidative burst. Later, the chloroplasts of dying cells generate NO, which only slightly affects cell viability. Finally, the mitochondria in dying cells have dramatically altered movements and cellular distribution. Overproduction of both ACD2 (localized to mitochondria and chloroplasts) and ascorbate peroxidase (localized to chloroplasts) greatly reduces P. syringae–induced PCD, suggesting a pro-PCD role for mitochondrial and chloroplast events. During infection, ACD2 may bind to and/or reduce PCD-inducing porphyrin-related molecules in mitochondria and possibly chloroplasts that generate reactive oxygen species, cause altered organelle behavior, and activate a cascade of PCD-inducing events. PMID:16387834

Autonomous rexinoid death signaling is suppressed by converging signaling pathways in immature leukemia cells.

PubMed

Benoit, G R; Flexor, M; Besançon, F; Altucci, L; Rossin, A; Hillion, J; Balajthy, Z; Legres, L; Ségal-Bendirdjian, E; Gronemeyer, H; Lanotte, M

2001-07-01

On their own, retinoid X receptor (RXR)-selective ligands (rexinoids) are silent in retinoic acid receptor (RAR)-RXR heterodimers, and no selective rexinoid program has been described as yet in cellular systems. We report here on the rexinoid signaling capacity that triggers apoptosis of immature promyelocytic NB4 cells as a default pathway in the absence of survival factors. Rexinoid-induced apoptosis displays all features of bona fide programmed cell death and is inhibited by RXR, but not RAR antagonists. Several types of survival signals block rexinoid-induced apoptosis. RARalpha agonists switch the cellular response toward differentiation and induce the expression of antiapoptosis factors. Activation of the protein kinase A pathway in the presence of rexinoid agonists induces maturation and blocks immature cell apoptosis. Addition of nonretinoid serum factors also blocks cell death but does not induce cell differentiation. Rexinoid-induced apoptosis is linked to neither the presence nor stability of the promyelocytic leukemia-RARalpha fusion protein and operates also in non-acute promyelocytic leukemia cells. Together our results support a model according to which rexinoids activate in certain leukemia cells a default death pathway onto which several other signaling paradigms converge. This pathway is entirely distinct from that triggered by RAR agonists, which control cell maturation and postmaturation apoptosis.

The role of necroptosis in the treatment of diseases.

PubMed

Cho, Young Sik

2018-04-11

Necroptosis is an emerging form of programmed cell death occurring via active and well-regulated necrosis, distinct from apoptosis morphologically, and biochemically. Necroptosis is mainly unmasked when apoptosis is compromised in response to cell stress. Unlike apoptotic cells, which are cleared by macrophages or neighboring cells, necrotic cells release danger signals, triggering inflammation, and exacerbating tissue damage. Evidence increasingly suggests that programmed necrosis is not only associated with pathophysiology of disease, but also induces innate immune response to viral infection. Therefore, necroptotic cell death plays both physiological and pathological roles. Physiologically, necroptosis induce an innate immune response as well as premature assembly of viral particles in cells infected with virus that abrogates host apoptotic machinery. On the other hand, necroptosis per se is detrimental, causing various diseases such as sepsis, neurodegenerative diseases and ischemic reperfusion injury. This review discusses the signaling pathways leading to necroptosis, associated necroptotic proteins with target-specific inhibitors and diseases involved. Several studies currently focus on protective approaches to inhibit necroptotic cell death. In cancer biology, however, anticancer drug resistance severely hampers the efficacy of chemotherapy based on apoptosis. Pharmacological switch of cell death finds therapeutic application in drug-resistant cancers. Therefore, the possible clinical role of necroptosis in cancer control will be discussed in brief.

TRAIL-induced programmed necrosis as a novel approach to eliminate tumor cells

PubMed Central

2014-01-01

Background The cytokine TRAIL represents one of the most promising candidates for the apoptotic elimination of tumor cells, either alone or in combination therapies. However, its efficacy is often limited by intrinsic or acquired resistance of tumor cells to apoptosis. Programmed necrosis is an alternative, molecularly distinct mode of programmed cell death that is elicited by TRAIL under conditions when the classical apoptosis machinery fails or is actively inhibited. The potential of TRAIL-induced programmed necrosis in tumor therapy is, however, almost completely uncharacterized. We therefore investigated its impact on a panel of tumor cell lines of wide-ranging origin. Methods Cell death/viability was measured by flow cytometry/determination of intracellular ATP levels/crystal violet staining. Cell surface expression of TRAIL receptors was detected by flow cytometry, expression of proteins by Western blot. Ceramide levels were quantified by high-performance thin layer chromatography and densitometric analysis, clonogenic survival of cells was determined by crystal violet staining or by soft agarose cloning. Results TRAIL-induced programmed necrosis killed eight out of 14 tumor cell lines. Clonogenic survival was reduced in all sensitive and even one resistant cell lines tested. TRAIL synergized with chemotherapeutics in killing tumor cell lines by programmed necrosis, enhancing their effect in eight out of 10 tested tumor cell lines and in 41 out of 80 chemotherapeutic/TRAIL combinations. Susceptibility/resistance of the investigated tumor cell lines to programmed necrosis seems to primarily depend on expression of the pro-necrotic kinase RIPK3 rather than the related kinase RIPK1 or cell surface expression of TRAIL receptors. Furthermore, interference with production of the lipid ceramide protected all tested tumor cell lines. Conclusions Our study provides evidence that TRAIL-induced programmed necrosis represents a feasible approach for the elimination of tumor cells, and that this treatment may represent a promising new option for the future development of combination therapies. Our data also suggest that RIPK3 expression may serve as a potential predictive marker for the sensitivity of tumor cells to programmed necrosis and extend the previously established role of ceramide as a key mediator of death receptor-induced programmed necrosis (and thus as a potential target for future therapies) also to the tumor cell lines examined here. PMID:24507727

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

PubMed

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

2016-04-21

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

Prokaryotic Caspase Homologs: Phylogenetic Patterns and Functional Characteristics Reveal Considerable Diversity

PubMed Central

Asplund-Samuelsson, Johannes; Bergman, Birgitta; Larsson, John

2012-01-01

Caspases accomplish initiation and execution of apoptosis, a programmed cell death process specific to metazoans. The existence of prokaryotic caspase homologs, termed metacaspases, has been known for slightly more than a decade. Despite their potential connection to the evolution of programmed cell death in eukaryotes, the phylogenetic distribution and functions of these prokaryotic metacaspase sequences are largely uncharted, while a few experiments imply involvement in programmed cell death. Aiming at providing a more detailed picture of prokaryotic caspase homologs, we applied a computational approach based on Hidden Markov Model search profiles to identify and functionally characterize putative metacaspases in bacterial and archaeal genomes. Out of the total of 1463 analyzed genomes, merely 267 (18%) were identified to contain putative metacaspases, but their taxonomic distribution included most prokaryotic phyla and a few archaea (Euryarchaeota). Metacaspases were particularly abundant in Alphaproteobacteria, Deltaproteobacteria and Cyanobacteria, which harbor many morphologically and developmentally complex organisms, and a distinct correlation was found between abundance and phenotypic complexity in Cyanobacteria. Notably, Bacillus subtilis and Escherichia coli, known to undergo genetically regulated autolysis, lacked metacaspases. Pfam domain architecture analysis combined with operon identification revealed rich and varied configurations among the metacaspase sequences. These imply roles in programmed cell death, but also e.g. in signaling, various enzymatic activities and protein modification. Together our data show a wide and scattered distribution of caspase homologs in prokaryotes with structurally and functionally diverse sub-groups, and with a potentially intriguing evolutionary role. These features will help delineate future characterizations of death pathways in prokaryotes. PMID:23185476

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

PubMed Central

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

Simultaneous induction of apoptotic, autophagic, and necrosis-like cell death by monoclonal antibodies recognizing chicken transferrin receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohno, Yoshiya; Yagi, Hideki; Nakamura, Masanori

Programmed cell death (PCD) is categorized as apoptotic, autophagic, or necrosis-like. Although the possibility that plural (two or three) death signals could be induced by a given stimulus has been reported, the precise mechanisms regulating PCD are not well understood. Recently, we have obtained two anti-chicken transferrin receptor (TfR) monoclonal antibodies (mAbs; D18 and D19) inducing a unique cell death. Although the cell death had several features of apoptosis, autophagic and necrosis-like morphological alterations were simultaneously observed in electron microphotographs. In addition to cells with condensed chromatin and an intact plasma membrane (apoptotic cells), cells having many vacuoles in themore » cytoplasm (autophagic cells), and enlarged cells with ruptured plasma membranes (necrosis-like cells) were observed in DT40 cells treated with the mAbs, however, the latter two types of dead cells were not detected upon treatment with staurosporine, a typical apoptosis inducer. In autophagic cells, numerous membrane-bound vesicles occupying most of the cytoplasmic space, which frequently contained electron-dense materials from cytoplasmic fragments and organelles, were observed. The simultaneous induction of multiple death signals from a stimulus via the TfR is of great interest to those researching cell death. In addition, activation of caspases was observed in DT40 cells treated with D19, however, the cell death was not inhibited with z-VAD-fmk, a pan-caspase inhibitor, suggesting that at least in part, a caspase-independent pathway is involved in the TfR-mediated cell death.« less

The phenoptosis problem: what is causing the death of an organism? Lessons from acute kidney injury.

PubMed

Zorov, D B; Plotnikov, E Y; Jankauskas, S S; Isaev, N K; Silachev, D N; Zorova, L D; Pevzner, I B; Pulkova, N V; Zorov, S D; Morosanova, M A

2012-07-01

Programmed execution of various cells and intracellular structures is hypothesized to be not the only example of elimination of biological systems - the general mechanism can also involve programmed execution of organs and organisms. Modern rating of programmed cell death mechanisms includes 13 mechanistic types. As for some types, the mechanism of actuation and manifestation of cell execution has been basically elucidated, while the causes and intermediate steps of the process of fatal failure of organs and organisms remain unknown. The analysis of deaths resulting from a sudden heart arrest or multiple organ failure and other acute and chronic pathologies leads to the conclusion of a special role of mitochondria and oxidative stress activating the immune system. Possible mechanisms of mitochondria-mediated induction of the signaling cascades involved in organ failure and death of the organism are discussed. These mechanisms include generation of reactive oxygen species and damage-associated molecular patterns in mitochondria. Some examples of renal failure-induced deaths are presented with mechanisms and settings determined by some hypothetical super system rather than by the kidneys themselves. This system plays the key role in the process of physiological senescence and termination of an organism. The facts presented suggest that it is the immune system involved in mitochondrial signaling that can act as the system responsible for the organism's death.

The contribution of the programmed cell death machinery in innate immune cells to lupus nephritis.

PubMed

Tsai, FuNien; Perlman, Harris; Cuda, Carla M

2017-12-01

Systemic lupus erythematosus (SLE) is a chronic multi-factorial autoimmune disease initiated by genetic and environmental factors, which in combination trigger disease onset in susceptible individuals. Damage to the kidney as a consequence of lupus nephritis (LN) is one of the most prevalent and severe outcomes, as LN affects up to 60% of SLE patients and accounts for much of SLE-associated morbidity and mortality. As remarkable strides have been made in unlocking new inflammatory mechanisms associated with signaling molecules of programmed cell death pathways, this review explores the available evidence implicating the action of these pathways specifically within dendritic cells and macrophages in the control of kidney disease. Although advancements into the underlying mechanisms responsible for inducing cell death inflammatory pathways have been made, there still exist areas of unmet need. By understanding the molecular mechanisms by which dendritic cells and macrophages contribute to LN pathogenesis, we can improve their viability as potential therapeutic targets to promote remission. Copyright © 2016 Elsevier Inc. All rights reserved.

Regulated Forms of Cell Death in Fungi

PubMed Central

Gonçalves, A. Pedro; Heller, Jens; Daskalov, Asen; Videira, Arnaldo; Glass, N. Louise

2017-01-01

Cell death occurs in all domains of life. While some cells die in an uncontrolled way due to exposure to external cues, other cells die in a regulated manner as part of a genetically encoded developmental program. Like other eukaryotic species, fungi undergo programmed cell death (PCD) in response to various triggers. For example, exposure to external stress conditions can activate PCD pathways in fungi. Calcium redistribution between the extracellular space, the cytoplasm and intracellular storage organelles appears to be pivotal for this kind of cell death. PCD is also part of the fungal life cycle, in which it occurs during sexual and asexual reproduction, aging, and as part of development associated with infection in phytopathogenic fungi. Additionally, a fungal non-self-recognition mechanism termed heterokaryon incompatibility (HI) also involves PCD. Some of the molecular players mediating PCD during HI show remarkable similarities to major constituents involved in innate immunity in metazoans and plants. In this review we discuss recent research on fungal PCD mechanisms in comparison to more characterized mechanisms in metazoans. We highlight the role of PCD in fungi in response to exogenic compounds, fungal development and non-self-recognition processes and discuss identified intracellular signaling pathways and molecules that regulate fungal PCD. PMID:28983298

High fat programming of beta cell compensation, exhaustion, death and dysfunction.

PubMed

Cerf, Marlon E

2015-03-01

Programming refers to events during critical developmental windows that shape progeny health outcomes. Fetal programming refers to the effects of intrauterine (in utero) events. Lactational programming refers to the effects of events during suckling (weaning). Developmental programming refers to the effects of events during both fetal and lactational life. Postnatal programming refers to the effects of events either from birth (lactational life) to adolescence or from weaning (end of lactation) to adolescence. Islets are most plastic during the early life course; hence programming during fetal and lactational life is most potent. High fat (HF) programming is the maintenance on a HF diet (HFD) during critical developmental life stages that alters progeny metabolism and physiology. HF programming induces variable diabetogenic phenotypes dependent on the timing and duration of the dietary insult. Maternal obesity reinforces HF programming effects in progeny. HF programming, through acute hyperglycemia, initiates beta cell compensation. However, HF programming eventually leads to chronic hyperglycemia that triggers beta cell exhaustion, death and dysfunction. In HF programming, beta cell dysfunction often co-presents with insulin resistance. Balanced, healthy nutrition during developmental windows is critical for preserving beta cell structure and function. Thus early positive nutritional interventions that coincide with the development of beta cells may reduce the overwhelming burden of diabetes and metabolic disease. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

6-shogaol induces autophagic cell death then triggered apoptosis in colorectal adenocarcinoma HT-29 cells.

PubMed

Li, Ting-Yi; Chiang, Been-Huang

2017-09-01

6-shogaol is a phytochemical of dietary ginger, we found that 6-shogaol could induced both autophagic and apoptotic death in human colon adenocarcinoma (HT-29) cells. Results of this study showed that 6-shogal induced cell cycle arrest, autophagy, and apoptosis in HT-29 cells in a time sequence. After 6h, 6-shogal induced apparent G2/M arrest, then the HT-29 cells formed numerous autophagosomes in each phase of the cell cycle. After 18h, increases in acidic vesicles and LAMP-1 (Lysosome-associated membrane proteins 1) showed that 6-shogaol had caused autophagic cell death. After 24h, cell shrinkage and Caspase-3/7 activities rising, suggesting that apoptotic cell death had increased. And after 48h, the result of TUNEL assay indicated the highest occurrence of apoptosis upon 6-shogaol treatment. It appeared that apoptosis is triggered by autophagy in 6-shogaol treated HT-29 cells, the damage of autophagic cell death initiated apoptosis program. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Hydrogen peroxide production and mitochondrial dysfunction contribute to the fusaric acid-induced programmed cell death in tobacco cells.

PubMed

Jiao, Jiao; Sun, Ling; Zhou, Benguo; Gao, Zhengliang; Hao, Yu; Zhu, Xiaoping; Liang, Yuancun

2014-08-15

Fusaric acid (FA), a non-specific toxin produced mainly by Fusarium spp., can cause programmed cell death (PCD) in tobacco suspension cells. The mechanism underlying the FA-induced PCD was not well understood. In this study, we analyzed the roles of hydrogen peroxide (H2O2) and mitochondrial function in the FA-induced PCD. Tobacco suspension cells were treated with 100 μM FA and then analyzed for H2O2 accumulation and mitochondrial functions. Here we demonstrate that cells undergoing FA-induced PCD exhibited H2O2 production, lipid peroxidation, and a decrease of the catalase and ascorbate peroxidase activities. Pre-treatment of tobacco suspension cells with antioxidant ascorbic acid and NADPH oxidase inhibitor diphenyl iodonium significantly reduced the rate of FA-induced cell death as well as the caspase-3-like protease activity. Moreover, FA treatment of tobacco cells decreased the mitochondrial membrane potential and ATP content. Oligomycin and cyclosporine A, inhibitors of the mitochondrial ATP synthase and the mitochondrial permeability transition pore, respectively, could also reduce the rate of FA-induced cell death significantly. Taken together, the results presented in this paper demonstrate that H2O2 accumulation and mitochondrial dysfunction are the crucial events during the FA-induced PCD in tobacco suspension cells. Copyright © 2014 Elsevier GmbH. All rights reserved.

Semaphorin 3A is a retrograde cell death signal in developing sympathetic neurons

PubMed Central

Wehner, Amanda B.; Abdesselem, Houari; Dickendesher, Travis L.; Imai, Fumiyasu; Yoshida, Yutaka; Giger, Roman J.; Pierchala, Brian A.

2016-01-01

ABSTRACT During development of the peripheral nervous system, excess neurons are generated, most of which will be lost by programmed cell death due to a limited supply of neurotrophic factors from their targets. Other environmental factors, such as ‘competition factors' produced by neurons themselves, and axon guidance molecules have also been implicated in developmental cell death. Semaphorin 3A (Sema3A), in addition to its function as a chemorepulsive guidance cue, can also induce death of sensory neurons in vitro. The extent to which Sema3A regulates developmental cell death in vivo, however, is debated. We show that in compartmentalized cultures of rat sympathetic neurons, a Sema3A-initiated apoptosis signal is retrogradely transported from axon terminals to cell bodies to induce cell death. Sema3A-mediated apoptosis utilizes the extrinsic pathway and requires both neuropilin 1 and plexin A3. Sema3A is not retrogradely transported in older, survival factor-independent sympathetic neurons, and is much less effective at inducing apoptosis in these neurons. Importantly, deletion of either neuropilin 1 or plexin A3 significantly reduces developmental cell death in the superior cervical ganglia. Taken together, a Sema3A-initiated apoptotic signaling complex regulates the apoptosis of sympathetic neurons during the period of naturally occurring cell death. PMID:27143756

A Single-Amino-Acid Substitution in Obg Activates a New Programmed Cell Death Pathway in Escherichia coli.

PubMed

Dewachter, Liselot; Verstraeten, Natalie; Monteyne, Daniel; Kint, Cyrielle Ines; Versées, Wim; Pérez-Morga, David; Michiels, Jan; Fauvart, Maarten

2015-12-22

Programmed cell death (PCD) is an important hallmark of multicellular organisms. Cells self-destruct through a regulated series of events for the benefit of the organism as a whole. The existence of PCD in bacteria has long been controversial due to the widely held belief that only multicellular organisms would profit from this kind of altruistic behavior at the cellular level. However, over the past decade, compelling experimental evidence has established the existence of such pathways in bacteria. Here, we report that expression of a mutant isoform of the essential GTPase ObgE causes rapid loss of viability in Escherichia coli. The physiological changes that occur upon expression of this mutant protein--including loss of membrane potential, chromosome condensation and fragmentation, exposure of phosphatidylserine on the cell surface, and membrane blebbing--point to a PCD mechanism. Importantly, key regulators and executioners of known bacterial PCD pathways were shown not to influence this cell death program. Collectively, our results suggest that the cell death pathway described in this work constitutes a new mode of bacterial PCD. Programmed cell death (PCD) is a well-known phenomenon in higher eukaryotes. In these organisms, PCD is essential for embryonic development--for example, the disappearance of the interdigital web--and also functions in tissue homeostasis and elimination of pathogen-invaded cells. The existence of PCD mechanisms in unicellular organisms like bacteria, on the other hand, has only recently begun to be recognized. We here demonstrate the existence of a bacterial PCD pathway that induces characteristics that are strikingly reminiscent of eukaryotic apoptosis, such as fragmentation of DNA, exposure of phosphatidylserine on the cell surface, and membrane blebbing. Our results can provide more insight into the mechanism and evolution of PCD pathways in higher eukaryotes. More importantly, especially in the light of the looming antibiotic crisis, they may point to a bacterial Achilles' heel and can inspire innovative ways of combating bacterial infections, directed at the targeted activation of PCD pathways. Copyright © 2015 Dewachter et al.

Reassessing apoptosis in plants.

PubMed

Dickman, Martin; Williams, Brett; Li, Yurong; de Figueiredo, Paul; Wolpert, Thomas

2017-10-01

Cell death can be driven by a genetically programmed signalling pathway known as programmed cell death (PCD). In plants, PCD occurs during development as well as in response to environmental and biotic stimuli. Our understanding of PCD regulation in plants has advanced significantly over the past two decades; however, the molecular machinery responsible for driving the system remains elusive. Thus, whether conserved PCD regulatory mechanisms include plant apoptosis remains enigmatic. Animal apoptotic regulators, including Bcl-2 family members, have not been identified in plants but expression of such regulators can trigger or suppress plant PCD. Moreover, plants exhibit nearly all of the biochemical and morphological features of apoptosis. One difference between plant and animal PCD is the absence of phagocytosis in plants. Evidence is emerging that the vacuole may be key to removal of unwanted plant cells, and may carry out functions that are analogous to animal phagocytosis. Here, we provide context for the argument that apoptotic-like cell death occurs in plants.

Molecular mechanisms of programmed cell death-1 dependent T cell suppression: relevance for immunotherapy

PubMed Central

Zuazo, Miren; Gato-Cañas, Maria; Llorente, Noelia; Ibañez-Vea, María; Arasanz, Hugo

2017-01-01

Programmed cell death-1 (PD1) has become a significant target for cancer immunotherapy. PD1 and its receptor programmed cell death 1 ligand 1 (PDL1) are key regulatory physiological immune checkpoints that maintain self-tolerance in the organism by regulating the degree of activation of T and B cells amongst other immune cell types. However, cancer cells take advantage of these immunosuppressive regulatory mechanisms to escape T and B cell-mediated immunity. PD1 engagement on T cells by PDL1 on the surface of cancer cells dramatically interferes with T cell activation and the acquisition of effector capacities. Interestingly, PD1-targeted therapies have demonstrated to be highly effective in rescuing T cell anti-tumor effector functions. Amongst these the use of anti-PD1/PDL1 monoclonal antibodies are particularly efficacious in human therapies. Furthermore, clinical findings with PD1/PDL1 blockers over several cancer types demonstrate clinical benefit. Despite the successful results, the molecular mechanisms by which PD1-targeted therapies rescue T cell functions still remain elusive. Therefore, it is a key issue to uncover the molecular pathways by which these therapies exert its function in T cells. A profound knowledge of PDL1/PD1 mechanisms will surely uncover a new array of targets susceptible of therapeutic intervention. Here, we provide an overview of the molecular events underlying PD1-dependent T cell suppression in cancer. PMID:29114543

Cell death in the thymus--it' s all a matter of contacts.

PubMed

Minter, Lisa M; Osborne, Barbara A

2003-06-01

Apoptosis, or programmed cell death, plays a critical role in shaping the T cell repertoire, deleting unproductive as well as potentially autoreactive T cells. Our understanding of how thymocyte apoptosis is regulated is continually evolving, as new essential modulators of this process are discovered. A conundrum that remains, however, is how signaling through essentially the same receptors and cascades evokes distinct biological responses: death by neglect, positive or negative selection. We hypothesize that the immunological synapse (IS) may be critical to transducing survival signals during thymocyte development, and suggest that factors affecting IS assembly may also influence T cell selection.

SPARC ectopic overexpression inhibits growth and promotes programmed cell death in acute myeloid leukemia transformed from myelodysplastic syndrome cells, alone and in combination with Ara-C treatment.

PubMed

Nian, Qing; Chi, Jianxiang; Xiao, Qing; Wei, Chunmei; Costeas, Paul; Yang, Zesong; Liu, Lin; Wang, Li

2015-09-01

Secreted protein acidic and rich in cysteine (SPARC) has a complex and pleiotropic biological role in cell life during disease. The role of SPARC in myelodysplastic syndrome (MDS) is not yet fully understood. In the present study, we investigated the role of SPARC protein overproduction in the proliferation and apoptosis of SKM-1 cells, an acute myeloid leukemia cell line transformed from MDS. SKM-1 cells were infected with the pGC-GV-SPARC vector. The cells were then assessed for proliferation and cell death following treatment with low-dose cytosine arabinoside (Ara‑C). The microarray analysis results revealed that samples from SPARC‑overexpressed cells compared to SPARC protein, in SKM-1 cells led to proliferation inhibition and promoted programmed cell death and these effects were greater when treated with Ara-C. The mRNA and protein expression levels of SPARC were detected by SPARC overexpression in cells treated with Ara-C resulting in a significant upregulation of the mixed lineage kinase domain-like (MLKL) gene expression and five other genes. The results showed that the necrotic signaling pathway may play a role when the two conditions were combined via the upregulation of the MLKL protein. MLKL upregulation in SPARC overexpressed cells treated with Ara-C, indicates necrosis as a possible cell death process for the SKM-1 cells under these stringent conditions.

Evolution of apoptosis-like programmed cell death in unicellular protozoan parasites.

PubMed

Kaczanowski, Szymon; Sajid, Mohammed; Reece, Sarah E

2011-03-25

Apoptosis-like programmed cell death (PCD) has recently been described in multiple taxa of unicellular protists, including the protozoan parasites Plasmodium, Trypanosoma and Leishmania. Apoptosis-like PCD in protozoan parasites shares a number of morphological features with programmed cell death in multicellular organisms. However, both the evolutionary explanations and mechanisms involved in parasite PCD are poorly understood. Explaining why unicellular organisms appear to undergo 'suicide' is a challenge for evolutionary biology and uncovering death executors and pathways is a challenge for molecular and cell biology. Bioinformatics has the potential to integrate these approaches by revealing homologies in the PCD machinery of diverse taxa and evaluating their evolutionary trajectories. As the molecular mechanisms of apoptosis in model organisms are well characterised, and recent data suggest similar mechanisms operate in protozoan parasites, key questions can now be addressed. These questions include: which elements of apoptosis machinery appear to be shared between protozoan parasites and multicellular taxa and, have these mechanisms arisen through convergent or divergent evolution? We use bioinformatics to address these questions and our analyses suggest that apoptosis mechanisms in protozoan parasites and other taxa have diverged during their evolution, that some apoptosis factors are shared across taxa whilst others have been replaced by proteins with similar biochemical activities.

Evolution of apoptosis-like programmed cell death in unicellular protozoan parasites

PubMed Central

2011-01-01

Apoptosis-like programmed cell death (PCD) has recently been described in multiple taxa of unicellular protists, including the protozoan parasites Plasmodium, Trypanosoma and Leishmania. Apoptosis-like PCD in protozoan parasites shares a number of morphological features with programmed cell death in multicellular organisms. However, both the evolutionary explanations and mechanisms involved in parasite PCD are poorly understood. Explaining why unicellular organisms appear to undergo 'suicide' is a challenge for evolutionary biology and uncovering death executors and pathways is a challenge for molecular and cell biology. Bioinformatics has the potential to integrate these approaches by revealing homologies in the PCD machinery of diverse taxa and evaluating their evolutionary trajectories. As the molecular mechanisms of apoptosis in model organisms are well characterised, and recent data suggest similar mechanisms operate in protozoan parasites, key questions can now be addressed. These questions include: which elements of apoptosis machinery appear to be shared between protozoan parasites and multicellular taxa and, have these mechanisms arisen through convergent or divergent evolution? We use bioinformatics to address these questions and our analyses suggest that apoptosis mechanisms in protozoan parasites and other taxa have diverged during their evolution, that some apoptosis factors are shared across taxa whilst others have been replaced by proteins with similar biochemical activities. PMID:21439063

Dandelion root extract affects colorectal cancer proliferation and survival through the activation of multiple death signalling pathways

PubMed Central

Ovadje, Pamela; Ammar, Saleem; Guerrero, Jose-Antonio; Arnason, John Thor; Pandey, Siyaram

2016-01-01

Dandelion extracts have been studied extensively in recent years for its anti-depressant and anti-inflammatory activity. Recent work from our lab, with in-vitro systems, shows the anti-cancer potential of an aqueous dandelion root extract (DRE) in several cancer cell models, with no toxicity to non-cancer cells. In this study, we examined the cancer cell-killing effectiveness of an aqueous DRE in colon cancer cell models. Aqueous DRE induced programmed cell death (PCD) selectively in > 95% of colon cancer cells, irrespective of their p53 status, by 48 hours of treatment. The anti-cancer efficacy of this extract was confirmed in in-vivo studies, as the oral administration of DRE retarded the growth of human colon xenograft models by more than 90%. We found the activation of multiple death pathways in cancer cells by DRE treatment, as revealed by gene expression analyses showing the expression of genes implicated in programmed cell death. Phytochemical analyses of the extract showed complex multi-component composition of the DRE, including some known bioactive phytochemicals such as α-amyrin, β-amyrin, lupeol and taraxasterol. This suggested that this natural extract could engage and effectively target multiple vulnerabilities of cancer cells. Therefore, DRE could be a non-toxic and effective anti-cancer alternative, instrumental for reducing the occurrence of cancer cells drug-resistance. PMID:27564258

Involvement of the Electrophilic Isothiocyanate Sulforaphane in Arabidopsis Local Defense Responses1

PubMed Central

Andersson, Mats X.; Nilsson, Anders K.; Johansson, Oskar N.; Boztaş, Gülin; Adolfsson, Lisa E.; Pinosa, Francesco; Petit, Christel Garcia; Aronsson, Henrik; Mackey, David; Tör, Mahmut; Hamberg, Mats; Ellerström, Mats

2015-01-01

Plants defend themselves against microbial pathogens through a range of highly sophisticated and integrated molecular systems. Recognition of pathogen-secreted effector proteins often triggers the hypersensitive response (HR), a complex multicellular defense reaction where programmed cell death of cells surrounding the primary site of infection is a prominent feature. Even though the HR was described almost a century ago, cell-to-cell factors acting at the local level generating the full defense reaction have remained obscure. In this study, we sought to identify diffusible molecules produced during the HR that could induce cell death in naive tissue. We found that 4-methylsulfinylbutyl isothiocyanate (sulforaphane) is released by Arabidopsis (Arabidopsis thaliana) leaf tissue undergoing the HR and that this compound induces cell death as well as primes defense in naive tissue. Two different mutants impaired in the pathogen-induced accumulation of sulforaphane displayed attenuated programmed cell death upon bacterial and oomycete effector recognition as well as decreased resistance to several isolates of the plant pathogen Hyaloperonospora arabidopsidis. Treatment with sulforaphane provided protection against a virulent H. arabidopsidis isolate. Glucosinolate breakdown products are recognized as antifeeding compounds toward insects and recently also as intracellular signaling and bacteriostatic molecules in Arabidopsis. The data presented here indicate that these compounds also trigger local defense responses in Arabidopsis tissue. PMID:25371552

Megasporogenesis and programmed cell death in Tillandsia (Bromeliaceae).

PubMed

Papini, Alessio; Mosti, Stefano; Milocani, Eva; Tani, Gabriele; Di Falco, Pietro; Brighigna, Luigi

2011-10-01

The degeneration of three of four meiotic products is a very common process in the female gender of oogamous eukaryotes. In Tillandsia (and many other angiosperms), the surviving megaspore has a callose-free wall in chalazal position while the other three megaspores are completely embedded in callose. Therefore, nutrients and signals can reach more easily the functional megaspore from the nucellus through the chalazal pole with respect to the other megaspores. The abortion of three of four megaspores was already recognized as the result of a programmed cell death (PCD) process. We investigated the process to understand the modality of this specific type of PCD and its relationship to the asymmetric callose deposition around the tetrad. The decision on which of the four megaspores will be the supernumerary megaspores in angiosperms, and hence destined to undergo programmed cell death, appears to be linked to the callose layer deposition around the tetrad. During supernumerary megaspores degeneration, events leading to the deletion of the cells do not appear to belong to a single type of cell death. The first morphological signs are typical of autophagy, including the formation of autophagosomes. The TUNEL positivity and a change in morphology of mitochondria and chloroplasts indicate the passage to an apoptotic-like PCD phase, while the cellular remnants undergo a final process resembling at least partially (ER swelling) necrotic morphological syndromes, eventually leading to a mainly lipidic cell corpse still separated from the functional megaspore by a callose layer.

Disruption of the vacuolar calcium-ATPases in Arabidopsis results in the activation of a salicylic acid-dependent programmed cell death pathway.

PubMed

Boursiac, Yann; Lee, Sang Min; Romanowsky, Shawn; Blank, Robert; Sladek, Chris; Chung, Woo Sik; Harper, Jeffrey F

2010-11-01

Calcium (Ca(2+)) signals regulate many aspects of plant development, including a programmed cell death pathway that protects plants from pathogens (hypersensitive response). Cytosolic Ca(2+) signals result from a combined action of Ca(2+) influx through channels and Ca(2+) efflux through pumps and cotransporters. Plants utilize calmodulin-activated Ca(2+) pumps (autoinhibited Ca(2+)-ATPase [ACA]) at the plasma membrane, endoplasmic reticulum, and vacuole. Here, we show that a double knockout mutation of the vacuolar Ca(2+) pumps ACA4 and ACA11 in Arabidopsis (Arabidopsis thaliana) results in a high frequency of hypersensitive response-like lesions. The appearance of macrolesions could be suppressed by growing plants with increased levels (greater than 15 mm) of various anions, providing a method for conditional suppression. By removing plants from a conditional suppression, lesion initials were found to originate primarily in leaf mesophyll cells, as detected by aniline blue staining. Initiation and spread of lesions could also be suppressed by disrupting the production or accumulation of salicylic acid (SA), as shown by combining aca4/11 mutations with a sid 2 (for salicylic acid induction-deficient2) mutation or expression of the SA degradation enzyme NahG. This indicates that the loss of the vacuolar Ca(2+) pumps by itself does not cause a catastrophic defect in ion homeostasis but rather potentiates the activation of a SA-dependent programmed cell death pathway. Together, these results provide evidence linking the activity of the vacuolar Ca(2+) pumps to the control of a SA-dependent programmed cell death pathway in plants.

Apoptosis in fish: environmental factors and programmed cell death.

PubMed

AnvariFar, Hossein; Amirkolaie, Abdolsamad Keramat; Miandare, Hamed Kolangi; Ouraji, Hossein; Jalali, M Ali; Üçüncü, Sema İşisağ

2017-06-01

Apoptosis, a form of programmed cell death, is a critical component in maintaining homeostasis and growth in all tissues and plays a significant role in immunity and cytotoxicity. In contrast to necrosis or traumatic cell death, apoptosis is a well-controlled and vital process characterized mainly by cytoplasmic shrinkage, chromatin condensation, DNA fragmentation, membrane blebbing and apoptotic bodies. Our understanding of apoptosis is partly based on observations in invertebrates but mainly in mammals. Despite the great advantages of fish models in studying vertebrate development and diseases and the tremendous interest observed in recent years, reports on apoptosis in fish are still limited. Although apoptotic machinery is well conserved between aquatic and terrestrial organisms throughout the history of evolution, some differences exist in key components of apoptotic pathways. Core parts of apoptotic machinery in fish are virtually expressed as equivalent to the mammalian models. Some differences are, however, evident, such as the extrinsic and intrinsic pathways of apoptosis including lack of a C-terminal region in the Fas-associated protein with a death domain in fish. Aquatic species inhabit a complex and highly fluctuating environment, making these species good examples to reveal features of apoptosis that may not be easily investigated in mammals. Therefore, in order to gain a wider view on programmed cell death in fish, interactions between the main environmental factors, chemicals and apoptosis are discussed in this review. It is indicated that apoptosis can be induced in fish by exposure to environmental stressors during different stages of the fish life cycle.

Deciphering early events involved in hyperosmotic stress-induced programmed cell death in tobacco BY-2 cells.

PubMed

Monetti, Emanuela; Kadono, Takashi; Tran, Daniel; Azzarello, Elisa; Arbelet-Bonnin, Delphine; Biligui, Bernadette; Briand, Joël; Kawano, Tomonori; Mancuso, Stefano; Bouteau, François

2014-03-01

Hyperosmotic stresses represent one of the major constraints that adversely affect plants growth, development, and productivity. In this study, the focus was on early responses to hyperosmotic stress- (NaCl and sorbitol) induced reactive oxygen species (ROS) generation, cytosolic Ca(2+) concentration ([Ca(2+)]cyt) increase, ion fluxes, and mitochondrial potential variations, and on their links in pathways leading to programmed cell death (PCD). By using BY-2 tobacco cells, it was shown that both NaCl- and sorbitol-induced PCD seemed to be dependent on superoxide anion (O2·(-)) generation by NADPH-oxidase. In the case of NaCl, an early influx of sodium through non-selective cation channels participates in the development of PCD through mitochondrial dysfunction and NADPH-oxidase-dependent O2·(-) generation. This supports the hypothesis of different pathways in NaCl- and sorbitol-induced cell death. Surprisingly, other shared early responses, such as [Ca(2+)]cyt increase and singlet oxygen production, do not seem to be involved in PCD.

Combining chemotherapy with PD-1 blockade in NSCLC.

PubMed

Mathew, Matthen; Enzler, Thomas; Shu, Catherine A; Rizvi, Naiyer A

2018-06-01

Antitumor immunity relies on the ability of the immune system to recognize tumor cells as foreign and eliminate them. An effective immune response in this setting is due to surveillance of tumor-specific antigens that induce an adaptive immune response resulting in T-cell mediated cytotoxicity. Immune checkpoint inhibitors, specifically those targeting the programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) axis, have demonstrated promising activity in non-small cell lung cancer (NSCLC). However, there remains a crucial need for better treatment strategies for the majority of patients with advanced NSCLC, particularly in the frontline setting. Chemotherapy can increase antigenicity via immunogenic cell death (ICD) of tumor cells as well as also reduce "off target" immunosuppression in the tumor microenvironment (TME). Combining chemotherapy with PD-1 blockade harnesses the potential synergy between these agents and has led to encouraging results in the up-front treatment of NSCLC. In this review, we summarize the preclinical rationale behind these combinations and review recent trial data demonstrating their efficacy. Copyright © 2018. Published by Elsevier Inc.

Cell death in neural precursor cells and neurons before neurite formation prevents the emergence of abnormal neural structures in the Drosophila optic lobe.

PubMed

Hara, Yusuke; Sudo, Tatsuya; Togane, Yu; Akagawa, Hiromi; Tsujimura, Hidenobu

2018-04-01

Programmed cell death is a conserved strategy for neural development both in vertebrates and invertebrates and is recognized at various developmental stages in the brain from neurogenesis to adulthood. To understand the development of the central nervous system, it is essential to reveal not only molecular mechanisms but also the role of neural cell death (Pinto-Teixeira et al., 2016). To understand the role of cell death in neural development, we investigated the effect of inhibition of cell death on optic lobe development. Our data demonstrate that, in the optic lobe of Drosophila, cell death occurs in neural precursor cells and neurons before neurite formation and functions to prevent various developmental abnormalities. When neuronal cell death was inhibited by an effector caspase inhibitor, p35, multiple abnormal neuropil structures arose during optic lobe development-e.g., enlarged or fused neuropils, misrouted neurons and abnormal neurite lumps. Inhibition of cell death also induced morphogenetic defects in the lamina and medulla development-e.g., failures in the separation of the lamina and medulla cortices and the medulla rotation. These defects were reproduced in the mutant of an initiator caspase, dronc. If cell death was a mechanism for removing the abnormal neuropil structures, we would also expect to observe them in mutants defective for corpse clearance. However, they were not observed in these mutants. When dead cell-membranes were visualized with Apoliner, they were observed only in cortices and not in neuropils. These results suggest that the cell death occurs before mature neurite formation. Moreover, we found that inhibition of cell death induced ectopic neuroepithelial cells, neuroblasts and ganglion mother cells in late pupal stages, at sites where the outer and inner proliferation centers were located at earlier developmental stages. Caspase-3 activation was observed in the neuroepithelial cells and neuroblasts in the proliferation centers. These results indicate that cell death is required for elimination of the precursor cells composing the proliferation centers. This study substantiates an essential role of early neural cell death for ensuring normal development of the central nervous system. Copyright © 2018 Elsevier Inc. All rights reserved.

18F-FDG PET/CT for Monitoring Response of Merkel Cell Carcinoma to the Novel Programmed Cell Death Ligand 1 Inhibitor Avelumab.

PubMed

Eshghi, Naghmehossadat; Lundeen, Tamara F; MacKinnon, Lea; Avery, Ryan; Kuo, Phillip H

2018-05-01

An 85-year-old man with stage IIIA Merkel cell carcinoma of the left arm was initially treated with local excision and axillary node dissection followed by radiation therapy. Eight months after surgery, whole-body FDG PET/CT demonstrated intensely hypermetabolic hepatic metastases and abdominal lymphadenopathy. Given his age and comorbidities, he was considered a poor candidate for chemotherapy, and therefore the novel programmed cell death ligand 1 inhibitor avelumab was initiated. FDG PET/CT after 4 cycles showed complete resolution of hepatic and nodal metastases. Whole-body FDG PET/CT can be used for monitoring response of multisystem metastases from Merkel cell carcinoma to active immunotherapy.

Human-Specific Bacterial Pore-Forming Toxins Induce Programmed Necrosis in Erythrocytes

PubMed Central

LaRocca, Timothy J.; Stivison, Elizabeth A.; Hod, Eldad A.; Spitalnik, Steven L.; Cowan, Peter J.; Randis, Tara M.

2014-01-01

ABSTRACT A subgroup of the cholesterol-dependent cytolysin (CDC) family of pore-forming toxins (PFTs) has an unusually narrow host range due to a requirement for binding to human CD59 (hCD59), a glycosylphosphatidylinositol (GPI)-linked complement regulatory molecule. hCD59-specific CDCs are produced by several organisms that inhabit human mucosal surfaces and can act as pathogens, including Gardnerella vaginalis and Streptococcus intermedius. The consequences and potential selective advantages of such PFT host limitation have remained unknown. Here, we demonstrate that, in addition to species restriction, PFT ligation of hCD59 triggers a previously unrecognized pathway for programmed necrosis in primary erythrocytes (red blood cells [RBCs]) from humans and transgenic mice expressing hCD59. Because they lack nuclei and mitochondria, RBCs have typically been thought to possess limited capacity to undergo programmed cell death. RBC programmed necrosis shares key molecular factors with nucleated cell necroptosis, including dependence on Fas/FasL signaling and RIP1 phosphorylation, necrosome assembly, and restriction by caspase-8. Death due to programmed necrosis in RBCs is executed by acid sphingomyelinase-dependent ceramide formation, NADPH oxidase- and iron-dependent reactive oxygen species formation, and glycolytic formation of advanced glycation end products. Bacterial PFTs that are hCD59 independent do not induce RBC programmed necrosis. RBC programmed necrosis is biochemically distinct from eryptosis, the only other known programmed cell death pathway in mature RBCs. Importantly, RBC programmed necrosis enhances the growth of PFT-producing pathogens during exposure to primary RBCs, consistent with a role for such signaling in microbial growth and pathogenesis. PMID:25161188

Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection

NASA Astrophysics Data System (ADS)

Doitsh, Gilad; Galloway, Nicole L. K.; Geng, Xin; Yang, Zhiyuan; Monroe, Kathryn M.; Zepeda, Orlando; Hunt, Peter W.; Hatano, Hiroyu; Sowinski, Stefanie; Muñoz-Arias, Isa; Greene, Warner C.

2014-01-01

The pathway causing CD4 T-cell death in HIV-infected hosts remains poorly understood although apoptosis has been proposed as a key mechanism. We now show that caspase-3-mediated apoptosis accounts for the death of only a small fraction of CD4 T cells corresponding to those that are both activated and productively infected. The remaining over 95% of quiescent lymphoid CD4 T cells die by caspase-1-mediated pyroptosis triggered by abortive viral infection. Pyroptosis corresponds to an intensely inflammatory form of programmed cell death in which cytoplasmic contents and pro-inflammatory cytokines, including IL-1β, are released. This death pathway thus links the two signature events in HIV infection--CD4 T-cell depletion and chronic inflammation--and creates a pathogenic vicious cycle in which dying CD4 T cells release inflammatory signals that attract more cells to die. This cycle can be broken by caspase 1 inhibitors shown to be safe in humans, raising the possibility of a new class of `anti-AIDS' therapeutics targeting the host rather than the virus.

Mammalian follicular development and atresia: role of apoptosis.

PubMed

Asselin, E; Xiao, C W; Wang, Y F; Tsang, B K

2000-01-01

The regulation of follicular development and atresia is a complex process and involves interactions between endocrine factors (gonadotropins) and intraovarian regulators (sex steroids, growth factors and cytokines) in the control of follicular cell fate (i.e. proliferation, differentiation and programmed cell death). Granulosa and theca cells are key players in this fascinating process. As atresia is the fate of most follicles, understanding of how these physiological regulators participate in determining the destiny of the follicle (to degenerate or to ovulate) at cellular and subcellular levels is fundamental. This short review summarizes the role of intraovarian modulators of programmed cell death in the induction of atresia during follicular development. Copyright 2000 S. Karger AG, Basel

Singlet Oxygen-Induced Membrane Disruption and Serpin-Protease Balance in Vacuolar-Driven Cell Death.

PubMed

Koh, Eugene; Carmieli, Raanan; Mor, Avishai; Fluhr, Robert

2016-07-01

Singlet oxygen plays a role in cellular stress either by providing direct toxicity or through signaling to initiate death programs. It was therefore of interest to examine cell death, as occurs in Arabidopsis, due to differentially localized singlet oxygen photosensitizers. The photosensitizers rose bengal (RB) and acridine orange (AO) were localized to the plasmalemma and vacuole, respectively. Their photoactivation led to cell death as measured by ion leakage. Cell death could be inhibited by the singlet oxygen scavenger histidine in treatments with AO but not with RB In the case of AO treatment, the vacuolar membrane was observed to disintegrate. Concomitantly, a complex was formed between a vacuolar cell-death protease, RESPONSIVE TO DESSICATION-21 and its cognate cytoplasmic protease inhibitor ATSERPIN1. In the case of RB treatment, the tonoplast remained intact and no complex was formed. Over-expression of AtSerpin1 repressed cell death, only under AO photodynamic treatment. Interestingly, acute water stress showed accumulation of singlet oxygen as determined by fluorescence of Singlet Oxygen Sensor Green, by electron paramagnetic resonance spectroscopy and the induction of singlet oxygen marker genes. Cell death by acute water stress was inhibited by the singlet oxygen scavenger histidine and was accompanied by vacuolar collapse and the appearance of serpin-protease complex. Over-expression of AtSerpin1 also attenuated cell death under this mode of cell stress. Thus, acute water stress damage shows parallels to vacuole-mediated cell death where the generation of singlet oxygen may play a role. © 2016 American Society of Plant Biologists. All Rights Reserved.

Singlet Oxygen-Induced Membrane Disruption and Serpin-Protease Balance in Vacuolar-Driven Cell Death1[OPEN

PubMed Central

Carmieli, Raanan; Mor, Avishai; Fluhr, Robert

2016-01-01

Singlet oxygen plays a role in cellular stress either by providing direct toxicity or through signaling to initiate death programs. It was therefore of interest to examine cell death, as occurs in Arabidopsis, due to differentially localized singlet oxygen photosensitizers. The photosensitizers rose bengal (RB) and acridine orange (AO) were localized to the plasmalemma and vacuole, respectively. Their photoactivation led to cell death as measured by ion leakage. Cell death could be inhibited by the singlet oxygen scavenger histidine in treatments with AO but not with RB. In the case of AO treatment, the vacuolar membrane was observed to disintegrate. Concomitantly, a complex was formed between a vacuolar cell-death protease, RESPONSIVE TO DESSICATION-21 and its cognate cytoplasmic protease inhibitor ATSERPIN1. In the case of RB treatment, the tonoplast remained intact and no complex was formed. Over-expression of AtSerpin1 repressed cell death, only under AO photodynamic treatment. Interestingly, acute water stress showed accumulation of singlet oxygen as determined by fluorescence of Singlet Oxygen Sensor Green, by electron paramagnetic resonance spectroscopy and the induction of singlet oxygen marker genes. Cell death by acute water stress was inhibited by the singlet oxygen scavenger histidine and was accompanied by vacuolar collapse and the appearance of serpin-protease complex. Over-expression of AtSerpin1 also attenuated cell death under this mode of cell stress. Thus, acute water stress damage shows parallels to vacuole-mediated cell death where the generation of singlet oxygen may play a role. PMID:26884487

Do antioxidants inhibit oxidative-stress-induced autophagy of tenofibroblasts?

PubMed

Kim, Ra-Jeong; Hah, Young-Sool; Sung, Chang-Meen; Kang, Jae-Ran; Park, Hyung Bin

2014-07-01

Recent research on tendinopathy has focused on its relationship to programmed cell death. Increased autophagy has been observed in ruptured rotator cuff tendon tissues, suggesting a causal relationship. We investigated whether autophagy occurs in human rotator cuff tenofibroblast death induced by oxidative stress and whether antioxidants protect against autophagic cell death. We used H2 O2 (0.75 mM) as oxidative stressor, cyanidin (100 µg/ml) as antioxidant, zVAD (20 µM) as apoptosis inhibitor, and 3-MA (10 mM) as autophagy inhibitor. We evaluated cell viability and known autophagic markers: LC3-II expression, GFP-LC3 puncta formation, autolysosomes, and Atg5-12 and Beclin 1 expression. H2 O2 exposure increased the rates of cell death, LC3-II expression, GFP-LC3 puncta formation, and autolysosomes. After we induced apoptosis arrest using zVAD, H2 O2 exposure still induced cell death, LC3-II expression, and GFP-LC3 puncta formation. H2 O2 exposure also increased Atg5-12 and Beclin 1 expressions, indicating autophagic cell death. However, cyanidin treatment reduced H2 O2 -induced cell death, LC3-II expression, GFP-LC3 puncta formation, and autolysosomes. Cyanidin and 3-MA similarly reduced the cell-death rate, and Atg5-12 and Beclin 1 expression. This study demonstrated that H2 O2 , an oxidative stressor, induces autophagic cell death in rotator cuff tenofibroblasts, and that cyanidin, a natural antioxidant, inhibits autophagic cell death. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Cytotoxic Activities of Physalis minima L. Chloroform Extract on Human Lung Adenocarcinoma NCI-H23 Cell Lines by Induction of Apoptosis

PubMed Central

Leong, Ooi Kheng; Muhammad, Tengku Sifzizul Tengku; Sulaiman, Shaida Fariza

2011-01-01

Physalis minima L. is reputed for having anticancer property. In this study, the chloroform extract of this plant exhibited remarkable cytotoxic activities on NCI-H23 (human lung adenocarcinoma) cell line at dose- and time-dependent manners (after 24, 48 and 72 h of incubation). Analysis of cell-death mechanism demonstrated that the extract exerted apoptotic programed cell death in NCI-H23 cells with typical DNA fragmentation, which is a biochemical hallmark of apoptosis. Morphological observation using transmission electron microscope (TEM) also displayed apoptotic characteristics in the treated cells, including clumping and margination of chromatins, followed by convolution of the nuclear and budding of the cells to produce membrane-bound apoptotic bodies. Different stages of apoptotic programed cell death as well as phosphatidylserine externalization were confirmed using annexin V and propidium iodide staining. Furthermore, acute exposure to the extract produced a significant regulation of c-myc, caspase-3 and p53 mRNA expression in this cell line. Due to its apoptotic effect on NCI-H23 cells, it is strongly suggested that the extract could be further developed as an anticancer drug. PMID:19541726

Honokiol induces autophagic cell death in malignant glioma through reactive oxygen species-mediated regulation of the p53/PI3K/Akt/mTOR signaling pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Chien-Ju

Honokiol, an active constituent extracted from the bark of Magnolia officinalis, possesses anticancer effects. Apoptosis is classified as type I programmed cell death, while autophagy is type II programmed cell death. We previously proved that honokiol induces cell cycle arrest and apoptosis of U87 MG glioma cells. Subsequently in this study, we evaluated the effect of honokiol on autophagy of glioma cells and examined the molecular mechanisms. Administration of honokiol to mice with an intracranial glioma increased expressions of cleaved caspase 3 and light chain 3 (LC3)-II. Exposure of U87 MG cells to honokiol also induced autophagy in concentration- andmore » time-dependent manners. Results from the addition of 3-methyladenine, an autophagy inhibitor, and rapamycin, an autophagy inducer confirmed that honokiol-induced autophagy contributed to cell death. Honokiol decreased protein levels of PI3K, phosphorylated (p)-Akt, and p-mammalian target of rapamycin (mTOR) in vitro and in vivo. Pretreatment with a p53 inhibitor or transfection with p53 small interfering (si)RNA suppressed honokiol-induced autophagy by reversing downregulation of p-Akt and p-mTOR expressions. In addition, honokiol caused generation of reactive oxygen species (ROS), which was suppressed by the antioxidant, vitamin C. Vitamin C also inhibited honokiol-induced autophagic and apoptotic cell death. Concurrently, honokiol-induced alterations in levels of p-p53, p53, p-Akt, and p-mTOR were attenuated following vitamin C administration. Taken together, our data indicated that honokiol induced ROS-mediated autophagic cell death through regulating the p53/PI3K/Akt/mTOR signaling pathway. - Highlights: • Exposure of mice with intracranial gliomas to honokiol induces cell apoptosis and autophagy. • Honokiol triggers autophagy of human glioma cells via the PISK/AKT/mTOR signaling pathway. • P53 induces autophagy via regulating the AKT/mTOR pathway in honokiol-treated glioma cells. • ROS participates in honokiol-induced cell death through the p53-mediated signaling pathway. • Honokiol induces ROS-mediated autophagic cell death via the p53/PI3K/Akt/mTOR mechanism.« less

Guidelines and recommendations on yeast cell death nomenclature

PubMed Central

Carmona-Gutierrez, Didac; Bauer, Maria Anna; Zimmermann, Andreas; Aguilera, Andrés; Austriaco, Nicanor; Ayscough, Kathryn; Balzan, Rena; Bar-Nun, Shoshana; Barrientos, Antonio; Belenky, Peter; Blondel, Marc; Braun, Ralf J.; Breitenbach, Michael; Burhans, William C.; Büttner, Sabrina; Cavalieri, Duccio; Chang, Michael; Cooper, Katrina F.; Côrte-Real, Manuela; Costa, Vítor; Cullin, Christophe; Dawes, Ian; Dengjel, Jörn; Dickman, Martin B.; Eisenberg, Tobias; Fahrenkrog, Birthe; Fasel, Nicolas; Fröhlich, Kai-Uwe; Gargouri, Ali; Giannattasio, Sergio; Goffrini, Paola; Gourlay, Campbell W.; Grant, Chris M.; Greenwood, Michael T.; Guaragnella, Nicoletta; Heger, Thomas; Heinisch, Jürgen; Herker, Eva; Herrmann, Johannes M.; Hofer, Sebastian; Jiménez-Ruiz, Antonio; Jungwirth, Helmut; Kainz, Katharina; Kontoyiannis, Dimitrios P.; Ludovico, Paula; Manon, Stéphen; Martegani, Enzo; Mazzoni, Cristina; Megeney, Lynn A.; Meisinger, Chris; Nielsen, Jens; Nyström, Thomas; Osiewacz, Heinz D.; Outeiro, Tiago F.; Park, Hay-Oak; Pendl, Tobias; Petranovic, Dina; Picot, Stephane; Polčic, Peter; Powers, Ted; Ramsdale, Mark; Rinnerthaler, Mark; Rockenfeller, Patrick; Ruckenstuhl, Christoph; Schaffrath, Raffael; Segovia, Maria; Severin, Fedor F.; Sharon, Amir; Sigrist, Stephan J.; Sommer-Ruck, Cornelia; Sousa, Maria João; Thevelein, Johan M.; Thevissen, Karin; Titorenko, Vladimir; Toledano, Michel B.; Tuite, Mick; Vögtle, F.-Nora; Westermann, Benedikt; Winderickx, Joris; Wissing, Silke; Wölfl, Stefan; Zhang, Zhaojie J.; Zhao, Richard Y.; Zhou, Bing; Galluzzi, Lorenzo; Kroemer, Guido; Madeo, Frank

2018-01-01

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death routines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the authors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the progress of this vibrant field of research. PMID:29354647

The Rab GTPase RabG3b Positively Regulates Autophagy and Immunity-Associated Hypersensitive Cell Death in Arabidopsis1[W

PubMed Central

Kwon, Soon Il; Cho, Hong Joo; Kim, Sung Ryul; Park, Ohkmae K.

2013-01-01

A central component of the plant defense response to pathogens is the hypersensitive response (HR), a form of programmed cell death (PCD). Rapid and localized induction of HR PCD ensures that pathogen invasion is prevented. Autophagy has been implicated in the regulation of HR cell death, but the functional relationship between autophagy and HR PCD and the regulation of these processes during the plant immune response remain controversial. Here, we show that a small GTP-binding protein, RabG3b, plays a positive role in autophagy and promotes HR cell death in response to avirulent bacterial pathogens in Arabidopsis (Arabidopsis thaliana). Transgenic plants overexpressing a constitutively active RabG3b (RabG3bCA) displayed accelerated, unrestricted HR PCD within 1 d of infection, in contrast to the autophagy-defective atg5-1 mutant, which gradually developed chlorotic cell death through uninfected sites over several days. Microscopic analyses showed the accumulation of autophagic structures during HR cell death in RabG3bCA cells. Our results suggest that RabG3b contributes to HR cell death via the activation of autophagy, which plays a positive role in plant immunity-triggered HR PCD. PMID:23404918

Dying dangerously: Necrotic cell death and chronic inflammation promote tumor growth.

PubMed

Lotze, Michael T; Demarco, Richard A

2004-12-01

Extract: We all shudder about untimely deaths or those that we were not prepared for. As such we perceive such "unscheduled" deaths as dangerous. Similarly, apoptotic death (literally falling leaves) or the programmed cell death of cells in multicellular organisms ranging from slime mold and simple worms through to mammals, has a level of tidiness and well-orchestrated activities with literally hundreds if not thousands of gene products employed with either the primary or secondary purpose of coordinating the orderly death of cells throughout life. During inflammation of any sort, driven by tissue damage or injury or infection by pathogens (virus, bacteria, and parasites), apoptotic death similarly serves to quickly rid the host of damaged cells, promote removal and digestion of the infected cell, and prepare the way for tissue remodeling and repair. When this goes awry, for example during periods of chronic inflammation, tissues are subjected to the contrasting needs of driving apoptotic death whilst maintaining the barrier function of the epithelia (such as skin cells) as well as the selective permeability of mucosal sites (i.e., areas where mucus is secreted to protect the cells from their surroundings, such as gut cells protecting themselves from the gastric acids). Prudently, they need to limit and husband local resources sufficiently for the maintenance of tissue integrity and renewal. It is our provocative and novel contention that cancer in adults (and not children) most often arises in a setting of chronic inflammation and disordered cell death rather than one associated primarily with disordered cell growth as it is popularly imagined by scientists, clinicians, and the general public.

Programmed Cell Death Ligand 1 Expression in Primary Central Nervous System Lymphomas: A Clinicopathological Study.

PubMed

Hayano, Azusa; Komohara, Yoshihiro; Takashima, Yasuo; Takeya, Hiroto; Homma, Jumpei; Fukai, Junya; Iwadate, Yasuo; Kajiwara, Koji; Ishizawa, Shin; Hondoh, Hiroaki; Yamanaka, Ryuya

2017-10-01

Programmed cell death ligand 1 (PD-L1)/programmed cell death 1 (PD-1) have been shown to predict response to PD-L1/PD-1-targeted therapy. We analyzed PD-L1 expression in primary central nervous system lymphomas (PCNSLs). PD-L1 protein and mRNA expression were evaluated in 64 PCNSL tissue samples. IFN-γ, IL-10, CD4, and CD8 mRNA expression was also evaluated. PD-L1 protein was detected in tumor cells in 2 (4.1%) cases and in tumor microenvironments in 25 (52%) cases. PD-L1 mRNA positively correlated with IFN-γ (p=0.0024) and CD4 (p=0.0005) mRNA expression. IFN-γ mRNA positively correlated with CD8 mRNA expression (p=0.0001). Furthermore, tumor cell PD-L1 expression correlated positively with overall survival (p=0.0177), whereas microenvironmental PD-L1 expression exhibited an insignificant negative trend with overall survival (p=0.188). PD-L1 was expressed on both tumor and/or tumor-infiltrating immune cells in PCNSL. The biological roles of this marker warrant further investigation. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Susceptibility of Mycobacterium tuberculosis-infected host cells to phospho-MLKL driven necroptosis is dependent on cell type and presence of TNFα.

PubMed

Butler, Rachel E; Krishnan, Nitya; Garcia-Jimenez, Waldo; Francis, Robert; Martyn, Abbe; Mendum, Tom; Felemban, Shaza; Locker, Nicolas; Salguero, Francisco J; Robertson, Brian; Stewart, Graham R

2017-11-17

An important feature of Mycobacterium tuberculosis pathogenesis is the ability to control cell death in infected host cells, including inhibition of apoptosis and stimulation of necrosis. Recently an alternative form of programmed cell death, necroptosis, has been described where necrotic cell death is induced by apoptotic stimuli under conditions where apoptotic execution is inhibited. We show for the first time that M. tuberculosis and TNFα synergise to induce necroptosis in murine fibroblasts via RIPK1-dependent mechanisms and characterized by phosphorylation of Ser345 of the MLKL necroptosis death effector. However, in murine macrophages M. tuberculosis and TNFα induce non-necroptotic cell death that is RIPK1-dependent but independent of MLKL phosphorylation. Instead, M. tuberculosis-infected macrophages undergo RIPK3-dependent cell death which occurs both in the presence and absence of TNFα and involves the production of mitochondrial ROS. Immunocytochemical staining for MLKL phosphorylation further demonstrated the occurrence of necroptosis in vivo in murine M. tuberculosis granulomas. Phosphorylated-MLKL immunoreactivity was observed associated with the cytoplasm and nucleus of fusiform cells in M. tuberculosis lesions but not in proximal macrophages. Thus whereas pMLKL-driven necroptosis does not appear to be a feature of M. tuberculosis-infected macrophage cell death, it may contribute to TNFα-induced cytotoxicity of the lung stroma and therefore contribute to necrotic cavitation and bacterial dissemination.

Interrogating the relevance of mitochondrial apoptosis for vertebrate development and postnatal tissue homeostasis

PubMed Central

Kaufmann, Thomas; Villunger, Andreas

2016-01-01

“Programmed cell death or ‘apoptosis’ is critical for organogenesis during embryonic development and tissue homeostasis in the adult. Its deregulation can contribute to a broad range of human pathologies, including neurodegeneration, cancer, or autoimmunity…” These or similar phrases have become generic opening statements in many reviews and textbooks describing the physiological relevance of apoptotic cell death. However, while the role in disease has been documented beyond doubt, facilitating innovative drug discovery, we wonder whether the former is really true. What goes wrong in vertebrate development or in adult tissue when the main route to apoptotic cell death, controlled by the BCL2 family, is impaired? Such scenarios have been mimicked by deletion of one or more prodeath genes within the BCL2 family, and gene targeting studies in mice exploring the consequences have been manifold. Many of these studies were geared toward understanding the role of BCL2 family proteins and mitochondrial apoptosis in disease, whereas fewer focused in detail on their role during normal development or tissue homeostasis, perhaps also due to an irritating lack of phenotype. Looking at these studies, the relevance of classical programmed cell death by apoptosis for development appears rather limited. Together, these many studies suggest either highly selective and context-dependent contributions of mitochondrial apoptosis or significant redundancy with alternative cell death mechanisms, as summarized and discussed here. PMID:27798841

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed Central

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

2017-01-01

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. PMID:28332589

Navigation to the graveyard-induction of various pathways of necrosis and their classification by flow cytometry.

PubMed

Janko, Christina; Munoz, Luis; Chaurio, Ricardo; Maueröder, Christian; Berens, Christian; Lauber, Kirsten; Herrmann, Martin

2013-01-01

Apoptosis and necrosis reflect the program of cell death employed by a dying cell and the final stage of death, respectively. Whereas apoptosis is defined as a physiological, highly organized cell death process, necrosis is commonly considered to be accidental and uncontrolled. Physiological and weak pathological death stimuli preferentially induce apoptosis, while harsh non-physiological insults often immediately instigate (primary) necrosis. If an apoptosing cell transits into a phase of plasma membrane disintegration, this stage of death is referred to as secondary or post-apoptotic necrosis.Here, we present several conditions that stimulate primary and/or secondary necrosis and show that necrosis displays considerably different time courses. For subclassification of necrotic phenotypes we employed a flow cytometric single-tube 4-color staining technique including annexin A5-FITC, propidium iodide, DiIC1(5), and Hoechst 33342.

Detecting contaminant-induced apoptosis and necrosis in lake trout thymocytes via flow cytometry.

USGS Publications Warehouse

Sweet, Leonard I.; Passino-Reader, Dora R.; Meier, Peter G.; Omann, Geneva M.; Stolen, J.S.; Fletcher, T.C.; Rowley, A.F.; Zelikoff, J.T.; Kaattari, S.L.; Smith, S.A.

1997-01-01

This chapter details the cytofluorometric techniques employed to assess levels of active (apoptosis) and passive (necrotic) cell death in untreated and contaminant-treated fish thymocytes. The thymus is believed to be a central component of hematopoiesis and immune function in teleosts (Abelli et al., 1996). Hence, chemically-elicited adverse effects to the thymus may result in immunomodulation and organ dysfunction. However, it is not well documented that environmental contaminants induce apoptosis, or programmed cell death. There is some evidence suggesting that low level exposure to waterborne contaminants can specifically induce cell death in the olfactory epithelium of rainbow trout (Julliard et al., 1996). Presently, only limited information is available in the literature regarding apoptotic death in piscine immune cells (Alford et al., 1994; Greenlee et al., 1991).

Regulation of programmed cell death or apoptosis in atherosclerosis.

PubMed

Geng, Y J

1997-01-01

Intimal thickening caused by accumulation of cells, lipids, and connective tissue characterizes atherosclerosis, an arterial disease that leads to cardiac and cerebral infarction. Apoptosis, or genetically programmed cell death, is important for the development and morphogenesis of organs and tissues. As in other tissues, cells of cardiovascular tissues can undergo apoptosis. Increased apoptosis has been found in both human and animal atherosclerotic lesions, mediating tissue turnover and lesion development. In addition to vascular cells, many activated immune cells, mainly macrophages and T cells, are present in atherosclerotic lesions, where these cells produce biologically active substances such as the proinflammatory cytokines tumor necrosis factor, interleukin-1 (IL-1), and interferon-gamma. Simultaneous exposure to these cytokines may trigger apoptosis of vascular smooth muscle cells. The products of death-regulating genes including Fas/Fas ligand, members of IL-1 beta cysteinyl protease (caspase) family, the tumor suppressive gene p53, and the protooncogene c-myc have been found in vascular cells and may participate in the regulation of vascular apoptosis during the development of atherosclerosis. Abnormal occurrence of apoptosis may take place in atherosclerotic lesions, including attenuation or acceleration of the apoptotic death process. The former may cause an increase in the cellularity of the lesions, and the latter can reduce cellular components important for maintaining the integrity and stability of the plaques. Clarification of the molecular mechanism that regulates apoptosis may help design a new strategy for treatment of patients with atherosclerosis and its major complications, heart attack and stroke.

Sulfated lentinan induced mitochondrial dysfunction leads to programmed cell death of tobacco BY-2 cells.

PubMed

Wang, Jie; Wang, Yaofeng; Shen, Lili; Qian, Yumei; Yang, Jinguang; Wang, Fenglong

2017-04-01

Sulphated lentinan (sLTN) is known to act as a resistance inducer by causing programmed cell death (PCD) in tobacco suspension cells. However, the underlying mechanism of this effect is largely unknown. Using tobacco BY-2 cell model, morphological and biochemical studies revealed that mitochondrial reactive oxygen species (ROS) production and mitochondrial dysfunction contribute to sLNT induced PCD. Cell viability, and HO/PI fluorescence imaging and TUNEL assays confirmed a typical cell death process caused by sLNT. Acetylsalicylic acid (an ROS scavenger), diphenylene iodonium (an inhibitor of NADPH oxidases) and protonophore carbonyl cyanide p-trifluoromethoxyphenyl hydrazone (a protonophore and an uncoupler of mitochondrial oxidative phosphorylation) inhibited sLNT-induced H 2 O 2 generation and cell death, suggesting that ROS generation linked, at least partly, to a mitochondrial dysfunction and caspase-like activation. This conclusion was further confirmed by double-stained cells with the mitochondria-specific marker MitoTracker RedCMXRos and the ROS probe H 2 DCFDA. Moreover, the sLNT-induced PCD of BY-2 cells required cellular metabolism as up-regulation of the AOX family gene transcripts and induction of the SA biosynthesis, the TCA cycle, and miETC related genes were observed. It is concluded that mitochondria play an essential role in the signaling pathway of sLNT-induced ROS generation, which possibly provided new insight into the sLNT-mediated antiviral response, including PCD. Copyright © 2016. Published by Elsevier Inc.

Contribution of TMEM16F to pyroptotic cell death.

PubMed

Ousingsawat, Jiraporn; Wanitchakool, Podchanart; Schreiber, Rainer; Kunzelmann, Karl

2018-02-20

Pyroptosis is a highly inflammatory form of programmed cell death that is caused by infection with intracellular pathogens and activation of canonical or noncanonical inflammasomes. The purinergic receptor P2X 7 is activated by the noncanonical inflammasome and contributes essentially to pyroptotic cell death. The Ca 2+ activated phospholipid scramblase and ion channel TMEM16F has been shown earlier to control cellular effects downstream of purinergic P2X 7 receptors that ultimately lead to cell death. As pyroptotic cell death is accompanied by an increases in intracellular Ca 2+ , we asked whether TMEM16F is activated during pyroptosis. The N-terminal cleavage product of gasdermin D (GD-N) is an executioner of pyroptosis by forming large plasma membrane pores. Expression of GD-N enhanced basal Ca 2+ levels and induced cell death. We observed that GD-N induced cell death in HEK293 and HAP1 cells, which was depending on expression of endogenous TMEM16F. GD-N activated large whole cell currents that were suppressed by knockdown or inhibition of TMEM16F. The results suggest that whole cell currents induced by the pore forming domain of gasdermin-D, are at least in part due to activation of TMEM16F. Knockdown of other TMEM16 paralogues expressed in HAP1 cells suggest TMEM16F as a crucial element during pyroptosis and excluded a role of other TMEM16 proteins. Thus TMEM16F supports pyroptosis and other forms of inflammatory cell death such as ferroptosis. Its potent inhibition by tannic acid may be part of the anti-inflammatory effects of flavonoids.

Cell Wall Invertase Promotes Fruit Set under Heat Stress by Suppressing ROS-Independent Cell Death1[OPEN

PubMed Central

2016-01-01

Reduced cell wall invertase (CWIN) activity has been shown to be associated with poor seed and fruit set under abiotic stress. Here, we examined whether genetically increasing native CWIN activity would sustain fruit set under long-term moderate heat stress (LMHS), an important factor limiting crop production, by using transgenic tomato (Solanum lycopersicum) with its CWIN inhibitor gene silenced and focusing on ovaries and fruits at 2 d before and after pollination, respectively. We found that the increase of CWIN activity suppressed LMHS-induced programmed cell death in fruits. Surprisingly, measurement of the contents of H2O2 and malondialdehyde and the activities of a cohort of antioxidant enzymes revealed that the CWIN-mediated inhibition on programmed cell death is exerted in a reactive oxygen species-independent manner. Elevation of CWIN activity sustained Suc import into fruits and increased activities of hexokinase and fructokinase in the ovaries in response to LMHS. Compared to the wild type, the CWIN-elevated transgenic plants exhibited higher transcript levels of heat shock protein genes Hsp90 and Hsp100 in ovaries and HspII17.6 in fruits under LMHS, which corresponded to a lower transcript level of a negative auxin responsive factor IAA9 but a higher expression of the auxin biosynthesis gene ToFZY6 in fruits at 2 d after pollination. Collectively, the data indicate that CWIN enhances fruit set under LMHS through suppression of programmed cell death in a reactive oxygen species-independent manner that could involve enhanced Suc import and catabolism, HSP expression, and auxin response and biosynthesis. PMID:27462084

Dynamic quantitative photothermal monitoring of cell death of individual human red blood cells upon glucose depletion

NASA Astrophysics Data System (ADS)

Vasudevan, Srivathsan; Chen, George Chung Kit; Andika, Marta; Agarwal, Shuchi; Chen, Peng; Olivo, Malini

2010-09-01

Red blood cells (RBCs) have been found to undergo ``programmed cell death,'' or eryptosis, and understanding this process can provide more information about apoptosis of nucleated cells. Photothermal (PT) response, a label-free photothermal noninvasive technique, is proposed as a tool to monitor the cell death process of living human RBCs upon glucose depletion. Since the physiological status of the dying cells is highly sensitive to photothermal parameters (e.g., thermal diffusivity, absorption, etc.), we applied linear PT response to continuously monitor the death mechanism of RBC when depleted of glucose. The kinetics of the assay where the cell's PT response transforms from linear to nonlinear regime is reported. In addition, quantitative monitoring was performed by extracting the relevant photothermal parameters from the PT response. Twofold increases in thermal diffusivity and size reduction were found in the linear PT response during cell death. Our results reveal that photothermal parameters change earlier than phosphatidylserine externalization (used for fluorescent studies), allowing us to detect the initial stage of eryptosis in a quantitative manner. Hence, the proposed tool, in addition to detection of eryptosis earlier than fluorescence, could also reveal physiological status of the cells through quantitative photothermal parameter extraction.

Programmed Cell Death and Caspase Functions During Neural Development.

PubMed

Yamaguchi, Yoshifumi; Miura, Masayuki

2015-01-01

Programmed cell death (PCD) is a fundamental component of nervous system development. PCD serves as the mechanism for quantitative matching of the number of projecting neurons and their target cells through direct competition for neurotrophic factors in the vertebrate peripheral nervous system. In addition, PCD plays roles in regulating neural cell numbers, canceling developmental errors or noise, and tissue remodeling processes. These findings are mainly derived from genetic studies that prevent cells from dying by apoptosis, which is a major form of PCD and is executed by activation of evolutionarily conserved cysteine protease caspases. Recent studies suggest that caspase activation can be coordinated in time and space at multiple levels, which might underlie nonapoptotic roles of caspases in neural development in addition to apoptotic roles. © 2015 Elsevier Inc. All rights reserved.

Love is a battlefield: programmed cell death during fertilization.

PubMed

Heydlauff, Juliane; Groß-Hardt, Rita

2014-03-01

Plant development and growth is sustained by the constant generation of tremendous amounts of cells, which become integrated into various types of tissues and organs. What is all too often overlooked is that this thriving life also requires the targeted degeneration of selected cells, which undergo cell death according to genetically encoded programmes or environmental stimuli. The side-by-side existence of generation and demise is particularly evident in the haploid phase of the flowering plants cycle. Here, the lifespan of terminally differentiated accessory cells contrasts with that of germ cells, which by definition live on to form the next generation. In fact, with research in recent years it is becoming increasingly clear that the gametophytes of flowering plants constitute an attractive and powerful system for investigating the molecular mechanisms underlying selective cell death.

Necroptosis in cancer: An angel or a demon?

PubMed

Wang, Tianzhen; Jin, Yinji; Yang, Weiwei; Zhang, Lei; Jin, Xiaoming; Liu, Xi; He, Yan; Li, Xiaobo

2017-06-01

In the past few decades, apoptosis has been regarded as the only form of programmed cell death. However, the traditional view has been challenged by the identification of several forms of regulated necrosis, including necroptosis. Necroptosis is typified by a necrotic cell death morphology and is controlled by RIP1, RIP3, and mixed lineage kinase domain-like protein. The physiological role of necroptosis is to serve as a "fail-safe" form of cell death for cells that fail to undergo apoptosis during embryonic development and disease defense. Currently, established studies have indicated that necroptosis is involved in cancer initiation and progression. Although elevated necroptosis contributes to cancer cell death, extensive cell death also increases the risk of proliferation and metastasis of the surviving cells by inducing the generation reactive oxygen species, activation of inflammation, and suppression of the immune response. Thus, questions regarding the overall impact of necroptosis on cancer remain open. In this review, we introduce the basic knowledge regarding necroptosis, summarize its dual effects on cancer progression, and analyze its advantages and disadvantages in clinical applications.

Fueling the Flames: Mammalian Programmed Necrosis in Inflammatory Diseases

PubMed Central

Chan, Francis Ka-Ming

2012-01-01

Programmed necrosis or necroptosis is an inflammatory form of cell death driven by TNF-like death cytokines, toll-like receptors, and antigen receptors. Unlike necrosis induced by physical trauma, a dedicated pathway is involved in programmed necrosis. In particular, a kinase complex composed of the receptor interacting protein kinase 1 (RIPK1) and RIPK3 is a central step in necrotic cell death. Assembly and activation of this RIPK1–RIPK3 “necrosome” is critically controlled by protein ubiquitination, phosphorylation, and caspase-mediated cleavage events. The molecular signals cumulate in formation of intracellular vacuoles, organelle swelling, internal membrane leakage, and eventually plasma membrane rupture. These morphological changes can result in spillage of intracellular adjuvants to promote inflammation and further exacerbate tissue injury. Because of the inflammatory nature of necrosis, it is an attractive pathway for therapeutic intervention in acute inflammatory diseases. PMID:23125016

The Life and Death of a Plant Cell.

PubMed

Kabbage, Mehdi; Kessens, Ryan; Bartholomay, Lyric C; Williams, Brett

2017-04-28

Like all eukaryotic organisms, plants possess an innate program for controlled cellular demise termed programmed cell death (PCD). Despite the functional conservation of PCD across broad evolutionary distances, an understanding of the molecular machinery underpinning this fundamental program in plants remains largely elusive. As in mammalian PCD, the regulation of plant PCD is critical to development, homeostasis, and proper responses to stress. Evidence is emerging that autophagy is key to the regulation of PCD in plants and that it can dictate the outcomes of PCD execution under various scenarios. Here, we provide a broad and comparative overview of PCD processes in plants, with an emphasis on stress-induced PCD. We also discuss the implications of the paradox that is functional conservation of apoptotic hallmarks in plants in the absence of core mammalian apoptosis regulators, what that means, and whether an equivalent form of death occurs in plants.

Defective TFH Cell Function and Increased TFR Cells Contribute to Defective Antibody Production in Aging.

PubMed

Sage, Peter T; Tan, Catherine L; Freeman, Gordon J; Haigis, Marcia; Sharpe, Arlene H

2015-07-14

Defective antibody production in aging is broadly attributed to immunosenescence. However, the precise immunological mechanisms remain unclear. Here, we demonstrate an increase in the ratio of inhibitory T follicular regulatory (TFR) cells to stimulatory T follicular helper (TFH) cells in aged mice. Aged TFH and TFR cells are phenotypically distinct from those in young mice, exhibiting increased programmed cell death protein-1 expression but decreased ICOS expression. Aged TFH cells exhibit defective antigen-specific responses, and programmed cell death protein-ligand 1 blockade can partially rescue TFH cell function. In contrast, young and aged TFR cells have similar suppressive capacity on a per-cell basis in vitro and in vivo. Together, these studies reveal mechanisms contributing to defective humoral immunity in aging: an increase in suppressive TFR cells combined with impaired function of aged TFH cells results in reduced T-cell-dependent antibody responses in aged mice. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

TNF-induced necroptosis requires the plasma membrane localization of the MLKL protein | Center for Cancer Research

Cancer.gov

The cell signaling protein tumor necrosis factor (TNF), produced by white blood cells, promotes inflammation and immunity processes such as fever and is involved in tumorigenesis and apoptosis (programmed cell death). However, dysregulation of TNF can also lead to another form of programmed cell death called necroptosis, which is characterized by a rise in intracellular Ca2+, generation of reactive oxygen species (ROS), intracellular acidity, depletion of ATP, and, eventually, plasma membrane rupture. TNF-induced necroptosis has been associated with a wide variety of diseases including neurodegenerative diseases, major depression, rheumatoid arthritis, and cancer. Whereas the signaling mechanisms underlying TNF-induced apoptosis have largely been determined, the events precipitating in TNF-initiated necroptosis are still unknown.

Mechanical stress mediated by both endosperm softening and embryo growth underlies endosperm elimination in Arabidopsis seeds.

PubMed

Fourquin, Chloé; Beauzamy, Léna; Chamot, Sophy; Creff, Audrey; Goodrich, Justin; Boudaoud, Arezki; Ingram, Gwyneth

2016-09-15

Seed development in angiosperms demands the tightly coordinated development of three genetically distinct structures. The embryo is surrounded by the endosperm, which is in turn enclosed within the maternally derived seed coat. In Arabidopsis, final seed size is determined by early expansion of the coenocytic endosperm, which then cellularises and subsequently undergoes developmental programmed cell death, breaking down as the embryo grows. Endosperm breakdown requires the endosperm-specific basic helix-loop-helix transcription factor ZHOUPI. However, to date, the mechanism underlying the Arabidopsis endosperm breakdown process has not been elucidated. Here, we provide evidence that ZHOUPI does not induce the developmental programmed cell death of the endosperm directly. Instead ZHOUPI indirectly triggers cell death by regulating the expression of cell wall-modifying enzymes, thus altering the physical properties of the endosperm to condition a mechanical environment permitting the compression of the cellularised endosperm by the developing embryo. © 2016. Published by The Company of Biologists Ltd.

Ricinosomes Predict Programmed Cell Death Leading to Anther Dehiscence in Tomato1[C][W][OA

PubMed Central

Senatore, Adriano; Trobacher, Christopher P.; Greenwood, John S.

2009-01-01

Successful development and dehiscence of the anther and release of pollen are dependent upon the programmed cell death (PCD) of the tapetum and other sporophytic tissues. Ultrastructural examination of the developing and dehiscing anther of tomato (Solanum lycopersicum) revealed that cells of the interlocular septum, the connective tissue, the middle layer/endothecium, and the epidermal cells surrounding the stomium all exhibit features consistent with progression through PCD. Ricinosomes, a subset of precursor protease vesicles that are unique to some incidents of plant PCD, were also present in all of these cell types. These novel organelles are known to harbor KDEL-tailed cysteine proteinases that act in the final stages of corpse processing following cell death. Indeed, a tomato KDEL-tailed cysteine proteinase, SlCysEP, was identified and its gene was cloned, sequenced, and characterized. SlCysEP transcript and protein were restricted to the anthers of the senescing tomato flower. Present in the interlocular septum and in the epidermal cells surrounding the stomium relatively early in development, SlCysEP accumulates later in the sporophytic tissues surrounding the locules as dehiscence ensues. At the ultrastuctural level, immunogold labeling localized SlCysEP to the ricinosomes within the cells of these tissues, but not in the tapetum. It is suggested that the accumulation of SlCysEP and the appearance of ricinosomes act as very early predictors of cell death in the tomato anther. PMID:19098090

Multiple programmed cell death pathways are involved in N-methyl-N-nitrosourea-induced photoreceptor degeneration.

PubMed

Reisenhofer, Miriam; Balmer, Jasmin; Zulliger, Rahel; Enzmann, Volker

2015-05-01

To identify programmed cell death (PCD) pathways involved in N-methyl-N-nitrosourea (MNU)-induced photoreceptor (PR) degeneration. Adult C57BL/6 mice received a single MNU i.p. injection (60 mg/kg bodyweight), and were observed over a period of 7 days. Degeneration was visualized by H&E overview staining and electron microscopy. PR cell death was measured by quantifying TUNEL-positive cells in the outer nuclear layer (ONL). Activity measurements of key PCD enzymes (calpain, caspases) were used to identify the involved cell death pathways. Furthermore, the expression level of C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78), key players in endoplasmic reticulum (ER) stress-induced apoptosis, was analyzed using quantitative real-time PCR. A decrease in ONL thickness and the appearance of apoptotic PR nuclei could be detected beginning 3 days post-injection (PI). This was accompanied by an increase of TUNEL-positive cells. Significant upregulation of activated caspases (3, 9, 12) was found at different time periods after MNU injection. Additionally, several other players of nonconventional PCD pathways were also upregulated. Consequently, calpain activity increased in the ONL, with a maximum on day 7 PI and an upregulation of CHOP and GRP78 expression beginning on day 1 PI was found. The data indicate that regular apoptosis is the major cause of MNU-induced PR cell death. However, alternative PCD pathways, including ER stress and calpain activation, are also involved. Knowledge about the mechanisms involved in this mouse model of PR degeneration could facilitate the design of putative combinatory therapeutic approaches.

Topological control of life and death in non-proliferative epithelia.

PubMed

Martinand-Mari, Camille; Maury, Benoit; Rousset, François; Sahuquet, Alain; Mennessier, Gérard; Rochal, Sergei; Lorman, Vladimir; Mangeat, Paul; Baghdiguian, Stephen

2009-01-01

Programmed cell death is one of the most fascinating demonstrations of the plasticity of biological systems. It is classically described to act upstream of and govern major developmental patterning processes (e.g. inter-digitations in vertebrates, ommatidia in Drosophila). We show here the first evidence that massive apoptosis can also be controlled and coordinated by a pre-established pattern of a specific 'master cell' population. This new concept is supported by the development and validation of an original model of cell patterning. Ciona intestinalis eggs are surrounded by a three-layered follicular organization composed of 60 elongated floating extensions made of as many outer and inner cells, and indirectly spread through an extracellular matrix over 1200 test cells. Experimental and selective ablation of outer and inner cells results in the abrogation of apoptosis in respective remaining neighbouring test cells. In addition incubation of outer/inner follicular cell-depleted eggs with a soluble extract of apoptotic outer/inner cells partially restores apoptosis to apoptotic-defective test cells. The 60 inner follicular cells were thus identified as 'apoptotic master' cells which collectively are induction sites for programmed cell death of the underlying test cells. The position of apoptotic master cells is controlled by topological constraints exhibiting a tetrahedral symmetry, and each cell spreads over and can control the destiny of 20 smaller test cells, which leads to optimized apoptosis signalling.

Defense responses regulated by jasmonate and delayed senescence caused by ethylene receptor mutation contribute to tolerance of petunia to Botrytis cinerea

USDA-ARS?s Scientific Manuscript database

The death of cells can be a programmed event that occurs when plants are attacked by pathogens. Botrytis cinerea (B. cinerea), a model necrotrophic pathogen, triggers the host cell death response because it produces toxins. A hypersensitive reaction (HR) occurs at the site of contact. In Arabidopsis...

Vacuolar processing enzyme in plant programmed cell death

PubMed Central

Hatsugai, Noriyuki; Yamada, Kenji; Goto-Yamada, Shino; Hara-Nishimura, Ikuko

2015-01-01

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 ortholog 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. PMID:25914711

1-Nitropyrene (1-NP) induces apoptosis and apparently a non-apoptotic programmed cell death (paraptosis) in Hepa1c1c7 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asare, Nana; Landvik, Nina E.; Lagadic-Gossmann, Dominique

2008-07-15

Mechanistic studies of nitro-PAHs (polycyclic aromatic hydrocarbons) of interest might help elucidate which chemical characteristics are most important in eliciting toxic effects. 1-Nitropyrene (1-NP) is the predominant nitrated PAH emitted in diesel exhaust. 1-NP-exposed Hepa1c1c7 cells exhibited marked changes in cellular morphology, decreased proliferation and different forms of cell death. A dramatic increase in cytoplasmic vacuolization was observed already after 6 h of exposure and the cells started to round up at 12 h. The rate of cell proliferation was markedly reduced at 24 h and apoptotic as well as propidium iodide (PI)-positive cells appeared. Electron microscopic examination revealed thatmore » the vacuolization was partly due to mitochondria swelling. The caspase inhibitor Z-VAD-FMK inhibited only the apoptotic cell death and Nec-1 (an inhibitor of necroptosis) exhibited no inhibitory effects on either cell death or vacuolization. In contrast, cycloheximide markedly reduced both the number of apoptotic and PI-positive cells as well as the cytoplasmic vacuolization, suggesting that 1-NP induced paraptotic cell death. All the MAPKs; ERK1/2, p38 and JNK, appear to be involved in the death process since marked activation was observed upon 1-NP exposure, and their inhibitors partly reduced the induced cell death. The ERK1/2 inhibitor PD 98057 completely blocked the induced vacuolization, whereas the other MAPKs inhibitors only had minor effects on this process. These findings suggest that 1-NP may cause apoptosis and paraptosis. In contrast, the corresponding amine (1-aminopyrene) elicited only minor apoptotic and necrotic cell death, and cells with characteristics typical of paraptosis were absent.« less

Human T cells engineered to express a programmed death 1/28 costimulatory retargeting molecule display enhanced antitumor activity.

PubMed

Ankri, Chen; Shamalov, Katerina; Horovitz-Fried, Miryam; Mauer, Shmuel; Cohen, Cyrille J

2013-10-15

Adoptive transfer of T cells genetically modified to express cancer-specific receptors can mediate impressive tumor regression in terminally ill patients. However, T cell function and persistence over time could be hampered by the activation of inhibitory costimulatory pathways, such as programmed death 1 (PD1)/programmed death ligand 1, leading to T cell exhaustion and providing tumor cells with an escape mechanism from immunosurveillance. In addition, the lack of positive costimulation at the tumor site can further dampen T cell response. Thus, as T cell genetic engineering has become clinically relevant, we aimed at enhancing T cell antitumor activity by genetically diverting T cell-negative costimulatory signals into positive ones using chimeric costimulatory retargeting molecules and which are composed of the PD1 extracellular domain fused to the signaling domains of positive costimulatory molecules such as CD28 and 4-1BB. After characterizing the optimal PD1 chimera, we designed and optimized a tripartite retroviral vector that enables the simultaneous expression of this chimeric molecule in conjunction with a cancer-specific TCR. Human T cells, transduced to express a PD1/28 chimeric molecule, exhibited enhanced cytokine secretion and upregulation of activation markers upon coculture with tumor cells. These engineered cells also proliferated better compared with control cells. Finally, we tested the function of these cells in two xenograft models of human melanoma tumors and show that PD1/28-engineered human T cells demonstrated superior antitumor function. Overall, we propose that engineering T cells with a costimulatory retargeting molecule can enhance their function, which bears important implications for the improvement of T cell immunotherapy.

Morphological classification of plant cell deaths.

PubMed

van Doorn, W G; Beers, E P; Dangl, J L; Franklin-Tong, V E; Gallois, P; Hara-Nishimura, I; Jones, A M; Kawai-Yamada, M; Lam, E; Mundy, J; Mur, L A J; Petersen, M; Smertenko, A; Taliansky, M; Van Breusegem, F; Wolpert, T; Woltering, E; Zhivotovsky, B; Bozhkov, P V

2011-08-01

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 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, 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 tissue and organ formation and elimination, whereas necrosis is typically found under abiotic stress. Some examples of plant PCD cannot be ascribed to either major class and are therefore classified as separate modalities. These are PCD associated with the hypersensitive response to biotrophic pathogens, which can express features of both necrosis and vacuolar cell death, PCD in starchy cereal endosperm and during self-incompatibility. The present classification is not static, but will be subject to further revision, especially when specific biochemical pathways are better defined.

Kex1 protease is involved in yeast cell death induced by defective N-glycosylation, acetic acid, and chronological aging.

PubMed

Hauptmann, Peter; Lehle, Ludwig

2008-07-04

N-glycosylation in the endoplasmic reticulum is an essential protein modification and highly conserved in evolution from yeast to humans. The key step of this pathway is the transfer of the lipid-linked core oligosaccharide to the nascent polypeptide chain, catalyzed by the oligosaccharyltransferase complex. Temperature-sensitive oligosaccharyltransferase mutants of Saccharomyces cerevisiae at the restrictive temperature, such as wbp1-1, as well as wild-type cells in the presence of the N-glycosylation inhibitor tunicamycin display typical apoptotic phenotypes like nuclear condensation, DNA fragmentation, phosphatidylserine translocation, caspase-like activity, and reactive oxygen species accumulation. Since deletion of the yeast metacaspase YCA1 did not abrogate this death pathway, we postulated a different proteolytic process to be responsible. Here, we show that Kex1 protease is involved in the programmed cell death caused by defective N-glycosylation. Its disruption decreases caspase-like activity, production of reactive oxygen species, and fragmentation of mitochondria and, conversely, improves growth and survival of cells. Moreover, we demonstrate that Kex1 contributes also to the active cell death program induced by acetic acid stress or during chronological aging, suggesting that Kex1 plays a more general role in cellular suicide of yeast.

RHIM-based protein:protein interactions in anti-microbial defence against programmed cell death by necroptosis.

PubMed

Baker, Max O D G; Shanmugam, Nirukshan; Pham, Chi L L; Strange, Merryn; Steain, Megan; Sunde, Margaret

2018-05-05

The Receptor-interacting protein kinase Homotypic Interaction Motif (RHIM) is an amino acid sequence that mediates multiple protein:protein interactions in the mammalian programmed cell death pathway known as necroptosis. At least one key RHIM-based complex has been shown to have a functional amyloid fibril structure, which provides a stable hetero-oligomeric platform for downstream signaling. RHIMs and related motifs are present in immunity-related proteins across nature, from viruses to fungi to metazoans. Necroptosis is a hallmark feature of cellular clearance of infection. For this reason, numerous pathogens, including viruses and bacteria, have developed varied methods to modulate necroptosis, focusing on inhibiting RHIM:RHIM interactions, and thus their downstream cell death effects. This review will discuss current understanding of RHIM:RHIM interactions in normal cellular activation of necroptosis, from a structural and cell biology perspective. It will compare the mechanisms by which pathogens subvert these interactions in order to maintain their replicative and infective cycles and consider the similarities between RHIMs and other functional amyloid-forming proteins associated with cell death and innate immunity. It will discuss the implications of the heteromeric nature and structure of RHIM-based amyloid complexes in the context of other functional amyloids. Copyright © 2018. Published by Elsevier Ltd.

Different toxic effects of YTX in tumor K-562 and lymphoblastoid cell lines

PubMed Central

Fernández-Araujo, Andrea; Sánchez, Jon A.; Alfonso, Amparo; Vieytes, Mercedes R.; Botana, Luis M.

2015-01-01

Yessotoxin (YTX) modulates cellular phosphodiesterases (PDEs). In this regard, opposite effects had been described in the tumor model K-562 cell line and fresh human lymphocytes in terms of cell viability, cyclic adenosine 3',5'-cyclic monophosphate (cAMP) production and protein expression after YTX treatment. Studies in depth of the pathways activated by YTX in K-562 cell line, have demonstrated the activation of two different cell death types, apoptosis, and autophagy after 24 and 48 h of treatment, respectively. Furthermore, the key role of type 4A PDE (PDE4A) in both pathways activated by YTX was demonstrated. Therefore, taking into account the differences between cellular lines and fresh cells, a study of cell death pathways activated by YTX in a non-tumor cell line with mitotic activity, was performed. The cellular model used was the lymphoblastoid cell line that represents a non-tumor model with normal apoptotic and mitotic machinery. In this context, cell viability and cell proliferation, expression of proteins involved in cell death activated by YTX and mitochondrial mass, were studied after the incubation with the toxin. Opposite to the tumor model, no cell death activation was observed in lymphoblastoid cell line in the presence of YTX. In this sense, variations in apoptosis hallmarks were not detected in the lymphoblastoid cell line after YTX incubation, whereas this type I of programmed cell death was observed in K-562 cells. On the other hand, autophagy cell death was triggered in this cellular line, while other autophagic process is suggested in lymphoblastoid cells. These YTX effects are related to PDE4A in both cellular lines. In addition, while cell death is triggered in K-562 cells after YTX treatment, in lymphoblastoid cells the toxin stops cellular proliferation. These results point to YTX as a specific toxic compound of tumor cells, since in the non-tumor lymphoblastoid cell line, no cell death hallmarks are observed. PMID:26136685

New-onset third-degree atrioventricular block because of autoimmune-induced myositis under treatment with anti-programmed cell death-1 (nivolumab) for metastatic melanoma.

PubMed

Behling, Juliane; Kaes, Joachim; Münzel, Thomas; Grabbe, Stephan; Loquai, Carmen

2017-04-01

There has been considerable progress in treating malignant melanoma over the last few years. The immune-checkpoint-inhibitors nivolumab and pembrolizumab have been approved by the Food and Drug Administration in 2014 for the therapy of metastatic melanoma. Anti-programmed cell death-1-blocking antibodies are known to cause immune-related adverse events. Physicians should be aware of common and rare side effects and pay attention to new ones. We therefore report a severe and life-threatening side effect of anti-programmed cell death-1 immunotherapy with nivolumab that has not been previously reported: the development of a third-degree atrioventricular block. After a second infusion with nivolumab, our patient developed a troponin I-positive and autoantibody-positive myositis and a few days later a new-onset third-degree atrioventricular block. This is most likely because of an autoimmune-induced myositis with a cardiac impairment in terms of a myocarditis, which led to an impairment of the conduction of cardiac electrical stimuli.

Guidelines and recommendations on yeast cell death nomenclature.

PubMed

Carmona-Gutierrez, Didac; Bauer, Maria Anna; Zimmermann, Andreas; Aguilera, Andrés; Austriaco, Nicanor; Ayscough, Kathryn; Balzan, Rena; Bar-Nun, Shoshana; Barrientos, Antonio; Belenky, Peter; Blondel, Marc; Braun, Ralf J; Breitenbach, Michael; Burhans, William C; Büttner, Sabrina; Cavalieri, Duccio; Chang, Michael; Cooper, Katrina F; Côrte-Real, Manuela; Costa, Vítor; Cullin, Christophe; Dawes, Ian; Dengjel, Jörn; Dickman, Martin B; Eisenberg, Tobias; Fahrenkrog, Birthe; Fasel, Nicolas; Fröhlich, Kai-Uwe; Gargouri, Ali; Giannattasio, Sergio; Goffrini, Paola; Gourlay, Campbell W; Grant, Chris M; Greenwood, Michael T; Guaragnella, Nicoletta; Heger, Thomas; Heinisch, Jürgen; Herker, Eva; Herrmann, Johannes M; Hofer, Sebastian; Jiménez-Ruiz, Antonio; Jungwirth, Helmut; Kainz, Katharina; Kontoyiannis, Dimitrios P; Ludovico, Paula; Manon, Stéphen; Martegani, Enzo; Mazzoni, Cristina; Megeney, Lynn A; Meisinger, Chris; Nielsen, Jens; Nyström, Thomas; Osiewacz, Heinz D; Outeiro, Tiago F; Park, Hay-Oak; Pendl, Tobias; Petranovic, Dina; Picot, Stephane; Polčic, Peter; Powers, Ted; Ramsdale, Mark; Rinnerthaler, Mark; Rockenfeller, Patrick; Ruckenstuhl, Christoph; Schaffrath, Raffael; Segovia, Maria; Severin, Fedor F; Sharon, Amir; Sigrist, Stephan J; Sommer-Ruck, Cornelia; Sousa, Maria João; Thevelein, Johan M; Thevissen, Karin; Titorenko, Vladimir; Toledano, Michel B; Tuite, Mick; Vögtle, F-Nora; Westermann, Benedikt; Winderickx, Joris; Wissing, Silke; Wölfl, Stefan; Zhang, Zhaojie J; Zhao, Richard Y; Zhou, Bing; Galluzzi, Lorenzo; Kroemer, Guido; Madeo, Frank

2018-01-01

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cel-lular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the defi-nition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differ-ential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death rou-tines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the au-thors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the pro-gress of this vibrant field of research.

Deciphering early events involved in hyperosmotic stress-induced programmed cell death in tobacco BY-2 cells

PubMed Central

Monetti, Emanuela; Kadono, Takashi; Bouteau, François

2014-01-01

Hyperosmotic stresses represent one of the major constraints that adversely affect plants growth, development, and productivity. In this study, the focus was on early responses to hyperosmotic stress- (NaCl and sorbitol) induced reactive oxygen species (ROS) generation, cytosolic Ca2+ concentration ([Ca2+]cyt) increase, ion fluxes, and mitochondrial potential variations, and on their links in pathways leading to programmed cell death (PCD). By using BY-2 tobacco cells, it was shown that both NaCl- and sorbitol-induced PCD seemed to be dependent on superoxide anion (O2·–) generation by NADPH-oxidase. In the case of NaCl, an early influx of sodium through non-selective cation channels participates in the development of PCD through mitochondrial dysfunction and NADPH-oxidase-dependent O2·– generation. This supports the hypothesis of different pathways in NaCl- and sorbitol-induced cell death. Surprisingly, other shared early responses, such as [Ca2+]cyt increase and singlet oxygen production, do not seem to be involved in PCD. PMID:24420571

Microtubule antagonists activate programmed cell death (apoptosis) in cultured rat hepatocytes.

PubMed Central

Tsukidate, K.; Yamamoto, K.; Snyder, J. W.; Farber, J. L.

1993-01-01

We investigated the mechanism of lethal injury following the disruption of microtubules in cultured hepatocytes treated with vinblastine (VBL) or colchicine (COL). These agents kill hepatocytes by a process readily distinguished from two well-known pathways that lead to a loss of viability, namely, oxidative stress and inhibition of mitochondrial electron transport. Cell killing with VBL and COL was accompanied by fragmentation of DNA. Both the loss of viability and the fragmentation of DNA were prevented by the inhibition of protein synthesis within 6 hours following exposure to VBL or COL. Cell death and the fragmentation of DNA were also prevented when Ca2+ was removed from the culture medium. By contrast, the inhibition of protein kinase C prevented cell killing by VBL or COL, but did not alter the extent of DNA fragmentation. The requirements here for protein synthesis, extracellular Ca2+, and protein kinase C activity define a model of apoptosis, or programmed cell death, that seems to involve mechanisms that can be dissociated from the fragmentation of DNA. Images Figure 2 PMID:8362985

N-Desmethyldauricine Induces Autophagic Cell Death in Apoptosis-Defective Cells via Ca2+ Mobilization.

PubMed

Law, Betty Y K; Mok, Simon W F; Chen, Juan; Michelangeli, Francesco; Jiang, Zhi-Hong; Han, Yu; Qu, Yuan Q; Qiu, Alena C L; Xu, Su-Wei; Xue, Wei-Wei; Yao, Xiao-Jun; Gao, Jia Y; Javed, Masood-Ul-Hassan; Coghi, Paolo; Liu, Liang; Wong, Vincent K W

2017-01-01

Resistance of cancer cells to chemotherapy remains a significant problem in oncology. Mechanisms regulating programmed cell death, including apoptosis, autophagy or necrosis, in the treatment of cancers have been extensively investigated over the last few decades. Autophagy is now emerging as an important pathway in regulating cell death or survival in cancer therapy. Recent studies demonstrated variety of natural small-molecules could induce autophagic cell death in apoptosis-resistant cancer cells, therefore, discovery of novel autophagic enhancers from natural products could be a promising strategy for treatment of chemotherapy-resistant cancer. By computational virtual docking analysis, biochemical assays, and advanced live-cell imaging techniques, we have identified N -desmethyldauricine (LP-4), isolated from rhizoma of Menispermum dauricum DC as a novel inducer of autophagy. LP-4 was shown to induce autophagy via the Ulk-1-PERK and Ca 2+ /Calmodulin-dependent protein kinase kinase β (CaMKKβ)-AMPK-mTOR signaling cascades, via mobilizing calcium release through inhibition of SERCA, and importantly, lead to autophagic cell death in a panel of cancer cells, apoptosis-defective and apoptosis-resistant cells. Taken together, this study provides detailed insights into the cytotoxic mechanism of a novel autophagic compound that targeting the apoptosis resistant cancer cells, and new implication on drug discovery from natural products for drug resistant cancer therapy.

Apoptosis: a guide for the perplexed.

PubMed

Sloviter, Robert S

2002-01-01

The term 'apoptosis' describes an active process of cellular deconstruction originally contrasted morphologically with necrosis. The mistaken equivalence of the terms apoptosis and 'programmed cell death' has caused confusion and implied that apoptosis is an identifiable therapeutic target rather than a name of a type of cell death. The roots of confusion are suggested to lie not in superficial disagreements about the morphology and biochemistry of cell death, but in the lamentable disconnection of modern science from its philosophical foundations (i.e. Socratic definition, nominalism versus realism, and William of Ockham's advocacy of Aristotelian metaphysics over Plato's Theory of Forms). Renewed awareness of these issues might be the key to understanding that apoptosis is a created concept, not a real entity, and that the use of terms that defy definition has become an obstacle to clear thinking about preventable cell death.

A homologue of the defender against the apoptotic death gene (dad1 )in UV-exposed Chlamydomonas cells is downregulated with the onset of programmed cell death.

PubMed

Moharikar, Swati; D'Souza, Jacinta S; Rao, Basuthkar J

2007-03-01

We report here the isolation of a homologue of the potential anti-apoptotic gene, defender against apoptotic death (dad1 )from Chlamydomonas reinhardtii cells.Using polymerase chain reaction (PCR),we investigated its expression in the execution process of programmed cell death (PCD)in UV-C exposed dying C.reinhardtii cells.Reverse- transcriptase (RT)-PCR showed that C.reinhardtii dad1 amplification was drastically reduced in UV-C exposed dying C.reinhardtii cells.We connect the downregulation of dad1 with the upregulation of apoptosis protease activating factor-1 (APAF-1)and the physiological changes that occur in C.reinhardtii cells upon exposure to 12 J/m 2 UV-C in order to show a reciprocal relationship between proapoptotic and inhibitor of apoptosis factors.The temporal changes indicate a correlation between the onset of cell death and dad1 downregulation.The sequence of the PCR product of the cDNA encoding the dad1 homologue was aligned with the annotated dad1 (C_20215)from the Chlamydomonas database (http://genome.jgi-psf.org:8080/annotator/servlet/jgi.annotation.Annotation?pDb=chlre2); Annotation?pDb=chlre2 );this sequence was found to show 100% identity,both at the nucleotide and amino acid level. The 327 bp transcript showed an open reading frame of 87 amino acid residues.The deduced amino acid sequence of the putative C.reinhardtii DAD1 homologue showed 54% identity with Oryza sativa, 56 identity with Drosophila melanogaster, 66% identity with Xenopus laevis, and 64% identity with Homo sapiens,Sus scrofa,Gallus gallus,Rattus norvegicus and Mus musculus.

Calpain Determines the Propensity of Adult Hippocampal Neural Stem Cells to Autophagic Cell Death Following Insulin Withdrawal.

PubMed

Chung, Kyung Min; Park, Hyunhee; Jung, Seonghee; Ha, Shinwon; Yoo, Seung-Jun; Woo, Hanwoong; Lee, Hyang Ju; Kim, Seong Who; Kim, Eun-Kyoung; Moon, Cheil; Yu, Seong-Woon

2015-10-01

Programmed cell death (PCD) has significant effects on the function of neural stem cells (NSCs) during brain development and degeneration. We have previously reported that adult rat hippocampal neural stem (HCN) cells underwent autophagic cell death (ACD) rather than apoptosis following insulin withdrawal despite their intact apoptotic capabilities. Here, we report a switch in the mode of cell death in HCN cells with calpain as a critical determinant. In HCN cells, calpain 1 expression was barely detectable while calpain 2 was predominant. Inhibition of calpain in insulin-deprived HCN cells further augmented ACD. In contrast, expression of calpain 1 switched ACD to apoptosis. The proteasome inhibitor lactacystin blocked calpain 2 degradation and elevated the intracellular Ca(2+) concentration. In combination, these effects potentiated calpain activity and converted the mode of cell death to apoptosis. Our results indicate that low calpain activity, due to absence of calpain 1 and degradation of calpain 2, results in a preference for ACD over apoptosis in insulin-deprived HCN cells. On the other hand, conditions leading to high calpain activity completely switch the mode of cell death to apoptosis. This is the first report on the PCD mode switching mechanism in NSCs. The dynamic change in calpain activity through the proteasome-mediated modulation of the calpain and intracellular Ca(2+) levels may be the critical contributor to the demise of NSCs. Our findings provide a novel insight into the complex mechanisms interconnecting autophagy and apoptosis and their roles in the regulation of NSC death. © 2015 AlphaMed Press.

Combined treatment with fenretinide and indomethacin induces AIF-mediated, non-classical cell death in human acute T-cell leukemia Jurkat cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hojka-Osinska, Anna, E-mail: hojka@immuno.iitd.pan.wroc.pl; Ziolo, Ewa, E-mail: ziolo@immuno.iitd.pan.wroc.pl; Rapak, Andrzej, E-mail: rapak@immuno.iitd.pan.wroc.pl

Highlights: Black-Right-Pointing-Pointer The combination of fenretinide and indomethacin induces a high level of cell death. Black-Right-Pointing-Pointer Apoptotic pathway is caspase-independent. Black-Right-Pointing-Pointer Jurkat cells undergo AIF-mediated cell death. -- Abstract: Currently used cytotoxic drugs in cancer therapy have a similar mechanism of action and low specificity. Applied simultaneously, they show an additive effect with strong side effects. Clinical trials with the use of different agents in cancer therapy show that the use of these compounds alone is not very effective in fighting cancer. An alternative solution could be to apply a combination of these agents, because their combination has a synergisticmore » effect on some cancer cells. Therefore, in our investigations we examined the effects of a synthetic retinoid-fenretinide when combined with a non-steroidal anti-inflammatory drug-indomethacin on the process of apoptosis in the acute human T-cell leukemia cell line Jurkat. We demonstrate that treatment with the combination of the tested compounds induces the death of cells, that is peculiar and combines features of apoptosis as well as non-apoptotic cell death. In detail we observed, cell membrane permeabilization, phosphatydylserine exposure, no oligonucleosomal DNA fragmentation, no caspase-3 activation, but apoptosis inducing factor (AIF) nuclear translocation. Taken together these results indicate, that Jurkat cells after treatment with a combination of fenretinide and indomethacin undergo AIF-mediated programmed cell death.« less

Interrogating the relevance of mitochondrial apoptosis for vertebrate development and postnatal tissue homeostasis.

PubMed

Tuzlak, Selma; Kaufmann, Thomas; Villunger, Andreas

2016-10-01

"Programmed cell death or 'apoptosis' is critical for organogenesis during embryonic development and tissue homeostasis in the adult. Its deregulation can contribute to a broad range of human pathologies, including neurodegeneration, cancer, or autoimmunity…" These or similar phrases have become generic opening statements in many reviews and textbooks describing the physiological relevance of apoptotic cell death. However, while the role in disease has been documented beyond doubt, facilitating innovative drug discovery, we wonder whether the former is really true. What goes wrong in vertebrate development or in adult tissue when the main route to apoptotic cell death, controlled by the BCL2 family, is impaired? Such scenarios have been mimicked by deletion of one or more prodeath genes within the BCL2 family, and gene targeting studies in mice exploring the consequences have been manifold. Many of these studies were geared toward understanding the role of BCL2 family proteins and mitochondrial apoptosis in disease, whereas fewer focused in detail on their role during normal development or tissue homeostasis, perhaps also due to an irritating lack of phenotype. Looking at these studies, the relevance of classical programmed cell death by apoptosis for development appears rather limited. Together, these many studies suggest either highly selective and context-dependent contributions of mitochondrial apoptosis or significant redundancy with alternative cell death mechanisms, as summarized and discussed here. © 2016 Tuzlak et al.; Published by Cold Spring Harbor Laboratory Press.

Programmed cell death acts at different stages of Drosophila neurodevelopment to shape the central nervous system

PubMed Central

Desplan, Claude

2016-01-01

Nervous system development is a process that integrates cell proliferation, differentiation and programmed cell death (PCD). PCD is an evolutionary conserved mechanism and a fundamental developmental process by which the final cell number in a nervous system is established. In vertebrates and invertebrates, PCD can be determined intrinsically by cell lineage and age, as well as extrinsically by nutritional, metabolic and hormonal states. Drosophila has been an instrumental model for understanding how this mechanism is regulated. We review the role of PCD in Drosophila central nervous system development from neural progenitors to neurons, its molecular mechanism and function, how it is regulated and implemented, and how it ultimately shapes the fly central nervous system from the embryo to the adult. Finally, we discuss ideas that emerge while integrating this information. PMID:27404003

Immune evasion mechanisms and immune checkpoint inhibition in advanced merkel cell carcinoma.

PubMed

Schadendorf, Dirk; Nghiem, Paul; Bhatia, Shailender; Hauschild, Axel; Saiag, Philippe; Mahnke, Lisa; Hariharan, Subramanian; Kaufman, Howard L

2017-01-01

Merkel cell carcinoma (MCC) is a rare skin cancer caused by Merkel cell polyomavirus (MCPyV) infection and/or ultraviolet radiation-induced somatic mutations. The presence of tumor-infiltrating lymphocytes is evidence that an active immune response to MCPyV and tumor-associated neoantigens occurs in some patients. However, inhibitory immune molecules, including programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1), within the MCC tumor microenvironment aid in tumor evasion of T-cell-mediated clearance. Unlike chemotherapy, treatment with anti-PD-L1 (avelumab) or anti-PD-1 (pembrolizumab) antibodies leads to durable responses in MCC, in both virus-positive and virus-negative tumors. As many tumors are established through the evasion of infiltrating immune-cell clearance, the lessons learned in MCC may be broadly relevant to many cancers.

Pyroptosis drives CD4 T-cell depletion in HIV-1 infection

PubMed Central

Doitsh, Gilad; Galloway, Nicole LK; Geng, Xin; Yang, Zhiyuan; Monroe, Kathryn M.; Zepeda, Orlando; Hunt, Peter W.; Hatano, Hiroyu; Sowinski, Stefanie; Muñoz-Arias, Isa; Greene, Warner C.

2014-01-01

The pathway causing CD4 T-cell death in HIV-infected hosts remains poorly understood. Apoptosis has been proposed as the key mechanism for CD4 T-cell loss. We now show that caspase-3-mediated apoptosis accounts for the death of only a small fraction of productively infected cells. The remaining >95% of quiescent lymphoid CD4 T-cells die by caspase-1-mediated pyroptosis triggered by abortive viral infection. Pyroptosis corresponds to an intensely inflammatory form of programmed cell death where cytoplasmic contents and pro-inflammatory cytokines including IL-1β, are released. This death pathway thus links the two signature events in HIV infection––CD4 T-cell depletion and chronic inflammation––and creates a vicious pathogenic cycle where dying CD4 T-cells release inflammatory signals that attract more cells to die. This cycle can be broken by caspase-1 inhibitors shown to be safe in humans, raising the possibility of a new class of “anti-AIDS” therapeutics targeting the host rather than the virus. PMID:24356306

c-Jun induces apoptosis of starved BM2 monoblasts by activating cyclin A-CDK2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanhara, Petr; Bryja, Vitezslav; Horvath, Viktor

2007-02-02

c-Jun is one of the major components of the activating protein-1 (AP-1), the transcription factor that participates in regulation of proliferation, differentiation, and apoptosis. In this study, we explored functional interactions of the c-Jun protein with several regulators of the G1/S transition in serum-deprived v-myb-transformed chicken monoblasts BM2. We show that the c-Jun protein induces expression of cyclin A, thus up-regulating activity of cyclin A-associated cyclin-dependent kinase 2 (CDK2), and causing massive programmed cell death of starved BM2cJUN cells. Specific inhibition of CDK2 suppresses frequency of apoptosis of BM2cJUN cells. We conclude that up-regulation of cyclin A expression and CDK2more » activity can represent important link between the c-Jun protein, cell cycle machinery, and programmed cell death pathway in leukemic cells.« less

Only in dying, life: programmed cell death during plant development.

PubMed

Van Hautegem, Tom; Waters, Andrew J; Goodrich, Justin; Nowack, Moritz K

2015-02-01

Programmed cell death (PCD) is a fundamental process of life. During the evolution of multicellular organisms, the actively controlled demise of cells has been recruited to fulfil a multitude of functions in development, differentiation, tissue homeostasis, and immune systems. In this review we discuss some of the multiple cases of PCD that occur as integral parts of plant development in a remarkable variety of cell types, tissues, and organs. Although research in the last decade has discovered a number of PCD regulators, mediators, and executers, we are still only beginning to understand the mechanistic complexity that tightly controls preparation, initiation, and execution of PCD as a process that is indispensable for successful vegetative and reproductive development of plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of Analysis and Quantification of Cell Death in vivo and in vitro

DTIC Science & Technology

1985-05-01

mammalian somatic cells appear to have a finite life span that is genetically programmed ( Hayflick , 1977). Following the consummation of this program... limited situations it is possible to evaluate the proliferation kinetics of cell populations in tis- sues by autoradiographically detecting radiolabeled...are, therefore, virtually limited to the analysis of toxicity of directly active chemicals. Primary cultures of target cells retain the ability to

Calcium-mediated apoptosis in a plant hypersensitive disease resistance response.

PubMed

Levine, A; Pennell, R I; Alvarez, M E; Palmer, R; Lamb, C

1996-04-01

Avirulent pathogens elicit a battery of plant defenses, often accompanied by collapse of the challenged cells. In soybean cells, sustained accumulation of H2O2 from an oxidative burst cues localized host cell death. Such hypersensitive cell death appears to be an active process, but little is known about the mechanisms underlying cellular collapse. We show that H2O2 stimulates a rapid influx of Ca2+ into soybean cells, which activates a physiological cell death program resulting in the generation of large (approximately 50 kb) DNA fragments and cell corpse morphology--including cell shrinkage, plasma membrane blebbing and nuclear condensation--characteristic of apoptosis. In contrast, H2O2 induction of the cellular protectant gene glutathione S-transferase is Ca(2+)-independent. Apoptosis in soybean cells and leaf tissue was induced by avirulent Pseudomonas syringae pv. glycinea but was not observed at comparable stages of the compatible interaction with the isogenic virulent strain, which fails to elicit a hypersensitive response. Apoptosis was also observed at the onset of the hypersensitive response in Arabidopsis leaves inoculated with avirulent P. syringae pv. tomato and in tobacco cells treated with the fungal peptide cryptogein, which is involved in the induction of non-host resistance to Phytophthora cryptogea. These observations establish a signal function for Ca2+ downstream of the oxidative burst in the activation of a physiological cell death program in soybean cells that is similar to apoptosis in animals. That the characteristic cell corpse morphology is also induced in Arabidopsis and tobacco by different avirulence signals suggests that apoptosis may prove to be a common, but not necessarily ubiquitous, feature of incompatible plant-pathogen interactions. Emerging similarities between facets of hypersensitive disease resistance and the mammalian native immune system indicate that apoptosis is a widespread defence mechanism in eukaryotes.

Cell Wall Invertase Promotes Fruit Set under Heat Stress by Suppressing ROS-Independent Cell Death.

PubMed

Liu, Yong-Hua; Offler, Christina E; Ruan, Yong-Ling

2016-09-01

Reduced cell wall invertase (CWIN) activity has been shown to be associated with poor seed and fruit set under abiotic stress. Here, we examined whether genetically increasing native CWIN activity would sustain fruit set under long-term moderate heat stress (LMHS), an important factor limiting crop production, by using transgenic tomato (Solanum lycopersicum) with its CWIN inhibitor gene silenced and focusing on ovaries and fruits at 2 d before and after pollination, respectively. We found that the increase of CWIN activity suppressed LMHS-induced programmed cell death in fruits. Surprisingly, measurement of the contents of H2O2 and malondialdehyde and the activities of a cohort of antioxidant enzymes revealed that the CWIN-mediated inhibition on programmed cell death is exerted in a reactive oxygen species-independent manner. Elevation of CWIN activity sustained Suc import into fruits and increased activities of hexokinase and fructokinase in the ovaries in response to LMHS Compared to the wild type, the CWIN-elevated transgenic plants exhibited higher transcript levels of heat shock protein genes Hsp90 and Hsp100 in ovaries and HspII17.6 in fruits under LMHS, which corresponded to a lower transcript level of a negative auxin responsive factor IAA9 but a higher expression of the auxin biosynthesis gene ToFZY6 in fruits at 2 d after pollination. Collectively, the data indicate that CWIN enhances fruit set under LMHS through suppression of programmed cell death in a reactive oxygen species-independent manner that could involve enhanced Suc import and catabolism, HSP expression, and auxin response and biosynthesis. © 2016 American Society of Plant Biologists. All rights reserved.

The anti-ErbB2 antibody H2-18 and the pan-PI3K inhibitor GDC-0941 effectively inhibit trastuzumab-resistant ErbB2-overexpressing breast cancer.

PubMed

Wang, Lingfei; Yu, Xiaojie; Wang, Chao; Pan, Shujun; Liang, Beibei; Zhang, Yajun; Chong, Xiaodan; Meng, Yanchun; Dong, Jian; Zhao, Yirong; Yang, Yang; Wang, Huajing; Gao, Jie; Wei, Huafeng; Zhao, Jian; Wang, Hao; Hu, Chaohua; Xiao, Wenze; Li, Bohua

2017-08-08

Trastuzumab, an anti-ErbB2 humanized antibody, brings benefit to patients with ErbB2-amplified metastatic breast cancers. However, the resistance to trastuzumab is common. Our previously reported H2-18, an anti-ErbB2 antibody, potently induced programmed cell death in trastuzumab-resistant breast cancer cells. Here, we aim to investigate the antitumor efficacy of H2-18 in combination with the pan-PI3K inhibitor GDC-0941 in trastuzumab-resistant breast cancer cell lines. The results showed that H2-18 and GDC-0941 synergistically inhibited the in vitro proliferation of BT-474, SKBR-3, HCC-1954 and HCC-1419 breast cancer cells. H2-18 plus GDC-0941 showed significantly enhanced programmed cell death-inducing activity compared with each drug used alone. The combination of H2-18 and GDC-0941 did not increase the effect of single agent on ROS production, cell cycle and ErbB2 signaling. Importantly, the in vivo antitumor efficacy of H2-18 plus GDC-0941 was superior to that of single agent. Thus, the enhanced in vivo antitumor efficacy of H2-18 plus GDC-0941 may mainly be attributable to its increased programmed cell death-inducing activity. Collectively, H2-18 plus GDC-0941 could effectively inhibit tumor growth, suggesting the potential to be translated into clinic as an efficient strategy for ErbB2-overexpressing breast cancers.

The anti-ErbB2 antibody H2-18 and the pan-PI3K inhibitor GDC-0941 effectively inhibit trastuzumab-resistant ErbB2-overexpressing breast cancer

PubMed Central

Liang, Beibei; Zhang, Yajun; Chong, Xiaodan; Meng, Yanchun; Dong, Jian; Zhao, Yirong; Yang, Yang; Wang, Huajing; Gao, Jie; Wei, Huafeng; Zhao, Jian; Wang, Hao; Hu, Chaohua; Xiao, Wenze; Li, Bohua

2017-01-01

Trastuzumab, an anti-ErbB2 humanized antibody, brings benefit to patients with ErbB2-amplified metastatic breast cancers. However, the resistance to trastuzumab is common. Our previously reported H2-18, an anti-ErbB2 antibody, potently induced programmed cell death in trastuzumab-resistant breast cancer cells. Here, we aim to investigate the antitumor efficacy of H2-18 in combination with the pan-PI3K inhibitor GDC-0941 in trastuzumab-resistant breast cancer cell lines. The results showed that H2-18 and GDC-0941 synergistically inhibited the in vitro proliferation of BT-474, SKBR-3, HCC-1954 and HCC-1419 breast cancer cells. H2-18 plus GDC-0941 showed significantly enhanced programmed cell death-inducing activity compared with each drug used alone. The combination of H2-18 and GDC-0941 did not increase the effect of single agent on ROS production, cell cycle and ErbB2 signaling. Importantly, the in vivo antitumor efficacy of H2-18 plus GDC-0941 was superior to that of single agent. Thus, the enhanced in vivo antitumor efficacy of H2-18 plus GDC-0941 may mainly be attributable to its increased programmed cell death-inducing activity. Collectively, H2-18 plus GDC-0941 could effectively inhibit tumor growth, suggesting the potential to be translated into clinic as an efficient strategy for ErbB2-overexpressing breast cancers. PMID:28881779

Use of programmed cell death protein ligand 1 assay to predict the outcomes of non-small cell lung cancer patients treated with immune checkpoint inhibitors

PubMed Central

Tibaldi, Carmelo; Lunghi, Alice; Baldini, Editta

2017-01-01

The recent discovery of immune checkpoints inhibitors, especially anti-programmed cell death protein 1 (PD-1) and anti-programmed cell death protein ligand 1 (PD-L1) monoclonal antibodies, has opened new scenarios in the management of non-small cell lung cancer (NSCLC) and this new class of drugs has achieved a rapid development in the treatment of this disease. However, considering the costs of these drugs and the fact that only a subset of patients experience long-term disease control, the identification of predictive biomarkers for the selection of candidates suitable for treatment has become a priority. The research focused mainly on the expression of the PD-L1 receptor on both tumor cells and/or immune infiltrates determined by immunohistochemistry (IHC). However, different checkpoint inhibitors were tested, different IHC assays were used, different targets were considered (tumor cells, immune infiltrates or both) and different expression thresholds were employed in clinical trials. In some trials the assay was used prospectively to select the patients, while in other trials it was evaluated retrospectively. Some confusion emerges, which makes it difficult to easily compare the literature data and to translate them in practice management. This mini-review shows the possibilities and pitfalls of the PD-L1 expression to predict the activity and efficacy of anti PD1/PD-L1 monoclonal antibodies in the treatment of NSCLC. PMID:28848698

Response to anti-programmed cell death protein-1 antibodies in men treated for platinum refractory germ cell cancer relapsed after high-dose chemotherapy and stem cell transplantation.

PubMed

Zschäbitz, Stefanie; Lasitschka, Felix; Hadaschik, Boris; Hofheinz, Ralf-Dieter; Jentsch-Ullrich, Kathleen; Grüner, Marcus; Jäger, Dirk; Grüllich, Carsten

2017-05-01

Treatment options for patients with platinum refractory metastatic germ cell tumours (GCT) relapsing after high-dose chemotherapy and autologous stem cell transplantation are limited and survival is poor. Antibodies directed against programmed cell death protein-1 (PD-1) and programmed cell death ligand-1 (PD-L1) are currently assessed within clinical trials. We present updated data on our experience with checkpoint inhibitors as a compassionate use off-label treatment attempt for highly-pretreated patients with GCT and provide an overview of the current literature on PD-L1 expression in this rare tumour entity. We analysed all patients with platinum refractory GCT treated with checkpoint inhibitors at our institutions between 2015 and 2017. Data were retrieved retrospectively from the patient charts. Seven patients were treated with nivolumab or pembrolizumab. Four patients received single-dose treatment and died shortly afterwards due to tumour progression; the remaining three patients received treatment for at least 6 months. No significant treatment toxicity was observed. Long-term tumour response was achieved in two of the three patients, both of them highly positive for PD-L1 staining. We consider checkpoint inhibition to be efficient in carefully selected patients with platinum refractory GCT. However, predictive markers associated with tumour response are not yet known and larger prospective clinical trials are warranted. Copyright © 2017 Elsevier Ltd. All rights reserved.

Xylogenesis in zinnia (Zinnia elegans) cell cultures: unravelling the regulatory steps in a complex developmental programmed cell death event.

PubMed

Iakimova, Elena T; Woltering, Ernst J

2017-04-01

Physiological and molecular studies support the view that xylogenesis can largely be determined as a specific form of vacuolar programmed cell death (PCD). The studies in xylogenic zinnia cell culture have led to many breakthroughs in xylogenesis research and provided a background for investigations in other experimental models in vitro and in planta . This review discusses the most essential earlier and recent findings on the regulation of xylem elements differentiation and PCD in zinnia and other xylogenic systems. Xylogenesis (the formation of water conducting vascular tissue) is a paradigm of plant developmental PCD. The xylem vessels are composed of fused tracheary elements (TEs)-dead, hollow cells with patterned lignified secondary cell walls. They result from the differentiation of the procambium and cambium cells and undergo cell death to become functional post-mortem. The TE differentiation proceeds through a well-coordinated sequence of events in which differentiation and the programmed cellular demise are intimately connected. For years a classical experimental model for studies on xylogenesis was the xylogenic zinnia (Zinnia elegans) cell culture derived from leaf mesophyll cells that, upon induction by cytokinin and auxin, transdifferentiate into TEs. This cell system has been proven very efficient for investigations on the regulatory components of xylem differentiation which has led to many discoveries on the mechanisms of xylogenesis. The knowledge gained from this system has potentiated studies in other xylogenic cultures in vitro and in planta. The present review summarises the previous and latest findings on the hormonal and biochemical signalling, metabolic pathways and molecular and gene determinants underlying the regulation of xylem vessels differentiation in zinnia cell culture. Highlighted are breakthroughs achieved through the use of xylogenic systems from other species and newly introduced tools and analytical approaches to study the processes. The mutual dependence between PCD signalling and the differentiation cascade in the program of TE development is discussed.

Proliferate and survive: cell division cycle and apoptosis in human neuroblastoma.

PubMed

Borriello, Adriana; Roberto, Roberta; Della Ragione, Fulvio; Iolascon, Achille

2002-02-01

Neuroblastoma is one of the most frequent childhood cancers and a major cause of death from neoplasias of infancy. Although a wealth of studies on its molecular bases have been carried out, little conclusive information about its origin and evolution is available. Some intriguing findings have correlated neuroblastoma development with aberrations of two pivotal cellular processes generally altered in human cancers, namely cell division cycle and apoptosis. Indeed, it has been reported that neuroblastoma cell lines show accumulation of Id2 protein, a factor which is able to hamper the pRb protein antiproliferative activity. The increased Id2 is due to N-myc gene amplification and overexpression, a phenomenon frequently observed in neuroblastoma and an important independent negative marker. Moreover, neuroblastoma cells are frequently characterized by increased levels of survivin, an inhibitor of the apoptotic response, and by a deficiency of procaspase 8, a key intermediate of the programmed cell death cascade. These two events, probably, make neuroblastomas more resistant to programmed cell death. These recent findings might suggest that neuroblastoma cells have acquired the capability to proliferate easily and die difficultly. The mechanistic meaning of these data will be discussed in the present review. Moreover, we will suggest new therapeutic scenarios opened up by the described alterations of cell cycle and apoptosis engines.

Changes in the Antioxidant Systems as Part of the Signaling Pathway Responsible for the Programmed Cell Death Activated by Nitric Oxide and Reactive Oxygen Species in Tobacco Bright-Yellow 2 Cells1

PubMed Central

de Pinto, Maria Concetta; Tommasi, Franca; De Gara, Laura

2002-01-01

Nitric oxide (NO) has been postulated to be required, together with reactive oxygen species (ROS), for the activation of the hypersensitive reaction, a defense response induced in the noncompatible plant-pathogen interaction. However, its involvement in activating programmed cell death (PCD) in plant cells has been questioned. In this paper, the involvement of the cellular antioxidant metabolism in the signal transduction triggered by these bioactive molecules has been investigated. NO and ROS levels were singularly or simultaneously increased in tobacco (Nicotiana tabacum cv Bright-Yellow 2) cells by the addition to the culture medium of NO and/or ROS generators. The individual increase in NO or ROS had different effects on the studied parameters than the simultaneous increase in the two reactive species. NO generation did not cause an increase in phenylalanine ammonia-lyase (PAL) activity or induction of cellular death. It only induced minor changes in ascorbate (ASC) and glutathione (GSH) metabolisms. An increase in ROS induced oxidative stress in the cells, causing an oxidation of the ASC and GSH redox pairs; however, it had no effect on PAL activity and did not induce cell death when it was generated at low concentrations. In contrast, the simultaneous increase of NO and ROS activated a process of death with the typical cytological and biochemical features of hypersensitive PCD and a remarkable rise in PAL activity. Under the simultaneous generation of NO and ROS, the cellular antioxidant capabilities were also suppressed. The involvement of ASC and GSH as part of the transduction pathway leading to PCD is discussed. PMID:12376637

HSF-1 activates the ubiquitin proteasome system to promote non-apoptotic developmental cell death in C. elegans.

PubMed

Kinet, Maxime J; Malin, Jennifer A; Abraham, Mary C; Blum, Elyse S; Silverman, Melanie R; Lu, Yun; Shaham, Shai

2016-03-08

Apoptosis is a prominent metazoan cell death form. Yet, mutations in apoptosis regulators cause only minor defects in vertebrate development, suggesting that another developmental cell death mechanism exists. While some non-apoptotic programs have been molecularly characterized, none appear to control developmental cell culling. Linker-cell-type death (LCD) is a morphologically conserved non-apoptotic cell death process operating in Caenorhabditis elegans and vertebrate development, and is therefore a compelling candidate process complementing apoptosis. However, the details of LCD execution are not known. Here we delineate a molecular-genetic pathway governing LCD in C. elegans. Redundant activities of antagonistic Wnt signals, a temporal control pathway, and mitogen-activated protein kinase kinase signaling control heat shock factor 1 (HSF-1), a conserved stress-activated transcription factor. Rather than protecting cells, HSF-1 promotes their demise by activating components of the ubiquitin proteasome system, including the E2 ligase LET-70/UBE2D2 functioning with E3 components CUL-3, RBX-1, BTBD-2, and SIAH-1. Our studies uncover design similarities between LCD and developmental apoptosis, and provide testable predictions for analyzing LCD in vertebrates.

Silver nanoparticles of different sizes induce a mixed type of programmed cell death in human pancreatic ductal adenocarcinoma

PubMed Central

Zielinska, Ewelina; Zauszkiewicz-Pawlak, Agata; Wojcik, Michal; Inkielewicz-Stepniak, Iwona

2018-01-01

Pancreatic ductal adenocarcinoma, with the high resistance to chemotherapeutic agents, remains the fourth leading cause of cancer-death in the world. Due to the wide range of biological activity and unique properties, silver nanoparticles (AgNPs) are indicated as agents with potential to overcome barriers involved in chemotherapy failure. Therefore, in our study we decided to assess the ability of AgNPs to kill pancreatic cancer cells, and then to identify the molecular mechanism underlying this effect. Moreover, we evaluated the cytotoxicity of AgNPs against non-tumor cell of the same tissue (hTERT-HPNE cells) for comparison. Our results indicated that AgNPs with size of 2.6 and 18 nm decreased viability, proliferation and caused death of pancreatic cancer cells in a size- and concentration-dependent manner. Ultrastructural analysis identified that cellular uptake of AgNPs resulted in apoptosis, autophagy, necroptosis and mitotic catastrophe. These alterations were associated with increased pro-apoptotic protein Bax and decreased level of anti-apoptotic protein Bcl-2. Moreover, AgNPs significantly elevated the level of tumor suppressor p53 protein as well as necroptosis- and autophagy-related proteins: RIP-1, RIP-3, MLKL and LC3-II, respectively. In addition, we found that PANC-1 cells were more vulnerable to AgNPs-induced cytotoxicity compared to pancreatic non-tumor cells. In conclusion, AgNPs by inducing mixed type of programmed cell death in PANC-1 cells, could provide a new therapeutic strategy to overcome chemoresistance in one of the deadliest human cancer. PMID:29435134

Comprehensive Evaluation of Programmed Death-Ligand 1 Expression in Primary and Metastatic Prostate Cancer.

PubMed

Haffner, Michael C; Guner, Gunes; Taheri, Diana; Netto, George J; Palsgrove, Doreen N; Zheng, Qizhi; Guedes, Liana Benevides; Kim, Kunhwa; Tsai, Harrison; Esopi, David M; Lotan, Tamara L; Sharma, Rajni; Meeker, Alan K; Chinnaiyan, Arul M; Nelson, William G; Yegnasubramanian, Srinivasan; Luo, Jun; Mehra, Rohit; Antonarakis, Emmanuel S; Drake, Charles G; De Marzo, Angelo M

2018-06-01

Antibodies targeting the programmed cell death protein 1/programmed death-ligand 1 (PD-L1) interaction have shown clinical activity in multiple cancer types. PD-L1 protein expression is a clinically validated predictive biomarker of response for such therapies. Prior studies evaluating the expression of PD-L1 in primary prostate cancers have reported highly variable rates of PD-L1 positivity. In addition, limited data exist on PD-L1 expression in metastatic castrate-resistant prostate cancer (mCRPC). Here, we determined PD-L1 protein expression by immunohistochemistry using a validated PD-L1-specific antibody (SP263) in a large and representative cohort of primary prostate cancers and prostate cancer metastases. The study included 539 primary prostate cancers comprising 508 acinar adenocarcinomas, 24 prostatic duct adenocarcinomas, 7 small-cell carcinomas, and a total of 57 cases of mCRPC. PD-L1 positivity was low in primary acinar adenocarcinoma, with only 7.7% of cases showing detectable PD-L1 staining. Increased levels of PD-L1 expression were noted in 42.9% of small-cell carcinomas. In mCRPC, 31.6% of cases showed PD-L1-specific immunoreactivity. In conclusion, in this comprehensive evaluation of PD-L1 expression in prostate cancer, PD-L1 expression is rare in primary prostate cancers, but increased rates of PD-L1 positivity were observed in mCRPC. These results will be important for the future clinical development of programmed cell death protein 1/PD-L1-targeting therapies in prostate cancer. Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Large-Scale Identification and Characterization of Heterodera avenae Putative Effectors Suppressing or Inducing Cell Death in Nicotiana benthamiana

PubMed Central

Chen, Changlong; Chen, Yongpan; Jian, Heng; Yang, Dan; Dai, Yiran; Pan, Lingling; Shi, Fengwei; Yang, Shanshan; Liu, Qian

2018-01-01

Heterodera avenae is one of the most important plant pathogens and causes vast losses in cereal crops. As a sedentary endoparasitic nematode, H. avenae secretes effectors that modify plant defenses and promote its biotrophic infection of its hosts. However, the number of effectors involved in the interaction between H. avenae and host defenses remains unclear. Here, we report the identification of putative effectors in H. avenae that regulate plant defenses on a large scale. Our results showed that 78 of the 95 putative effectors suppressed programmed cell death (PCD) triggered by BAX and that 7 of the putative effectors themselves caused cell death in Nicotiana benthamiana. Among the cell-death-inducing effectors, three were found to be dependent on their specific domains to trigger cell death and to be expressed in esophageal gland cells by in situ hybridization. Ten candidate effectors that suppressed BAX-triggered PCD also suppressed PCD triggered by the elicitor PsojNIP and at least one R-protein/cognate effector pair, suggesting that they are active in suppressing both pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Notably, with the exception of isotig16060, these putative effectors could also suppress PCD triggered by cell-death-inducing effectors from H. avenae, indicating that those effectors may cooperate to promote nematode parasitism. Collectively, our results indicate that the majority of the tested effectors of H. avenae may play important roles in suppressing cell death induced by different elicitors in N. benthamiana. PMID:29379510

MLKL-PITPα signaling-mediated necroptosis contributes to cisplatin-triggered cell death in lung cancer A549 cells.

PubMed

Jing, Lin; Song, Fei; Liu, Zhenyu; Li, Jianghua; Wu, Bo; Fu, Zhiguang; Jiang, Jianli; Chen, Zhinan

2018-02-01

Necroptosis has been reported to be involved in cisplatin-induced cell death, but the mechanisms underlying the occurrence of necroptosis are not fully elucidated. In this study, we show that apart from apoptosis, cisplatin induces necroptosis in A549 cells. The alleviation of cell death by two necroptosis inhibitors-necrostatin-1 (Nec-1) and necrosulfonamide (NSA), and the phosphorylation of mixed lineage kinase domain-like protein (MLKL) at serine 358, suggest the involvement of receptor-interacting protein kinase 1 (RIPK1)-RIPK3-MLKL signaling in cisplatin-treated A549 cells. Additionally, the initiation of cisplatin-induced necroptosis relies on autocrine tumor necrosis factor alpha (TNF-α). Furthermore, we present the first evidence that phosphatidylinositol transfer protein alpha (PITPα) is involved in MLKL-mediated necroptosis by interacting with the N terminal MLKL on its sixth helix and the preceding loop, which facilitates MLKL oligomerization and plasma membrane translocation in necroptosis. Silencing of PITPα expression interferes with MLKL function and reduces cell death. Our data elucidate that cisplatin-treated lung cancer cells undergo a new type of programmed cell death called necroptosis and shed new light on how MLKL translocates to the plasma membrane. Copyright © 2017 Elsevier B.V. All rights reserved.

Methuosis

PubMed Central

Maltese, William A.; Overmeyer, Jean H.

2015-01-01

Apoptosis is the most widely recognized form of physiological programmed cell death. During the past three decades, various nonapoptotic forms of cell death have gained increasing attention, largely because of their potential importance in pathological processes, toxicology, and cancer therapy. A recent addition to the panoply of cell death phenotypes is methuosis. The neologism is derived from the Greek methuo (to drink to intoxication) because the hallmark of this form of cell death is displacement of the cytoplasm by large fluid-filled vacuoles derived from macropinosomes. The demise of the cell resembles many forms of necrosis, insofar as there is a loss of metabolic capacity and plasma membrane integrity, without the cell shrinkage and nuclear fragmentation associated with apoptosis. Methuosis was initially defined in glioblastoma cells after ectopic expression of activated Ras, but recent reports have described small molecules that can induce the features of methuosis in a broad spectrum of cancer cells, including those that are resistant to conventional apoptosis-inducing drugs. This review summarizes the available information about the distinguishing morphological characteristics and underlying mechanisms of methuosis. We compare and contrast methuosis with other cytopathological conditions in which accumulation of clear cytoplasmic vacuoles is a prominent feature. Finally, we highlight key questions that need to be answered to determine whether methuosis truly represents a unique form of regulated cell death. PMID:24726643

Novel Mechanisms of Target Cell Death and Survival and of Therapeutic Action of IVIg in Pemphigus

PubMed Central

Arredondo, Juan; Chernyavsky, Alexander I.; Karaouni, Ali; Grando, Sergei A.

2005-01-01

Pemphigus vulgaris (PV) is a potentially lethal mucocutaneous blistering disease characterized by cell-cell detachment within the stratified epithelium (acantholysis) caused by IgG autoantibodies. Intravenous immunoglobulin (IVIg) therapy effectively treats PV, but the mechanism is not fully understood. To further understand acantholysis and the efficacy of IVIg, we measured effects of IgG fractions from PV patients on keratinocyte death processes. Using IgGs from representative PV patients who improved with IVIg, we identified apoptotic and oncotic signaling pathways in in vitro and in vivo PV models. We identified two groups of PV patients, each producing autoantibodies activating predominantly either apoptotic or oncotic cell death pathway. Experimental treatments with caspase 3 or calpain inhibitors demonstrated that PV IgGs induced acantholysis through both pathways. Upstream, the apoptotic signaling involved activation of caspases 8 and 3 and up-regulation of Fas ligand mRNA, whereas calpain-mediated cell death depended on elevated intracellular free Ca2+. IVIg reduced PV IgG-mediated acantholysis and cell death and up-regulated the caspase inhibitor FLIP and the calpain inhibitor calpastatin. These results indicate that in different PV patients, IgG-induced acantholysis proceeds predominantly via distinct, yet complementary, pathways of programmed cell death differentially mediated by apoptosis and oncosis effectors, with IVIg protecting target cells by up-regulating endogenous caspase and calpain inhibitors. PMID:16314468

A novel Meloidogyne enterolobii effector MeTCTP promotes parasitism by suppressing programmed cell death in host plants.

PubMed

Zhuo, Kan; Chen, Jiansong; Lin, Borong; Wang, Jing; Sun, Fengxia; Hu, Lili; Liao, Jinling

2017-01-01

Meloidogyne enterolobii is one of the most important plant-parasitic nematodes that can overcome the Mi-1 resistance gene and damage many economically important crops. Translationally controlled tumour protein (TCTP) is a multifunctional protein that exists in various eukaryotes and plays an important role in parasitism. In this study, a novel M. enterolobii TCTP effector, named MeTCTP, was identified and functionally characterized. MeTCTP was specifically expressed within the dorsal gland and was up-regulated during M. enterolobii parasitism. Transient expression of MeTCTP in protoplasts from tomato roots showed that MeTCTP was localized in the cytoplasm of the host cells. Transgenic Arabidopsis thaliana plants overexpressing MeTCTP were more susceptible to M. enterolobii infection than wild-type plants in a dose-dependent manner. By contrast, in planta RNA interference (RNAi) targeting MeTCTP suppressed the expression of MeTCTP in infecting nematodes and attenuated their parasitism. Furthermore, MeTCTP could suppress programmed cell death triggered by the pro-apoptotic protein BAX. These results demonstrate that MeTCTP is a novel plant-parasitic nematode effector that promotes parasitism, probably by suppressing programmed cell death in host plants. © 2016 BSPP and John Wiley & Sons Ltd.

Programmed death receptor-1/programmed death receptor ligand-1 blockade after transient lymphodepletion to treat myeloma.

PubMed

Kearl, Tyce J; Jing, Weiqing; Gershan, Jill A; Johnson, Bryon D

2013-06-01

Early phase clinical trials targeting the programmed death receptor-1/ligand-1 (PD-1/PD-L1) pathway to overcome tumor-mediated immunosuppression have reported promising results for a variety of cancers. This pathway appears to play an important role in the failure of immune reactivity to malignant plasma cells in multiple myeloma patients, as the tumor cells express relatively high levels of PD-L1, and T cells show increased PD-1 expression. In the current study, we demonstrate that PD-1/PD-L1 blockade with a PD-L1-specific Ab elicits rejection of a murine myeloma when combined with lymphodepleting irradiation. This particular combined approach by itself has not previously been shown to be efficacious in other tumor models. The antitumor effect of lymphodepletion/anti-PD-L1 therapy was most robust when tumor Ag-experienced T cells were present either through cell transfer or survival after nonmyeloablative irradiation. In vivo depletion of CD4 or CD8 T cells completely eliminated antitumor efficacy of the lymphodepletion/anti-PD-L1 therapy, indicating that both T cell subsets are necessary for tumor rejection. Elimination of myeloma by T cells occurs relatively quickly as tumor cells in the bone marrow were nearly nondetectable by 5 d after the first anti-PD-L1 treatment, suggesting that antimyeloma reactivity is primarily mediated by preactivated T cells, rather than newly generated myeloma-reactive T cells. Anti-PD-L1 plus lymphodepletion failed to improve survival in two solid tumor models, but demonstrated significant efficacy in two hematologic malignancy models. In summary, our results support the clinical testing of lymphodepletion and PD-1/PD-L1 blockade as a novel approach for improving the survival of patients with multiple myeloma.

Statins and Voriconazole Induce Programmed Cell Death in Acanthamoeba castellanii

PubMed Central

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

2015-01-01

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. PMID:25733513

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

PubMed

Kang, Jongkyun; Yeom, Eunbyul; Lim, Janghoo; Choi, Kwang-Wook

2014-01-01

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.

Crystalline structure of pulverized dental calculus induces cell death in oral epithelial cells.

PubMed

Ziauddin, S M; Yoshimura, A; Montenegro Raudales, J L; Ozaki, Y; Higuchi, K; Ukai, T; Kaneko, T; Miyazaki, T; Latz, E; Hara, Y

2018-06-01

Dental calculus is a mineralized deposit attached to the tooth surface. We have shown that cellular uptake of dental calculus triggers nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation, leading to the processing of the interleukin-1β precursor into its mature form in mouse and human phagocytes. The activation of the NLRP3 inflammasome also induced a lytic form of programmed cell death, pyroptosis, in these cells. However, the effects of dental calculus on other cell types in periodontal tissue have not been investigated. The aim of this study was to determine whether dental calculus can induce cell death in oral epithelial cells. HSC-2 human oral squamous carcinoma cells, HOMK107 human primary oral epithelial cells and immortalized mouse macrophages were exposed to dental calculus or 1 of its components, hydroxyapatite crystals. For inhibition assays, the cells were exposed to dental calculus in the presence or absence of cytochalasin D (endocytosis inhibitor), z-YVAD-fmk (caspase-1 inhibitor) or glyburide (NLRP3 inflammasome inhibitor). Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) release and staining with propidium iodide. Tumor necrosis factor-α production was quantified by enzyme-linked immunosorbent assay. Oral epithelial barrier function was examined by permeability assay. Dental calculus induced cell death in HSC-2 cells, as judged by LDH release and propidium iodide staining. Dental calculus also induced LDH release from HOMK107 cells. Following heat treatment, dental calculus lost its capacity to induce tumor necrosis factor-α in mouse macrophages, but could induce LDH release in HSC-2 cells, indicating a major role of inorganic components in cell death. Hydroxyapatite crystals also induced cell death in both HSC-2 and HOMK107 cells, as judged by LDH release, indicating the capacity of crystal particles to induce cell death. Cell death induced by dental calculus was significantly inhibited by cytochalasin D, z-YVAD-fmk and glyburide, indicating NLRP3 inflammasome involvement. In permeability assays, dental calculus attenuated the barrier function of HSC-2 cell monolayers. Dental calculus induces pyroptotic cell death in human oral epithelial cells and the crystalline structure plays a major role in this process. Oral epithelial cell death induced by dental calculus might be important for the etiology of periodontitis. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Signaling via the transcriptionally regulated activin receptor 2B is a novel mediator of neuronal cell death during chicken ciliary ganglion development.

PubMed

Koszinowski, S; Buss, K; Kaehlcke, K; Krieglstein, K

2015-04-01

The TGF-β ligand superfamily members activin A and BMP control important aspects of embryonic neuronal development and differentiation. Both are known to bind to activin receptor subtypes IIA (ActRIIA) and IIB, while in the avian ciliary ganglion (CG), so far only ActRIIA-expression has been described. We show that the expression of ACVR2B, coding for the ActRIIB, is tightly regulated during CG development and the knockdown of ACVR2B expression leads to a deregulation in the execution of neuronal apoptosis and therefore affects ontogenetic programmed cell death in vivo. While the differentiation of choroid neurons was impeded in the knockdown, pointing toward a reduction in activin A-mediated neural differentiation signaling, naturally occurring neuronal cell death in the CG was not prevented by follistatin treatment. Systemic injections of the BMP antagonist noggin, on the other hand, reduced the number of apoptotic neurons to a similar extent as ACVR2B knockdown. We therefore propose a novel pathway in the regulation of CG neuron ontogenetic programmed cell death, which could be mediated by BMP and signals via the ActRIIB. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Violacein Induces Death of Resistant Leukaemia Cells via Kinome Reprogramming, Endoplasmic Reticulum Stress and Golgi Apparatus Collapse

PubMed Central

Queiroz, Karla C. S.; Milani, Renato; Ruela-de-Sousa, Roberta R.; Fuhler, Gwenny M.; Justo, Giselle Z.; Zambuzzi, Willian F.; Duran, Nelson; Diks, Sander H.; Spek, C. Arnold; Ferreira, Carmen V.; Peppelenbosch, Maikel P.

2012-01-01

It is now generally recognised that different modes of programmed cell death (PCD) are intimately linked to the cancerous process. However, the mechanism of PCD involved in cancer chemoprevention is much less clear and may be different between types of chemopreventive agents and tumour cell types involved. Therefore, from a pharmacological view, it is crucial during the earlier steps of drug development to define the cellular specificity of the candidate as well as its capacity to bypass dysfunctional tumoral signalling pathways providing insensitivity to death stimuli. Studying the cytotoxic effects of violacein, an antibiotic dihydro-indolone synthesised by an Amazon river Chromobacterium, we observed that death induced in CD34+/c-Kit+/P-glycoprotein+/MRP1+ TF1 leukaemia progenitor cells is not mediated by apoptosis and/or autophagy, since biomarkers of both types of cell death were not significantly affected by this compound. To clarify the working mechanism of violacein, we performed kinome profiling using peptide arrays to yield comprehensive descriptions of cellular kinase activities. Pro-death activity of violacein is actually carried out by inhibition of calpain and DAPK1 and activation of PKA, AKT and PDK, followed by structural changes caused by endoplasmic reticulum stress and Golgi apparatus collapse, leading to cellular demise. Our results demonstrate that violacein induces kinome reprogramming, overcoming death signaling dysfunctions of intrinsically resistant human leukaemia cells. PMID:23071514

On the paradigm of altruistic suicide in the unicellular world.

PubMed

Nedelcu, Aurora M; Driscoll, William W; Durand, Pierre M; Herron, Matthew D; Rashidi, Armin

2011-01-01

Altruistic suicide is best known in the context of programmed cell death (PCD) in multicellular individuals, which is understood as an adaptive process that contributes to the development and functionality of the organism. After the realization that PCD-like processes can also be induced in single-celled lineages, the paradigm of altruistic cell death has been extended to include these active cell death processes in unicellular organisms. Here, we critically evaluate the current conceptual framework and the experimental data used to support the notion of altruistic suicide in unicellular lineages, and propose new perspectives. We argue that importing the paradigm of altruistic cell death from multicellular organisms to explain active death in unicellular lineages has the potential to limit the types of questions we ask, thus biasing our understanding of the nature, origin, and maintenance of this trait. We also emphasize the need to distinguish between the benefits and the adaptive role of a trait. Lastly, we provide an alternative framework that allows for the possibility that active death in single-celled organisms is a maladaptive trait maintained as a byproduct of selection on pro-survival functions, but that could-under conditions in which kin/group selection can act-be co-opted into an altruistic trait. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

Catalase and NO CATALASE ACTIVITY1 Promote Autophagy-Dependent Cell Death in Arabidopsis[C][W][OPEN

PubMed Central

Hackenberg, Thomas; Juul, Trine; Auzina, Aija; Gwiżdż, Sonia; Małolepszy, Anna; Van Der Kelen, Katrien; Dam, Svend; Bressendorff, Simon; Lorentzen, Andrea; Roepstorff, Peter; Lehmann Nielsen, Kåre; Jørgensen, Jan-Elo; Hofius, Daniel; Breusegem, Frank Van; Petersen, Morten; Andersen, Stig Uggerhøj

2013-01-01

Programmed cell death often depends on generation of reactive oxygen species, which can be detoxified by antioxidative enzymes, including catalases. We previously isolated catalase-deficient mutants (cat2) in a screen for resistance to hydroxyurea-induced cell death. Here, we identify an Arabidopsis thaliana hydroxyurea-resistant autophagy mutant, atg2, which also shows reduced sensitivity to cell death triggered by the bacterial effector avrRpm1. To test if catalase deficiency likewise affected both hydroxyurea and avrRpm1 sensitivity, we selected mutants with extremely low catalase activities and showed that they carried mutations in a gene that we named NO CATALASE ACTIVITY1 (NCA1). nca1 mutants showed severely reduced activities of all three catalase isoforms in Arabidopsis, and loss of NCA1 function led to strong suppression of RPM1-triggered cell death. Basal and starvation-induced autophagy appeared normal in the nca1 and cat2 mutants. By contrast, autophagic degradation induced by avrRpm1 challenge was compromised, indicating that catalase acted upstream of immunity-triggered autophagy. The direct interaction of catalase with reactive oxygen species could allow catalase to act as a molecular link between reactive oxygen species and the promotion of autophagy-dependent cell death. PMID:24285797

A Policy Impact Analysis of the Mandatory NCAA Sickle Cell Trait Screening Program

PubMed Central

Tarini, Beth A; Brooks, Margaret Alison; Bundy, David G

2012-01-01

Objective To estimate the impact of the mandatory National Collegiate Athletic Association (NCAA) sickle cell trait (SCT) screening policy on the identification of sickle cell carriers and prevention of sudden death. Data Source We used NCAA reports, population-based SCT prevalence estimates, and published risks for exercise-related sudden death attributable to SCT. Study Design We estimated the number of sickle cell carriers identified and the number of potentially preventable sudden deaths with mandatory SCT screening of NCAA Division I athletes. We calculated the number of student-athletes with SCT using a conditional probability based upon SCT prevalence data and self-identified race/ethnicity status. We estimated sudden deaths over 10 years based on published attributable risk of exercise-related sudden death due to SCT. Principal Findings We estimate that over 2,000 NCAA Division I student-athletes with SCT will be identified under this screening policy and that, without intervention, about seven NCAA Division I student-athletes would die suddenly as a complication of SCT over a 10-year period. Conclusion Universal sickle cell screening of NCAA Division I student-athletes will identify a substantial number of sickle cell carriers. A successful intervention could prevent about seven deaths over a decade. PMID:22150647

Programed death-1/programed death-ligand 1 expression in lymph nodes of HIV infected patients: results of a pilot safety study in rhesus macaques using anti–programed death-ligand 1 (Avelumab)

PubMed Central

Gill, Amanda L.; Green, Samantha A.; Abdullah, Shahed; Le Saout, Cecile; Pittaluga, Stefania; Chen, Hui; Turnier, Refika; Lifson, Jeffrey; Godin, Steven; Qin, Jing; Sneller, Michael C.; Cuillerot, Jean-Marie; Sabzevari, Helen; Lane, H. Clifford; Catalfamo, Marta

2016-01-01

Objective: The programed death-1 (PD1)/programed death-ligand 1 (PD-L1) pathway plays a critical role in balancing immunity and host immunopathology. During chronic HIV/SIV infection, there is persistent immune activation accompanied by accumulation of virus-specific cells with terminally differentiated phenotypes and expression of regulatory receptors such as PD1. These observations led us to hypothesize that the PD1/PD-L1 pathway contributes to the functional dysregulation and ineffective viral control, and its blockade may be a potential immunotherapeutic target. Methods: Lymph node biopsies from HIV-infected patients (n = 23) were studied for expression of PD1 and PD-L1. In addition, we assessed the safety and biological activity of a human anti-PD-L1 antibody (Avelumab) in chronically SIV-infected rhesus macaques. Results: PD-L1 expression was observed in cells with myloid/macrophage morphology in HIV-infected lymph nodes. Administration of anti-PD-L1 was well tolerated, and no changes in body weights, hematologic, or chemistry parameters were observed during the study. Blockade of PD-L1 led to a trend of transient viral control after discontinuation of treatment. Conclusion: Administration of anti-PD-L1 in chronic SIV-infected rhesus macaques was well tolerated. Overall, these data warrant further investigation to assess the efficacy of anti-PD-L1 treatment on viral control in chronic SIV infection as a prelude to such therapy in humans. PMID:27490642

Programed death-1/programed death-ligand 1 expression in lymph nodes of HIV infected patients: results of a pilot safety study in rhesus macaques using anti-programed death-ligand 1 (Avelumab).

PubMed

Gill, Amanda L; Green, Samantha A; Abdullah, Shahed; Le Saout, Cecile; Pittaluga, Stefania; Chen, Hui; Turnier, Refika; Lifson, Jeffrey; Godin, Steven; Qin, Jing; Sneller, Michael C; Cuillerot, Jean-Marie; Sabzevari, Helen; Lane, H Clifford; Catalfamo, Marta

2016-10-23

The programed death-1 (PD1)/programed death-ligand 1 (PD-L1) pathway plays a critical role in balancing immunity and host immunopathology. During chronic HIV/SIV infection, there is persistent immune activation accompanied by accumulation of virus-specific cells with terminally differentiated phenotypes and expression of regulatory receptors such as PD1. These observations led us to hypothesize that the PD1/PD-L1 pathway contributes to the functional dysregulation and ineffective viral control, and its blockade may be a potential immunotherapeutic target. Lymph node biopsies from HIV-infected patients (n = 23) were studied for expression of PD1 and PD-L1. In addition, we assessed the safety and biological activity of a human anti-PD-L1 antibody (Avelumab) in chronically SIV-infected rhesus macaques. PD-L1 expression was observed in cells with myloid/macrophage morphology in HIV-infected lymph nodes. Administration of anti-PD-L1 was well tolerated, and no changes in body weights, hematologic, or chemistry parameters were observed during the study. Blockade of PD-L1 led to a trend of transient viral control after discontinuation of treatment. Administration of anti-PD-L1 in chronic SIV-infected rhesus macaques was well tolerated. Overall, these data warrant further investigation to assess the efficacy of anti-PD-L1 treatment on viral control in chronic SIV infection as a prelude to such therapy in humans.

Activation of cellular death programs associated with immunosenescence-like phenotype in TPPII knockout mice

PubMed Central

Huai, Jisen; Firat, Elke; Nil, Ahmed; Million, Daniele; Gaedicke, Simone; Kanzler, Benoit; Freudenberg, Marina; van Endert, Peter; Kohler, Gabriele; Pahl, Heike L.; Aichele, Peter; Eichmann, Klaus; Niedermann, Gabriele

2008-01-01

The giant cytosolic protease tripeptidyl peptidase II (TPPII) has been implicated in the regulation of proliferation and survival of malignant cells, particularly lymphoma cells. To address its functions in normal cellular and systemic physiology we have generated TPPII-deficient mice. TPPII deficiency activates cell type-specific death programs, including proliferative apoptosis in several T lineage subsets and premature cellular senescence in fibroblasts and CD8+ T cells. This coincides with up-regulation of p53 and dysregulation of NF-κB. Prominent degenerative alterations at the organismic level were a decreased lifespan and symptoms characteristic of immunohematopoietic senescence. These symptoms include accelerated thymic involution, lymphopenia, impaired proliferative T cell responses, extramedullary hematopoiesis, and inflammation. Thus, TPPII is important for maintaining normal cellular and systemic physiology, which may be relevant for potential therapeutic applications of TPPII inhibitors. PMID:18362329

Lack of HXK2 induces localization of active Ras in mitochondria and triggers apoptosis in the yeast Saccharomyces cerevisiae.

PubMed

Amigoni, Loredana; Martegani, Enzo; Colombo, Sonia

2013-01-01

We recently showed that activated Ras proteins are localized to the plasma membrane and in the nucleus in wild-type cells growing exponentially on glucose, while in the hxk2Δ strain they accumulated mainly in mitochondria. An aberrant accumulation of activated Ras in these organelles was previously reported and correlated to mitochondrial dysfunction, accumulation of ROS, and cell death. Here we show that addition of acetic acid to wild-type cells results in a rapid recruitment of Ras-GTP from the nucleus and the plasma membrane to the mitochondria, providing a further proof that Ras proteins might be involved in programmed cell death. Moreover, we show that Hxk2 protects against apoptosis in S. cerevisiae. In particular, cells lacking HXK2 and showing a constitutive accumulation of activated Ras at the mitochondria are more sensitive to acetic-acid-induced programmed cell death compared to the wild type strain. Indeed, deletion of HXK2 causes an increase of apoptotic cells with several morphological and biochemical changes that are typical of apoptosis, including DNA fragmentation, externalization of phosphatidylserine, and ROS production. Finally, our results suggest that apoptosis induced by lack of Hxk2 may not require the activation of Yca1, the metacaspase homologue identified in yeast.

Can a single "powerless" mitochondrion in the malaria parasite contribute to parasite programmed cell death in the asexual stages?

PubMed

Ch'ng, Jun-Hong; Yeo, Su-Ping; Shyong-Wei Tan, Kevin

2013-05-01

The protozoan pathogens responsible for malaria are from the Plasmodium genus, with Plasmodium falciparum and Plasmodium vivax accounting for almost all clinical infections. With recent estimates of mortality exceeding 800,000 annually, malaria continues to take a terrible toll on lives and the early promises of medicine to eradicate the disease have yet to approach realization, in part due to the spread of drug resistant parasites. Recent reports of artemisinin-resistance have prompted renewed efforts to identify novel therapeutic options, and one such pathway being considered for antimalarial exploit is the parasite's programmed cell death (PCD) pathway. In this mini-review, we will discuss the roles of the plasmodium mitochondria in cell death and as a target of antimalarial compounds, taking into account recent data suggesting that PCD pathways involving the mitochondria may be attractive antimalarial targets. Copyright © 2012 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

Peptide bioregulators inhibit apoptosis.

PubMed

Khavinson, V K; Kvetnoii, I M

2000-12-01

The effects of peptide bioregulators epithalon and vilon on the dynamics of irradiation-induced apoptotic death of spleen lymphocytes in rats indicate that these agents inhibit physiologically programmed cell death. The antiapoptotic effect of vilon was more pronounced, which corroborates the concept on tissue-specific effect of peptide bioregulators.

Epidermal Cell Death in Rice Is Regulated by Ethylene, Gibberellin, and Abscisic Acid

PubMed Central

Steffens, Bianka; Sauter, Margret

2005-01-01

Programmed cell death (PCD) of epidermal cells that cover adventitious root primordia in deepwater rice (Oryza sativa) is induced by submergence. Early suicide of epidermal cells may prevent injury to the growing root that emerges under flooding conditions. Induction of PCD is dependent on ethylene signaling and is further promoted by gibberellin (GA). Ethylene and GA act in a synergistic manner, indicating converging signaling pathways. Treatment of plants with GA alone did not promote PCD. Treatment with the GA biosynthesis inhibitor paclobutrazol resulted in increased PCD in response to ethylene and GA presumably due to an increased sensitivity of epidermal cells to GA. Abscisic acid (ABA) was shown to efficiently delay ethylene-induced as well as GA-promoted cell death. The results point to ethylene signaling as a target of ABA inhibition of PCD. Accumulation of ethylene and GA and a decreased ABA level in the rice internode thus favor induction of epidermal cell death and ensure that PCD is initiated as an early response that precedes adventitious root growth. PMID:16169967

Life and death of female gametes during oogenesis and folliculogenesis.

PubMed

Krysko, Dmitri V; Diez-Fraile, Araceli; Criel, Godelieve; Svistunov, Andrei A; Vandenabeele, Peter; D'Herde, Katharina

2008-09-01

The vertebrate ovary is an extremely dynamic organ in which excessive or defective follicles are rapidly and effectively eliminated early in ontogeny and thereafter continuously throughout reproductive life. More than 99% of follicles disappear, primarily due to apoptosis of granulosa cells, and only a minute fraction of the surviving follicles successfully complete the path to ovulation. The balance between signals for cell death and survival determines the destiny of the follicles. An abnormally high rate of cell death followed by atresia can negatively affect fertility and eventually lead irreversibly to premature ovarian failure. In this review we provide a short overview of the role of programmed cell death in prenatal differentiation of the primordial germ cells and in postnatal folliculogenesis. We also discuss the issue of neo-oogenesis. Next, we highlight molecules involved in regulation of granulosa cell apoptosis. We further discuss the potential use of scores for apoptosis in granulosa cells and characteristics of follicular fluid as prognostic markers for predicting the outcome of assisted reproduction. Potential therapeutic strategies for combating premature ovarian failure are also addressed.

In vivo inhibition of the mitochondrial H+-ATP synthase in neurons promotes metabolic preconditioning.

PubMed

Formentini, Laura; Pereira, Marta P; Sánchez-Cenizo, Laura; Santacatterina, Fulvio; Lucas, José J; Navarro, Carmen; Martínez-Serrano, Alberto; Cuezva, José M

2014-04-01

A key transducer in energy conservation and signaling cell death is the mitochondrial H(+)-ATP synthase. The expression of the ATPase inhibitory factor 1 (IF1) is a strategy used by cancer cells to inhibit the activity of the H(+)-ATP synthase to generate a ROS signal that switches on cellular programs of survival. We have generated a mouse model expressing a mutant of human IF1 in brain neurons to assess the role of the H(+)-ATP synthase in cell death in vivo. The expression of hIF1 inhibits the activity of oxidative phosphorylation and mediates the shift of neurons to an enhanced aerobic glycolysis. Metabolic reprogramming induces brain preconditioning affording protection against quinolinic acid-induced excitotoxicity. Mechanistically, preconditioning involves the activation of the Akt/p70S6K and PARP repair pathways and Bcl-xL protection from cell death. Overall, our findings provide the first in vivo evidence highlighting the H(+)-ATP synthase as a target to prevent neuronal cell death.

KIRA1 and ORESARA1 terminate flower receptivity by promoting cell death in the stigma of Arabidopsis.

PubMed

Gao, Zhen; Daneva, Anna; Salanenka, Yuliya; Van Durme, Matthias; Huysmans, Marlies; Lin, Zongcheng; De Winter, Freya; Vanneste, Steffen; Karimi, Mansour; Van de Velde, Jan; Vandepoele, Klaas; Van de Walle, Davy; Dewettinck, Koen; Lambrecht, Bart N; Nowack, Moritz K

2018-05-28

Flowers have a species-specific functional life span that determines the time window in which pollination, fertilization and seed set can occur. The stigma tissue plays a key role in flower receptivity by intercepting pollen and initiating pollen tube growth toward the ovary. In this article, we show that a developmentally controlled cell death programme terminates the functional life span of stigma cells in Arabidopsis. We identified the leaf senescence regulator ORESARA1 (also known as ANAC092) and the previously uncharacterized KIRA1 (also known as ANAC074) as partially redundant transcription factors that modulate stigma longevity by controlling the expression of programmed cell death-associated genes. KIRA1 expression is sufficient to induce cell death and terminate floral receptivity, whereas lack of both KIRA1 and ORESARA1 substantially increases stigma life span. Surprisingly, the extension of stigma longevity is accompanied by only a moderate extension of flower receptivity, suggesting that additional processes participate in the control of the flower's receptive life span.

Hepatic Leukemia Factor Promotes Resistance To Cell Death: Implications For Therapeutics and Chronotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waters, Katrina M.; Sontag, Ryan L.; Weber, Thomas J.

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 programmore » 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.« less

The diphenylether herbicide lactofen induces cell death and expression of defense-related genes in soybean.

PubMed

Graham, Madge Y

2005-12-01

Lactofen belongs to the diphenylether class of herbicides, which targets protoporphyrinogen oxidase, which in turn causes singlet oxygen generation. In tolerant plants like soybean (Glycine max), the chemical nonetheless causes necrotic patches called "bronzing" in contact areas. Here it is shown that such bronzing is accompanied by cell death, which was quantified from digital microscopic images using Assess Software. Cellular autofluorescence accompanied cell death, and a homolog of the cell death marker gene, Hsr203j, was induced by lactofen in treated soybean tissues. Thus, this form of chemically induced cell death shares some hallmarks of certain types of programmed cell death. In addition to the cell death phenotype, lactofen caused enhanced expressions of chalcone synthase and chalcone reductase genes, mainly in the exposed and immediately adjacent (proximal) cells. Furthermore, isoflavone synthase genes, which are wound inducible in soybean, were up-regulated by lactofen in both proximal and distal cell zones in minimally wounded cotyledons and further enhanced in wounded tissues. Moreover, if the wall glucan elicitor from Phytophthora sojae was present during lactofen treatment, the induction of isoflavone synthase was even more rapid. These results are consistent with the fact that lactofen triggers massive isoflavone accumulations and activates the capacity for glyceollin elicitation competency. In addition, lactofen induces late expression of a selective set of pathogenesis-related (PR) protein genes, including PR-1a, PR-5, and PR-10, mainly in treated proximal tissues. These various results are discussed in the context of singlet oxygen-induced responses and lactofen's potential as a disease resistance-inducing agent.

Advances in the Treatment of Non-small Cell Lung Cancer: Focus on Nivolumab, Pembrolizumab, and Atezolizumab.

PubMed

Leventakos, Konstantinos; Mansfield, Aaron S

2016-10-01

Immunotherapy is revolutionizing the treatment of non-small cell lung cancer (NSCLC). Immune checkpoint inhibitors, including programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) monoclonal antibodies, are being introduced to routine clinical practice. This review summarizes clinical trials of nivolumab, pembrolizumab, and atezolizumab in patients with NSCLC. These agents have efficacy against NSCLC and a unique toxicity profile. The role of PD-L1 as a predictive biomarker is still unclear, partially because of the nuances of PD-L1 testing. These novel therapies also challenge our existing methodologies of radiologic assessment and efficacy analysis. This new era of immunotherapy has ushered in as much hope for patients as questions from physicians that need to be answered to clarify the optimal use of these agents.

Uveitis induced by programmed cell death protein 1 inhibitor therapy with nivolumab in metastatic melanoma patient.

PubMed

Kanno, Hiroaki; Ishida, Kyoko; Yamada, Wataru; Nishida, Takashi; Takahashi, Nobumichi; Mochizuki, Kiyofumi; Mizuno, Yuki; Matsuyama, Kanako; Takahashi, Tomoko; Seishima, Mariko

2017-11-01

Nivolumab, a new immune checkpoint inhibitor, binds to programmed cell death-protein 1 receptors on T cell, blockades binding of its ligands, and augments the immunologic reaction against tumor cells. Augmented immune response, however, may lead to immune-related adverse events. Herein we describe a rare case of bilateral anterior uveitis induced by nivolumab treatment for metastatic melanoma. A 54-year-old woman presented with mild conjunctival redness and blurred vision two months after initiating nivolumab treatment. Ophthalmological examination revealed bilateral non-granulomatous anterior uveitis. The flare values in the anterior chamber were monitored as an objective inflammatory index during nivolumab therapy and clinical time course was reported in this paper. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Induction of cell death in a glioblastoma line by hyperthermic therapy based on gold nanorods

PubMed Central

Fernandez Cabada, Tamara; Sanchez Lopez de Pablo, Cristina; Martinez Serrano, Alberto; del Pozo Guerrero, Francisco; Serrano Olmedo, Jose Javier; Ramos Gomez, Milagros

2012-01-01

Background Metallic nanorods are promising agents for a wide range of biomedical applications. In this study, we developed an optical hyperthermia method capable of inducing in vitro death of glioblastoma cells. Methods The procedure used was based on irradiation of gold nanorods with a continuous wave laser. This kind of nanoparticle converts absorbed light into localized heat within a short period of time due to the surface plasmon resonance effect. The effectiveness of the method was determined by measuring changes in cell viability after laser irradiation of glioblastoma cells in the presence of gold nanorods. Results Laser irradiation in the presence of gold nanorods induced a significant decrease in cell viability, while no decrease in cell viability was observed with laser irradiation or incubation with gold nanorods alone. The mechanism of cell death mediated by gold nanorods during photothermal ablation was analyzed, indicating that treatment compromised the integrity of the cell membrane instead of initiating the process of programmed cell death. Conclusion The use of gold nanorods in hyperthermal therapies is very effective in eliminating glioblastoma cells, and therefore represents an important area of research for therapeutic development. PMID:22619509

RIP1 Inhibition Rescues from LPS-Induced RIP3-Mediated Programmed Cell Death, Distributed Energy Metabolism and Spatial Memory Impairment.

PubMed

Nikseresht, Sara; Khodagholi, Fariba; Nategh, Mohsen; Dargahi, Leila

2015-10-01

Receptor interacting protein 1 (RIP1) has a critical role in initiation of programmed necrosis or necroptosis. RIP1 in a close collaboration with RIP3 not only mediates necroptosis but also is involved in apoptosis and inflammatory signaling. However, the interpretation of the distinct function of RIP1 and RIP3 is complicated. Herein, we demonstrated that RIP1 inhibition in the context of LPS-induced neuroinflammation decreases RIP3 expression. Concomitant administration of Nec-1, specific inhibitor of RIP1, with LPS also attenuated the activating effect of RIP3 on metabolic enzymes, glutamate-ammonia ligase and glutamate dehydrogenase as bioenergetic determinants, in hippocampal and cortical cells. RIP1 inhibition possessed an anti-inflammatory effect and improved the antioxidant capacity against LPS. Interestingly, and opposed to some reports that necroptosis inhibition sensitizes cells to apoptosis, our results showed that RIP1 inhibition attenuates apoptotic cell death in response to LPS. The survival of neuronal function was also confirmed by measuring spontaneous alternations of rats in Y-maze. In conclusion, effects of RIP1 inhibition on RIP3 and cell death provide new approaches to ameliorate neuroinflammation and relative disorders.

Apoptosis and necrosis in the liver.

PubMed

Guicciardi, Maria Eugenia; Malhi, Harmeet; Mott, Justin L; Gores, Gregory J

2013-04-01

Because of its unique function and anatomical location, the liver is exposed to a multitude of toxins and xenobiotics, including medications and alcohol, as well as to infection by hepatotropic viruses, and therefore, is highly susceptible to tissue injury. Cell death in the liver occurs mainly by apoptosis or necrosis, with apoptosis also being the physiologic route to eliminate damaged or infected cells and to maintain tissue homeostasis. Liver cells, especially hepatocytes and cholangiocytes, are particularly susceptible to death receptor-mediated apoptosis, given the ubiquitous expression of the death receptors in the organ. In a quite unique way, death receptor-induced apoptosis in these cells is mediated by both mitochondrial and lysosomal permeabilization. Signaling between the endoplasmic reticulum and the mitochondria promotes hepatocyte apoptosis in response to excessive free fatty acid generation during the metabolic syndrome. These cell death pathways are partially regulated by microRNAs. Necrosis in the liver is generally associated with acute injury (i.e., ischemia/reperfusion injury) and has been long considered an unregulated process. Recently, a new form of "programmed" necrosis (named necroptosis) has been described: the role of necroptosis in the liver has yet to be explored. However, the minimal expression of a key player in this process in the liver suggests this form of cell death may be uncommon in liver diseases. Because apoptosis is a key feature of so many diseases of the liver, therapeutic modulation of liver cell death holds promise. An updated overview of these concepts is given in this article.

INF-γ sensitizes head and neck squamous cell carcinoma cells to chemotherapy-induced apoptosis and necroptosis through up-regulation of Egr-1.

PubMed

Xu, Bei; Shu, Yongqian; Liu, Peng

2014-11-01

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. Acquired resistance to standard chemotherapy accounts for most of treatment failure. Here we demonstrate that Interferon-γ (INF-γ) may up-regulate Egr-1 gene expression in HNSCC cell line SCC-25. Forced expression of Egr-1 sensitizes SCC-25 cells to chemotherapy-induced apoptosis and necroptosis, a novel form of programmed cell death. Egr-1 up-regulation also significantly increases the production of Thrombospondin-1 (TSP-1), a matricellular glycoprotein which has been described to induce cell death in HNSCC. Moreover, INF-γ-induced sensitization of cells to chemotherapy-mediated cell death and TSP-1 production could be markedly abolished by Egr-1 silencing. The present investigation provides the first evidence that INF-γ may sensitize HNSCC cells to chemotherapy-induced apoptosis and necroptosis through up-regulation of Egr-1. These data support the combination use of INF-γ and cytotoxic drugs for HNSCC Therapy.

Hemoglobins, programmed cell death and somatic embryogenesis.

PubMed

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. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A primer on caspase mechanisms.

PubMed

Ramirez, Monica L Gonzalez; Salvesen, Guy S

2018-01-12

Caspases belong to a diverse clan of proteolytic enzymes known as clan CD with highly disparate functions in cell signaling. The caspase members of this clan are only found in animals, and most of them orchestrate the demise of cells by the highly distinct regulated cell death phenotypes known as apoptosis and pyroptosis. This review looks at the mechanistic distinctions between the activity and activation mechanisms of mammalian caspases compared to other members of clan CD. We also compare and contrast the role of different caspase family members that program anti-inflammatory and pro-inflammatory cell death pathways. Copyright © 2018. Published by Elsevier Ltd.

The Activity of Differentiation Factors Induces Apoptosis in Polyomavirus Large T-Expressing Myoblasts

PubMed Central

Fimia, Gian Maria; Gottifredi, Vanesa; Bellei, Barbara; Ricciardi, Maria Rosaria; Tafuri, Agostino; Amati, Paolo; Maione, Rossella

1998-01-01

It is commonly accepted that pathways that regulate proliferation/differentiation processes, if altered in their normal interplay, can lead to the induction of programmed cell death. In a previous work we reported that Polyoma virus Large Tumor antigen (PyLT) interferes with in vitro terminal differentiation of skeletal myoblasts by binding and inactivating the retinoblastoma antioncogene product. This inhibition occurs after the activation of some early steps of the myogenic program. In the present work we report that myoblasts expressing wild-type PyLT, when subjected to differentiation stimuli, undergo cell death and that this cell death can be defined as apoptosis. Apoptosis in PyLT-expressing myoblasts starts after growth factors removal, is promoted by cell confluence, and is temporally correlated with the expression of early markers of myogenic differentiation. The block of the initial events of myogenesis by transforming growth factor β or basic fibroblast growth factor prevents PyLT-induced apoptosis, while the acceleration of this process by the overexpression of the muscle-regulatory factor MyoD further increases cell death in this system. MyoD can induce PyLT-expressing myoblasts to accumulate RB, p21, and muscle- specific genes but is unable to induce G00 arrest. Several markers of different phases of the cell cycle, such as cyclin A, cdk-2, and cdc-2, fail to be down-regulated, indicating the occurrence of cell cycle progression. It has been frequently suggested that apoptosis can result from an unbalanced cell cycle progression in the presence of a contrasting signal, such as growth factor deprivation. Our data involve differentiation pathways, as a further contrasting signal, in the generation of this conflict during myoblast cell apoptosis. PMID:9614186

Vacuolar and cytoskeletal dynamics during elicitor-induced programmed cell death in tobacco BY-2 cells.

PubMed

Higaki, Takumi; Kadota, Yasuhiro; Goh, Tatsuaki; Hayashi, Teruyuki; Kutsuna, Natsumaro; Sano, Toshio; Hasezawa, Seiichiro; Kuchitsu, Kazuyuki

2008-09-01

Responses of plant cells to environmental stresses often involve morphological changes, differentiation and redistribution of various organelles and cytoskeletal network. Tobacco BY-2 cells provide excellent model system for in vivo imaging of these intracellular events. Treatment of the cell cycle-synchronized BY-2 cells with a proteinaceous oomycete elicitor, cryptogein, induces highly synchronous programmed cell death (PCD) and provide a model system to characterize vacuolar and cytoskeletal dynamics during the PCD. Sequential observation revealed dynamic reorganization of the vacuole and actin microfilaments during the execution of the PCD. We further characterized the effects cryptogein on mitotic microtubule organization in cell cycle-synchronized cells. Cryptogein treatment at S phase inhibited formation of the preprophase band, a cortical microtubule band that predicts the cell division site. Cortical microtubules kept their random orientation till their disruption that gradually occurred during the execution of the PCD twelve hours after the cryptogein treatment. Possible molecular mechanisms and physiological roles of the dynamic behavior of the organelles and cytoskeletal network in the pathogenic signal-induced PCD are discussed.

Control of retinoic acid synthesis and FGF expression in the nasal pit is required to pattern the craniofacial skeleton.

PubMed

Song, Y; Hui, J N; Fu, K K; Richman, J M

2004-12-15

Endogenous retinoids are important for patterning many aspects of the embryo including the branchial arches and frontonasal region of the embryonic face. The nasal placodes express retinaldehyde dehydrogenase-3 (RALDH3) and thus retinoids from the placode are a potential patterning influence on the developing face. We have carried out experiments that have used Citral, a RALDH antagonist, to address the function of retinoid signaling from the nasal pit in a whole embryo model. When Citral-soaked beads were implanted into the nasal pit of stage 20 chicken embryos, the result was a specific loss of derivatives from the lateral nasal prominences. Providing exogenous retinoic acid residue development of the beak demonstrating that most Citral-induced defects were produced by the specific blocking of RA synthesis. The mechanism of Citral effects was a specific increase in programmed cell death on the lateral (lateral nasal prominence) but not the medial side (frontonasal mass) of the nasal pit. Gene expression studies were focused on the Bone Morphogenetic Protein (BMP) pathway, which has a well-established role in programmed cell death. Unexpectedly, blocking RA synthesis decreased rather than increased Msx1, Msx2, and Bmp4 expression. We also examined cell survival genes, the most relevant of which was Fgf8, which is expressed around the nasal pit and in the frontonasal mass. We found that Fgf8 was not initially expressed along the lateral side of the nasal pit at the start of our experiments, whereas it was expressed on the medial side. Citral prevented upregulation of Fgf8 along the lateral edge and this may have contributed to the specific increase in programmed cell death in the lateral nasal prominence. Consistent with this idea, exogenous FGF8 was able to prevent cell death, rescue most of the morphological defects and was able to prevent a decrease in retinoic acid receptorbeta (Rarbeta) expression caused by Citral. Together, our results demonstrate that endogenous retinoids act upstream of FGF8 and the balance of these two factors is critical for regulating programmed cell death and morphogenesis in the face. In addition, our data suggest a novel role for endogenous retinoids from the nasal pit in controlling the precise downregulation of FGF in the center of the frontonasal mass observed during normal vertebrate development.

Broad targeting of resistance to apoptosis in cancer

PubMed Central

Mohammad, Ramzi M.; Muqbil, Irfana; Lowe, Leroy; Yedjou, Clement; Hsu, Hsue-Yin; Lin, Liang-Tzung; Siegelin, Markus David; Fimognari, Carmela; Kumar, Nagi B.; Dou, Q. Ping; Yang, Huanjie; Samadi, Abbas K.; Russo, Gian Luigi; Spagnuolo, Carmela; Ray, Swapan K.; Chakrabarti, Mrinmay; Morre, James D.; Coley, Helen M.; Honoki, Kanya; Fujii, Hiromasa; Georgakilas, Alexandros G.; Amedei, Amedeo; Niccolai, Elena; Amin, Amr; Ashraf, S. Salman; Helferich, William G.; Yang, Xujuan; Boosani, Chandra S.; Guha, Gunjan; Bhakta, Dipita; Ciriolo, Maria Rosa; Aquilano, Katia; Chen, Sophie; Mohammed, Sulma I.; Keith, W. Nicol; Bilsland, Alan; Halicka, Dorota; Nowsheen, Somaira; Azmi, Asfar S.

2015-01-01

Apoptosis or programmed cell death is natural way of removing aged cells from the body. Most of the anti-cancer therapies trigger apoptosis induction and related cell death networks to eliminate malignant cells. However, in cancer, de-regulated apoptotic signaling, particularly the activation of an anti-apoptotic systems, allows cancer cells to escape this program leading to uncontrolled proliferation resulting in tumor survival, therapeutic resistance and recurrence of cancer. This resistance is a complicated phenomenon that emanates from the interactions of various molecules and signaling pathways. In this comprehensive review we discuss the various factors contributing to apoptosis resistance in cancers. The key resistance targets that are discussed include (1) Bcl-2 and Mcl-1 proteins; (2) autophagy processes; (3) necrosis and necroptosis; (4) heat shock protein signaling; (5) the proteasome pathway; (6) epigenetic mechanisms; and (7) aberrant nuclear export signaling. The shortcomings of current therapeutic modalities are highlighted and a broad spectrum strategy using approaches including (a) gossypol; (b) epigallocatechin-3-gallate; (c) UMI-77 (d) triptolide and (e) selinexor that can be used to overcome cell death resistance is presented. This review provides a roadmap for the design of successful anti-cancer strategies that overcome resistance to apoptosis for better therapeutic outcome in patients with cancer. PMID:25936818

Modulation of eukaryotic cell apoptosis by members of the bacterial order Actinomycetales.

PubMed

Barry, Daniel P; Beaman, Blaine L

2006-10-01

Apoptosis, or programmed cell death, is normally responsible for the orderly elimination of aged or damaged cells, and is a necessary part of the homeostasis and development of multicellular organisms. Some pathogenic bacteria can disrupt this process by triggering excess apoptosis or by preventing it when appropriate. Either event can lead to disease. There has been extensive research into the modulation of host cell death by microorganisms, and several reviews have been published on the phenomenon. Rather than covering the entire field, this review focuses on the dysregulation of host cell apoptosis by members of the order Actinomycetales, containing the genera Corynebacterium, Mycobacterium, Rhodococcus, and Nocardia.

Molecular aspects of ultraviolet radiation-induced apoptosis in the skin.

PubMed

Chow, Jeffrey; Tron, Victor A

2005-12-01

Apoptosis, or programmed cell death, is an essential physiological process that controls cell numbers during physiological processes, and eliminates abnormal cells that can potentially harm an organism. This review summarizes our current state of knowledge of apoptosis induction in skin by UV radiation. A review of the literature was undertaken focusing on cell death in the skin secondary to UV radiation. It is evident that a number of apoptotic pathways, both intrinsic and extrinsic, are induced following exposure to damaging UV radiation. Although our understanding of the apoptotic processes is gradually increasing, many important aspects remain obscure. These include interconnections between pathways, wavelength-specific differences and cell type differences.

Antiapoptotic and Trophic Effects of Dominant-Negative Forms of Dual Leucine Zipper Kinase in Dopamine Neurons of the Substantia Nigra In Vivo

PubMed Central

Chen, Xiqun; Rzhetskaya, Margarita; Kareva, Tatyana; Bland, Ross; During, Matthew J.; Tank, A. William; Kholodilov, Nikolai; Burke, Robert E.

2009-01-01

There is extensive evidence that the mitogen-activated protein kinase (MAPK) signaling cascade mediates programmed cell death in neurons. However, current evidence that the mixed linage kinases (MLKs), upstream in this cascade, mediate cell death is based, in the in vivo context, entirely on pharmacological approaches. The compounds used in these studies have neither complete specificity nor selectivity among these kinases. Therefore, to better address the molecular specificity of the MLKs in mediating neuron death, we used dominant-negative constructs delivered by AAV (adenoassociated virus) vector transfer. We assessed effects in a neurotoxin model of parkinsonism, in which neuroprotection by pharmacologic MLK inhibition has been reported. We find that two dominant-negative forms of dual leucine zipper kinase (DLK) inhibit apoptosis and enhance long-term survival of dopamine neurons, but a dominant negative of MLK3 does not. Interestingly, the kinase-dead form of DLK not only blocks apoptosis but also has trophic effects on dopamine neurons. Although the MAPK cascade activates a number of downstream cell death mediators, we find that inhibition of DLK correlates closely with blockade of phosphorylation of c-jun and prevention of cell death. We conclude that DLK acts primarily through c-jun phosphorylation to mediate cell death in this model. PMID:18199767

APOPTOSIS DURING DEVELOPMENT AND AGING AND IN RESPONSE TO MERCURY EXPOSURE.

EPA Science Inventory

In the central nervous system from embryogenesis through senescence, cell number is regulated, in part, by apoptosis. Each region of the nervous system has a characteristic temporal pattern of programmed cell death, which includes far greater numbers of cells undergoing apop...

Atezolizumab: feasible second-line therapy for patients with non-small cell lung cancer? A review of efficacy, safety and place in therapy.

PubMed

Jean, Fanny; Tomasini, Pascale; Barlesi, Fabrice

2017-12-01

Advanced non-small cell lung cancer (NSCLC) prognosis is still poor and has recently been reformed by the development of immune checkpoint inhibitors and the approval of anti-PD-1 (programmed cell-death 1) treatments such as nivolumab and pembrolizumab in second line. More recently, atezolizumab (MDPL 3280A), a programmed cell-death-ligand 1 (PD-L1) inhibitor, was also studied in this setting. Here, we report a review of the literature assessing the efficacy, safety, and place of atezolizumab in the second-line treatment of advanced NSCLC. We performed a literature search of PubMed, American Society of Clinical Oncology, European Society of Medical Oncology and World Conference on Lung Cancer meetings. Atezolizumab showed a good tolerance profile and efficacy in comparison with docetaxel for second-line treatment of advanced NSCLC. Potential predictive biomarkers also have to be assessed.

Atezolizumab: feasible second-line therapy for patients with non-small cell lung cancer? A review of efficacy, safety and place in therapy

PubMed Central

Jean, Fanny; Tomasini, Pascale; Barlesi, Fabrice

2017-01-01

Advanced non-small cell lung cancer (NSCLC) prognosis is still poor and has recently been reformed by the development of immune checkpoint inhibitors and the approval of anti-PD-1 (programmed cell-death 1) treatments such as nivolumab and pembrolizumab in second line. More recently, atezolizumab (MDPL 3280A), a programmed cell-death-ligand 1 (PD-L1) inhibitor, was also studied in this setting. Here, we report a review of the literature assessing the efficacy, safety, and place of atezolizumab in the second-line treatment of advanced NSCLC. We performed a literature search of PubMed, American Society of Clinical Oncology, European Society of Medical Oncology and World Conference on Lung Cancer meetings. Atezolizumab showed a good tolerance profile and efficacy in comparison with docetaxel for second-line treatment of advanced NSCLC. Potential predictive biomarkers also have to be assessed. PMID:29449897

Variability in Immunohistochemical Detection of Programmed Death Ligand 1 (PD-L1) in Cancer Tissue Types

PubMed Central

Scognamiglio, Giosuè; De Chiara, Anna; Di Bonito, Maurizio; Tatangelo, Fabiana; Losito, Nunzia Simona; Anniciello, Annamaria; De Cecio, Rossella; D’Alterio, Crescenzo; Scala, Stefania; Cantile, Monica; Botti, Gerardo

2016-01-01

In normal cell physiology, programmed death 1 (PD-1) and its ligand, PD-L1, play an immunoregulatory role in T-cell activation, tolerance, and immune-mediated tissue damage. The PD-1/PD-L1 pathway also plays a critical role in immune escape of tumor cells and has been demonstrated to correlate with a poor prognosis of patients with several types of cancer. However, recent reports have revealed that the immunohistochemical (IHC) expression of the PD-L1 in tumor cells is not uniform for the use of different antibodies clones, with variable specificity, often doubtful topographical localization, and with a score not uniquely defined. The purpose of this study was to analyze the IHC expression of PD-L1 on a large series of several human tumors to correctly define its staining in different tumor tissues. PMID:27213372

Recent developments in small molecule therapies for renal cell carcinoma.

PubMed

Song, Minsoo

2017-12-15

Renal cell carcinoma (RCC) is the most common type of kidney cancer in adults and is known to be the 10th most common type of cancer in the world. Most of the currently available RCC drugs are tyrosine kinase inhibitors (TKIs). However, combination therapies of TKIs and immune checkpoint inhibitors such as programmed cell death protein 1 (PD-1) and programmed cell death protein 1 ligand 1 (PD-L1) inhibitors are the focus of most of the final stage clinical trials. Meanwhile, other small molecule therapies for RCC that target indoleamine-2,3-dioxygenase (IDO1), glutaminase, C-X-C chemokine receptor 4 (CXCR4), and transglutaminase 2 (TG2) are emerging as the next generation of therapeutics. In this review, these three major streams for the development of small molecule drugs for RCC are described. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Examining live cell cultures during apoptosis by digital holographic phase imaging and Raman spectroscopy

NASA Astrophysics Data System (ADS)

Khmaladze, Alexander

2017-11-01

Cellular apoptosis is a unique, organized series of events, leading to programmed cell death. In this work, we present a combined digital holography/Raman spectroscopy technique to study live cell cultures during apoptosis. Digital holographic microscopy measurements of live cell cultures yield information about cell shape and volume, changes to which are indicative of alterations in cell cycle and initiation of cell death mechanisms. Raman spectroscopic measurements provide complementary information about cells, such as protein, lipid and nucleic acid content, and the spectral signatures associated with structural changes in molecules. Our work indicates that the chemical changes in proteins, which were detected by Raman measurements, preceded morphological changes, which were seen with digital holographic microscopy.

Activation of the NLRP3 inflammasome by proteins that signal for necroptosis.

PubMed

Kang, Tae-Bong; Yang, Seung-Hoon; Toth, Beata; Kovalenko, Andrew; Wallach, David

2014-01-01

Necroptosis-a form of programmed necrotic cell death-and its resulting release of damage-associated molecular patterns (DAMPs) are believed to participate in the triggering of inflammatory processes. To assess the relative contribution of this cell death mode to inflammation, we need to know what other cellular effects can be exerted by molecules shown to trigger necrotic death, and the extent to which those effects might themselves contribute to inflammation. Here, we describe the technical approaches that have been applied to assess the impact of the main signaling molecules known to mediate activation of necroptosis upon generation of inflammatory cytokines in LPS-treated mouse bone marrow-derived dendritic cells. The findings obtained by this assessment indicated that signaling molecules known to initiate necroptosis can also initiate activation of the NLRP3 inflammasome, thereby inducing inflammation independently of cell death by triggering the generation of proinflammatory cytokines such as IL-1β. © 2014 Elsevier Inc. All rights reserved.

Necroptosis, necrostatins and tissue injury

PubMed Central

Smith, Christopher CT; Yellon, Derek M

2011-01-01

Abstract Cell death is an integral part of the life of an organism being necessary for the maintenance of organs and tissues. If, however, cell death is allowed to proceed unrestricted, tissue damage and degenerative disease may ensue. Until recently, three morphologically distinct types of cell death were recognized, apoptosis (type I), autophagy (type II) and necrosis (type III). Apoptosis is a highly regulated, genetically determined mechanism designed to dismantle cells systematically (e.g. cells that are no longer functionally viable), via protease (caspase) action, and maintain homeostasis. Autophagy is responsible for the degradation of cytoplasmic material, e.g. proteins and organelles, through autophagosome formation and subsequent proteolytic degradation by lysosomes, and is normally considered in the context of survival although it is sometimes associated with cell death. Necrosis was formerly considered to be an accidental, unregulated form of cell death resulting from excessive stress, although it has been suggested that this is an over-simplistic view as necrosis may under certain circumstances involve the mobilization of specific transduction mechanisms. Indeed, recently, an alternative death pathway, termed necroptosis, was delineated and proposed as a form of ‘programmed necrosis’. Identified with the aid of specific inhibitors called necrostatins, necroptosis shares characteristics with both necrosis and apoptosis. Necroptosis involves Fas/tumour necrosis factor-α death domain receptor activation and inhibition of receptor-interacting protein I kinase, and it has been suggested that it may contribute to the development of neurological and myocardial diseases. Significantly, necrostatin-like drugs have been mooted as possible future therapeutic agents for the treatment of degenerative conditions. PMID:21564515

Mouse lung fibroblasts are highly susceptible to necroptosis in a reactive oxygen species-dependent manner.

PubMed

Hussain, Muadh; Zimmermann, Vanessa; van Wijk, Sjoerd J L; Fulda, Simone

2018-07-01

Mouse embryonic fibroblasts (MEFs) have extensively been used to study necroptosis, a recently identified form of programmed cell death. However, very little is yet known about the role of necroptosis and its regulation by reactive oxygen species (ROS) in cell types naturally exposed to high oxygen levels such as mouse lung fibroblasts (MLFs). Here, we discover that MLFs are highly susceptible to undergo necroptosis in a ROS-dependent manner upon exposure to a prototypic death receptor-mediated necroptotic stimulus, i.e. cotreatment with tumor necrosis factor (TNF)α, Smac mimetic and the caspase inhibitor zVAD.fmk (TSZ). Kinetic analysis revealed that TSZ rapidly induces cell death in MLFs. Pharmacological inhibition of receptor-interacting protein kinase (RIPK)1 by necrostatin-1 (Nec-1) or RIPK3 by GSK'872 significantly rescues TSZ-stimulated cell death. Also, genetic silencing of RIPK3 or mixed lineage kinase domain-like pseudokinase (MLKL) significantly protects MLFs from TSZ-mediated cell death. Prior to cell death, TSZ significantly increases production of ROS. Importantly, addition of radical scavengers such as butylated hydroxyanisole (BHA) or α-Tocopherol (α-Toc) significantly suppresses TSZ-induced cell death in parallel with a significant reduction of ROS generation. Consistently, BHA prevented TSZ-triggered phosphorylation of MLKL similar to the addition of GSK'872. Thus, our study demonstrates for the first time that MLFs are prone to undergo necroptosis in response to a prototypic necroptotic stimulus and identifies ROS as important mediators of TSZ-triggered necroptosis. Copyright © 2018 Elsevier Inc. All rights reserved.

Identification of a subset of human natural killer cells expressing high levels of programmed death 1: A phenotypic and functional characterization.

PubMed

Pesce, Silvia; Greppi, Marco; Tabellini, Giovanna; Rampinelli, Fabio; Parolini, Silvia; Olive, Daniel; Moretta, Lorenzo; Moretta, Alessandro; Marcenaro, Emanuela

2017-01-01

Programmed death 1 (PD-1) is an immunologic checkpoint that limits immune responses by delivering potent inhibitory signals to T cells on interaction with specific ligands expressed on tumor/virus-infected cells, thus contributing to immune escape mechanisms. Therapeutic PD-1 blockade has been shown to mediate tumor eradication with impressive clinical results. Little is known about the expression/function of PD-1 on human natural killer (NK) cells. We sought to clarify whether human NK cells can express PD-1 and analyze their phenotypic/functional features. We performed multiparametric cytofluorimetric analysis of PD-1 + NK cells and their functional characterization using degranulation, cytokine production, and proliferation assays. We provide unequivocal evidence that PD-1 is highly expressed (PD-1 bright ) on an NK cell subset detectable in the peripheral blood of approximately one fourth of healthy subjects. These donors are always serologically positive for human cytomegalovirus. PD-1 is expressed by CD56 dim but not CD56 bright NK cells and is confined to fully mature NK cells characterized by the NKG2A - KIR + CD57 + phenotype. Proportions of PD-1 bright NK cells were higher in the ascites of a cohort of patients with ovarian carcinoma, suggesting their possible induction/expansion in tumor environments. Functional analysis revealed a reduced proliferative capability in response to cytokines, low degranulation, and impaired cytokine production on interaction with tumor targets. We have identified and characterized a novel subpopulation of human NK cells expressing high levels of PD-1. These cells have the phenotypic characteristics of fully mature NK cells and are increased in patients with ovarian carcinoma. They display low proliferative responses and impaired antitumor activity that can be partially restored by antibody-mediated disruption of PD-1/programmed death ligand interaction. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Vitamin D protects keratinocytes from deleterious effects of ionizing radiation.

PubMed

Langberg, M; Rotem, C; Fenig, E; Koren, R; Ravid, A

2009-01-01

Radiotherapy can induce severe skin responses that may limit the clinically acceptable radiation dose. The responses include erythema, dry and moist desquamation, erosions and dermal-epidermal blister formation. These effects reflect injury to, and reproductive failure of, epidermal cells and may also be due to dysregulation of the tissue remodelling process caused by excessive proteolytic activity. Calcitriol, the hormonally active vitamin D metabolite, protects keratinocytes from programmed cell death induced by various noxious stimuli. To examine whether calcitriol protects proliferating keratinocytes from the damage inflicted by ionizing radiation under conditions similar to those employed during radiotherapy. Autonomously proliferating HaCaT keratinocytes, used as a model for basal layer keratinocytes, were irradiated using a linear accelerator. Cell death was monitored by vital staining, executioner caspase activation, lactic dehydrogenase release and colony formation assay. Induction of matrix metalloproteinase-9 was assessed by gelatinase activity assay and mRNA determination. Levels of specific proteins were determined by immunoblotting. Treatment with calcitriol inhibited both caspase-dependent and -independent programmed cell death occurring within 48 h of irradiation and increased the colony formation capacity of irradiated cells. These effects may be attributable to inhibition of the c-Jun NH(2)-terminal kinase cascade and to upregulation of the truncated antiapoptotic isoform of p63. Treatment with the hormone also attenuated radiation-induced increase in matrix metalloproteinase-9 protein and mRNA levels. The results of this study suggest that active vitamin D derivatives may attenuate cell death and excessive proteolytic activity in the epidermis due to exposure to ionizing radiation in the course of radiotherapy.

How well can morphology assess cell death modality? A proteomics study

PubMed Central

Chernobrovkin, Alexey L; Zubarev, Roman A

2016-01-01

While the focus of attempts to classify cell death programs has finally shifted in 2010s from microscopy-based morphological characteristics to biochemical assays, more recent discoveries have put the underlying assumptions of many such assays under severe stress, mostly because of the limited specificity of the assays. On the other hand, proteomics can quantitatively measure the abundances of thousands of proteins in a single experiment. Thus proteomics could develop a modern alternative to both semiquantitative morphology assessment as well as single-molecule biochemical assays. Here we tested this hypothesis by analyzing the proteomes of cells dying after been treated with various chemical agents. The most striking finding is that, for a multivariate model based on the proteome changes in three cells lines, the regulation patterns of the 200–500 most abundant proteins typically attributed to household type more accurately reflect that of the proteins directly interacting with the drug than any other protein subset grouped by common function or biological process, including cell death. This is in broad agreement with the 'rigid cell death mechanics' model where drug action mechanism and morphological changes caused by it are bijectively linked. This finding, if confirmed, will open way for a broad use of proteomics in death modality assessment. PMID:27752363

BAX Inhibitor-1, an ancient cell death suppressor in animals and plants with prokaryotic relatives.

PubMed

Hückelhoven, R

2004-05-01

BAX Inhibitor-1 (BI-1) was originally described as testis enhanced gene transcript in mammals. Functional screening in yeast for human proteins that can inhibit the cell death provoking function of BAX, a proapoptotic Bcl-2 family member, led to functional characterisation and renaming of BI-1. The identification of functional homologues of BI-1 in plants and yeast widened the understanding of BI-1 function as an ancient suppressor of programmed cell death. BI-1 is one of the few cell death suppressors conserved in animals and plants. Computer predictions and experimental data together suggest that BI-1 is a membrane spanning protein with 6 to 7 transmembrane domains and a cytoplasmic C-terminus sticking in the endoplasmatic reticulum and nuclear envelope. Proteins similar to BI-1 are present in other eukaryotes, bacteria, and even viruses encode BI-1 like proteins. BI-1 is involved in development, response to biotic and abiotic stress and probably represents an indispensable cell protectant. BI-1 appears to suppress cell death induced by mitochondrial dysfunction, reactive oxygen species or elevated cytosolic Ca(2+) levels. This review focuses on the present understanding about BI-1 and suggests potential directions for further analyses of this increasingly noticed protein.

Apoptosis in lung injury and remodeling.

PubMed

Li, Xiaopeng; Shu, Ruijie; Filippatos, Gerasimos; Uhal, Bruce D

2004-10-01

The mode of cell death termed apoptosis, sometimes referred to as programmed cell death, is as critical a determinant of cell population size as is cell proliferation. Although best characterized in cells of the immune system, apoptosis is now known to be a key factor in the maintenance of normal cell turnover within structural cells in the parenchyma of virtually every organ. Recent interest in apoptosis in the lung has sparked a surge of investigations designed to determine the roles of apoptosis in lung development, injury, and remodeling. Of particular recent interest are the roles of apoptosis in disease pathogenesis and resolution, in which the concept of apoptosis as a "programmed" cell death, i.e., genetically determined, is often more accurately viewed as "inappropriate cell suicide" with regard to its extent and/or timing. Data accumulating over the past decade have made clear the complexity of the control of lung cell apoptosis; concepts of the regulation of apoptosis originally determined in classical cell culture models are often, but not always, applicable to structural cells. For this reason, each of the many cell types of the lung must be studied as a potentially new subject with its own idiosyncrasies yet to be discovered. In light of the large volume of literature now available, this article focuses on the roles of apoptosis in three pathophysiological contexts: acute respiratory distress syndrome, chronic obstructive pulmonary disease, and pulmonary fibrosis. Each section presents key data describing the evidence for apoptosis in the lung, its possible relevance to disease pathogenesis, and proposed mechanisms that might suggest potential avenues for therapeutic intervention.

Essential versus accessory aspects of cell death: recommendations of the NCCD 2015

PubMed Central

Galluzzi, L; Bravo-San Pedro, J M; Vitale, I; Aaronson, S A; Abrams, J M; Adam, D; Alnemri, E S; Altucci, L; Andrews, D; Annicchiarico-Petruzzelli, M; Baehrecke, E H; Bazan, N G; Bertrand, M J; Bianchi, K; Blagosklonny, M V; Blomgren, K; Borner, C; Bredesen, D E; Brenner, C; Campanella, M; Candi, E; Cecconi, F; Chan, F K; Chandel, N S; Cheng, E H; Chipuk, J E; Cidlowski, J A; Ciechanover, A; Dawson, T M; Dawson, V L; De Laurenzi, V; De Maria, R; Debatin, K-M; Di Daniele, N; Dixit, V M; Dynlacht, B D; El-Deiry, W S; Fimia, G M; Flavell, R A; Fulda, S; Garrido, C; Gougeon, M-L; Green, D R; Gronemeyer, H; Hajnoczky, G; Hardwick, J M; Hengartner, M O; Ichijo, H; Joseph, B; Jost, P J; Kaufmann, T; Kepp, O; Klionsky, D J; Knight, R A; Kumar, S; Lemasters, J J; Levine, B; Linkermann, A; Lipton, S A; Lockshin, R A; López-Otín, C; Lugli, E; Madeo, F; Malorni, W; Marine, J-C; Martin, S J; Martinou, J-C; Medema, J P; Meier, P; Melino, S; Mizushima, N; Moll, U; Muñoz-Pinedo, C; Nuñez, G; Oberst, A; Panaretakis, T; Penninger, J M; Peter, M E; Piacentini, M; Pinton, P; Prehn, J H; Puthalakath, H; Rabinovich, G A; Ravichandran, K S; Rizzuto, R; Rodrigues, C M; Rubinsztein, D C; Rudel, T; Shi, Y; Simon, H-U; Stockwell, B R; Szabadkai, G; Tait, S W; Tang, H L; Tavernarakis, N; Tsujimoto, Y; Vanden Berghe, T; Vandenabeele, P; Villunger, A; Wagner, E F; Walczak, H; White, E; Wood, W G; Yuan, J; Zakeri, Z; Zhivotovsky, B; Melino, G; Kroemer, G

2015-01-01

Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as ‘accidental cell death' (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. ‘Regulated cell death' (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to classify it into a few subtypes, which often (but not always) exhibit stereotyped morphologic features. Nonetheless, efficiently inhibiting the processes that are commonly thought to cause RCD, such as the activation of executioner caspases in the course of apoptosis, does not exert true cytoprotective effects in the mammalian system, but simply alters the kinetics of cellular demise as it shifts its morphologic and biochemical correlates. Conversely, bona fide cytoprotection can be achieved by inhibiting the transduction of lethal signals in the early phases of the process, when adaptive responses are still operational. Thus, the mechanisms that truly execute RCD may be less understood, less inhibitable and perhaps more homogeneous than previously thought. Here, the Nomenclature Committee on Cell Death formulates a set of recommendations to help scientists and researchers to discriminate between essential and accessory aspects of cell death. PMID:25236395

Essential versus accessory aspects of cell death: recommendations of the NCCD 2015.

PubMed

Galluzzi, L; Bravo-San Pedro, J M; Vitale, I; Aaronson, S A; Abrams, J M; Adam, D; Alnemri, E S; Altucci, L; Andrews, D; Annicchiarico-Petruzzelli, M; Baehrecke, E H; Bazan, N G; Bertrand, M J; Bianchi, K; Blagosklonny, M V; Blomgren, K; Borner, C; Bredesen, D E; Brenner, C; Campanella, M; Candi, E; Cecconi, F; Chan, F K; Chandel, N S; Cheng, E H; Chipuk, J E; Cidlowski, J A; Ciechanover, A; Dawson, T M; Dawson, V L; De Laurenzi, V; De Maria, R; Debatin, K-M; Di Daniele, N; Dixit, V M; Dynlacht, B D; El-Deiry, W S; Fimia, G M; Flavell, R A; Fulda, S; Garrido, C; Gougeon, M-L; Green, D R; Gronemeyer, H; Hajnoczky, G; Hardwick, J M; Hengartner, M O; Ichijo, H; Joseph, B; Jost, P J; Kaufmann, T; Kepp, O; Klionsky, D J; Knight, R A; Kumar, S; Lemasters, J J; Levine, B; Linkermann, A; Lipton, S A; Lockshin, R A; López-Otín, C; Lugli, E; Madeo, F; Malorni, W; Marine, J-C; Martin, S J; Martinou, J-C; Medema, J P; Meier, P; Melino, S; Mizushima, N; Moll, U; Muñoz-Pinedo, C; Nuñez, G; Oberst, A; Panaretakis, T; Penninger, J M; Peter, M E; Piacentini, M; Pinton, P; Prehn, J H; Puthalakath, H; Rabinovich, G A; Ravichandran, K S; Rizzuto, R; Rodrigues, C M; Rubinsztein, D C; Rudel, T; Shi, Y; Simon, H-U; Stockwell, B R; Szabadkai, G; Tait, S W; Tang, H L; Tavernarakis, N; Tsujimoto, Y; Vanden Berghe, T; Vandenabeele, P; Villunger, A; Wagner, E F; Walczak, H; White, E; Wood, W G; Yuan, J; Zakeri, Z; Zhivotovsky, B; Melino, G; Kroemer, G

2015-01-01

Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as 'accidental cell death' (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. 'Regulated cell death' (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to classify it into a few subtypes, which often (but not always) exhibit stereotyped morphologic features. Nonetheless, efficiently inhibiting the processes that are commonly thought to cause RCD, such as the activation of executioner caspases in the course of apoptosis, does not exert true cytoprotective effects in the mammalian system, but simply alters the kinetics of cellular demise as it shifts its morphologic and biochemical correlates. Conversely, bona fide cytoprotection can be achieved by inhibiting the transduction of lethal signals in the early phases of the process, when adaptive responses are still operational. Thus, the mechanisms that truly execute RCD may be less understood, less inhibitable and perhaps more homogeneous than previously thought. Here, the Nomenclature Committee on Cell Death formulates a set of recommendations to help scientists and researchers to discriminate between essential and accessory aspects of cell death.

Evaluation of Biomarkers Predictive of Benefit from the PD-1 Inhibitor MK-3475 in Patients with Non-Small Cell Lung Cancer and Brain Metastases

DTIC Science & Technology

2017-07-01

Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Immunotherapies inhibiting the Programmed Death -1 (PD-1) axis can result in dramatic responses and durable...9. Appendices……………………………………………………………14 4 1. INTRODUCTION: Lung cancer is the leading cause of cancer death in the United States, resulting in more...than 160,000 deaths each year. The majority of patients with lung cancer have non-small cell lung cancer (NSCLC) and present with disease at an

Cell death features induced in Leishmania major by 1,3,4-thiadiazole derivatives.

PubMed

Ardestani, Sussan K; Poorrajab, Fatemeh; Razmi, Sepideh; Foroumadi, Alireza; Ajdary, Soheila; Gharegozlou, Behnaz; Behrouzi-Fardmoghadam, Mina; Shafiee, Abbas

2012-10-01

Under a variety of stress conditions, Leishmania species display some morphological and biochemical features characteristic of mammalian programmed cell death or necrosis. Nitroheteroaryl-1,3,4-thiadiazoles induce cell death in Leishmania major (L. major). Putative mechanisms of action of these compounds were investigated in vitro at cellular and molecular levels. We used colorimetric assay to measure acid phosphatase activity which is an indicator of cell viability in the promastigotes. The mode of toxicity was determined by detection of phosphatidylserine translocation to the surface, evaluation of cell membrane integrity, and in situ dUTP nick end-labeling assay. We also determined poly-ADP-ribose polymerase-like protein (PARP) level in the parasites after treatment. A significant reduction of acid phosphatase level, one of the most crucial and virulent factors of the parasite was found in parasites treated with 1,3,4-thiadiazole derivatives. In addition, 1,3,4-thiadiazole derivatives induced loss of plasma membrane integrity, DNA breakage, proteolysis of PARP and necrotic-like death in the parasites. Copyright © 2012 Elsevier Inc. All rights reserved.

BAX inhibitor-1 silencing suppresses white spot syndrome virus replication in red swamp crayfish, Procambarus clarkii.

PubMed

Du, Zhi-Qiang; Lan, Jiang-Feng; Weng, Yu-Ding; Zhao, Xiao-Fan; Wang, Jin-Xing

2013-07-01

BAX inhibitor-1 (BI-1) was originally described as an anti-apoptotic protein in both animal and plant cells. BI-1 overexpression suppresses ER stress-induced apoptosis in animal cells. Inhibition of BI-1 activity could induce the cell death in mammals and plants. However, the function of BI-1 in crustacean immunity was unclear. In this paper, the full-length cDNA of a BI-1 protein in red swamp crayfish, Procambarus clarkii (PcBI-1) was cloned and its expression profiles in normal and infected crayfish were analyzed. The results showed that PcBI-1 was expressed in hemocytes, heart, hepatopancreas, gills, stomach, and intestines of the crayfish and was upregulated after challenged with Vibrio anguillarum and with white spot syndrome virus (WSSV). To determine the function of PcBI-1 in the innate immunity of the crayfish, the RNA interference against PcBI-1 was performed and the results indicated the hemocyte programmed cell death rate was increased significantly and WSSV replication was declined after PcBI-1 knocked down. Altogether, PcBI-1 plays an anti-apoptotic role, wherein high PcBI-1 expression suppresses programmed cell death, which is beneficial for WSSW replication in crayfish. Copyright © 2013 Elsevier Ltd. All rights reserved.

Function of endoplasmic reticulum calcium ATPase in innate immunity-mediated programmed cell death

PubMed Central

Zhu, Xiaohong; Caplan, Jeffrey; Mamillapalli, Padmavathi; Czymmek, Kirk; Dinesh-Kumar, Savithramma P

2010-01-01

Programmed cell death (PCD) initiated at the pathogen-infected sites during the plant innate immune response is thought to prevent the development of disease. Here, we describe the identification and characterization of an ER-localized type IIB Ca2+-ATPase (NbCA1) that function as a regulator of PCD. Silencing of NbCA1 accelerates viral immune receptor N- and fungal-immune receptor Cf9-mediated PCD, as well as non-host pathogen Pseudomonas syringae pv. tomato DC3000 and the general elicitor cryptogein-induced cell death. The accelerated PCD rescues loss-of-resistance phenotype of Rar1, HSP90-silenced plants, but not SGT1-silenced plants. Using a genetically encoded calcium sensor, we show that downregulation of NbCA1 results in the modulation of intracellular calcium signalling in response to cryptogein elicitor. We further show that NbCAM1 and NbrbohB function as downstream calcium decoders in N-immune receptor-mediated PCD. Our results indicate that ER-Ca2+-ATPase is a component of the calcium efflux pathway that controls PCD during an innate immune response. PMID:20075858

Programmed cell death in periodontitis: recent advances and future perspectives.

PubMed

Song, B; Zhou, T; Yang, W L; Liu, J; Shao, L Q

2017-07-01

Periodontitis is a highly prevalent infectious disease, characterized by destruction of the periodontium, and is the main cause of tooth loss. Periodontitis is initiated by periodontal pathogens, while other risk factors including smoking, stress, and systemic diseases aggravate its progression. Periodontitis affects many people worldwide, but the molecular mechanisms by which pathogens and risk factors destroy the periodontium are unclear. Programmed cell death (PCD), different from necrosis, is an active cell death mediated by a cascade of gene expression events and can be mainly classified into apoptosis, autophagy, necroptosis, and pyroptosis. Although PCD is involved in many inflammatory diseases, its correlation with periodontitis is unclear. After reviewing the relevant published articles, we found that apoptosis has indeed been reported to play a role in periodontitis. However, the role of autophagy in periodontitis needs further verification. Additionally, implication of necroptosis or pyroptosis in periodontitis remains unknown. Therefore, we recommend future studies, which will unravel the pivotal role of PCD in periodontitis, allowing us to prevent, diagnose, and treat the disease, as well as predict its outcomes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Soluble Programmed Death 1 (PD-1) Is Decreased in Patients With Immune Thrombocytopenia (ITP): Potential Involvement of PD-1 Pathway in ITP Immunopathogenesis.

PubMed

Birtas Atesoglu, Elif; Tarkun, Pinar; Demirsoy, Esra Terzi; Geduk, Ayfer; Mehtap, Ozgur; Batman, Adnan; Kaya, Fatih; Cekmen, Mustafa Baki; Gulbas, Zafer; Hacıhanefioglu, Abdullah

2016-04-01

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by dysregulation of T cells. Programmed death (PD) 1 and programmed death 1 ligand 1 (PD-L1) are cosignaling molecules, and the major role of the PD-1 pathway is the inhibition of self-reactive T cells and to protect against autoimmune diseases. We measured levels of serum soluble PD 1 (sPD-1) and serum soluble PD-L1 (sPD-L1) in 67 patients with ITP (24 newly diagnosed ITP [ndITP], 43 chronic ITP [cITP]) and 21 healthy controls (HCs). We determined decreased serum sPD-1 levels both in patients with ndITP and in patients with cITP when compared to HC. Moreover, there was a positive correlation between sPD-1 levels and platelet counts. The sPD-L1 levels were decreased in patients with ndITP when compared to patients with cITP. This is the first study investigating PD-1 signaling pathway in ITP. Decreased sPD-1 levels may have a role in ITP pathogenesis as without the inhibitory regulation of PD-1, sustained activation of T cells may cause inflammatory responses which is the case in ITP. © The Author(s) 2014.

Lack of association of programmed cell death 1 gene (PDCD1) polymorphisms with susceptibility to chronic urticaria in patients with positive autologous serum skin test.

PubMed

Brzoza, Z; Grzeszczak, W; Trautsolt, W; Moczulski, D

2012-01-01

Autoimmune mechanisms play an important role in the pathophysiology of chronic urticaria (CU), and the autologous serum skin test (ASST) helps to identify patients with autoreactive CU. One of the factors involved in autoreactive mechanisms is the cell surface receptor programmed death-1 which is encoded by the programmed cell death 1 gene (PDCD1). To investigate whether PDCD1 polymorphisms influence susceptibility to CU. We enrolled 93 ASST-positive patients with CU and a control group consisting of 105 healthy volunteers. In all individuals, PD1.3 (7146 A/G; rs 11568821) and PD1.5 (7785 C/T; rs 2227981) polymorphisms were analyzed. No statistically significant differences were found between CU patients and controls for allele or genotype distribution. We also did not observe any association between PDCD1 genotypes and severity of urticaria or age of disease onset. PD1.3 and PD1.5 polymorphisms were not proven to be implicated in susceptibility to ASST-positive CU in the Polish population. A more comprehensive analysis of the 2q33-2q37 genomic region might reveal whether variants of 1 or more of the genes in this region are involved in susceptibility to CU.

Physician Education: Apoptosis.

PubMed

Kataoka; Tsuruo

1996-01-01

We have come to understand apoptosis as not merely a single form of cell death, but as a fundamental theme in cell biology that has far-reaching implications in the fields of physiology and pathology. At the present time, however, the mechanism of apoptosis is not clearly understood, as research into apoptosis is still at the initial stages. Nevertheless, the links between apoptosis and a variety of pathological conditions are gradually becoming clearer. In this article, we will provide a simple explanation of apoptosis and its mechanism as a novel concept of cell death and discuss the way in which apoptosis has been linked to a variety of pathological conditions. WHAT IS APOPTOSIS?: In normal tissue, cells that are no longer needed are rapidly eliminated without affecting the overall function of the tissue. In this process cells undergo an active and spontaneous suicide called programmed cell death. In fact, the majority of physiological cell deaths take the form of apoptosis. The word apoptosis is used, in contrast to necrosis, to describe the situation in which a cell actively pursues a course toward death upon receiving certain stimuli [1]. The morphological changes of apoptosis found in most cell types first involve contraction in cell volume and condensation of the nucleus. When this happens the intracellular organelles such as the mitochondria retain their normal morphology. As apoptosis proceeds, blebbing of the plasma membrane occurs, and the nucleus becomes fragmented. Finally, the cell itself fragments to form apoptotic bodies that are engulfed by nearby phagocytes. With respect to biochemical changes, it is known that the chromosomes become fragmented into nucleosome units, and DNA forms characteristic ladder patterns when subjected to agarose gel electrophoresis. MECHANISM OF APOPTOSIS: It has been reported that apoptosis is induced in various cells by many kinds of irritations, but the precise mechanism is still unclear. Cell injuries that induce apoptosis include those that cause DNA damage such as radiation and anticancer drugs, those that are mediated by the TNF receptor and Fas receptor (the so-called "death signal receptors"), and the deprivation of cytokines that supply survival signals such as IL-3 and erythropoietin. The tumor suppressor gene p53 plays a very important role in apoptosis induced by damage to DNA. This has been demonstrated by studying resistance to apoptosis of cells derived from p53 knockout mice [2]. Other than the irritations that induce apoptosis, molecules that have been strongly implicated as major players in the drama of apoptosis include the Bcl-2 family proteins and the IL-1 converting enzyme (ICE) and its homolog proteases (caspase family). Both groups of proteins show homology with proteins that affect cell death in nematodes. It is believed that molecules that contribute to cell death have been well conserved in multicellular organisms all the way from the relatively primitive nematodes to mammals including humans. It was discovered that Bcl-2 suppressed apoptosis induced in IL-3 dependent cells by deprivation of IL-3 [3]. It has since become the gene around which apoptosis research revolves. Recently, it has become clear that cell death involving the Bcl-2 protein is under the control of similar proteins from the same family [4]. It is interesting that the phenomenon of cell death may be regulated by the balance of the molecules involved in it. APOPTOSIS ABNORMALITIES AND DISEASE: Physiological cell death plays a major role in the growth and permanent maintenance of the human body [5]. In the process of forming the nervous system, neurons that do not form proper connections die. Physiological cell death also accompanies the removal of virus-infected cells by cytotoxic T cells, the elimination of autoreactive immune cells, the formation of the gut, the reconstitution of cartilage and bone, etc. When physiological cell death that normally should occur is inhibited, inappropriate physiological cell death may occur that is harmful to the body and forms the basis of disease. For example, in patients with neural degenerative disorders such as Alzheimer's disease and Parkinson's disease, we can find premature cell death in a particular subset of neurons. The death of T cells in AIDS patients is also a form of physiological cell death. Inhibition of cell death in the immune system enables the survival of autoreactive B cells and T cells, and is therefore a cause of autoimmune disorders. Apoptosis has been particularly linked to cancer. Normal cells are programmed for death if they are subjected to many types of non-physiological stress such as anticancer drugs or radiation, if they become isolated from surrounding cells and are unable to receive their tissue-specific survival signals [6], or if oncogenes are expressed haphazardly [7]. On the other hand, it is believed that the ability to survive is enhanced in transformed cancer cells because they are more resistant to apoptosis, they exhibit resistance to anticancer drugs, they are no longer dependent on survival signals, and they can metastasize. Therefore, the cancer progresses as the cancer cells maintain the proliferative superiority they acquire from their oncogenes. In other words, when cancer cells become resistant to apoptosis, they become resistant to treatment, metastasize, and proliferate destructively. The concept that the malignancy of cancer is due to its resistance to apoptosis is a relatively new one and is worthy of further study.

Senescence Meets Dedifferentiation

PubMed Central

Givaty Rapp, Yemima; Ransbotyn, Vanessa; Grafi, Gideon

2015-01-01

Senescence represents the final stage of leaf development but is often induced prematurely following exposure to biotic and abiotic stresses. Leaf senescence is manifested by color change from green to yellow (due to chlorophyll degradation) or to red (due to de novo synthesis of anthocyanins coupled with chlorophyll degradation) and frequently culminates in programmed death of leaves. However, the breakdown of chlorophyll and macromolecules such as proteins and RNAs that occurs during leaf senescence does not necessarily represent a one-way road to death but rather a reversible process whereby senescing leaves can, under certain conditions, re-green and regain their photosynthetic capacity. This phenomenon essentially distinguishes senescence from programmed cell death, leading researchers to hypothesize that changes occurring during senescence might represent a process of trans-differentiation, that is the conversion of one cell type to another. In this review, we highlight attributes common to senescence and dedifferentiation including chromatin structure and activation of transposable elements and provide further support to the notion that senescence is not merely a deterioration process leading to death but rather a unique developmental state resembling dedifferentiation. PMID:27135333

Crosslinking CD4 by human immunodeficiency virus gp120 primes T cells for activation-induced apoptosis

PubMed Central

1992-01-01

During human immunodeficiency virus (HIV) infection there is a profound and selective decrease in the CD4+ population of T lymphocytes. The mechanism of this depletion is not understood, as only a small fraction of all CD4+ cells appear to be productively infected with HIV-1 in seropositive individuals. In the present study, crosslinking of bound gp120 on human CD4+ T cells followed by signaling through the T cell receptor for antigen was found to result in activation-dependent cell death by a form of cell suicide termed apoptosis, or programmed cell death. The data indicate that even picomolar concentrations of gp120 prime T cells for activation-induced cell death, suggesting a mechanism for CD4+ T cell depletion in acquired immune deficiency syndrome (AIDS), particularly in the face of concurrent infection and antigenic challenge with other organisms. These results also provide an explanation for the enhancement of infection by certain antibodies against HIV, and for the paradox that HIV appears to cause AIDS after the onset of antiviral immunity. PMID:1402655

An endogenous nanomineral chaperones luminal antigen and peptidoglycan to intestinal immune cells

NASA Astrophysics Data System (ADS)

Powell, Jonathan J.; Thomas-McKay, Emma; Thoree, Vinay; Robertson, Jack; Hewitt, Rachel E.; Skepper, Jeremy N.; Brown, Andy; Hernandez-Garrido, Juan Carlos; Midgley, Paul A.; Gomez-Morilla, Inmaculada; Grime, Geoffrey W.; Kirkby, Karen J.; Mabbott, Neil A.; Donaldson, David S.; Williams, Ifor R.; Rios, Daniel; Girardin, Stephen E.; Haas, Carolin T.; Bruggraber, Sylvaine F. A.; Laman, Jon D.; Tanriver, Yakup; Lombardi, Giovanna; Lechler, Robert; Thompson, Richard P. H.; Pele, Laetitia C.

2015-05-01

In humans and other mammals it is known that calcium and phosphate ions are secreted from the distal small intestine into the lumen. However, why this secretion occurs is unclear. Here, we show that the process leads to the formation of amorphous magnesium-substituted calcium phosphate nanoparticles that trap soluble macromolecules, such as bacterial peptidoglycan and orally fed protein antigens, in the lumen and transport them to immune cells of the intestinal tissue. The macromolecule-containing nanoparticles utilize epithelial M cells to enter Peyer's patches, small areas of the intestine concentrated with particle-scavenging immune cells. In wild-type mice, intestinal immune cells containing these naturally formed nanoparticles expressed the immune tolerance-associated molecule ‘programmed death-ligand 1’, whereas in NOD1/2 double knockout mice, which cannot recognize peptidoglycan, programmed death-ligand 1 was undetected. Our results explain a role for constitutively formed calcium phosphate nanoparticles in the gut lumen and show how this helps to shape intestinal immune homeostasis.

Competing Death Programs in Poliovirus-Infected Cells: Commitment Switch in the Middle of the Infectious Cycle

PubMed Central

Agol, Vadim I.; Belov, George A.; Bienz, Kurt; Egger, Denise; Kolesnikova, Marina S.; Romanova, Lyudmila I.; Sladkova, Larissa V.; Tolskaya, Elena A.

2000-01-01

Productive poliovirus infection of HeLa cells leads to the canonical cytopathic effect (CPE), whereas certain types of abortive infection result in apoptosis. To define the time course of commitment to the different types of poliovirus-induced death, inhibitors of viral replication (guanidine HCl) or translation (cycloheximide) were added at different times postinfection (p.i.). Early in the infection (during the first ∼2 h p.i.), predominantly proapoptotic viral function was expressed, rendering the cells committed to apoptosis, which developed several hours after viral expression was arrested. In the middle of infection, concomitantly with the onset of fast generation of viral progeny, the implementation of the viral apoptotic program was abruptly interrupted. In particular, activation of an Asp-Glu-Val-Asp (DEVD)-specific caspase(s) occurring in the apoptosis-committed cells was prevented by the ongoing productive infection. Simultaneously, the cells retaining normal or nearly normal morphology became committed to CPE, which eventually developed regardless of whether or not further viral expression was allowed to proceed. The implementation of the poliovirus-induced apoptotic program was suppressed in HeLa cells overexpressing the Bcl-2 protein, indicating that the fate of poliovirus-infected cells depends on the balance of host and viral pro- and antiapoptotic factors. PMID:10823859

Taxol induces concentration-dependent phosphatidylserine (PS) externalization and cell cycle arrest in ASTC-a-1 cells

NASA Astrophysics Data System (ADS)

Guo, Wen-jing; Chen, Tong-sheng

2010-02-01

Taxol (Paclitaxel) is an important natural product for the treatment of solid tumors. Different concentrations of taxol can trigger distinct effects on both the cellular microtubule network and biochemical pathways. Apoptosis induced by low concentrations (5-30 nM) of taxol was associated with mitotic arrest, alteration of microtubule dynamics and/or G2/M cell cycle arrest, whereas high concentrations of this drug (0.2-30 μM) caused significant microtubule damage, and was found recently to induce cytoplasm vacuolization in human lung adenocarcinoma (ASTC-a-1) cells. In present study, cell counting kit (CCK-8) assay, confocal microscope, and flow cytometry analysis were used to analyze the cell death form induced by 35 nM and 70 μM of taxol respectively in human lung adenocarcinoma (ASTC-a-1) cells. After treatment of 35 nM taxol for 48 h, the OD450 value was 0.80, and 35 nM taxol was found to induce dominantly cell death in apoptotic pathway such as phosphatidylserine (PS) externalization, G2/M phase arrest after treatment for 24 h, and nuclear fragmentation after treatment for 48 h. After 70 μM taxol treated the cell for 24 h, the OD450 value was 1.01, and 70 μM taxol induced cytoplasm vacuolization programmed cell death (PCD) and G2/M phase as well as the polyploidy phase arrest in paraptotic-like cell death. These findings imply that the regulated signaling pathway of cell death induced by taxol is dependent on taxol concentration in ASTC-a-1 cells.

Evidence for the activation of pyroptotic and apoptotic pathways in RPE cells associated with NLRP3 inflammasome in the rodent eye.

PubMed

Gao, Jiangyuan; Cui, Jing Z; To, Eleanor; Cao, Sijia; Matsubara, Joanne A

2018-01-12

Age-related macular degeneration (AMD) is a devastating eye disease causing irreversible vision loss in the elderly. Retinal pigment epithelium (RPE), the primary cell type that is afflicted in AMD, undergoes programmed cell death in the late stages of the disease. However, the exact mechanisms for RPE degeneration in AMD are still unresolved. The prevailing theories consider that each cell death pathway works independently and without regulation of each other. Building upon our previous work in which we induced a short burst of inflammasome activity in vivo, we now investigate the effects of prolonged inflammasome activity on RPE cell death mechanisms in rats. Long-Evans rats received three intravitreal injections of amyloid beta (Aβ), once every 4 days, and were sacrificed at day 14. The vitreous samples were collected to assess the levels of secreted cytokines. The inflammasome activity was evaluated by both immunohistochemistry and western blot. The types of RPE cell death mechanisms were determined using specific cell death markers and morphological characterizations. We found robust inflammasome activation evident by enhanced caspase-1 immunoreactivity, augmented NF-κB nuclear translocalization, increased IL-1β vitreal secretion, and IL-18 protein levels. Moreover, we observed elevated proteolytic cleavage of caspase-3 and gasdermin D, markers for apoptosis and pyroptosis, respectively, in RPE-choroid tissues. There was also a significant reduction in the anti-apoptotic factor, X-linked inhibitor of apoptosis protein, consistent with the overall changes of RPE cells. Morphological analysis showed phenotypic characteristics of pyroptosis including RPE cell swelling. Our data suggest that two cell death pathways, pyroptosis and apoptosis, were activated in RPE cells after exposure to prolonged inflammasome activation, induced by a drusen component, Aβ. The involvement of two distinct cell death pathways in RPE sheds light on the potential interplay between these pathways and provides insights on the future development of therapeutic strategies for AMD.

Time-resolved, single-cell analysis of induced and programmed cell death via non-invasive propidium iodide and counterstain perfusion.

PubMed

Krämer, Christina E M; Wiechert, Wolfgang; Kohlheyer, Dietrich

2016-09-01

Conventional propidium iodide (PI) staining requires the execution of multiple steps prior to analysis, potentially affecting assay results as well as cell vitality. In this study, this multistep analysis method has been transformed into a single-step, non-toxic, real-time method via live-cell imaging during perfusion with 0.1 μM PI inside a microfluidic cultivation device. Dynamic PI staining was an effective live/dead analytical tool and demonstrated consistent results for single-cell death initiated by direct or indirect triggers. Application of this method for the first time revealed the apparent antibiotic tolerance of wild-type Corynebacterium glutamicum cells, as indicated by the conversion of violet fluorogenic calcein acetoxymethyl ester (CvAM). Additional implementation of this method provided insight into the induced cell lysis of Escherichia coli cells expressing a lytic toxin-antitoxin module, providing evidence for non-lytic cell death and cell resistance to toxin production. Finally, our dynamic PI staining method distinguished necrotic-like and apoptotic-like cell death phenotypes in Saccharomyces cerevisiae among predisposed descendants of nutrient-deprived ancestor cells using PO-PRO-1 or green fluorogenic calcein acetoxymethyl ester (CgAM) as counterstains. The combination of single-cell cultivation, fluorescent time-lapse imaging, and PI perfusion facilitates spatiotemporally resolved observations that deliver new insights into the dynamics of cellular behaviour.

Pepper pathogenesis-related protein 4c is a plasma membrane-localized cysteine protease inhibitor that is required for plant cell death and defense signaling.

PubMed

Kim, Nak Hyun; Hwang, Byung Kook

2015-01-01

Xanthomonas campestris pv. vesicatoria (Xcv) type III effector AvrBsT triggers programmed cell death (PCD) and activates the hypersensitive response (HR) in plants. Here, we isolated and identified the plasma membrane localized pathogenesis-related (PR) protein 4c gene (CaPR4c) from pepper (Capsicum annuum) leaves undergoing AvrBsT-triggered HR cell death. CaPR4c encodes a protein with a signal peptide and a Barwin domain. Recombinant CaPR4c protein expressed in Escherichia coli exhibited cysteine protease-inhibitor activity and ribonuclease (RNase) activity. Subcellular localization analyses revealed that CaPR4c localized to the plasma membrane in plant cells. CaPR4c expression was rapidly and specifically induced by avirulent Xcv (avrBsT) infection. Transient expression of CaPR4c caused HR cell death in pepper leaves, which was accompanied by enhanced accumulation of H2 O2 and significant induction of some defense-response genes. Deletion of the signal peptide from CaPR4c abolished the induction of HR cell death, indicating a requirement for plasma membrane localization of CaPR4c for HR cell death. CaPR4c silencing in pepper disrupted both basal and AvrBsT-triggered resistance responses, and enabled Xcv proliferation in infected leaves. H2 O2 accumulation, cell-death induction, and defense-response gene expression were distinctly reduced in CaPR4c-silenced pepper. CaPR4c overexpression in transgenic Arabidopsis plants conferred greater resistance against infection by Pseudomonas syringae pv. tomato and Hyaloperonospora arabidopsidis. These results collectively suggest that CaPR4c plays an important role in plant cell death and defense signaling. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

Involvement of tumour necrosis factor-α-related apoptosis-inducing ligand in enhanced cytotoxicity of lipopolysaccharide-stimulated dendritic cells to activated T cells

PubMed Central

Yu, Yizhi; Liu, Shuxun; Wang, Wenya; Song, Wengang; Zhang, Minghui; Zhang, Weiping; Qin, Zhihai; Cao, Xuetao

2002-01-01

Dendritic cells (DC) are potent antigen-presenting cells (APC) specialized in T-cell mediated immune responses, and also play critical roles in the homeostasis of T cells for controlling immune responses. In the present study, we demonstrated that during mouse bone-marrow-derived DC activation of ovalbumin (OVA)-specific Ia-kb-restricted T hybridoma cells, MF2.2D9 and OVA257–264-specific H-2kb-restricted RF33.70 T cells, respectively, both hybridomas undergo cell death, partially mediated via apoptotic ligand–tumour necrosis factor-α (TNF-α)-related apoptosis-inducing ligand (TRAIL). Lipopolysaccharide enhanced the cytotoxic effect on the two activated T hybridoma cells, which was correlated with up-regulation of TRAIL-expression on DC to some extent. The activation of caspase-3 in activated T hybridoma cells cocultured with DC contributed to the programmed cell death pathway T cells underwent. Therefore, our results show that activation-induced cell death of T hybridoma cells can be influenced by DC, suggesting that DC may be involved in elimination of activated T cells at the end of primary immune responses. PMID:12100718

Involvement of tumour necrosis factor-alpha-related apoptosis-inducing ligand in enhanced cytotoxicity of lipopolysaccharide-stimulated dendritic cells to activated T cells.

PubMed

Yu, Yizhi; Liu, Shuxun; Wang, Wenya; Song, Wengang; Zhang, Minghui; Zhang, Weiping; Qin, Zhihai; Cao, Xuetao

2002-07-01

Dendritic cells (DC) are potent antigen-presenting cells (APC) specialized in T-cell mediated immune responses, and also play critical roles in the homeostasis of T cells for controlling immune responses. In the present study, we demonstrated that during mouse bone-marrow-derived DC activation of ovalbumin (OVA)-specific Ia-kb-restricted T hybridoma cells, MF2.2D9 and OVA257-264-specific H-2kb-restricted RF33.70 T cells, respectively, both hybridomas undergo cell death, partially mediated via apoptotic ligand-tumour necrosis factor-alpha (TNF-alpha)-related apoptosis-inducing ligand (TRAIL). Lipopolysaccharide enhanced the cytotoxic effect on the two activated T hybridoma cells, which was correlated with up-regulation of TRAIL-expression on DC to some extent. The activation of caspase-3 in activated T hybridoma cells cocultured with DC contributed to the programmed cell death pathway T cells underwent. Therefore, our results show that activation-induced cell death of T hybridoma cells can be influenced by DC, suggesting that DC may be involved in elimination of activated T cells at the end of primary immune responses.

Hypoxic Switch in Mitochondrial Myeloid Cell Leukemia Factor-1/Mtd Apoptotic Rheostat Contributes to Human Trophoblast Cell Death in Preeclampsia

PubMed Central

Soleymanlou, Nima; Jurisicova, Andrea; Wu, Yuanhong; Chijiiwa, Mari; Ray, Jocelyn E.; Detmar, Jacqui; Todros, Tullia; Zamudio, Stacy; Post, Martin; Caniggia, Isabella

2007-01-01

Preeclampsia, a disorder of pregnancy, is characterized by increased trophoblast cell death and altered trophoblast-mediated remodeling of myometrial spiral arteries resulting in reduced uteroplacental perfusion. Mitochondria-associated Bcl-2 family members are important regulators of programed cell death. The mechanism whereby hypoxia alters the mitochondrial apoptotic rheostat is essential to our understanding of placental disease. Herein, myeloid cell leukemia factor-1 (Mcl-1) isoform expression was examined in physiological/pathological models of placental hypoxia. Preeclamptic placentae were characterized by caspase-dependent cleavage of death-suppressing Mcl-1L and switch toward cell death-inducing Mcl-1S. In vitro, Mcl-1L cleavage was induced by hypoxia-reoxygenation in villous explants, whereas Mcl-1L overexpression under hypoxia-reoxygenation rescued trophoblast cells from undergoing apoptosis. Cleavage was mediated by caspase-3/-7 because pharmacological caspase inhibition prevented this process. Altitude-induced chronic hypoxia was characterized by expression of Mcl-1L; resulting in a reduction of apoptotic markers (cleaved caspase-3/-8 and p85 poly-ADP-ribose polymerase). Moreover, in both physiological (explants and high altitude) and pathological (preeclampsia) placental hypoxia, decreased trophoblast syncytin expression was observed. Hence, although both pathological and physiological placental hypoxia are associated with slowed trophoblast differentiation, trophoblast apoptosis is only up-regulated in preeclampsia, because of a hypoxia-reoxygenation-induced switch in generation of proapoptotic Mcl-1 isoforms. PMID:17600131

The targeted inhibition of mitochondrial Hsp90 overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Chunlan; Department of Physiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058; Oh, Joon Seok

Previous studies have reported that a Gamitrinib variant containing triphenylphosphonium (G-TPP) binds to mitochondrial Hsp90 and rapidly inhibits its activity, thus inducing the apoptotic pathway in the cells. Accordingly, G-TPP shows a potential as a promising drug for the treatment of cancer. A cell can die from different types of cell death such as apoptosis, necrosis, necroptosis, and autophagic cell death. In this study, we further investigated the mechanisms and modes of cell death in the G-TPP-treated Hep3B and U937 cell lines. We discovered that G-TPP kills the U937 cells through the apoptotic pathway and the overexpression of Bcl-2 significantlymore » inhibits U937 cell death to G-TPP. We further discovered that G-TPP kills the Hep3B cells by activating necroptosis in combination with the partial activation of caspase-dependent apoptosis. Importantly, G-TPP overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis. We also observed that G-TPP induces compensatory autophagy in the Hep3B cell line. We further found that whereas there is a Bcl-2-Beclin 1 interaction in response to G-TPP, silencing the beclin 1 gene failed to block LC3-II accumulation in the Hep3B cells, indicating that G-TPP triggers Beclin 1-independent protective autophagy in Hep3B cells. Taken together, these data reveal that G-TPP induces cell death through a combination of death pathways, including necroptosis and apoptosis, and overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis. These findings are important for the therapeutic exploitation of necroptosis as an alternative cell death program to bypass the resistance to apoptosis. Highlights: ► G-TPP binds to mitochondrial Hsp90. ► G-TPP induces apoptosis in U937 human leukemia cancer cells. ► G-TPP induces combination of death pathways in Hep3B cell. ► G-TPP overcomes the resistance conferred by Bcl-2 in Hep3B cells via necroptosis. ► G-TPP triggers Beclin 1-independent protective autophagy in Hep3B cells.« less

Ecdysone-dependent and ecdysone-independent programmed cell death in the developing optic lobe of Drosophila.

PubMed

Hara, Yusuke; Hirai, Keiichiro; Togane, Yu; Akagawa, Hiromi; Iwabuchi, Kikuo; Tsujimura, Hidenobu

2013-02-01

The adult optic lobe of Drosophila develops from the primordium during metamorphosis from mid-3rd larval stage to adult. Many cells die during development of the optic lobe with a peak of the number of dying cells at 24 h after puparium formation (h APF). Dying cells were observed in spatio-temporal specific clusters. Here, we analyzed the function of a component of the insect steroid hormone receptor, EcR, in this cell death. We examined expression patterns of two EcR isoforms, EcR-A and EcR-B1, in the optic lobe. Expression of each isoform altered during development in isoform-specific manner. EcR-B1 was not expressed in optic lobe neurons from 0 to 6h APF, but was expressed between 9 and 48 h APF and then disappeared by 60 h APF. In each cortex, its expression was stronger in older glia-ensheathed neurons than in younger ones. EcR-B1 was also expressed in some types of glia. EcR-A was expressed in optic lobe neurons and many types of glia from 0 to 60 h APF in a different pattern from EcR-B1. Then, we genetically analyzed EcR function in the optic lobe cell death. At 0 h APF, the optic lobe cell death was independent of any EcR isoforms. In contrast, EcR-B1 was required for most optic lobe cell death after 24 h APF. It was suggested that cell death cell-autonomously required EcR-B1 expressed after puparium formation. βFTZ-F1 was also involved in cell death in many dying-cell clusters, but not in some of them at 24 h APF. Altogether, the optic lobe cell death occurred in ecdysone-independent manner at prepupal stage and ecdysone-dependent manner after 24 h APF. The acquisition of ecdysone-dependence was not directly correlated with the initiation or increase of EcR-B1 expression. Copyright © 2012 Elsevier Inc. All rights reserved.

Characterization of the programmed cell death induced by metabolic products of Alternaria alternata in tobacco BY-2 cells.

PubMed

Cheng, Dan-Dan; Jia, Yu-Jiao; Gao, Hui-Yuan; Zhang, Li-Tao; Zhang, Zi-Shan; Xue, Zhong-Cai; Meng, Qing-Wei

2011-02-01

Alternaria alternata has received considerable attention in current literature and most of the studies are focused on its pathogenic effects on plant chloroplasts, but little is known about the characteristics of programmed cell death (PCD) induced by metabolic products (MP) of A. alternata, the effects of the MP on mitochondrial respiration and its relation to PCD. The purpose of this study was to explore the mechanism of MP-induced PCD in non-green tobacco BY-2 cells and to explore the role of mitochondrial inhibitory processes in the PCD of tobacco BY-2 cells. MP treatment led to significant cell death that was proven to be PCD by the concurrent cytoplasm shrinkage, chromatin condensation and DNA laddering observed in the cells. Moreover, MP treatment resulted in the overproduction of reactive oxygen species (ROS), rapid ATP depletion and a respiratory decline in the tobacco BY-2 cells. It was concluded that the direct inhibition of the mitochondrial electron transport chain (ETC), alternative pathway (AOX) capacity and catalase (CAT) activity by the MP might be the main contributors to the MP-induced ROS burst observed in tobacco BY-2 cells. The addition of adenosine together with the MP significantly inhibited ATP depletion without preventing PCD; however, when the cells were treated with the MP plus CAT, ROS overproduction was blocked and PCD did not occur. The data presented here demonstrate that the ROS burst played an important role in MP-induced PCD in the tobacco BY-2 cells.

Modern Radiobiology: Contention Of Concepts: Advanced Technology And Development Of Effective Prophylaxis, Prevention And Treatment Of Biological Consequences After Irradiation.

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Maliev, Vecheslav; Jones, Jeffrey

"Alle Ding' sind Gift, und nichts ohn' Gift; allein die Dosis macht, daß ein Ding kein Gift ist." Paracelsus Philippus Aureolus Theophrastus Bombastus von Hohenheim. Key worlds: Apoptosis, Necrosis, Domains associated with Cell Death, Caspase (catalytic) Domains, Death Domains (DDs), Death Effector Domains (DEDs), Caspase-Associated Recruitment Domains (CARDs, BIR Domains (IAPs), Bcl-2 Homology (BH) Domains, death ligands - TRAIL (TNF-Related Apoptosis-Inducing Ligand), FasL (Fas Ligand), TNFalpha (Tumor Necrosis Factor alpha), Toll-like receptors (TLR), Systemic inflammatory response syndrome (SIRS), Toxic Multiple Organ Injury (TMOI), Toxic Multiple Organ Dysfunction Syndromes (TMODS), Toxic Multiple Organ Failure (TMOF), Anaphylatoxins, or complement peptides; membrane attack complex (MAC), ROS - Reactive Oxygen Species; ASMase, acid sphingomyelinase; Neurotoxins, Cytotoxins, Haemotoxins. Introduction: Radiation affects many cell structures, organelles and metabolic pathways. Different doses and types of radiation ( gamma-radiation, neutron, heavy ion radiation) progress to reversible and irreversible forms of cell injury. Consideration: Apoptosis and Necrosis, major forms of post-radiation cell death, can be initiated and modulated by programmed control and proceed by similar or different pathways.[Akadi et al.,1993, Dunlacht J., et al. 1999] Radiation induced cell death by triggering apoptosis pathways was described in many articles and supported by many scientists. [Rio et al. 2002, Rakesh et al. 1997.] However some authors present results that two distinct pathways can initiate or apoptotic or necrotic responses: the death receptors and mitochondrial pathways.

Smac mimetics and type II interferon synergistically induce necroptosis in various cancer cell lines.

PubMed

Cekay, Michael John; Roesler, Stefanie; Frank, Tanja; Knuth, Anne-Kathrin; Eckhardt, Ines; Fulda, Simone

2017-12-01

Since cancer cells often evade apoptosis, induction of necroptosis as another mode of programmed cell death is considered a promising therapeutic alternative. Here, we identify a novel synergistic interaction of Smac mimetics that antagonize x-linked Inhibitor of Apoptosis (XIAP), cellular Inhibitor of Apoptosis (cIAP) 1 and 2 with interferon (IFN)γ to induce necroptosis in apoptosis-resistant cancer cells in which caspase activation is blocked. This synergism is confirmed by calculation of combination indices (CIs) and found in both solid and hematological cancer cell lines as well as for different Smac mimetics (i.e. BV6, Birinapant), pointing to a broader relevance. Importantly, individual genetic knockdown of key components of necroptosis signaling, i.e. receptor-interacting protein (RIP) 1, RIP3 or mixed lineage kinase domain-like pseudokinase (MLKL), significantly protects from BV6/IFNγ-induced cell death. Similarly, pharmacological inhibitors of RIP1 (necrostatin-1(Nec-1)), RIP3 (GSK'872) or MLKL (necrosulfonamide (NSA)) significantly reduce BV6/IFNγ-stimulated cell death. Of note, IFN-regulatory factor (IRF)1 is required for BV6/IFNγ-mediated necroptosis, as IRF1 silencing provides protection from cell death. By comparison, antibodies blocking tumor necrosis factor (TNF)α, TNF-related apoptosis-inducing ligand (TRAIL) or CD95 ligand fail to inhibit BV6/IFNγ-induced cell death, pointing to a mechanism independently of death receptor ligands. This is the first report showing that Smac mimetics synergize with IFNγ to trigger necroptosis in apoptosis-resistant cancer cells with important implications for Smac mimetic-based strategies for the treatment of cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

Loss of BID Delays FASL-Induced Cell Death of Mouse Neutrophils and Aggravates DSS-Induced Weight Loss.

PubMed

Wicki, Simone; Gurzeler, Ursina; Corazza, Nadia; Genitsch, Vera; Wong, Wendy Wei-Lynn; Kaufmann, Thomas

2018-02-28

Neutrophils are key players in the early defense against invading pathogens. Due to their potent effector functions, programmed cell death of activated neutrophils has to be tightly controlled; however, its underlying mechanisms remain unclear. Fas ligand (FASL/CD95L) has been shown to induce neutrophil apoptosis, which is accelerated by the processing of the BH3-only protein BH3 interacting domain death agonist (BID) to trigger mitochondrial apoptotic events, and been attributed a regulatory role during viral and bacterial infections. Here, we show that, in accordance with previous works, mouse neutrophils underwent caspase-dependent apoptosis in response to FASL, and that this cell death was significantly delayed upon loss of BID. However, pan-caspase inhibition failed to protect mouse neutrophils from FASL-induced apoptosis and caused a switch to RIPK3-dependent necroptotic cell death. Intriguingly, such a switch was less evident in the absence of BID, particularly under inflammatory conditions. Delayed neutrophil apoptosis has been implicated in several auto-inflammatory diseases, including inflammatory bowel disease. We show that neutrophil and macrophage driven acute dextran sulfate sodium (DSS) induced colitis was slightly more aggravated in BID-deficient mice, based on significantly increased weight loss compared to wild-type controls. Taken together, our data support a central role for FASL > FAS and BID in mouse neutrophil cell death and further underline the anti-inflammatory role of BID.

Loss of BID Delays FASL-Induced Cell Death of Mouse Neutrophils and Aggravates DSS-Induced Weight Loss

PubMed Central

Wicki, Simone; Gurzeler, Ursina; Corazza, Nadia; Genitsch, Vera

2018-01-01

Neutrophils are key players in the early defense against invading pathogens. Due to their potent effector functions, programmed cell death of activated neutrophils has to be tightly controlled; however, its underlying mechanisms remain unclear. Fas ligand (FASL/CD95L) has been shown to induce neutrophil apoptosis, which is accelerated by the processing of the BH3-only protein BH3 interacting domain death agonist (BID) to trigger mitochondrial apoptotic events, and been attributed a regulatory role during viral and bacterial infections. Here, we show that, in accordance with previous works, mouse neutrophils underwent caspase-dependent apoptosis in response to FASL, and that this cell death was significantly delayed upon loss of BID. However, pan-caspase inhibition failed to protect mouse neutrophils from FASL-induced apoptosis and caused a switch to RIPK3-dependent necroptotic cell death. Intriguingly, such a switch was less evident in the absence of BID, particularly under inflammatory conditions. Delayed neutrophil apoptosis has been implicated in several auto-inflammatory diseases, including inflammatory bowel disease. We show that neutrophil and macrophage driven acute dextran sulfate sodium (DSS) induced colitis was slightly more aggravated in BID-deficient mice, based on significantly increased weight loss compared to wild-type controls. Taken together, our data support a central role for FASL > FAS and BID in mouse neutrophil cell death and further underline the anti-inflammatory role of BID. PMID:29495595

FDA approved Immunosuppressants Targeting Staphylococcal Superantigens: Mechanisms and Insights

DTIC Science & Technology

2016-12-02

cells , resulting in polyclonal T- cell activation [4-6]. Staphylococcal superantigens hyperactivate cells of the innate immune system and adaptive T... innate host defense responses, antiviral genes, apoptotic programs, immunoproteasomes, and has many immunomodulatory functions. The cell death...1692. 104. Mendis C, Das R, Hammamieh R, Royaee A, Yang D, Peel S, et al. Transcriptional response signature of human lymphoid cells to

The role of the Fas/FasL signaling pathway in environmental toxicant-induced testicular cell apoptosis: An update.

PubMed

Wang, Mei; Su, Ping

2018-04-01

The Fas/FasL signaling pathway is one of the major pathways that regulate apoptosis. Increasing studies have shown that the activation of the Fas/FasL signaling pathway is closely associated with testicular cell apoptosis. However, the mechanism involved is still unclear. We discuss recent findings regarding the molecular mechanisms by which environmental toxicants induce testicular pathology via Fas/FasL signaling. These findings suggest that Fas/FasL signaling is employed to impact the sensitivity (a response to external factors) of germ cells, disrupt steroidogenic hormone and cytokine metabolism mediated by Sertoli cells, and elicit the activation of NFAT (nuclear factor of activated T-cells) in Leydig cell apoptosis. Consequently, degeneration of testicular somatic (Sertoli and Leydig) and spermatogenic cells, leads to decreased numbers of mature sperm and subsequently translates into infertility issues. Collectively, these findings illustrate that it is beneficial to develop potential targets for a new generation of new pharmaceutical therapies that would alleviate testicular dysfunctions. BTB: blood-testis barrier; DD: death domains; DR3: death receptor 3; DR4: death receptor 4; DR5: death receptor 5; DED: death effector domain; DISC: death-inducing signaling complex; ERα: estrogen receptor alpha; FADD: Fas-associated death domain; FSH: follicle- stimulating hormone; IL-1β: interleukin 1 beta; LH: luteinizing hormone; LPS: lipopolysaccharide; mFas: membrane Fas; MMP2: matrix metalloproteinase-2; MTA1: metastasis-associated protein 1; NAC: N-acetylcysteine; NCCD: the Nomenclature Committee on Cell Death; NFAT: nuclear factor of activated T-cells; NF-kB: nuclear transcription factor-kappaB; NO: nitric oxide; NP: 4-nonylphenol; PCD: programmed cell death; PP1/PP2A: protein phosphatase 1 and 2A; ROS: reactive oxygen species; sFas: soluble Fas; T: testosterone; TGF-β: transforming growth factor-beta; THD: TNF homology domain; TIMP-2: tissue inhibitor of metalloproteinase-2; TNF: tumor necrosis factor; TNF-α: tumor necrosis factor-alpha; TNF-R1: Tumor necrosis factor receptor 1; TNFRSF1A: TNF receptor superfamily member 1A.

RIG-I-like helicases induce immunogenic cell death of pancreatic cancer cells and sensitize tumors toward killing by CD8+ T cells

PubMed Central

Duewell, P; Steger, A; Lohr, H; Bourhis, H; Hoelz, H; Kirchleitner, S V; Stieg, M R; Grassmann, S; Kobold, S; Siveke, J T; Endres, S; Schnurr, M

2014-01-01

Pancreatic cancer is characterized by a microenvironment suppressing immune responses. RIG-I-like helicases (RLH) are immunoreceptors for viral RNA that induce an antiviral response program via the production of type I interferons (IFN) and apoptosis in susceptible cells. We recently identified RLH as therapeutic targets of pancreatic cancer for counteracting immunosuppressive mechanisms and apoptosis induction. Here, we investigated immunogenic consequences of RLH-induced tumor cell death. Treatment of murine pancreatic cancer cell lines with RLH ligands induced production of type I IFN and proinflammatory cytokines. In addition, tumor cells died via intrinsic apoptosis and displayed features of immunogenic cell death, such as release of HMGB1 and translocation of calreticulin to the outer cell membrane. RLH-activated tumor cells led to activation of dendritic cells (DCs), which was mediated by tumor-derived type I IFN, whereas TLR, RAGE or inflammasome signaling was dispensable. Importantly, CD8α+ DCs effectively engulfed apoptotic tumor material and cross-presented tumor-associated antigen to naive CD8+ T cells. In comparison, tumor cell death mediated by oxaliplatin, staurosporine or mechanical disruption failed to induce DC activation and antigen presentation. Tumor cells treated with sublethal doses of RLH ligands upregulated Fas and MHC-I expression and were effectively sensitized towards Fas-mediated apoptosis and cytotoxic T lymphocyte (CTL)-mediated lysis. Vaccination of mice with RLH-activated tumor cells induced protective antitumor immunity in vivo. In addition, MDA5-based immunotherapy led to effective tumor control of established pancreatic tumors. In summary, RLH ligands induce a highly immunogenic form of tumor cell death linking innate and adaptive immunity. PMID:25012502

What a Shock: No Apoptosis without Heat Shock Protein 90α | Center for Cancer Research

Cancer.gov

Apoptosis, also known as programmed cell death, consists of a series of reactions designed to systematically chop up a cell and its contents. The process is used to eliminate specific cells during development or to remove old or damaged cells without harming any surrounding cells. Since cancer cells can develop mechanisms to avoid apoptosis, researchers may be able to identify

Tumor necrosis factor (TNF) biology and cell death.

PubMed

Bertazza, Loris; Mocellin, Simone

2008-01-01

Tumor necrosis factor (TNF) was the first cytokine to be used in humans for cancer therapy. However, its role in the treatment of cancer patients is debated. Most uncertainties in this field stem from the knowledge that the pathways directly activated or indirectly affected upon TNF engagement with its receptors can ultimately lead to very different outcomes in terms of cell survival. In this article, we summarize the fundamental molecular biology aspects of this cytokine. Such a basis is a prerequisite to critically approach the sometimes conflicting preclinical and clinical findings regarding the relationship between TNF, tumor biology and anticancer therapy. Although the last decade has witnessed remarkable advances in this field, we still do not know in detail how cells choose between life and death after TNF stimulation. Understanding this mechanism will not only shed new light on the physiological significance of TNF-driven programmed cell death but also help investigators maximize the anticancer potential of this cytokine.

Molecular mechanisms and functions of pyroptosis, inflammatory caspases and inflammasomes in infectious diseases

PubMed Central

Man, Si Ming; Karki, Rajendra; Kanneganti, Thirumala-Devi

2017-01-01

SUMMARY Cell death is a fundamental biological phenomenon that is essential for the survival and development of an organism. Emerging evidence also indicate that cell death contributes to immune defense against infectious diseases. Pyroptosis is a form of inflammatory programed cell death pathway activated by human and mouse caspase-1, human caspase-4 and caspase-5, or mouse caspase-11. These inflammatory caspases are used by the host to control bacterial, viral, fungal or protozoan pathogens. Pyroptosis requires cleavage and activation of the pore-forming effector protein gasdermin D by inflammatory caspases. Physical rupture of the cell causes release of the pro-inflammatory cytokines IL-1β and IL-18, alarmins and endogenous danger-associated molecular patterns, signifying the inflammatory potential of pyroptosis. Here, we describe the central role of inflammatory caspases and pyroptosis in mediating immunity to infection and clearance of pathogens. PMID:28462526

Ongoing clinical trials of PD-1 and PD-L1 inhibitors for lung cancer in China.

PubMed

Liu, Si-Yang; Wu, Yi-Long

2017-07-05

Compared to chemotherapy, promising results have been obtained by blocking the PD-1 pathway using antibodies that inhibit programmed cell death protein 1 (PD-1) or programmed cell death protein ligand 1 (PD-L1). Furthermore, global researchers and doctors are exploring how to optimize this immunotherapy in 270 clinical studies. However, Chinese clinical trials of these agents remain in the early stages. We summarize the ongoing international and domestic clinical trials using PD-1 and PD-L1 inhibitors to treat lung cancer. This information can help researchers better understand the active and approved clinical trials in China, as well as the ongoing research regarding PD-1 and PD-L1 inhibitors.

Programmed death ligand 1 expression and CD8+ tumor-infiltrating lymphocyte density differences between paired primary and brain metastatic lesions in non-small cell lung cancer.

PubMed

Zhou, Jie; Gong, Zhihua; Jia, Qingzhu; Wu, Yan; Yang, Zhen-Zhou; Zhu, Bo

2018-04-15

Immunotherapy targeting the programmed cell death-1/programmed death ligand 1(PD-L1) pathway has shown promising antitumor activity in brain metastases (BMs) of non-small cell lung cancer (NSCLC) patients with an acceptable safety profile; however, the response rates often differ between primary lesions and intracranial lesions. Studies are necessary to identify detailed characterizations of the response biomarkers. In this study, we aimed to compare the differences of PD-L1 expression and CD8 + tumor-infiltrating lymphocyte (TIL) density, two major response biomarkers of PD-1/PD-L1 blockade, between paired primary and brain metastatic lesions in advanced NSCLC. We observed that among primary lesions or BMs, only a small number of patients harbored common PD-L1 expression on both tumor cells and tumor-infiltrating immune cells. Additionally, we found that the numbers of CD8 + TILs were significantly fewer in BMs than in primary lung cancers. Low stromal CD8 + TIL numbers in BMs were associated with significantly shorter overall survival compared to high stromal CD8 + TIL counts. Notably, we demonstrated a discrepancy in PD-L1 expression and CD8 + TIL density between primary lung cancers and their corresponding BMs. Such heterogeneities are significantly associated with the time at which BMs occurred. Our study emphasizes the spatial and temporal heterogeneity of biomarkers for anti-PD-1/PD-L1 therapy, which should be concerned in clinical practice. Copyright © 2018 Elsevier Inc. All rights reserved.

To Be or Not to Be: Controlling Cellular Suicide | Center for Cancer Research

Cancer.gov

When a cell is damaged and can no longer function properly, a complex series of molecular steps is triggered that allows it to die in a controlled manner. This cellular suicide is called programmed cell death, or apoptosis.

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

PubMed

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.

Detection of high PD-L1 expression in oral cancers by a novel monoclonal antibody L1Mab-4.

PubMed

Yamada, Shinji; Itai, Shunsuke; Kaneko, Mika K; Kato, Yukinari

2018-03-01

Programmed cell death-ligand 1 (PD-L1), which is a ligand of programmed cell death-1 (PD-1), is a type I transmembrane glycoprotein that is expressed on antigen-presenting cells and several tumor cells, including melanoma and lung cancer cells. There is a strong correlation between human PD-L1 (hPD-L1) expression on tumor cells and negative prognosis in cancer patients. In this study, we produced a novel anti-hPD-L1 monoclonal antibody (mAb), L 1 Mab-4 (IgG 2b , kappa), using cell-based immunization and screening (CBIS) method and investigated hPD-L1 expression in oral cancers. L 1 Mab-4 reacted with oral cancer cell lines (Ca9-22, HO-1-u-1, SAS, HSC-2, HSC-3, and HSC-4) in flow cytometry and stained oral cancers in a membrane-staining pattern. L 1 Mab-4 stained 106/150 (70.7%) of oral squamous cell carcinomas, indicating the very high sensitivity of L 1 Mab-4. These results indicate that L 1 Mab-4 could be useful for investigating the function of hPD-L1 in oral cancers.

Apoptosis: its role in pituitary development and neoplastic pituitary tissue.

PubMed

Guzzo, M F; Carvalho, L R S; Bronstein, M D

2014-04-01

Apoptosis, also known as programmed cell death, is a phenomenon in which different stimuli trigger cellular mechanisms that culminate in death, in the absence of inflammatory cell response. Two different activation pathways are known, the intrinsic pathway (or mitochondrial) and extrinsic (or death-receptor pathway), both pathways trigger enzymatic reactions that lead cells to break up and be phagocytized by neighboring cells. This process is a common occurrence in physiological and pathological states, participating in the control of cell proliferation, differentiation and remodeling of organs. In the early steps of pituitary gland formation, numerous apoptotic cells are detected in the separation of Rathke's pouch from the roof of oral ectoderm. In the distal part of the gland, which will form the adenohypophysis, the ratio of apoptosis was significantly lower. However, there is evidence that neoplastic pituitary cells undergo unbalance in genes that control apoptosis leading to uncontrolled cell growth. No direct evidence of apoptosis was found in the drugs used for tumors producing prolactin and growth hormone. In conclusion, an unbalancing in the apoptosis process is the boundary between development and tumor growth.

IKKβ and NFκB transcription govern lymphoma cell survival through AKT-induced plasma membrane trafficking of GLUT1

PubMed Central

Sommermann, Thomas; O’Neill, Kathleen; Plas, David R.; Cahir-McFarland, Ellen

2011-01-01

All cancer cells require increased nutrient uptake to support proliferation. Here we investigated the signals that govern glucose uptake in B-cell lymphomas and determined that the protein kinase IKKβ induced GLUT1 membrane trafficking in both viral and spontaneous B-cell lymphomas. IKKβ induced AKT activity, while IKKβ-driven NFκB transcription was required for GLUT1 surface localization downstream of AKT. Activated NFκB promoted AKT-mediated phosphorylation of the GLUT1 regulator, AKT Substrate 160kD (AS160), but was not required for AKT phosphorylation of the mammalian target of rapamycin (mTOR) regulator Tuberous Sclerosis 2 (TSC2). In Epstein Barr virus (EBV) transformed B-cells, NFκB inhibition repressed glucose uptake and induced caspase-independent cell death associated with autophagy. After NFκB inhibition, an alternate carbon source ameliorated both autophagy and cell death, whereas autophagy inhibitors specifically accelerated cell death. Taken together, the results suggest that NFκB signaling establishes a metabolic program supporting proliferation and apoptosis resistance by driving glucose import. PMID:21987722

Treatment-Induced Autophagy Associated with Tumor Dormancy and Relapse

DTIC Science & Technology

2016-07-01

Payne KK. Cancer immunotherapy: re-programming cells of the innate and adaptive immune systems. Oncoimmunology 1(2):201-204, 2012. Mast EE, Margolis HS...2012) Innate IFN-g is essential for programmed death ligand-1-mediated T cell stimulation following Listeria monocytogenes infection. J. Immunol. 189...immunoediting and escape. Adoptive  immunotherapy (AIT) was also found to support regression of ADR‐induced dormant tumor  cells .  15. SUBJECT TERMS Autophagy

PD-1 regulates extrathymic regulatory T-cell differentiation

PubMed Central

Chen, Xiufen; Fosco, Dominick; Kline, Douglas E.; Meng, Liping; Nishi, Saki; Savage, Peter A.; Kline, Justin

2014-01-01

Regulatory T (Treg) cells and the programmed death-1/programmed death ligand-1 (PD-1/PD-L1) pathway are both critical for maintaining peripheral tolerance to self antigens. A significant subset of Treg cells constitutively expresses PD-1, which prompted an investigation into the role of PD-1/PD-L1 interactions in Treg-cell development, function and induction in vivo. The phenotype and abundance of Treg cells was not significantly altered in PD-1-deficient mice. The thymic development of polyclonal and monospecific Treg cells was not negatively impacted by PD-1 deficiency. The suppressive function of PD-1−/− Treg cells was similar to their PD-1+/+ counterparts both in vitro and in vivo. However, in three different in vivo experimental settings, PD-1−/− conventional CD4+ T cells demonstrated a strikingly diminished tendency toward differentiation into peripherally induced Treg (pTreg) cells. Our results demonstrate that PD-1 is dispensable for thymic (tTreg) Treg-cell development and suppressive function, but is critical for the extrathymic differentiation of pTreg cells in vivo. These data suggest that antibody blockade of the PD-1/PD-L1 pathway may augment T-cell responses by acting directly on conventional T cells, and also by suppressing the differentiation of pTreg cells. PMID:24975127

Necroptotic cells release find-me signal and are engulfed without proinflammatory cytokine production.

PubMed

Wang, Qiang; Ju, Xiaoli; Zhou, Yang; Chen, Keping

2015-11-01

Necroptosis is a form of caspase-independent programmed cell death which is mediated by the RIP1-RIP3 complex. Although phagocytosis of apoptotic cells has been extensively investigated, how necroptotic cells are engulfed has remained elusive. Here, we investigated how necroptotic cells attracted and were engulfed by macrophages. We found that necroptotic cells induced the migration of THP-1 cells in a transwell migration assay. Further analysis showed that ATP released from necroptotic cells acted as a find-me signal that induced the migration of THP-1 cells. We also found that Annexin V blocked phagocytosis of necroptotic cells by macrophages. Furthermore, necroptotic cells were shown to be silently cleared by macrophages without any proinflammatory cytokine production. These data uncover an evolutionarily conserved mechanism of the find-me signal in different types of cell death and immunological consequences between apoptotic and necroptotic cells during phagocytosis.

Programmed cell death progressively models the development of anther sporophytic tissues from the tapetum and is triggered in pollen grains during maturation.

PubMed

Varnier, Anne-Lise; Mazeyrat-Gourbeyre, Florence; Sangwan, Rajbir S; Clément, Christophe

2005-11-01

To characterize the spatial and temporal occurrence of programmed cell death (PCD) in Lilium anther tissues, we used both microscopical and molecular markers of apoptosis for developmental stages from meiosis to pollen release. The first hallmarks of PCD include cell condensation and shrinkage of the cytoplasm, separation of chromatin into delineated masses, and DNA fragmentation in the tapetum as early as the premeiosis stage. PCD then extended to other anther sporophytic tissues, leading to anther dehiscence. Although the PCD clearly affected the endothecium and the epidermis, these two cell layers remained alive until anther dehiscence. In pollen, no sign of PCD was found until pollen mitosis I, after what apoptotic features developed progressively in the vegetative cell. In addition, DNA ladders were detected in all sporophytic tissues and cell types throughout pollen development, whereas in the male gametophyte DNA ladders were only detected during pollen maturation. Our data suggest that PCD is a progressive and active process affecting all the anther tissues, first being triggered in the tapetum.

Rapidly responsive silk fibroin hydrogels as an artificial matrix for the programmed tumor cells death.

PubMed

Ribeiro, Viviana P; Silva-Correia, Joana; Gonçalves, Cristiana; Pina, Sandra; Radhouani, Hajer; Montonen, Toni; Hyttinen, Jari; Roy, Anirban; Oliveira, Ana L; Reis, Rui L; Oliveira, Joaquim M

2018-01-01

Timely and spatially-regulated injectable hydrogels, able to suppress growing tumors in response to conformational transitions of proteins, are of great interest in cancer research and treatment. Herein, we report rapidly responsive silk fibroin (SF) hydrogels formed by a horseradish peroxidase (HRP) crosslinking reaction at physiological conditions, and demonstrate their use as an artificial biomimetic three-dimensional (3D) matrix. The proposed SF hydrogels presented a viscoelastic nature of injectable hydrogels and spontaneous conformational changes from random coil to β-sheet conformation under physiological conditions. A human neuronal glioblastoma (U251) cell line was used for screening cell encapsulation and in vitro evaluation within the SF hydrogels. The transparent random coil SF hydrogels promoted cell viability and proliferation up to 10 days of culturing, while the crystalline SF hydrogels converted into β-sheet structure induced the formation of TUNEL-positive apoptotic cells. Therefore, this work provides a powerful tool for the investigation of the microenvironment on the programed tumor cells death, by using rapidly responsive SF hydrogels as 3D in vitro tumor models.

Drosophila caspases involved in developmentally regulated programmed cell death of peptidergic neurons during early metamorphosis.

PubMed

Lee, Gyunghee; Wang, Zixing; Sehgal, Ritika; Chen, Chun-Hong; Kikuno, Keiko; Hay, Bruce; Park, Jae H

2011-01-01

A great number of obsolete larval neurons in the Drosophila central nervous system are eliminated by developmentally programmed cell death (PCD) during early metamorphosis. To elucidate the mechanisms of neuronal PCD occurring during this period, we undertook genetic dissection of seven currently known Drosophila caspases in the PCD of a group of interneurons (vCrz) that produce corazonin (Crz) neuropeptide in the ventral nerve cord. The molecular death program in the vCrz neurons initiates within 1 hour after pupariation, as demonstrated by the cytological signs of cell death and caspase activation. PCD was significantly suppressed in dronc-null mutants, but not in null mutants of either dredd or strica. A double mutation lacking both dronc and strica impaired PCD phenotype more severely than did a dronc mutation alone, but comparably to a triple dredd/strica/dronc mutation, indicating that dronc is a main initiator caspase, while strica plays a minor role that overlaps with dronc's. As for effector caspases, vCrz PCD requires both ice and dcp-1 functions, as they work cooperatively for a timely removal of the vCrz neurons. Interestingly, the activation of the Ice and Dcp-1 is not solely dependent on Dronc and Strica, implying an alternative pathway to activate the effectors. Two remaining effector caspase genes, decay and damm, found no apparent functions in the neuronal PCD, at least during early metamorphosis. Overall, our work revealed that vCrz PCD utilizes dronc, strica, dcp-1, and ice wherein the activation of Ice and Dcp-1 requires a novel pathway in addition to the initiator caspases.

Evaluation of programmed cell death protein 1 (PD-1) expression as a prognostic biomarker in patients with clear cell renal cell carcinoma.

PubMed

Kim, Kyu Seo; Sekar, Rishi R; Patil, Dattatraya; Dimarco, Michelle A; Kissick, Haydn T; Bilen, Mehmet A; Osunkoya, Adeboye O; Master, Viraj A

2018-01-01

Programmed cell death protein 1 (PD-1) immune checkpoint inhibitors have shown activity in patients with advanced renal cell carcinoma (RCC). However, the role of PD-1 expression in tumor-infiltrating lymphocytes (TILs) as a biomarker for poor outcome is not clear. In this study, we evaluated the prognostic value of TIL PD-1 expression in patients with clear cell RCC (ccRCC). 82 patients who underwent nephrectomy for localized or metastatic ccRCC and followed up for at least four years were searched from our database and retrospectively enrolled. Their fixed primary tumor specimens were stained with anti-PD-1 (NAT105). The specimens were classified as negative or positive for PD-1 expression, and the positive specimens were further scored in 10% increments. 37 (45.12%) patients were negative (<1% stained), 26 (31.71%) patients were low (<10 and 10%), and 19 (23.17%) patients were high (20-50%) for PD-1 expression. The prognostic value of TIL PD-1 expression was evaluated by univariate Cox proportional hazards regression on overall and recurrence-free survivals. Higher TIL PD-1 expression was not associated with increased risk of death (P = 0.336) or with increased risk of recurrence (P = 0.572). Higher primary tumor stage was associated with increased risk of recurrence (P = 0.003), and higher Fuhrman nuclear grade was associated with increased risk of death (P <0.001) and with increased risk of recurrence (P <0.001). Our study shows that TIL PD-1 expression by immunohistochemistry (IHC) does not correlate with poor clinical outcome in patients with ccRCC and is inferior to established prognosticating tools.

Heme induces programmed necrosis on macrophages through autocrine TNF and ROS production

PubMed Central

Fortes, Guilherme B.; Alves, Leticia S.; de Oliveira, Rosane; Dutra, Fabianno F.; Rodrigues, Danielle; Fernandez, Patricia L.; Souto-Padron, Thais; De Rosa, María José; Kelliher, Michelle; Golenbock, Douglas; Chan, Francis K. M.

2012-01-01

Diseases that cause hemolysis or myonecrosis lead to the leakage of large amounts of heme proteins. Free heme has proinflammatory and cytotoxic effects. Heme induces TLR4-dependent production of tumor necrosis factor (TNF), whereas heme cytotoxicity has been attributed to its ability to intercalate into cell membranes and cause oxidative stress. We show that heme caused early macrophage death characterized by the loss of plasma membrane integrity and morphologic features resembling necrosis. Heme-induced cell death required TNFR1 and TLR4/MyD88-dependent TNF production. Addition of TNF to Tlr4−/− or to Myd88−/− macrophages restored heme-induced cell death. The use of necrostatin-1, a selective inhibitor of receptor-interacting protein 1 (RIP1, also known as RIPK1), or cells deficient in Rip1 or Rip3 revealed a critical role for RIP proteins in heme-induced cell death. Serum, antioxidants, iron chelation, or inhibition of c-Jun N-terminal kinase (JNK) ameliorated heme-induced oxidative burst and blocked macrophage cell death. Macrophages from heme oxygenase-1 deficient mice (Hmox1−/−) had increased oxidative stress and were more sensitive to heme. Taken together, these results revealed that heme induces macrophage necrosis through 2 synergistic mechanisms: TLR4/Myd88-dependent expression of TNF and TLR4-independent generation of ROS. PMID:22262768

A mechanistic study on the effect of dexamethasone in moderating cell death in Chinese Hamster Ovary cell cultures.

PubMed

Jing, Ying; Qian, Yueming; Ghandi, Mahmoud; He, Aiqing; Borys, Michael C; Pan, Shih-Hsie; Li, Zheng Jian

2012-01-01

Dexamethasone (DEX) was previously shown (Jing et al., Biotechnol Bioeng. 2010;107:488-496) to play a dual role in increasing sialylation of recombinant glycoproteins produced by Chinese Hamster Ovary (CHO) cells. DEX addition increased sialic acid levels of a recombinant fusion protein through increased expression of α2,3-sialyltransferase and β1,4-galactosyltransferase, but also decreased the sialidase-mediated, extracellular degradation of sialic acid through slowing cell death at the end of the culture period. This study examines the underlying mechanism for this cytoprotective action by studying the transcriptional response of the CHO cell genome upon DEX treatment using DNA microarrays and gene ontology term analysis. Many of those genes showing a significant transcriptional response were associated with the regulation of programmed cell death. The gene with the highest change in expression level, as validated by Quantitative PCR assays with TaqMan® probes and confirmed by Western Blot analysis, was the antiapoptotic gene Tsc22d3, also referred to as GILZ (glucocorticoid-induced leucine zipper). The pathway by which DEX suppressed cell death towards the end of the culture period was also confirmed by showing involvement of glucocorticoid receptors and GILZ through studies using the glucocorticoid antagonist mifepristone (RU-486). These findings advance the understanding of the mechanism by which DEX suppresses cell death in CHO cells and provide a rationale for the application of glucocorticoids in CHO cell culture processes. Copyright © 2011 American Institute of Chemical Engineers (AIChE).

Renal Cell Carcinoma Programmed Death-ligand 1, a New Direct Target of Hypoxia-inducible Factor-2 Alpha, is Regulated by von Hippel-Lindau Gene Mutation Status.

PubMed

Messai, Yosra; Gad, Sophie; Noman, Muhammad Zaeem; Le Teuff, Gwenael; Couve, Sophie; Janji, Bassam; Kammerer, Solenne Florence; Rioux-Leclerc, Nathalie; Hasmim, Meriem; Ferlicot, Sophie; Baud, Véronique; Mejean, Arnaud; Mole, David Robert; Richard, Stéphane; Eggermont, Alexander M M; Albiges, Laurence; Mami-Chouaib, Fathia; Escudier, Bernard; Chouaib, Salem

2016-10-01

Clear cell renal cell carcinomas (ccRCC) frequently display a loss of function of the von Hippel-Lindau (VHL) gene. To elucidate the putative relationship between VHL mutation status and immune checkpoint ligand programmed death-ligand 1 (PD-L1) expression. A series of 32 renal tumors composed of 11 VHL tumor-associated and 21 sporadic RCCs were used to evaluate PD-L1 expression levels after sequencing of the three exons and exon-intron junctions of the VHL gene. The 786-O, A498, and RCC4 cell lines were used to investigate the mechanisms of PD-L1 regulation. Fisher's exact test was used for VHL mutation and Kruskal-Wallis test for PD-L1 expression. If no covariate accounted for the association of VHL and PD-L1, then a Kruskal-Wallis test was used; otherwise Cochran-Mantel-Haenzsel test was used. We also used the Fligner-Policello test to compare two medians when the distributions had different dispersions. We demonstrated that tumors from ccRCC patients with VHL biallelic inactivation (ie, loss of function) display a significant increase in PD-L1 expression compared with ccRCC tumors carrying one VHL wild-type allele. Using the inducible VHL 786-O-derived cell lines with varying hypoxia-inducible factor-2 alpha (HIF-2α) stabilization levels, we showed that PD-L1 expression levels positively correlate with VHL mutation and HIF-2α expression. Targeting HIF-2α decreased PD-L1, while HIF-2α overexpression increased PD-L1 mRNA and protein levels in ccRCC cells. Interestingly, chromatin immunoprecipitation and luciferase assays revealed a direct binding of HIF-2α to a transcriptionally active hypoxia-response element in the human PD-L1 proximal promoter in 786-O cells. Our work provides the first evidence that VHL mutations positively correlate with PD-L1 expression in ccRCC and may influence the response to ccRCC anti-PD-L1/PD-1 immunotherapy. We investigated the relationship between von Hippel-Lindau mutations and programmed death-ligand 1 expression. We demonstrated that von Hippel-Lindau mutation status significantly correlated with programmed death-ligand 1 expression in clear cell renal cell carcinomas. Copyright © 2015 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Induction of autophagy by spermidine promotes longevity.

PubMed

Eisenberg, Tobias; Knauer, Heide; Schauer, Alexandra; Büttner, Sabrina; Ruckenstuhl, Christoph; Carmona-Gutierrez, Didac; Ring, Julia; Schroeder, Sabrina; Magnes, Christoph; Antonacci, Lucia; Fussi, Heike; Deszcz, Luiza; Hartl, Regina; Schraml, Elisabeth; Criollo, Alfredo; Megalou, Evgenia; Weiskopf, Daniela; Laun, Peter; Heeren, Gino; Breitenbach, Michael; Grubeck-Loebenstein, Beatrix; Herker, Eva; Fahrenkrog, Birthe; Fröhlich, Kai-Uwe; Sinner, Frank; Tavernarakis, Nektarios; Minois, Nadege; Kroemer, Guido; Madeo, Frank

2009-11-01

Ageing results from complex genetically and epigenetically programmed processes that are elicited in part by noxious or stressful events that cause programmed cell death. Here, we report that administration of spermidine, a natural polyamine whose intracellular concentration declines during human ageing, markedly extended the lifespan of yeast, flies and worms, and human immune cells. In addition, spermidine administration potently inhibited oxidative stress in ageing mice. In ageing yeast, spermidine treatment triggered epigenetic deacetylation of histone H3 through inhibition of histone acetyltransferases (HAT), suppressing oxidative stress and necrosis. Conversely, depletion of endogenous polyamines led to hyperacetylation, generation of reactive oxygen species, early necrotic death and decreased lifespan. The altered acetylation status of the chromatin led to significant upregulation of various autophagy-related transcripts, triggering autophagy in yeast, flies, worms and human cells. Finally, we found that enhanced autophagy is crucial for polyamine-induced suppression of necrosis and enhanced longevity.

Development of Halo Nevi in a Lung Cancer Patient: A Novel Immune-Related Cutaneous Event from Atezolizumab.

PubMed

Birnbaum, Mathew R; Ma, Michelle W; Casey, Michael A; Amin, Bijal D; Jacobson, Mark; Cheng, Haiying; McLellan, Beth N

2017-10-01

Immunotherapy-induced vitiligo is an immune-related adverse event (irAE) observed in metastatic melanoma patients treated with immune checkpoint inhibitors that target the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death-1 (PD-1) pathways. To date, the development of leukoderma, poliosis, and halo nevi during immunotherapy has largely been reported in metastatic melanoma patients. We report a case of immunotherapy-induced leukoderma presenting as halo nevi in a patient with non-small cell lung cancer (NSCLC) treated with atezolizumab, a programmed cell death ligand (PD-L1) antibody. Immunotherapy-induced vitiligo in metastatic melanoma patients may be associated with improved survival, but it remains to be determined whether its occurrence in non-melanoma cancers has the same prognostic significance.

J Drugs Dermatol. 2017;16(10):1047-1049.

Cell death and immunity in cancer: From danger signals to mimicry of pathogen defense responses.

PubMed

Garg, Abhishek D; Agostinis, Patrizia

2017-11-01

The immunogenicity of cancer cells is an emerging determinant of anti-cancer immunotherapy. Beyond developing immunostimulatory regimens like dendritic cell-based vaccines, immune-checkpoint blockers, and adoptive T-cell transfer, investigators are beginning to focus on the immunobiology of dying cancer cells and its relevance for the success of anticancer immunotherapies. It is currently accepted that cancer cells may die in response to anti-cancer therapies through regulated cell death programs, which may either repress or increase their immunogenic potential. In particular, the induction of immunogenic cancer cell death (ICD), which is hallmarked by the emission of damage-associated molecular patterns (DAMPs); molecules analogous to pathogen-associated molecular patterns (PAMPs) acting as danger signals/alarmins, is of great relevance in cancer therapy. These ICD-associated danger signals favor immunomodulatory responses that lead to tumor-associated antigens (TAAs)-directed T-cell immunity, which paves way for the removal of residual, treatment-resistant cancer cells. It is also emerging that cancer cells succumbing to ICD can orchestrate "altered-self mimicry" i.e. mimicry of pathogen defense responses, on the levels of nucleic acids and/or chemokines (resulting in type I interferon/IFN responses or pathogen response-like neutrophil activity). In this review, we exhaustively describe the main molecular, immunological, preclinical, and clinical aspects of immunosuppressive cell death or ICD (with respect to apoptosis, necrosis and necroptosis). We also provide an extensive historical background of these fields, with special attention to the self/non-self and danger models, which have shaped the field of cell death immunology. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Expression of programmed cell death ligand 1 is associated with poor overall survival in patients with diffuse large B-cell lymphoma

PubMed Central

Kiyasu, Junichi; Miyoshi, Hiroaki; Hirata, Akie; Arakawa, Fumiko; Ichikawa, Ayako; Niino, Daisuke; Sugita, Yasuo; Yufu, Yuji; Choi, Ilseung; Abe, Yasunobu; Uike, Naokuni; Nagafuji, Koji; Okamura, Takashi; Akashi, Koichi; Takayanagi, Ryoichi; Shiratsuchi, Motoaki

2015-01-01

Programmed cell death ligand 1 (PD-L1) is expressed on both select diffuse large B-cell lymphoma (DLBCL) tumor cells and on tumor-infiltrating nonmalignant cells. The programmed cell death 1 (PD-1)/PD-L1 pathway inhibits host antitumor responses; however, little is known about how this pathway functions in the tumor microenvironment. The aim of this study was to determine the clinicopathological impact of PD-L1+ DLBCL. We performed PD-L1/PAX5 double immunostaining in 1253 DLBCL biopsy samples and established a new definition of PD-L1+ DLBCL. We also defined the criteria for microenvironmental PD-L1+ (mPD-L1+) DLBCL (ie, PD-L1– DLBCL in which PD-L1+ nonmalignant cells are abundant in the tumor microenvironment). Of the 273 patients whose clinical information was available, quantitative analysis of PD-1+ tumor-infiltrating lymphocytes (TILs) was performed. The prevalence rates of PD-L1+ and mPD-L1+ DLBCL were 11% and 15.3%, respectively. Both PD-L1+ and mPD-L1+ DLBCL were significantly associated with non–germinal center B-cell (GCB) type and Epstein-Barr virus positivity. The number of PD-1+ TILs was significantly higher in GCB-type tumors and lower in mPD-L1– and PD-L1+ DLBCL. Patients with PD-L1+ DLBCL had inferior overall survival (OS) compared with that in patients with PD-L1– DLBCL (P = .0009). In contrast, there was no significant difference in OS between mPD-L1+ and mPD-L1– DLBCL (P = .31). The expression of PD-L1 maintained prognostic value for OS in multivariate analysis (P = .0323). This is the first report describing the clinicopathological features and outcomes of PD-L1+ DLBCL. Immunotherapy targeting the PD-1/PD-L1 pathway should be considered in this distinct DLBCL subgroup. PMID:26239088

Clinical Use of Programmed Cell Death-1 and Its Ligand Expression as Discriminatory and Predictive Markers in Ovarian Cancer.

PubMed

Chatterjee, Jayanta; Dai, Wei; Aziz, Nor Haslinda Abd; Teo, Pei Yun; Wahba, John; Phelps, David L; Maine, Christian J; Whilding, Lynsey M; Dina, Roberto; Trevisan, Giorgia; Flower, Kirsty J; George, Andrew J T; Ghaem-Maghami, Sadaf

2017-07-01

Purpose: We aimed to establish whether programmed cell death-1 (PD-1) and programmed cell death ligand 1 (PD-L1) expression, in ovarian cancer tumor tissue and blood, could be used as biomarkers for discrimination of tumor histology and prognosis of ovarian cancer. Experimental Design: Immune cells were separated from blood, ascites, and tumor tissue obtained from women with suspected ovarian cancer and studied for the differential expression of possible immune biomarkers using flow cytometry. PD-L1 expression on tumor-associated inflammatory cells was assessed by immunohistochemistry and tissue microarray. Plasma soluble PD-L1 was measured using sandwich ELISA. The relationships among immune markers were explored using hierarchical cluster analyses. Results: Biomarkers from the discovery cohort that associated with PD-L1 + cells were found. PD-L1 + CD14 + cells and PD-L1 + CD11c + cells in the monocyte gate showed a distinct expression pattern when comparing benign tumors and epithelial ovarian cancers (EOCs)-confirmed in the validation cohort. Receiver operating characteristic curves showed PD-L1 + and PD-L1 + CD14 + cells in the monocyte gate performed better than the well-established tumor marker CA-125 alone. Plasma soluble PD-L1 was elevated in patients with EOC compared with healthy women and patients with benign ovarian tumors. Low total PD-1 + expression on lymphocytes was associated with improved survival. Conclusions: Differential expression of immunological markers relating to the PD-1/PD-L1 pathway in blood can be used as potential diagnostic and prognostic markers in EOC. These data have implications for the development and trial of anti-PD-1/PD-L1 therapy in ovarian cancer. Clin Cancer Res; 23(13); 3453-60. ©2016 AACR . ©2016 American Association for Cancer Research.

Genetic mapping of paternal sorting of mitochondria in cucumber

USDA-ARS?s Scientific Manuscript database

Mitochondria are organelles that have their own DNA; serve as the powerhouses of eukaryotic cells; play important roles in stress responses, programmed cell death, and ageing; and in the vast majority of eukaryotes, are maternally transmitted. Strict maternal transmission of mitochondria makes it di...

Cucumber as a Model for Organellar Genetics

USDA-ARS?s Scientific Manuscript database

Mitochondria are found in the cells of all eukaryotes, are imperative for energy production, and play important roles in programmed cell death, ageing, and disease development. Mitochondria possess their own DNA and encode for approximately 20 proteins, as well as their own ribosomal and transfer R...

A case of fulminant Type 1 diabetes following anti-PD1 immunotherapy in a genetically susceptible patient.

PubMed

Araújo, Manuel; Ligeiro, Dário; Costa, Luís; Marques, Filipa; Trindade, Helder; Correia, José Manuel; Fonseca, Candida

2017-06-01

Programmed cell death-1 protein (PD-1) is an immune checkpoint that has gained popularity in the treatment of several advanced cancers. Inhibiting this checkpoint is known to enhance immune response, but is also known to diminish immune tolerance and to increase autoimmune toxicity. We discuss a case of rapid onset fulminant Type 1 diabetes induced by treatment with anti-programmed cell death-1 monoclonal antibody, nivolumab, in a patient with late-stage non-small-cell lung adenocarcinoma. The patient had no history of previous diabetes but did reveal a high-risk genotype for Type 1 diabetes development (DR3-DQ2; DR4-DQ8). This finding supports that acute Type 1 diabetes can be an important adverse effect of immunotherapies targeting T-cell activation regulation. Because of the severity of this adverse effect, physicians should be aware of it, and studies directed to the detection of new biomarkers for early risk stratification (e.g., HLA) should be sought.

Supportive care in the era of immunotherapies for advanced non-small-cell lung cancer.

PubMed

Awada, Gil; Klastersky, Jean

2018-03-01

The therapeutic armamentarium for advanced non-small-cell lung cancer has evolved considerably over the past years. Immune checkpoint inhibitors targeting programmed cell death-1 such as pembrolizumab and nivolumab or programmed cell death ligand 1 such as atezolizumab, durvalumab and avelumab have shown favorable efficacy results in this patient population in the first-line and second-line setting. These immunotherapies are associated with a distinct toxicity profile based on autoimmune organ toxicity which is a new challenge for supportive care during treatment with these drugs. The differential diagnosis of events occurring during immune checkpoint inhibitor treatment is broad: they can be due to immune-related or nonimmune-related adverse events, atypical tumor responses (pseudoprogression or hyperprogression) or events related to comorbidities or other treatments. The management of these patients includes a thorough baseline clinical, biological and radiologic evaluation, patient education, correct follow-up and management by a multidisciplinary team with a central role for the medical oncologist. Immune-related toxicities should be managed according to available guidelines.

Autophagy Therapeutic Potential of Garlic in Human Cancer Therapy

PubMed Central

Chu, Yung-Lin; Raghu, Rajasekaran; Lu, Kuan-Hung; Liu, Chun-Ting; Lin, Shu-Hsi; Lai, Yi-Syuan; Cheng, Wei-Cheng; Lin, Shih-Hang; Sheen, Lee-Yan

2013-01-01

Cancer is one of the deadliest diseases against humans. To tackle this menace, humans have developed several high-technology therapies, such as chemotherapy, tomotherapy, targeted therapy, and antibody therapy. However, all these therapies have their own adverse side effects. Therefore, recent years have seen increased attention being given to the natural food for complementary therapy, which have less side effects. Garlic (Dà Suàn; Allium sativum), is one of most powerful food used in many of the civilizations for both culinary and medicinal purpose. In general, these foods induce cancer cell death by apoptosis, autophagy, or necrosis. Studies have discussed how natural food factors regulate cell survival or death by autophagy in cancer cells. From many literature reviews, garlic could not only induce apoptosis but also autophagy in cancer cells. Autophagy, which is called type-II programmed cell death, provides new strategy in cancer therapy. In conclusion, we wish that garlic could be the pioneer food of complementary therapy in clinical cancer treatment and increase the life quality of cancer patients. PMID:24716172

Inositol pyrophosphates mediate the DNA-PK/ATM-p53 cell death pathway by regulating CK2 phosphorylation of Tti1/Tel2

PubMed Central

Rao, Feng; Cha, Jiyoung; Xu, Jing; Xu, Risheng; Vandiver, M. Scott; Tyagi, Richa; Tokhunts, Robert; Koldobskiy, Michael A.; Fu, Chenglai; Barrow, Roxanne; Wu, Mingxuan; Fiedler, Dorothea; Barrow, James C.; Snyder, Solomon H.

2014-01-01

The apoptotic actions of p53 require its phosphorylation by a family of phosphoinositide-3-kinase-related-kinases (PIKKs), which include DNA-PKcs and ATM. These kinases are stabilized by the TTT (Tel2, Tti1, Tti2) co-chaperone family, whose actions are mediated by CK2 phosphorylation. The inositol pyrophosphates, such as 5-diphosphoinositol pentakisphosphate (IP7), are generated by a family of inositol hexakisphosphate kinases (IP6Ks) of which IP6K2 has been implicated in p53-associated cell death. In the present study we report a novel apoptotic signaling cascade linking CK2, TTT, the PIKKs, and p53. We demonstrate that IP7, formed by IP6K2, binds CK2 to enhance its phosphorylation of the TTT complex thereby stabilizing DNA-PKcs and ATM. This process stimulates p53 phosphorylation at serine-15 to activate the cell death program in human cancer cells and in murine B cells. PMID:24657168

Altered Cytochrome c Display Precedes Apoptotic Cell Death in Drosophila

PubMed Central

Varkey, Johnson; Chen, Po; Jemmerson, Ronald; Abrams, John M.

1999-01-01

Drosophila affords a genetically well-defined system to study apoptosis in vivo. It offers a powerful extension to in vitro models that have implicated a requirement for cytochrome c in caspase activation and apoptosis. We found that an overt alteration in cytochrome c anticipates programmed cell death (PCD) in Drosophila tissues, occurring at a time that considerably precedes other known indicators of apoptosis. The altered configuration is manifested by display of an otherwise hidden epitope and occurs without release of the protein into the cytosol. Conditional expression of the Drosophila death activators, reaper or grim, provoked apoptogenic cytochrome c display and, surprisingly, caspase activity was necessary and sufficient to induce this alteration. In cell-free studies, cytosolic caspase activation was triggered by mitochondria from apoptotic cells but identical preparations from healthy cells were inactive. Our observations provide compelling validation of an early role for altered cytochrome c in PCD and suggest propagation of apoptotic physiology through reciprocal, feed-forward amplification involving cytochrome c and caspases. PMID:10037791

Autophagy therapeutic potential of garlic in human cancer therapy.

PubMed

Chu, Yung-Lin; Raghu, Rajasekaran; Lu, Kuan-Hung; Liu, Chun-Ting; Lin, Shu-Hsi; Lai, Yi-Syuan; Cheng, Wei-Cheng; Lin, Shih-Hang; Sheen, Lee-Yan

2013-07-01

Cancer is one of the deadliest diseases against humans. To tackle this menace, humans have developed several high-technology therapies, such as chemotherapy, tomotherapy, targeted therapy, and antibody therapy. However, all these therapies have their own adverse side effects. Therefore, recent years have seen increased attention being given to the natural food for complementary therapy, which have less side effects. Garlic (Dà Suàn; Allium sativum), is one of most powerful food used in many of the civilizations for both culinary and medicinal purpose. In general, these foods induce cancer cell death by apoptosis, autophagy, or necrosis. Studies have discussed how natural food factors regulate cell survival or death by autophagy in cancer cells. From many literature reviews, garlic could not only induce apoptosis but also autophagy in cancer cells. Autophagy, which is called type-II programmed cell death, provides new strategy in cancer therapy. In conclusion, we wish that garlic could be the pioneer food of complementary therapy in clinical cancer treatment and increase the life quality of cancer patients.

Natural Compounds from Herbs that can Potentially Execute as Autophagy Inducers for Cancer Therapy

PubMed Central

Fu, Yaw-Syan; Tsai, May-Jywan; Cheng, Henrich

2017-01-01

Accumulated evidence indicates that autophagy is a response of cancer cells to various anti-cancer therapies. Autophagy is designated as programmed cell death type II, and is characterized by the formation of autophagic vacuoles in the cytoplasm. Numerous herbs, including Chinese herbs, have been applied to cancer treatments as complementary and alternative medicines, supplements, or nutraceuticals to dampen the side or adverse effects of chemotherapy drugs. Moreover, the tumor suppressive actions of herbs and natural products induced autophagy that may lead to cell senescence, increase apoptosis-independent cell death or complement apoptotic processes. Hereby, the underlying mechanisms of natural autophagy inducers are cautiously reviewed in this article. Additionally, three natural compounds—curcumin, 16-hydroxycleroda-3,13-dien-15,16-olide, and prodigiosin—are presented as candidates for autophagy inducers that can trigger cell death in a supplement or alternative medicine for cancer therapy. Despite recent advancements in therapeutic drugs or agents of natural products in several cancers, it warrants further investigation in preclinical and clinical studies. PMID:28671583

Human replication protein Cdc6 is selectively cleaved by caspase 3 during apoptosis

PubMed Central

Pelizon, Cristina; d’Adda di Fagagna, Fabrizio; Farrace, Lorena; Laskey, Ronald A.

2002-01-01

In eukaryotes, the initiation of DNA replication involves the ordered assembly on chromatin of pre-replicative complexes (pre-RCs), including the origin recognition complex (ORC), Cdc6, Cdt1 and the minichromosome maintenance proteins (MCMs). In light of its indispensable role in the formation of pre-RCs, Cdc6 binding to chromatin represents a key step in the regulation of DNA replication and cell proliferation. Here, we study the human Cdc6 (HuCdc6) protein during programmed cell death (apoptosis). We find that HuCdc6, but not HuOrc2 (a member of the ORC) or HuMcm5 (one of the MCMs), is specifically cleaved in several human cell lines induced to undergo apoptosis by a variety of stimuli. Expression of caspase-uncleavable mutant HuCdc6 attenuates apoptosis, delaying cell death. Therefore, an important function for cleavage of HuCdc6 is to prevent a wounded cell from replicating and to facilitate death. PMID:12151338

Natural Compounds from Herbs that can Potentially Execute as Autophagy Inducers for Cancer Therapy.

PubMed

Lin, Shian-Ren; Fu, Yaw-Syan; Tsai, May-Jywan; Cheng, Henrich; Weng, Ching-Feng

2017-07-01

Accumulated evidence indicates that autophagy is a response of cancer cells to various anti-cancer therapies. Autophagy is designated as programmed cell death type II, and is characterized by the formation of autophagic vacuoles in the cytoplasm. Numerous herbs, including Chinese herbs, have been applied to cancer treatments as complementary and alternative medicines, supplements, or nutraceuticals to dampen the side or adverse effects of chemotherapy drugs. Moreover, the tumor suppressive actions of herbs and natural products induced autophagy that may lead to cell senescence, increase apoptosis-independent cell death or complement apoptotic processes. Hereby, the underlying mechanisms of natural autophagy inducers are cautiously reviewed in this article. Additionally, three natural compounds-curcumin, 16-hydroxycleroda-3,13-dien-15,16-olide, and prodigiosin-are presented as candidates for autophagy inducers that can trigger cell death in a supplement or alternative medicine for cancer therapy. Despite recent advancements in therapeutic drugs or agents of natural products in several cancers, it warrants further investigation in preclinical and clinical studies.

Requirement for the Murine Zinc Finger Protein ZFR in Perigastrulation Growth and Survival

PubMed Central

Meagher, Madeleine J.; Braun, Robert E.

2001-01-01

The transition from preimplantation to postimplantation development leads to the initiation of complex cellular differentiation and morphogenetic movements, a dramatic decrease in cell cycle length, and a commensurate increase in the size of the embryo. Accompanying these changes is the need for the transfer of nutrients from the mother to the embryo and the elaboration of sophisticated genetic networks that monitor genomic integrity and the homeostatic control of cellular growth, differentiation, and programmed cell death. To determine the function of the murine zinc finger protein ZFR in these events, we generated mice carrying a null mutation in the gene encoding it. Homozygous mutant embryos form normal-appearing blastocysts that implant and initiate the process of gastrulation. Mutant embryos form mesoderm but they are delayed in their development and fail to form normal anterior embryonic structures. Loss of ZFR function leads to both an increase in programmed cell death and a decrease in mitotic index, especially in the region of the distal tip of the embryonic ectoderm. Mutant embryos also have an apparent reduction in apical vacuoles in the columnar visceral endoderm cells in the extraembryonic region. Together, these cellular phenotypes lead to a dramatic development delay and embryonic death by 8 to 9 days of gestation, which are independent of p53 function. PMID:11283266

Alpha cyano-4-hydroxy-3-methoxycinnamic acid inhibits proliferation and induces apoptosis in human breast cancer cells.

PubMed

Hamdan, Lamia; Arrar, Zoheir; Al Muataz, Yacoub; Suleiman, Lutfi; Négrier, Claude; Mulengi, Joseph Kajima; Boukerche, Habib

2013-01-01

This study investigated the underlying mechanism of 4-hydroxy-3-methoxycinnamic acid (ACCA), on the growth of breast cancer cells and normal immortal epithelial cells, and compared their cytotoxic effects responses. Treatment of breast cancer cells (MCF-7, T47D, and MDA-231) with ACCA resulted in dose- and time-dependent decrease of cell proliferation, viability in colony formation assay, and programmed cell death (apoptosis) with minimal effects on non-tumoral cells. The ability of ACCA to suppress growth in cancer cells not expressing or containing defects in p53 gene indicates a lack of involvement of this critical tumor suppressor element in mediating ACCA-induced growth inhibition. Induction of apoptosis correlated with an increase in Bax protein, an established inducer of programmed cell death, and the ratio of Bax to Bcl-2, an established inhibitor of apoptosis. We also documented the ability of ACCA to inhibit the migration and invasion of MDA-231 cells with ACCA in vitro. Additionally, tumor growth of MDA-231 breast cancer cells in vivo was dramatically affected with ACCA. On the basis of its selective anticancer inhibitory activity on tumor cells, ACCA may represent a promising therapeutic drug that should be further evaluated as a chemotherapeutic agent for human breast cancer.

Alpha Cyano-4-Hydroxy-3-Methoxycinnamic Acid Inhibits Proliferation and Induces Apoptosis in Human Breast Cancer Cells

PubMed Central

Hamdan, Lamia; Arrar, Zoheir; Al Muataz, Yacoub; Suleiman, Lutfi; Négrier, Claude; Mulengi, Joseph Kajima; Boukerche, Habib

2013-01-01

This study investigated the underlying mechanism of 4-hydroxy-3-methoxycinnamic acid (ACCA), on the growth of breast cancer cells and normal immortal epithelial cells, and compared their cytotoxic effects responses. Treatment of breast cancer cells (MCF-7, T47D, and MDA-231) with ACCA resulted in dose- and time-dependent decrease of cell proliferation, viability in colony formation assay, and programmed cell death (apoptosis) with minimal effects on non-tumoral cells. The ability of ACCA to suppress growth in cancer cells not expressing or containing defects in p53 gene indicates a lack of involvement of this critical tumor suppressor element in mediating ACCA-induced growth inhibition. Induction of apoptosis correlated with an increase in Bax protein, an established inducer of programmed cell death, and the ratio of Bax to Bcl-2, an established inhibitor of apoptosis. We also documented the ability of ACCA to inhibit the migration and invasion of MDA-231 cells with ACCA in vitro. Additionally, tumor growth of MDA-231 breast cancer cells in vivo was dramatically affected with ACCA. On the basis of its selective anticancer inhibitory activity on tumor cells, ACCA may represent a promising therapeutic drug that should be further evaluated as a chemotherapeutic agent for human breast cancer. PMID:24039831

Cell Death and Heart Failure in Obesity: Role of Uncoupling Proteins

PubMed Central

Ruiz-Ramírez, Angélica; López-Acosta, Ocarol; Barrios-Maya, Miguel Angel

2016-01-01

Metabolic diseases such as obesity, metabolic syndrome, and type II diabetes are often characterized by increased reactive oxygen species (ROS) generation in mitochondrial respiratory complexes, associated with fat accumulation in cardiomyocytes, skeletal muscle, and hepatocytes. Several rodents studies showed that lipid accumulation in cardiac myocytes produces lipotoxicity that causes apoptosis and leads to heart failure, a dynamic pathological process. Meanwhile, several tissues including cardiac tissue develop an adaptive mechanism against oxidative stress and lipotoxicity by overexpressing uncoupling proteins (UCPs), specific mitochondrial membrane proteins. In heart from rodent and human with obesity, UCP2 and UCP3 may protect cardiomyocytes from death and from a state progressing to heart failure by downregulating programmed cell death. UCP activation may affect cytochrome c and proapoptotic protein release from mitochondria by reducing ROS generation and apoptotic cell death. Therefore the aim of this review is to discuss recent findings regarding the role that UCPs play in cardiomyocyte survival by protecting against ROS generation and maintaining bioenergetic metabolism homeostasis to promote heart protection. PMID:27642497

Microparticulate Caspase-1 Regulates Gasdermin-D and Pulmonary Vascular Endothelial Cell Injury.

PubMed

Mitra, Srabani; Exline, Matthew; Habyarimana, Fabien; Gavrilin, Mikhail; Baker, Paul; Masters, Seth L; Wewers, Mark D; Sarkar, Anasuya

2018-01-24

Lung endothelial cell apoptosis and injury occurs throughout all stages of acute lung injury (ALI/ARDS) and impacts disease progression. Caspases 1, 4 and 5 are essential for completion of the apoptotic program known as pyroptosis that also involves pro-inflammatory cytokines. Because GSDM-D mediates pyroptotic death and is essential for pore formation, we hypothesized that it may direct caspase-1 encapsulated microparticle (MP) release and mediate endothelial cell death. Our current work provides evidence that GSDM-D is released by LPS stimulated THP1 monocytic cells where it is packaged into microparticles along with active caspase-1. Furthermore, only MP released from stimulated monocytic cells that contain both cleaved GSDM-D and active caspase-1 induce endothelial cell apoptosis. MPs pretreated with caspase-1 inhibitor, YVAD, or pan-caspase inhibitor, ZVAD, do not contain cleaved GSDM-D. MPs from caspase-1KO cells are also deficient in p30 active GSDM-D, further confirming that caspase-1 regulates GSDM-D function. Although control MPs contained cleaved GSDM-D without caspase-1, these fractions were unable to induce cell death, suggesting that encapsulation of both caspase-1 and GSDM-D is essential for cell death induction. Release of microparticulate active caspase-1 was abrogated in GSDM-KO cells, although cytosolic caspase-1 activation was not impaired. Lastly, higher levels of microparticulate GSDM-D was detected in septic ARDS patient plasma when compared to healthy donors. Taken together, these findings suggest that GSDM-D regulates the release of microparticulate active caspase-1 from monocytes essential for induction of cell death and thereby may play a critical role in sepsis-induced endothelial cell injury.

Physiological, molecular and ultrastructural analyses during ripening and over-ripening of banana (Musa spp., AAA group, Cavendish sub-group) fruit suggest characteristics of programmed cell death.

PubMed

Ramírez-Sánchez, Maricruz; Huber, Donald J; Vallejos, C Eduardo; Kelley, Karen

2018-01-01

Programmed cell death (PCD) is a part of plant development that has been studied for petal senescence and vegetative tissue but has not been thoroughly investigated for fleshy fruits. The purpose of this research was to examine ripening and over-ripening in banana fruit to determine if there were processes in common to previously described PCD. Loss of cellular integrity (over 40%) and development of senescence related dark spot (SRDS) occurred after day 8 in banana peel. Nuclease and protease activity in the peel increased during ripening starting from day 2, and decreased during over-ripening. The highest activity was for proteases and nucleases with apparent molecular weights of 86 kDa and 27 kDa, respectively. Images of SRDS showed shrinkage of the upper layers of cells, visually suggesting cell death. Decrease of electron dense areas was evident in TEM micrographs of nuclei. This study shows for the first time that ripening and over-ripening of banana peel share physiological and molecular processes previously described in plant PCD. SRDS could represent a morphotype of PCD that characterizes a structural and biochemical failure in the upper layers of the peel, thereafter spreading to lower and adjacent layers of cells. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

The Significance of the PD-L1 Expression in Non-Small-Cell Lung Cancer: Trenchant Double Swords as Predictive and Prognostic Markers.

PubMed

Takada, Kazuki; Toyokawa, Gouji; Shoji, Fumihiro; Okamoto, Tatsuro; Maehara, Yoshihiko

2018-03-01

Lung cancer is the leading cause of death due to cancer worldwide. Surgery, chemotherapy, and radiotherapy have been the standard treatment for lung cancer, and targeted molecular therapy has greatly improved the clinical course of patients with non-small-cell lung cancer (NSCLC) harboring driver mutations, such as in epidermal growth factor receptor and anaplastic lymphoma kinase genes. Despite advances in such therapies, the prognosis of patients with NSCLC without driver oncogene mutations remains poor. Immunotherapy targeting programmed cell death-1 (PD-1) and programmed cell death-ligand 1 (PD-L1) has recently been shown to improve the survival in advanced NSCLC. The PD-L1 expression on the surface of tumor cells has emerged as a potential biomarker for predicting responses to immunotherapy and prognosis after surgery in NSCLC. However, the utility of PD-L1 expression as a predictive and prognostic biomarker remains controversial because of the existence of various PD-L1 antibodies, scoring systems, and positivity cutoffs. In this review, we summarize the data from representative clinical trials of PD-1/PD-L1 immune checkpoint inhibitors in NSCLC and previous reports on the association between PD-L1 expression and clinical outcomes in patients with NSCLC. Furthermore, we discuss the future perspectives of immunotherapy and immune checkpoint factors. Copyright © 2017 Elsevier Inc. All rights reserved.

The impairment of HCCS leads to MLS syndrome by activating a non-canonical cell death pathway in the brain and eyes

PubMed Central

Indrieri, Alessia; Conte, Ivan; Chesi, Giancarlo; Romano, Alessia; Quartararo, Jade; Tatè, Rosarita; Ghezzi, Daniele; Zeviani, Massimo; Goffrini, Paola; Ferrero, Ileana; Bovolenta, Paola; Franco, Brunella

2013-01-01

Mitochondrial-dependent (intrinsic) programmed cell death (PCD) is an essential homoeostatic mechanism that selects bioenergetically proficient cells suitable for tissue/organ development. However, the link between mitochondrial dysfunction, intrinsic apoptosis and developmental anomalies has not been demonstrated to date. Now we provide the evidence that non-canonical mitochondrial-dependent apoptosis explains the phenotype of microphthalmia with linear skin lesions (MLS), an X-linked developmental disorder caused by mutations in the holo-cytochrome c-type synthase (HCCS) gene. By taking advantage of a medaka model that recapitulates the MLS phenotype we demonstrate that downregulation of hccs, an essential player of the mitochondrial respiratory chain (MRC), causes increased cell death via an apoptosome-independent caspase-9 activation in brain and eyes. We also show that the unconventional activation of caspase-9 occurs in the mitochondria and is triggered by MRC impairment and overproduction of reactive oxygen species (ROS). We thus propose that HCCS plays a key role in central nervous system (CNS) development by modulating a novel non-canonical start-up of cell death and provide the first experimental evidence for a mechanistic link between mitochondrial dysfunction, intrinsic apoptosis and developmental disorders. PMID:23239471

Effect of Immortalization-Upregulated Protein-2 (IMUP-2) on Cell Death of Trophoblast

PubMed Central

Jung, Ran; Choi, Jong Ho; Lee, Hyun Jung; Kim, Jin Kyeoung; Kim, Gi Jin

2013-01-01

Trophoblasts, in the placenta, play a role for placental development as well as implantation in the early pregnancy. The characteristics and functions of trophoblast are identified by their localization and potency for proliferation, differentiation, and invasion. Thus, inadequate trophoblast cell death induces trophoblast dysfunction resulting in abnormal placental development and several gynecological diseases. Recently, it was reported that increased immortalization-upregulated protein-2 (IMUP-2) by hypoxia influences trophoblast apoptosis. However, IMUP-2 function on autophagy, which is type II programmed cell death remains unclear. In this study, we analyzed IMUP-2 expression in trophoblast cells (HTR8-SVneo) and compared IMUP-2 effects on cell death including apoptosis and autophagy in trophoblast regardless of IMUP-2 expression. Increased IMUP-2 in trophoblast by IMUP-2 gene transfection induces cell death, especially, apoptosis increases more than autophagy (p<0.05). However, the decreased IMUP-2 in trophoblasts after siRNA treatment decreased apoptosis with the decreased activities of caspase 3 and 7. The expressions of LC3 and MDC as an autophagosome makers and phosphorylated mTOR, which is a negative regulator for autophagy, increased. In addition, the S phase of cell cycle increased in trophoblasts when IMUP-2 expression decreased. Taken together, the alteration of IMUP-2 can control the balance between apoptosis and autophagy of trophoblasts resulting in functional involvement in placental development and in gynecological diseases by regulating the function of trophoblasts. PMID:25949126

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

PubMed Central

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-apoptosis, we screened a human heart cDNA expression library in yeast cells undergoing PCD due to the conditional expression of a mammalian pro-apoptotic Bax cDNA. Analysis of the multiple Bax suppressors identified revealed several previously known as well as a large number of clones representing potential novel anti-apoptotic sequences. The focus of this review is to report on recent achievements in the use of humanized yeast in genetic screens to identify novel stress-induced PCD suppressors, supporting the use of yeast as a unicellular model organism to elucidate anti-apoptotic and cell survival mechanisms. PMID:22708116

Novel cell-biological ideas deducible from morphological observations on "dark" neurons revisited.

PubMed

Gallyas, Ferenc

2007-05-30

The origin, nature and fate of "dark" (dramatically shrunken and hyperbasophilic) neurons are century-old problems in both human and experimental neuropathology. Until a few years ago, hardly any cell-biological conclusion had been drawn from their histological investigation. On the basis of light and electron microscopic findings in animal experiments performed during the past few years, my research team has put forward novel ideas concerning 1. the nature of "dark" neurons (malfunction of an energy-storing gel-structure that is ubiquitously present in all intracellular spaces between the ultrastructural elements), 2. the mechanism of their formation (non-programmed initiation of a whole-cell phase-transition in this gel-structure), 3. their capability of recovery (programmed for some physiological purpose), 4. their death mode (neither necrotic nor apoptotic), and 5. their relationship with the apoptotic cell death (the gel structure in question is programmed for the morphological execution of ontogenetic apoptosis). Based on morphological observations, this paper revisits these ideas in order to bring them to the attention of researchers who are in a position to investigate their validity by means of experimental paradigms other than those used here.

The release of cytochrome c and the regulation of the programmed cell death progress in the endosperm of winter wheat (Triticum aestivum L.) under waterlogging.

PubMed

Qi, Yuan-Hong; Mao, Fang-Fang; Zhou, Zhu-Qing; Liu, Dong-Cheng; Min-Yu; Deng, Xiang-Yi; Li, Ji-Wei; Mei, Fang-Zhu

2018-05-02

It has been shown in mammalian systems that the mitochondria can play a key role in the regulation of apoptosis by releasing intermembrane proteins (such as cytochrome c) into the cytosol. Cytochrome c released from the mitochondria to the cytoplasm activates proteolytic enzyme cascades, leading to specific nuclear DNA degradation and cell death. This pathway is considered to be one of the important regulatory mechanisms of apoptosis. Previous studies have shown that endosperm cell development in wheat undergoes specialized programmed cell death (PCD) and that waterlogging stress accelerates the PCD process; however, little is known regarding the associated molecular mechanism. In this study, changes in mitochondrial structure, the release of cytochrome c, and gene expression were studied in the endosperm cells of the wheat (Triticum aestivum L.) cultivar "huamai 8" during PCD under different waterlogging durations. The results showed that waterlogging aggravated the degradation of mitochondrial structure, increased the mitochondrial permeability transition (MPT), and decreased mitochondrial transmembrane potential (ΔΨm), resulting in the advancement of the endosperm PCD process. In situ localization and western blotting of cytochrome c indicated that with the development of the endosperm cell, cytochrome c was gradually released from the mitochondria to the cytoplasm, and waterlogging stress led to an advancement and increase in the release of cytochrome c. In addition, waterlogging stress resulted in the increased expression of the voltage-dependent anion channel (VDAC) and adenine nucleotide translocator (ANT), suggesting that the mitochondrial permeability transition pore (MPTP) may be involved in endosperm PCD under waterlogging stress. The MPTP inhibitor cyclosporine A effectively suppressed cell death and cytochrome c release during wheat endosperm PCD. Our results indicate that the mitochondria play important roles in the PCD of endosperm cells and that the increase in mitochondrial damage and corresponding release of cytochrome c may be one of the major causes of endosperm PCD advancement under waterlogging.

Nitric Oxide Inhibits Al-Induced Programmed Cell Death in Root Tips of Peanut (Arachis hypogaea L.) by Affecting Physiological Properties of Antioxidants Systems and Cell Wall

PubMed Central

Pan, Chun-Liu; Yao, Shao-Chang; Xiong, Wei-Jiao; Luo, Shu-Zhen; Wang, Ya-Lun; Wang, Ai-Qin; Xiao, Dong; Zhan, Jie; He, Long-Fei

2017-01-01

It has been reported that nitric oxide (NO) is a negative regulator of aluminum (Al)-induced programmed cell death (PCD) in peanut root tips. However, the inhibiting mechanism of NO on Al-induced PCD is unclear. In order to investigate the mechanism by which NO inhibits Al-induced PCD, the effects of co-treatment Al with the exogenous NO donor or the NO-specific scavenger on peanut root tips, the physiological properties of antioxidants systems and cell wall (CW) in root tip cells of NO inhibiting Al-induced PCD were studied with two peanut cultivars. The results showed that Al exposure induced endogenous NO accumulation, and endogenous NO burst increased antioxidant enzyme activity in response to Al stress. The addition of NO donor sodium nitroprusside (SNP) relieved Al-induced root elongation inhibition, cell death and Al adsorption in CW, as well as oxidative damage and ROS accumulation. Furthermore, co-treatment with the exogenous NO donor decreased MDA content, LOX activity and pectin methylesterase (PME) activity, increased xyloglucan endotransglucosylase (XET) activity and relative expression of the xyloglucan endotransglucosylase/hydrolase (XTH-32) gene. Taken together, exogenous NO alleviated Al-induced PCD by inhibiting Al adsorption in CW, enhancing antioxidant defense and reducing peroxidation of membrane lipids, alleviating the inhibition of Al on root elongation by maintaining the extensibility of CW, decreasing PME activity, and increasing XET activity and relative XTH-32 expression of CW. PMID:29311970

Nitric Oxide Inhibits Al-Induced Programmed Cell Death in Root Tips of Peanut (Arachis hypogaea L.) by Affecting Physiological Properties of Antioxidants Systems and Cell Wall.

PubMed

Pan, Chun-Liu; Yao, Shao-Chang; Xiong, Wei-Jiao; Luo, Shu-Zhen; Wang, Ya-Lun; Wang, Ai-Qin; Xiao, Dong; Zhan, Jie; He, Long-Fei

2017-01-01

It has been reported that nitric oxide (NO) is a negative regulator of aluminum (Al)-induced programmed cell death (PCD) in peanut root tips. However, the inhibiting mechanism of NO on Al-induced PCD is unclear. In order to investigate the mechanism by which NO inhibits Al-induced PCD, the effects of co-treatment Al with the exogenous NO donor or the NO-specific scavenger on peanut root tips, the physiological properties of antioxidants systems and cell wall (CW) in root tip cells of NO inhibiting Al-induced PCD were studied with two peanut cultivars. The results showed that Al exposure induced endogenous NO accumulation, and endogenous NO burst increased antioxidant enzyme activity in response to Al stress. The addition of NO donor sodium nitroprusside (SNP) relieved Al-induced root elongation inhibition, cell death and Al adsorption in CW, as well as oxidative damage and ROS accumulation. Furthermore, co-treatment with the exogenous NO donor decreased MDA content, LOX activity and pectin methylesterase (PME) activity, increased xyloglucan endotransglucosylase (XET) activity and relative expression of the xyloglucan endotransglucosylase/hydrolase ( XTH-32 ) gene. Taken together, exogenous NO alleviated Al-induced PCD by inhibiting Al adsorption in CW, enhancing antioxidant defense and reducing peroxidation of membrane lipids, alleviating the inhibition of Al on root elongation by maintaining the extensibility of CW, decreasing PME activity, and increasing XET activity and relative XTH-32 expression of CW.

Spontaneous T-cell responses against the immune check point programmed-death-ligand 1 (PD-L1) in patients with chronic myeloproliferative neoplasms correlate with disease stage and clinical response.

PubMed

Holmström, Morten Orebo; Riley, Caroline Hasselbalch; Skov, Vibe; Svane, Inge Marie; Hasselbalch, Hans Carl; Andersen, Mads Hald

2018-01-01

The Chronic Myeloproliferative Neoplasms (MPN) are cancers characterized by hyperinflammation and immune deregulation. Concurrently, the expression of the immune check point programmed death ligand 1 (PD-L1) is induced by inflammation. In this study we report on the occurrence of spontaneous T cell responses against a PD-L1 derived epitope in patients with MPN. We show that 71% of patients display a significant immune response against PD-L1, and patients with advanced MPN have significantly fewer and weaker PD-L1 specific immune responses compared to patients with non-advanced MPN. The PD-L1 specific T cell responses are CD4 + T cell responses, and by gene expression analysis we show that expression of PD-L1 is enhanced in patients with MPN. This could imply that the tumor specific immune response in MPN could be enhanced by vaccination with PD-L1 derived epitopes by boosting the anti-regulatory immune response hereby allowing tumor specific T cell to exert anti-tumor immunity.

[Apoptosis: cellular and clinical aspects].

PubMed

Løvschall, H; Mosekilde, L

1997-04-01

Removal of damaged cells is essential for the maintenance of life in multicellular organisms. The process of self destruction, apoptosis, eliminates surplus or damaged cells as part of the pathophysiological defence system. Apoptosis is essential in structural and functional organogenesis during embryological development. The physiological regulation of tissue kinetics is a product of both cell proliferation and cell death. Internal and external regulatory stimuli regulate the balance between apoptosis and mitosis by genetic interaction. Apoptosis is characterized by condensation of chromatine as a result of DNA degradation, formation of blebs in the plasma and nuclear membranes, condensation of cytoplasma, formation of vesicular apoptotic bodies, and phagocytosis by neighbouring cells without inflammatory response. A number of observations indicate that programmed cell death plays an important role in the regulation of cytofunctional homeostasis and defense against accumulation of damaged cells, eg with DNA alterations. Dysregulation of the apoptotic gene program, eg by mutations, may not only lead to loss or degeneration of tissue, but also to hyperproliferative and tumorigenic disorders. New evidence indicates that apoptosis regulation is important both in aging processes and diseases such as: neuropathies, immunopathies, viral infections, cancer, etc. Pharmacological intervention designed to modulate apoptosis seems to raise new possibilities in the treatment of disease.

PD-1 and its ligands are important immune checkpoints in cancer

PubMed Central

Dong, Yinan; Sun, Qian; Zhang, Xinwei

2017-01-01

Checkpoint programmed death-1 (PD-1)/programmed cell death ligands (PD-Ls) have been identified as negative immunoregulatory molecules that promote immune evasion of tumor cells. The interaction of PD-1 and PD-Ls inhibits the function of T cells and tumor-infiltrating lymphocytes (TIL) while increasing the function of immunosuppressive regulatory T cells (Tregs). This condition causes the tumor cells to evade immune response. Thus, the blockade of PD-1/PD-L1 enhances anti-tumor immunity by reducing the number and/or the suppressive activity of Tregs and by restoring the activity of effector T cells. Furthermore, some monoclonal antibodies blockading PD-1/PD-Ls axis have achieved good effect and received Food and Drug Administration approval. The role of PD-1/PD-Ls in tumors has been well studied, but little is known on the mechanism by which PD-1 blocks T-cell activation. In this study, we provide a brief overview on the discovery and regulatory mechanism of PD-1 and PD-L1 dysregulation in tumors, as well as the function and signaling pathway of PD-1 and its ligands; their roles in tumor evasion and clinical treatment were also studied. PMID:27974689

A Novel Bcl-x Isoform Connected to the T Cell Receptor Regulates Apoptosis in T Cells

PubMed Central

Yang, Xiao-Feng; Weber, Georg F.

2014-01-01

Summary We define a novel Bcl-x isoform, Bcl-xγ, that is generated by alternative splicing and characterized by a unique 47 amino acid C-terminus. Bcl-xγ is expressed primarily in thymocytes, where it may depend on an interaction between the TCR and host MHC products, and in mature T cells, where its expression is associated with ligation of the T cell receptor. Overexpression of Bcl-xγ in T cells inhibits activation-induced apoptosis; inhibition of Bcl-xγ, after stable expression of Bcl-xγ antisense cDNA, enhances activation-induced apoptosis. In contrast to other Bcl-x isoforms, cells that fail to express Bcl-xγ after CD3 ligation undergo programmed cell death, while activated T cells that express Bcl-xγ are spared. Identification of Bcl-xγ helps provide amolecular explanation of T cell activation and death after antigen engagement. PMID:9390687

Live imaging of muscle histolysis in Drosophila metamorphosis.

PubMed

Kuleesha, Yadav; Puah, Wee Choo; Wasser, Martin

2016-05-04

The contribution of programmed cell death (PCD) to muscle wasting disorders remains a matter of debate. Drosophila melanogaster metamorphosis offers the opportunity to study muscle cell death in the context of development. Using live cell imaging of the abdomen, two groups of larval muscles can be observed, doomed muscles that undergo histolysis and persistent muscles that are remodelled and survive into adulthood. To identify and characterize genes that control the decision between survival and cell death of muscles, we developed a method comprising in vivo imaging, targeted gene perturbation and time-lapse image analysis. Our approach enabled us to study the cytological and temporal aspects of abnormal cell death phenotypes. In a previous genetic screen for genes controlling muscle size and cell death in metamorphosis, we identified gene perturbations that induced cell death of persistent or inhibit histolysis of doomed larval muscles. RNA interference (RNAi) of the genes encoding the helicase Rm62 and the lysosomal Cathepsin-L homolog Cysteine proteinase 1 (Cp1) caused premature cell death of persistent muscle in early and mid-pupation, respectively. Silencing of the transcriptional co-repressor Atrophin inhibited histolysis of doomed muscles. Overexpression of dominant-negative Target of Rapamycin (TOR) delayed the histolysis of a subset of doomed and induced ablation of all persistent muscles. RNAi of AMPKα, which encodes a subunit of the AMPK protein complex that senses AMP and promotes ATP formation, led to loss of attachment and a spherical morphology. None of the perturbations affected the survival of newly formed adult muscles, suggesting that the method is useful to find genes that are crucial for the survival of metabolically challenged muscles, like those undergoing atrophy. The ablation of persistent muscles did not affect eclosion of adult flies. Live imaging is a versatile approach to uncover gene functions that are required for the survival of muscle undergoing remodelling, yet are dispensable for other adult muscles. Our approach promises to identify molecular mechanisms that can explain the resilience of muscles to PCD.

Using Terminal Transferase-mediated dUTP Nick End-labelling (TUNEL) and Caspase 3/7 Assays to Measure Epidermal Cell Death in Frogs with Chytridiomycosis.

PubMed

Brannelly, Laura A; Roberts, Alexandra A; Skerratt, Lee F; Berger, Lee

2018-05-16

Amphibians are experiencing a great loss in biodiversity globally and one of the major causes is the infectious disease chytridiomycosis. This disease is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), which infects and disrupts frog epidermis; however, pathological changes have not been explicitly characterized. Apoptosis (programmed cell death) can be used by pathogens to damage host tissue, but can also be a host mechanism of disease resistance for pathogen removal. In this study, we quantify epidermal cell death of infected and uninfected animals using two different assays: terminal transferase-mediated dUTP nick end-labelling (TUNEL), and caspase 3/7. Using ventral, dorsal, and thigh skin tissue in the TUNEL assay, we observe cell death in the epidermal cells in situ of clinically infected animals and compare cell death with uninfected animals using fluorescent microscopy. In order to determine how apoptosis levels in the epidermis change over the course of infection we remove toe-tip samples fortnightly over an 8-week period, and use a caspase 3/7 assay with extracted proteins to quantify activity within the samples. We then correlate caspase 3/7 activity with infection load. The TUNEL assay is useful for localization of cell death in situ, but is expensive and time intensive per sample. The caspase 3/7 assay is efficient for large sample sizes and time course experiments. However, because frog toe tip biopsies are small there is limited extract available for sample standardization via protein quantification methods, such as the Bradford assay. Therefore, we suggest estimating skin surface area through photographic analysis of toe biopsies to avoid consuming extracts during sample standardization.

Inhibiting NANOG Enhances Efficacy of BH3 Mimetics | Center for Cancer Research

Cancer.gov

BCL-2 family proteins regulate cell fate. Some members promote cell survival while others induce programmed cell death. A third group, the BH3-only members, modulates the activities of the rest of the family. Some cancers, including those of the colon and rectum, express elevated levels of pro-survival BCL-2 members, which may protect cancer cells from chemotherapy. BH3

Sheeppox virus SPPV14 encodes a Bcl-2-like cell death inhibitor that counters a distinct set of mammalian proapoptotic proteins.

PubMed

Okamoto, Toru; Campbell, Stephanie; Mehta, Ninad; Thibault, John; Colman, Peter M; Barry, Michele; Huang, David C S; Kvansakul, Marc

2012-11-01

Many viruses express inhibitors of programmed cell death (apoptosis), thereby countering host defenses that would otherwise rapidly clear infected cells. To counter this, viruses such as adenoviruses and herpesviruses express recognizable homologs of the mammalian prosurvival protein Bcl-2. In contrast, the majority of poxviruses lack viral Bcl-2 (vBcl-2) homologs that are readily identified by sequence similarities. One such virus, myxoma virus, which is the causative agent of myxomatosis, expresses a virulence factor that is a potent inhibitor of apoptosis. In spite of the scant sequence similarity to Bcl-2, myxoma virus M11L adopts an almost identical 3-dimensional fold. We used M11L as bait in a sequence similarity search for other Bcl-2-like proteins and identified six putative vBcl-2 proteins from poxviruses. Some are potent inhibitors of apoptosis, in particular sheeppox virus SPPV14, which inhibited cell death induced by multiple agents. Importantly, SPPV14 compensated for the loss of antiapoptotic F1L in vaccinia virus and acts to directly counter the cell death mediators Bax and Bak. SPPV14 also engages a unique subset of the death-promoting BH3-only ligands, including Bim, Puma, Bmf, and Hrk. This suggests that SPPV14 may have been selected for specific biological roles as a virulence factor for sheeppox virus.

Pyroptosis induced by enterovirus A71 infection in cultured human neuroblastoma cells.

PubMed

Zhu, Xiaojuan; Wu, Tao; Chi, Ying; Ge, Yiyue; Wu, Bin; Zhou, Minghao; Zhu, Fengcai; Ji, Minjun; Cui, Lunbiao

2018-06-07

Enterovirus A71 (EV-A71) infection can cause hand, foot and mouth disease (HFMD), and even fatal meningoencephalitis. Unfortunately, there is currently no effective treatment for EV-A71 infection due to the lack of understanding of the mechanism of neurological diseases. In this study, we employed SH-SY5Y human neuroblastoma cells to explore the roles of caspase-1 in neuropathogenesis. The expression and activity of caspase-1 were analyzed. The potential immuneconsequences mediated by caspase-1 including cell death, lysis, DNA degradation, and secretion of pro-inflammatory were also examined. We found the gene expression levels of caspase-1, IL-1β, IL-18 and active caspase-1 were markedly increased in the SH-SY5Y cells at 48 h post EV-A71 infection. The cell death, lysis, and DNA degradation were also increased during infection, which could be significantly alleviated by caspase-1 inhibition. These observations provided additional experimental evidence supporting caspase-1-mediated pyroptosis as a novel pathway of inflammatory programmed cell death. Copyright © 2018 Elsevier Inc. All rights reserved.

Autophagic activity in BC3H1 cells exposed to yessotoxin.

PubMed

Korsnes, Mónica Suárez; Kolstad, Hilde; Kleiveland, Charlotte Ramstad; Korsnes, Reinert; Ørmen, Elin

2016-04-01

The marine toxin yessotoxin (YTX) can induce programmed cell death through both caspase-dependent and -independent pathways in various cellular systems. It appears to stimulate different forms of cellular stress causing instability among cell death mechanisms and making them overlap and cross-talk. Autophagy is one of the key pathways that can be stimulated by multiple forms of cellular stress which may determine cell survival or death. The present work evaluates a plausible link between ribotoxic stress and autophagic activity in BC3H1 cells treated with YTX. Such treatment produces massive cytoplasmic compartments as well as double-membrane vesicles termed autophagosomes which are typically observed in cells undergoing autophagy. The observed autophagosomes contain a large amount of ribosomes associated with the endoplasmic reticulum (ER). Western blotting analysis of Atg proteins and detection of the autophagic markers LC3-II and SQSTM1/p62 by flow cytometry and immunofluorescence verified autophagic activity during YTX-treatment. The present work supports the idea that autophagic activity upon YTX exposure may represent a response to ribotoxic stress. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Prognostic impact of programmed cell death 1 ligand 1 expression in human leukocyte antigen class I-positive hepatocellular carcinoma after curative hepatectomy.

PubMed

Umemoto, Yuichiroh; Okano, Shinji; Matsumoto, Yoshihiro; Nakagawara, Hidekazu; Matono, Rumi; Yoshiya, Shohei; Yamashita, Yo-Ichi; Yoshizumi, Tomoharu; Ikegami, Toru; Soejima, Yuji; Harada, Mamoru; Aishima, Shinichi; Oda, Yoshinao; Shirabe, Ken; Maehara, Yoshihiko

2015-01-01

Hepatocellular carcinoma (HCC) is one of the most common solid tumors worldwide. Surgery is potentially curative, but high recurrence rates worsen patient prognosis. The interaction between the proteins programmed cell death 1 (PD-1) and programmed cell death 1 ligand 1 (PD-L1) is an important immune checkpoint. The significance of PD-L1 expression and human leukocyte antigen class I (HLA class I), recognized by CD8 T cells, in the prognosis of patients with HCC remains to be determined. We assessed the levels of PD-L1 and HLA class I expression on HCC samples from 80 patients who had undergone hepatectomy at our institution, and evaluated the correlations between PD-L1 and HLA class I expression and patient prognosis. High HLA class I expression was correlated with significantly better recurrence-free survival (RFS), but not overall survival (OS). Multivariate analysis showed that high HLA class I expression was an independent predictor of improved RFS. Low expression of PD-L1 on HCC tended to predict better OS, but the difference was not statistically significant. PD-L1 expression on HCC correlated with the number of CD163-positive macrophages and HLA class I expression with CD3-positive cell infiltration. Univariable and multivariable analyses showed that combined PD-L1 low/HLA class I high expression on HCCs was prognostic for improved OS and RFS. PD-L1 status may be a good predictor of prognosis in HCC patients with high HLA class I expression. Novel therapies targeting the PD-L1/PD-1 pathway may improve the prognosis of patients with HCC.

Caspase blockade induces RIP3-mediated programmed necrosis in Toll-like receptor-activated microglia.

PubMed

Kim, S J; Li, Jianrong

2013-07-11

Microglia are the resident immune cells in the central nervous system and key players against pathogens and injury. However, persistent microglial activation often exacerbates pathological damage and has been implicated in many neurological diseases. Despite their pivotal physiological and pathophysiological roles, how the survival and death of activated microglia is regulated remains poorly understood. We report here that microglia activated through Toll-like receptors (TLRs) undergo RIP1/RIP3-dependent programmed necrosis (necroptosis) when exposed to the pan caspase inhibitor zVAD-fmk. Although zVAD-fmk and the caspase-8 inhibitor IETD-fmk had no effect on unstimulated primary microglia, they markedly sensitized microglia to TLR1/2,3,4,7/8 ligands or TNF treatment, triggering programmed necrosis that was completely blocked by R1P1 kinase inhibitor necrostatin-1. Interestingly, necroptosis induced by TLR ligands and zVAD was restricted to microglial cells and was not observed in astrocytes, neurons or oligodendrocytes even though they are known to express certain TLRs. Deletion of genes encoding TNF or TNFR1 failed to prevent lipopolysaccharide- and poly(I:C)-induced microglial necroptosis, unveiling a TNF-independent programmed necrosis pathway in TLR3- and TLR4-activated microglia. Microglia from mice lacking functional TRIF were fully protected against TLR3/4 activation and zVAD-fmk-induced necrosis, and genetic deletion of rip3 also prevented microglia necroptosis. Activation of c-jun N-terminal kinase and generation of specific reactive oxygen species were downstream signaling events required for microglial cell death execution. Taken together, this study reveals a robust RIP3-dependent necroptosis signaling pathway in TLR-activated microglia upon caspase blockade and suggests that TLR signaling and programmed cell death pathways are closely linked in microglia, which could contribute to neuropathology and neuroinflammation when dysregulated.

A role for oxalic acid generation in ozone-induced signallization in Arabidopis cells.

PubMed

Tran, Daniel; Kadono, Takashi; Molas, Maria Lia; Errakhi, Rafik; Briand, Joël; Biligui, Bernadette; Kawano, Tomonori; Bouteau, François

2013-03-01

Ozone (O(3) ) is an air pollutant with an impact increasingly important in our industrialized world. It affects human health and productivity in various crops. We provide the evidences that treatment of Arabidopsis thaliana with O(3) results in ascorbate-derived oxalic acid production. Using cultured cells of A. thaliana as a model, here we further showed that oxalic acid induces activation of anion channels that trigger depolarization of the cell, increase in cytosolic Ca(2+) concentration, generation of reactive oxygen species and cell death. We confirmed that O(3) reacts with ascorbate in the culture, thus resulting in production of oxalic acid and this could be part of the O(3) -induced signalling pathways that trigger programmed cell death. © 2012 Blackwell Publishing Ltd.

Identification of a nuclear-localized nuclease from wheat cells undergoing programmed cell death that is able to trigger DNA fragmentation and apoptotic morphology on nuclei from human cells

PubMed Central

Domínguez, Fernando; Cejudo, Francisco J.

2006-01-01

PCD (programmed cell death) in plants presents important morphological and biochemical differences compared with apoptosis in animal cells. This raises the question of whether PCD arose independently or from a common ancestor in plants and animals. In the present study we describe a cell-free system, using wheat grain nucellar cells undergoing PCD, to analyse nucleus dismantling, the final stage of PCD. We have identified a Ca2+/Mg2+ nuclease and a serine protease localized to the nucleus of dying nucellar cells. Nuclear extracts from nucellar cells undergoing PCD triggered DNA fragmentation and other apoptotic morphology in nuclei from different plant tissues. Inhibition of the serine protease did not affect DNA laddering. Furthermore, we show that the nuclear extracts from plant cells triggered DNA fragmentation and apoptotic morphology in nuclei from human cells. The inhibition of the nucleolytic activity with Zn2+ or EDTA blocked the morphological changes of the nucleus. Moreover, nuclear extracts from apoptotic human cells triggered DNA fragmentation and apoptotic morphology in nuclei from plant cells. These results show that degradation of the nucleus is morphologically and biochemically similar in plant and animal cells. The implication of this finding on the origin of PCD in plants and animals is discussed. PMID:16613587

Physangulidine A, a withanolide from Physalis angulata, perturbs the cell cycle and induces cell death by apoptosis in prostate cancer cells.

PubMed

Reyes-Reyes, E Merit; Jin, Zhuang; Vaisberg, Abraham J; Hammond, Gerald B; Bates, Paula J

2013-01-25

Recently, our group reported the discovery of three new withanolides, physangulidines A-C, from Physalis angulata. In this study, the biological effects of physangulidine A (1), which was the most active and abundant of the three new constituents, are described. It was found that 1 significantly reduces survival in clonogenic assays for two hormone-independent prostate cancer cell lines. Flow cytometry and confocal microscopy studies in DU145 human prostate cancer cells indicated that 1 induces cell cycle arrest in the G(2)/M phase and causes defective mitosis. It was determined also that 1 produces programed cell death by apoptosis, as evidenced by biochemical markers and distinct changes in cell morphology. These results imply that the antimitotic and proapoptotic effects of 1 may contribute significantly to the biological activities and potential medicinal properties of its plant of origin.

UV-Induced cell death in plants.

PubMed

Nawkar, Ganesh M; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

2013-01-14

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).

UV-Induced Cell Death in Plants

PubMed Central

Nawkar, Ganesh M.; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

2013-01-01

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). PMID:23344059

Mechanisms Involved in Injury and Repair of the Murine Lacrimal Gland: Role of Programmed Cell Death and Mesenchymal Stem Cells

PubMed Central

Zoukhri, Driss

2011-01-01

The non-keratinized epithelia of the ocular surface are constantly challenged by environmental insults, such as smoke, dust, and airborne pathogens. Tears are the sole physical protective barrier for the ocular surface. Production of tears in inadequate quantity or of inadequate quality results in constant irritation of the ocular surface, leading to dry eye disease, also referred to as keratoconjunctivitis sicca (KCS). Inflammation of the lacrimal gland, such as occurs in Sjögren’s syndrome, sarcoidosis, chronic graft versus-host disease, and other pathological conditions, results in inadequate secretion of the aqueous layer of the tear film, and is a leading cause of dry eye disease. The hallmarks of lacrimal gland inflammation are the presence of immune cell infiltrates, loss of acinar epithelial cells (the secreting cells), and increased production of proinflammatory cytokines. To date, the mechanisms leading to acinar cell loss and the associated decline in lacrimal gland secretion are still poorly understood. It is also not understood why the remaining lacrimal gland cells are unable to proliferate in order to regenerate a functioning lacrimal gland. This article reviews recent advances in exocrine tissue injury and repair, with emphasis on the roles of programmed cell death and stem/progenitor cells. PMID:20427009

Vesicles between plasma membrane and cell wall prior to visible senescence of Iris and Dendrobium flowers.

PubMed

Kamdee, Channatika; Kirasak, Kanjana; Ketsa, Saichol; van Doorn, Wouter G

2015-09-01

Cut Iris flowers (Iris x hollandica, cv. Blue Magic) show visible senescence about two days after full opening. Epidermal cells of the outer tepals collapse due to programmed cell death (PCD). Transmission electron microscopy (TEM) showed irregular swelling of the cell walls, starting prior to cell collapse. Compared to cells in flowers that had just opened, wall thickness increased up to tenfold prior to cell death. Fibrils were visible in the swollen walls. After cell death very little of the cell wall remained. Prior to and during visible wall swelling, vesicles (paramural bodies) were observed between the plasma membrane and the cell walls. The vesicles were also found in groups and were accompanied by amorphous substance. They usually showed a single membrane, and had a variety of diameters and electron densities. Cut Dendrobium hybrid cv. Lucky Duan flowers exhibited visible senescence about 14 days after full flower opening. Paramural bodies were also found in Dendrobium tepal epidermis and mesophyll cells, related to wall swelling and degradation. Although alternative explanations are well possible, it is hypothesized that paramural bodies carry enzymes involved in cell wall breakdown. The literature has not yet reported such bodies in association with senescence/PCD. Copyright © 2015 Elsevier GmbH. All rights reserved.

Opposite extremes in ethylene/nitric oxide ratio induce cell death in suspension culture and root apices of tomato exposed to salt stress.

PubMed

Poór, P; Borbély, P; Kovács, Judit; Papp, Anita; Szepesi, Ágnes; Takács, Z; Tari, Irma

2014-12-01

The plant hormone ethylene or the gaseous signalling molecule nitric oxide (NO) may enhance salt stress tolerance by maintaining ion homeostasis, first of all K+/Na+ ratio of tissues. Ethylene and NO accumulation increased in the root apices and suspension culture cells of tomato at sublethal salt stress caused by 100 mM NaCl, however, the induction phase of programmed cell death (PCD) was different at lethal salt concentration. The production of ethylene by root apices and the accumulation of NO in the cells of suspension culture did not increase during the initiation of PCD after 250 mM NaCl treatment. Moreover, cells in suspension culture accumulated higher amount of reactive oxygen species which, along with NO deficiency contributed to cell death induction. The absence of ethylene in the apical root segments and the absence of NO accumulation in the cell suspension resulted in similar ion disequilibrium, namely K+/Na+ ratio of 1.41 ± 0.1 and 1.68 ± 0.3 in intact plant tissues and suspension culture cells, respectively that was not tolerated by tomato.

Determination of ACC-induced cell-programmed death in roots of Vicia faba ssp. minor seedlings by acridine orange and ethidium bromide staining.

PubMed

Byczkowska, Anna; Kunikowska, Anita; Kaźmierczak, Andrzej

2013-02-01

Fluorescence staining with acridine orange (AO) and ethidium bromide (EB) showed that nuclei of cortex root cells of 1-aminocyclopropane-1-carboxylic acid (ACC)-treated Vicia faba ssp. minor seedlings differed in color. Measurement of resultant fluorescence intensity (RFI) showed that it increased when the color of nuclear chromatin was changed from green to red, indicating that EB moved to the nuclei via the cell membrane which lost its integrity and stained nuclei red. AO/EB staining showed that changes in color of the nuclear chromatin were accompanied by DNA condensation, nuclei fragmentation, and chromatin degradation which were also shown after 4,6-diamidino-2-phenylindol staining. These results indicate that ACC induced programmed cell death. The increasing values of RFI together with the corresponding morphological changes of nuclear chromatin were the basis to prepare the standard curve; cells with green unchanged nuclear chromatin were alive while those with dark orange and bright red nuclei were dead. The cells with nuclei with green-yellow, yellow-orange, and bright orange chromatin with or without their condensation and fragmentation chromatin were dying. The prepared curve has became the basis to draw up the digital method for detection and determination of the number of living, dying, and dead cells in an in planta system and revealed that ACC induced death in about 20% of root cortex cells. This process was accompanied by increase in ion leakage, shortening of cells and whole roots, as well as by increase in weight and width of the apical part of roots and appearance of few aerenchymatic spaces while not by internucleosomal DNA degradation.

Diverse cutaneous adverse eruptions caused by anti-programmed cell death-1 (PD-1) and anti-programmed cell death ligand-1 (PD-L1) immunotherapies: clinical features and management.

PubMed

Shen, John; Chang, Jason; Mendenhall, Melody; Cherry, Grace; Goldman, Jonathan W; Kulkarni, Rajan P

2018-01-01

The anti-programmed cell death-1 (PD-1) and anti-programmed cell death ligand-1 (PD-L1) immunotherapies have shown exceptional activity in many cancers. However, these immunotherapies can also result in diverse adverse cutaneous eruptions that need to be better characterized for ongoing management. The objective was to provide clinical and histopathologic descriptions of the variety of cutaneous adverse events seen in patients who received anti-PD-1/PD-L1 treatment and discuss their management. Patients with advanced cancers in clinical trials at University of California Los Angeles (UCLA), receiving anti-PD-1/PD-L1 treatment between 2012 and 2016 who developed cutaneous eruptions and were evaluated in the dermatology clinic were included in this retrospective case series study. A total of 16 patients were included in this study; of these, five were treated with pembrolizumab alone, two with avelumab alone, eight with nivolumab plus ipilimumab and one with nivolumab plus T-Vec. Of these 16 patients, eight had received systemic chemotherapy, six had received radiotherapy, and one had received trememlimumab prior to the immunotherapies described in this study. Cutaneous eruptions occurred at variable times, from week 1 to 88, with a median of 11.5 weeks; the morphologies included lichenoid, bullous, psoriasiform, macular, morbiliform appearances, and alopecia which were confirmed histopathologically in several of the cases. All cutaneous immune-related adverse events were either grade 1 or 2. Ten patients were treated with topical corticosteroids, and one also received NBUVB. Four patients eventually required systemic steroids. Three required discontinuation of their anti-PD-1/PD-L1 therapy secondary to the cutaneous eruptions. There are several different types of adverse cutaneous morphologies that may be seen with administration of PD-1 and PD-L1 inhibitors. Identifying the patterns of eruption may assist in prompt treatment. Most eruptions could be managed with topical corticosteroids and without discontinuation of the systemic treatment.

Trametinib plus 4-Methylumbelliferone Exhibits Antitumor Effects by ERK Blockade and CD44 Downregulation and Affects PD-1 and PD-L1 in Malignant Pleural Mesothelioma.

PubMed

Cho, Hiroyuki; Matsumoto, Seiji; Fujita, Yoshiko; Kuroda, Ayumi; Menju, Toshi; Sonobe, Makoto; Kondo, Nobuyuki; Torii, Ikuko; Nakano, Takashi; Lara, Primo N; Gandara, David R; Date, Hiroshi; Hasegawa, Seiki

2017-03-01

Malignant pleural mesothelioma (MPM) is a highly aggressive malignancy in which the mitogen-activated protein kinase pathway plays a critical role in the regulation of tumorigenesis. Hyaluronic acid (HA) is a major component of the extracellular matrix, and elevated HA levels with a concurrent increase in malignant properties are associated with MPM. We evaluated the effects of trametinib, a mitogen-activated protein kinase (MEK) inhibitor, and 4-methylumbelliferone (4-MU), an HA synthesis inhibitor, alone and in combination on MPM cells in vitro and in vivo. We studied the effects of trametinib, 4-MU, and their combination on MPM cells by using cell viability assays, Western blot analysis, and a mouse xenograft model. Trametinib and 4-MU exhibited antiproliferative activity in MPM cells. Trametinib blocked MEK-dependent extracellular signal-regulated kinase (ERK) phosphorylation and decreased CD44 expression in a concentration-dependent manner. Trametinib inhibited the expression of Fra-1 (the activator protein 1 [AP1] component), inhibited ERK phosphorylation, and decreased CD44 expression. 4-MU inhibited ERK phosphorylation but not CD44 expression. In a mouse xenograft model, trametinib and 4-MU alone suppressed tumor growth compared with a control. The combination had a greater inhibitory effect than either monotherapy. Immunohistochemical analysis showed that trametinib treatment alone significantly reduced expression of programmed cell death 1 ligand 1. Furthermore, the combination of trametinib and 4-MU resulted in higher expression of programmed cell death 1 and programmed cell death 1 ligand 1 than did the 4-MU treatment alone. Our results suggest that trametinib and 4-MU are promising therapeutic agents in MPM and that further study of the combination is warranted. Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Molecular mechanisms and functions of pyroptosis, inflammatory caspases and inflammasomes in infectious diseases.

PubMed

Man, Si Ming; Karki, Rajendra; Kanneganti, Thirumala-Devi

2017-05-01

Cell death is a fundamental biological phenomenon that is essential for the survival and development of an organism. Emerging evidence also indicates that cell death contributes to immune defense against infectious diseases. Pyroptosis is a form of inflammatory programmed cell death pathway activated by human and mouse caspase-1, human caspase-4 and caspase-5, or mouse caspase-11. These inflammatory caspases are used by the host to control bacterial, viral, fungal, or protozoan pathogens. Pyroptosis requires cleavage and activation of the pore-forming effector protein gasdermin D by inflammatory caspases. Physical rupture of the cell causes release of the pro-inflammatory cytokines IL-1β and IL-18, alarmins and endogenous danger-associated molecular patterns, signifying the inflammatory potential of pyroptosis. Here, we describe the central role of inflammatory caspases and pyroptosis in mediating immunity to infection and clearance of pathogens. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Granzyme B Disrupts Central Metabolism and Protein Synthesis in Bacteria to Promote an Immune Cell Death Program.

PubMed

Dotiwala, Farokh; Sen Santara, Sumit; Binker-Cosen, Andres Ariel; Li, Bo; Chandrasekaran, Sriram; Lieberman, Judy

2017-11-16

Human cytotoxic lymphocytes kill intracellular microbes. The cytotoxic granule granzyme proteases released by cytotoxic lymphocytes trigger oxidative bacterial death by disrupting electron transport, generating superoxide anion and inactivating bacterial oxidative defenses. However, they also cause non-oxidative cell death because anaerobic bacteria are also killed. Here, we use differential proteomics to identify granzyme B substrates in three unrelated bacteria: Escherichia coli, Listeria monocytogenes, and Mycobacteria tuberculosis. Granzyme B cleaves a highly conserved set of proteins in all three bacteria, which function in vital biosynthetic and metabolic pathways that are critical for bacterial survival under diverse environmental conditions. Key proteins required for protein synthesis, folding, and degradation are also substrates, including multiple aminoacyl tRNA synthetases, ribosomal proteins, protein chaperones, and the Clp system. Because killer cells use a multipronged strategy to target vital pathways, bacteria may not easily become resistant to killer cell attack. Copyright © 2017 Elsevier Inc. All rights reserved.

Leukemia cell proliferation and death in chronic lymphocytic leukemia patients on therapy with the BTK inhibitor ibrutinib.

PubMed

Burger, Jan A; Li, Kelvin W; Keating, Michael J; Sivina, Mariela; Amer, Ahmed M; Garg, Naveen; Ferrajoli, Alessandra; Huang, Xuelin; Kantarjian, Hagop; Wierda, William G; O'Brien, Susan; Hellerstein, Marc K; Turner, Scott M; Emson, Claire L; Chen, Shih-Shih; Yan, Xiao-Jie; Wodarz, Dominik; Chiorazzi, Nicholas

2017-01-26

BACKGROUND. Ibrutinib is an effective targeted therapy for patients with chronic lymphocytic leukemia (CLL) that inhibits Bruton's tyrosine kinase (BTK), a kinase involved in B cell receptor signaling. METHODS. We used stable isotopic labeling with deuterated water ( 2 H 2 O) to measure directly the effects of ibrutinib on leukemia cell proliferation and death in 30 patients with CLL. RESULTS. The measured average CLL cell proliferation ("birth") rate before ibrutinib therapy was 0.39% of the clone per day (range 0.17%-1.04%); this decreased to 0.05% per day (range 0%-0.36%) with treatment. Death rates of blood CLL cells increased from 0.18% per day (average, range 0%-0.7%) prior to treatment to 1.5% per day (range 0%-3.0%) during ibrutinib therapy, and they were even higher in tissue compartments. CONCLUSIONS. This study provides the first direct in vivo measurements to our knowledge of ibrutinib's antileukemia actions, demonstrating profound and immediate inhibition of CLL cell proliferation and promotion of high rates of CLL cell death. TRIAL REGISTRATION. This trial was registered at clinicaltrials.gov (NCT01752426). FUNDING. This study was supported by a Cancer Center Support Grant (National Cancer Institute grant P30 CA016672), an NIH grant (CA081554) from the National Cancer Institute, MD Anderson's Moon Shots Program in CLL, and Pharmacyclics, an AbbVie company.

A Constructivist Approach to Inquiry-Based Learning: A TUNEL Assay for the Detection of Apoptosis in Cheek Cells

ERIC Educational Resources Information Center

Correiro, Elizabeth E.; Griffin, Leanne R.; Hart, Peter E.

2008-01-01

A laboratory exercise is presented that incorporates constructivist principles into a learning experience designed for upper-level university biology courses. The specific objectives for this exercise are as follows: (1) To introduce students to cancer biology and to the regulation of programmed cell death as part of the cell cycle; (2) To engage…

Programmed Death-1 Ligand 2-Mediated Regulation of the PD-L1 to PD-1 Axis Is Essential for Establishing CD4(+) T Cell Immunity.

PubMed

Karunarathne, Deshapriya S; Horne-Debets, Joshua M; Huang, Johnny X; Faleiro, Rebecca; Leow, Chiuan Yee; Amante, Fiona; Watkins, Thomas S; Miles, John J; Dwyer, Patrick J; Stacey, Katryn J; Yarski, Michael; Poh, Chek Meng; Lee, Jason S; Cooper, Matthew A; Rénia, Laurent; Richard, Derek; McCarthy, James S; Sharpe, Arlene H; Wykes, Michelle N

2016-08-16

Many pathogens, including Plasmodium spp., exploit the interaction of programmed death-1 (PD-1) with PD-1-ligand-1 (PD-L1) to "deactivate" T cell functions, but the role of PD-L2 remains unclear. We studied malarial infections to understand the contribution of PD-L2 to immunity. Here we have shown that higher PD-L2 expression on blood dendritic cells, from Plasmodium falciparum-infected individuals, correlated with lower parasitemia. Mechanistic studies in mice showed that PD-L2 was indispensable for establishing effective CD4(+) T cell immunity against malaria, because it not only inhibited PD-L1 to PD-1 activity but also increased CD3 and inducible co-stimulator (ICOS) expression on T cells. Importantly, administration of soluble multimeric PD-L2 to mice with lethal malaria was sufficient to dramatically improve immunity and survival. These studies show immuno-regulation by PD-L2, which has the potential to be translated into an effective treatment for malaria and other diseases where T cell immunity is ineffective or short-lived due to PD-1-mediated signaling. Copyright © 2016 Elsevier Inc. All rights reserved.

Pools of programmed death-ligand within the oral cavity tumor microenvironment: Variable alteration by targeted therapies.

PubMed

Shah, Sujay; Caruso, Andria; Cash, Harrison; Waes, Carter Van; Allen, Clint T

2016-08-01

Enhanced understanding of programmed death-ligand (PD-L) expression in oral cancer is important for establishing rational combinations of emerging immune checkpoint and molecular targeted therapies. We assessed PD-L and interferon (IFN) expression in immunogenic murine oral cancer-1 (MOC1) and poorly immunogenic MOC2 cell models after treatment with mammalian target of rapamycin (mTOR) and MEK1/2 small molecule inhibitors in vitro and in vivo. PD-L1 but not PD-L2 is expressed on MOC1 and 2 cells and is type I and II IFN-dependent. PD-L1 is differentially expressed on cancer and endothelial cells and infiltrating myeloid-derived suppressor cells, macrophages, and regulatory T cells (Tregs) in highly and poorly immunogenic tumors. PD-L1 expression is variably altered after treatment with inhibitors in vivo, with an imperfect relationship to alterations in IFN levels in the tumor microenvironment. PD-L1 expressed on cancer and infiltrating immune cells is variably altered by targeted therapies and may, in part, reflect changes in tumor IFN. © 2016 Wiley Periodicals, Inc. Head Neck 38:1176-1186, 2016. © 2016 Wiley Periodicals, Inc.

Modeling activity and target-dependent developmental cell death of mouse retinal ganglion cells ex vivo.

PubMed

Voyatzis, Sylvie; Muzerelle, Aude; Gaspar, Patricia; Nicol, Xavier

2012-01-01

Programmed cell death is widespread during the development of the central nervous system and serves multiple purposes including the establishment of neural connections. In the mouse retina a substantial reduction of retinal ganglion cells (RGCs) occurs during the first postnatal week, coinciding with the formation of retinotopic maps in the superior colliculus (SC). We previously established a retino-collicular culture preparation which recapitulates the progressive topographic ordering of RGC projections during early post-natal life. Here, we questioned whether this model could also be suitable to examine the mechanisms underlying developmental cell death of RGCs. Brn3a was used as a marker of the RGCs. A developmental decline in the number of Brn3a-immunolabelled neurons was found in the retinal explant with a timing that paralleled that observed in vivo. In contrast, the density of photoreceptors or of starburst amacrine cells increased, mimicking the evolution of these cell populations in vivo. Blockade of neural activity with tetrodotoxin increased the number of surviving Brn3a-labelled neurons in the retinal explant, as did the increase in target availability when one retinal explant was confronted with 2 or 4 collicular slices. Thus, this ex vivo model reproduces the developmental reduction of RGCs and recapitulates its regulation by neural activity and target availability. It therefore offers a simple way to analyze developmental cell death in this classic system. Using this model, we show that ephrin-A signaling does not participate to the regulation of the Brn3a population size in the retina, indicating that eprhin-A-mediated elimination of exuberant projections does not involve developmental cell death.

Photothermal effects of laser-activated surface plasmonic gold nanoparticles on the apoptosis and osteogenesis of osteoblast-like cells

PubMed Central

Rau, Lih-Rou; Huang, Wan-Yu; Liaw, Jiunn-Woei; Tsai, Shiao-Wen

2016-01-01

The specific properties of gold nanoparticles (AuNPs) make them a novel class of photothermal agents that can induce cancer cell damage and even death through the conversion of optical energy to thermal energy. Most relevant studies have focused on increasing the precision of cell targeting, improving the efficacy of energy transfer, and exploring additional functions. Nevertheless, most cells can uptake nanosized particles through nonspecific endocytosis; therefore, before hyperthermia via AuNPs can be applied for clinical use, it is important to understand the adverse optical–thermal effects of AuNPs on nontargeted cells. However, few studies have investigated the thermal effects induced by pulsed laser-activated AuNPs on nearby healthy cells due to nonspecific treatment. The aim of this study is to evaluate the photothermal effects induced by AuNPs plus a pulsed laser on MG63, an osteoblast-like cell line, specifically examining the effects on cell morphology, viability, death program, and differentiation. The cells were treated with media containing 50 nm AuNPs at a concentration of 5 ppm for 1 hour. Cultured cells were then exposed to irradiation at 60 mW/cm2 and 80 mW/cm2 by a Nd:YAG laser (532 nm wavelength). We observed that the cytoskeletons of MG63 cells treated with bare AuNPs followed by pulsed laser irradiation were damaged, and these cells had few bubbles on the cell membrane compared with those that were not treated (control) or were treated with AuNPs or the laser alone. There were no significant differences between the AuNPs plus laser treatment group and the other groups in terms of cell viability, death program analysis results, or alkaline phosphatase and calcium accumulation during culture for up to 21 days. However, the calcium deposit areas in the cells treated with AuNPs plus laser were larger than those in other groups during the early culture period. PMID:27555768

Photothermal effects of laser-activated surface plasmonic gold nanoparticles on the apoptosis and osteogenesis of osteoblast-like cells.

PubMed

Rau, Lih-Rou; Huang, Wan-Yu; Liaw, Jiunn-Woei; Tsai, Shiao-Wen

2016-01-01

The specific properties of gold nanoparticles (AuNPs) make them a novel class of photothermal agents that can induce cancer cell damage and even death through the conversion of optical energy to thermal energy. Most relevant studies have focused on increasing the precision of cell targeting, improving the efficacy of energy transfer, and exploring additional functions. Nevertheless, most cells can uptake nanosized particles through nonspecific endocytosis; therefore, before hyperthermia via AuNPs can be applied for clinical use, it is important to understand the adverse optical-thermal effects of AuNPs on nontargeted cells. However, few studies have investigated the thermal effects induced by pulsed laser-activated AuNPs on nearby healthy cells due to nonspecific treatment. The aim of this study is to evaluate the photothermal effects induced by AuNPs plus a pulsed laser on MG63, an osteoblast-like cell line, specifically examining the effects on cell morphology, viability, death program, and differentiation. The cells were treated with media containing 50 nm AuNPs at a concentration of 5 ppm for 1 hour. Cultured cells were then exposed to irradiation at 60 mW/cm(2) and 80 mW/cm(2) by a Nd:YAG laser (532 nm wavelength). We observed that the cytoskeletons of MG63 cells treated with bare AuNPs followed by pulsed laser irradiation were damaged, and these cells had few bubbles on the cell membrane compared with those that were not treated (control) or were treated with AuNPs or the laser alone. There were no significant differences between the AuNPs plus laser treatment group and the other groups in terms of cell viability, death program analysis results, or alkaline phosphatase and calcium accumulation during culture for up to 21 days. However, the calcium deposit areas in the cells treated with AuNPs plus laser were larger than those in other groups during the early culture period.

Docosahexaenoic acid counteracts attenuation of CD95-induced cell death by inorganic mercury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Randall; Lanni, Lydia; Jen, K.-L. Catherine

In the United States the principal environmental exposure to mercury is through dietary consumption of sea food. Although the mechanism by which low levels of mercury affect the nervous system is not well established, epidemiological studies suggest that low level exposure of pregnant women to dietary mercury can adversely impact cognitive development in their children, but that Docosahexaenoic acid (DHA), the most prominent n-polyunsaturated fatty acid (n-PUFA) present in fish may counteract negative effects of mercury on the nervous system. Aside from effects on the nervous system, epidemiological and animal studies have also suggested that low level mercury exposure maymore » be a risk factor for autoimmune disease. However unlike the nervous system where a mechanism linking mercury to impaired cognitive development remains elusive, we have previously suggested a potential mechanism linking low level mercury exposures to immune system dysfunction and autoimmunity. In the immune system it is well established that disruption of CD95 mediated apoptosis leads to autoimmune disease. We have previously shown in vitro as well as in vivo that in lymphocytes burdened with low levels of mercury, CD95 mediated cell death is impaired. In this report we now show that DHA counteracts the negative effect of mercury on CD95 signaling in T lymphocytes. T cells which have been pre-exposed to DHA are able to cleave pro-caspase 3 and efficiently signal programmed cell death through the CD95 signaling pathway, whether or not they are burdened with low levels of mercury. Thus DHA may lower the risk of autoimmune disease after low level mercury exposures. - Highlights: • Inorganic mercury (Hg{sup 2+}) interferes with CD95 mediated cell death in Jurkat T cells • DHA restores the ability of CD95 to signal cell death in Hg{sup 2+} intoxicated T cells • The restoration of CD95 mediated cell death by DHA is correlated with increased activation of Caspase 3.« less

Morusin induces paraptosis-like cell death through mitochondrial calcium overload and dysfunction in epithelial ovarian cancer.

PubMed

Xue, Jing; Li, Rui; Zhao, Xinrui; Ma, Congcong; Lv, Xin; Liu, Lidong; Liu, Peishu

2018-03-01

Epithelial ovarian cancer (EOC) is the leading cause of death among all gynecological cancers. Morusin, a prenylated flavonoid extracted from the root bark of Morus australis, has been reported to exhibit anti-tumor activity against various human cancers except EOC. In the present study, we explored the potential anti-cancer activity of morusin against EOC in vitro and in vivo and possible underlying mechanisms for the first time. We first found that morusin effectively inhibited EOC cell proliferation and survival in vitro and suppressed tumor growth in vivo. Then we observed that treatment of EOC cells with morusin resulted in paraptosis-like cell death, a novel mode of non-apoptotic programmed cell death that is characterized by extensive cytoplasmic vacuolation due to dilation of the endoplasmic reticulum (ER) and mitochondria and lack of apoptotic hallmarks. In addition, we discovered that morusin induced obvious increase in mitochondrial Ca 2+ levels, accumulation of ER stress markers, generation of reactive oxygen species (ROS), and loss of mitochondrial membrane potential (Δψm) in EOC cells. Furthermore, pretreatment with 4, 4'-diisothiocyanostilbene-2, 2'-disulfonic acid (DIDS), a chemical inhibitor of voltage-dependent anion channel (VDAC) on the outer mitochondrial membrane, effectively inhibited mitochondrial Ca 2+ influx, cytoplasmic vacuolation and cell death induced by morusin in EOC cells. Moreover, DIDS pretreatment also suppressed morusin-induced accumulation of ER stress markers, ROS production and depletion of Δψm. Consistently, tumor xenograft assays showed that co-treatment with DIDS partially reversed the inhibitory effects of morusin on tumor growth in vivo and inhibited the increased levels of ER stress markers induced by morusin in tumor tissues. Collectively, our results suggest that VDAC-mediated Ca 2+ influx into mitochondria and subsequent mitochondrial Ca 2+ overload contribute to mitochondrial swelling and dysfunction, leading to morusin-induced paraptosis-like cell death in EOC. This study may provide alternative therapeutic strategies for EOC exhibiting resistance to apoptosis. Copyright © 2018 Elsevier B.V. All rights reserved.

Signaling mechanisms of apoptosis-like programmed cell death in unicellular eukaryotes.

PubMed

Shemarova, Irina V

2010-04-01

In unicellular eukaryotes, apoptosis-like cell death occurs during development, aging and reproduction, and can be induced by environmental stresses and exposure to toxic agents. The essence of the apoptotic machinery in unicellular organisms is similar to that in mammals, but the apoptotic signal network is less complex and of more ancient origin. The review summarizes current data about key apoptotic proteins and mechanisms of the transduction of apoptotic signals by caspase-like proteases and mitochondrial apoptogenic proteins in unicellular eukaryotes. The roles of receptor-dependent and receptor-independent caspase cascades are reviewed. 2010 Elsevier Inc. All rights reserved.

Induction of cell death by tospoviral protein NSs and the motif critical for cell death does not control RNA silencing suppression activity.

PubMed

Singh, Ajeet; Permar, Vipin; Jain, R K; Goswami, Suneha; Kumar, Ranjeet Ranjan; Canto, Tomas; Palukaitis, Peter; Praveen, Shelly

2017-08-01

Groundnut bud necrosis virus induces necrotic symptoms in different hosts. Previous studies showed reactive oxygen species-mediated programmed cell death (PCD) resulted in necrotic symptoms. Transgenic expression of viral protein NSs mimics viral symptoms. Here, we showed a role for NSs in influencing oxidative burst in the cell, by analyzing H 2 O 2 accumulation, activities of antioxidant enzymes and expression levels of vacuolar processing enzymes, H 2 O 2 -responsive microRNA 319a.2 plus its possible target metacaspase-8. The role of NSs in PCD, was shown using two NSs mutants: one in the Trp/GH3 motif (a homologue of pro-apototic domain) (NSs S189R ) and the other in a non-Trp/GH3 motif (NSs L172R ). Tobacco rattle virus (TRV) expressing NSs S189R enhanced the PCD response, but not TRV-NSs L172R , while RNA silencing suppression activity was lost in TRV-NSs L172R , but not in TRV-NSs S189R . Therefore, we propose dual roles of NSs in RNA silencing suppression and induction of cell death, controlled by different motifs. Copyright © 2017 Elsevier Inc. All rights reserved.

Antiproliferative Activity and Induction of Apoptosis in Human Melanoma Cells by Houttuynia cordata Thunb Extract.

PubMed

Yanarojana, Mongkol; Nararatwanchai, Thamthiwat; Thairat, Sarut; Tancharoen, Salunya

2017-12-01

To analyze the apoptotic effect of Houttuynia cordata Thunb (HCT) extract on human melanoma A375 cells and its underlying mechanisms. The effects of HCT on cell death were determined using the MTT assay. Hoechst 33342 staining was conducted to confirm the detection of cell apoptosis. Caspase-3 and caspase-8 mRNA and cleaved protein levels were investigated by RT-PCR and western blotting, respectively. The release of high mobility group box 1 (HMGB1) and phosphorylation of mitogen-activated protein kinase (MAPK) were determined by ELISA. Caspase-3 and caspase-8 specific inhibitors suppressed HCT-induced cell death. HCT increased caspase-3 and caspase-8 mRNA, protein levels, and caspase activities in a concentration- and time-dependent manner. HCT induced MAPK phosphorylation in a time-dependent fashion. Pretreatment of cells with a selective inhibitor of p38 MAPK reduced apoptosis and reversed the levels of HMGB1 release in response to HCT treatment. HCT induces A375 programmed cell death by activating the caspase-dependent pathway and by p38 phosphorylation associated with HMGB1 reduction. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Heterologous expression of anti-apoptotic human 14-3-3β/α enhances iron-mediated programmed cell death in yeast

PubMed Central

Eid, Rawan; Zhou, David R.; Arab, Nagla T. T.; Boucher, Eric; Young, Paul G.; Mandato, Craig A.

2017-01-01

The induction of Programmed Cell Death (PCD) requires the activation of complex responses involving the interplay of a variety of different cellular proteins, pathways, and processes. Uncovering the mechanisms regulating PCD requires an understanding of the different processes that both positively and negatively regulate cell death. Here we have examined the response of normal as well as PCD resistant yeast cells to different PCD inducing stresses. As expected cells expressing the pro-survival human 14-3-3β/α sequence show increased resistance to numerous stresses including copper and rapamycin. In contrast, other stresses including iron were more lethal in PCD resistant 14-3-3β/α expressing cells. The increased sensitivity to PCD was not iron and 14-3-3β/α specific since it was also observed with other stresses (hydroxyurea and zinc) and other pro-survival sequences (human TC-1 and H-ferritin). Although microscopical examination revealed little differences in morphology with iron or copper stresses, cells undergoing PCD in response to high levels of prolonged copper treatment were reduced in size. This supports the interaction some forms of PCD have with the mechanisms regulating cell growth. Analysis of iron-mediated effects in yeast mutant strains lacking key regulators suggests that a functional vacuole is required to mediate the synergistic effects of iron and 14-3-3β/α on yeast PCD. Finally, mild sub-lethal levels of copper were found to attenuate the observed inhibitory effects of iron. Taken together, we propose a model in which a subset of stresses like iron induces a complex process that requires the cross-talk of two different PCD inducing pathways. PMID:28854230

Mitochondrial Dysfunction and Ca(2+) Overload Contributes to Hesperidin Induced Paraptosis in Hepatoblastoma Cells, HepG2.

PubMed

Yumnam, Silvia; Hong, Gyeong Eun; Raha, Suchismita; Saralamma, Venu Venkatarame Gowda; Lee, Ho Jeong; Lee, Won-Sup; Kim, Eun-Hee; Kim, Gon Sup

2016-06-01

Paraptosis is a programmed cell death which is morphologically and biochemically different from apoptosis. In this study, we have investigated the role of Ca(2+) in hesperidin-induced paraptotic cell death in HepG2 cells. Increase in mitochondrial Ca(2+) level was observed in hesperidin treated HepG2 cells but not in normal liver cancer cells. Inhibition of inositol-1,4,5-triphosphate receptor (IP3 R) and ryanodine receptor also block the mitochondrial Ca(2+) accumulation suggesting that the release of Ca(2+) from the endoplasmic reticulum (ER) may probably lead to the increase in mitochondrial Ca(2+) level. Pretreatment with ruthenium red (RuRed), a Ca(2+) uniporter inhibitor inhibited the hesperidin-induced mitochondrial Ca(2+) overload, swelling of mitochondria, and cell death in HepG2 cells. It has also been demonstrated that mitochondrial Ca(2+) influxes act upstream of ROS and mitochondrial superoxide production. The increased ROS production further leads to mitochondrial membrane loss in hesperidin treated HepG2 cells. Taken together our results show that IP3 R and ryanodine receptor mediated release of Ca(2+) from the ER and its subsequent influx through the uniporter into mitochondria contributes to hesperidin-induced paraptosis in HepG2 cells. © 2015 Wiley Periodicals, Inc.

Pyroptosis: Gasdermin-Mediated Programmed Necrotic Cell Death.

PubMed

Shi, Jianjin; Gao, Wenqing; Shao, Feng

2017-04-01

Pyroptosis was long regarded as caspase-1-mediated monocyte death in response to certain bacterial insults. Caspase-1 is activated upon various infectious and immunological challenges through different inflammasomes. The discovery of caspase-11/4/5 function in sensing intracellular lipopolysaccharide expands the spectrum of pyroptosis mediators and also reveals that pyroptosis is not cell type specific. Recent studies identified the pyroptosis executioner, gasdermin D (GSDMD), a substrate of both caspase-1 and caspase-11/4/5. GSDMD represents a large gasdermin family bearing a novel membrane pore-forming activity. Thus, pyroptosis is redefined as gasdermin-mediated programmed necrosis. Gasdermins are associated with various genetic diseases, but their cellular function and mechanism of activation (except for GSDMD) are unknown. The gasdermin family suggests a new area of research on pyroptosis function in immunity, disease, and beyond. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rho-associated kinases play an essential role in cardiac morphogenesis and cardiomyocyte proliferation.

PubMed

Zhao, Zhiyong; Rivkees, Scott A

2003-01-01

Rho-associated coiled-coil kinases (ROCKs), initially identified as effectors for Rho GTPases, play a role in cardiac cell physiology and are also expressed in the developing heart. However, their role in cardiac development is not known. To investigate the role of these kinases in cardiac development, we examined cardiac development in cultured murine embryos treated with the ROCK inhibitor Y27632. After inhibition of ROCK activity, we found disturbed cardiac chamber formation and trabeculation. To further examine the mechanisms by which ROCK blockade causes cardiac hypoplasia, we assessed programmed cell death and cell proliferation in the hearts. We found decreased cell proliferation in the Y27632-treated hearts, but no changes in programmed cell death. We further observed that ROCK inhibition decreased cardiac myocyte proliferation, suggesting that ROCK kinases regulate cardiomyocyte division. To identify factors involved in ROCK action in regulation of cardiac cell division, we examined expression of cell cycle proteins by using Western blot analysis. We found that ROCK blockade decreased expression of cell cycle proteins, cyclin D3, CDK6, and p27(KIP1) in the hearts and cardiomyocytes, which are required for initiation of cell cycle and G1/S phase transition. These observations show that ROCK kinases play a role in cardiac development and that ROCK kinases regulate cardiac cell proliferation and cell cycle protein expression. Copyright 2002 Wiley-Liss, Inc.

Construction of an anti-programmed death-ligand 1 chimeric antigen receptor and determination of its antitumor function with transduced cells

PubMed Central

Xie, Jiasen; Zhou, Zishan; Jiao, Shunchang; Li, Xiaokun

2018-01-01

A chimeric antigen receptor (CAR) is a type of fusion protein that comprises an antigen-recognition domain and signaling domains. In the present study, a programmed death-ligand 1 (PD-L1)-specific CAR, comprised of a single-chain variable fragment (scFv) derived from a monoclonal antibody, co-stimulatory domains of cluster of differentiation (CD) 28 and 4-1BB and a T-cell-activation domain derived from CD3ζ, was designed. The construction was cloned and packaged into the lentiviral vector pLVX. Flow cytometry confirmed that peripheral blood mononuclear cells were efficiently transduced and that the CAR was successfully expressed on T cells. The cytotoxicity of transduced T cells was detected using PD-L1-positive NCI-H358 bronchioalveolar carcinoma cells and A549 lung adenocarcinoma cells (with a low expression of PD-L1, only in the A549 cells). The results demonstrated mild cytotoxicity at an effector-to-target ratio of 10:1. An ELISA revealed a significant increase in the level of interferon-γ released from T cells transduced with scFv-28Bz when the cells were co-cultured with PD-L1-positive NCI-H358 cells, while interkeukin-2 and tumor necrosis factor-α levels remained unchanged. These data indicated a potential method for the treatment of solid tumors. PMID:29928397

Proteases and caspase-like activity in the yeast Saccharomyces cerevisiae.

PubMed

Wilkinson, Derek; Ramsdale, Mark

2011-10-01

A variety of proteases have been implicated in yeast PCD (programmed cell death) including the metacaspase Mca1 and the separase Esp1, the HtrA-like serine protease Nma111, the cathepsin-like serine carboxypeptideases and a range of vacuolar proteases. Proteasomal activity is also shown to have an important role in determining cell fate, with both pro- and anti-apoptotic roles. Caspase 3-, 6- and 8-like activities are detected upon stimulation of yeast PCD, but not all of this activity is associated with Mca1, implicating other proteases with caspase-like activity in the yeast cell death response. Global proteolytic events that accompany PCD are discussed alongside a consideration of the conservation of the death-related degradome (both at the level of substrate choice and cleavage site). The importance of both gain-of-function changes in the degradome as well as loss-of-function changes are highlighted. Better understanding of both death-related proteases and their substrates may facilitate the design of future antifungal drugs or the manipulation of industrial yeasts for commercial exploitation.

Extracellular calcium triggers unique transcriptional programs and modulates staurosporine-induced cell death in Neurospora crassa

PubMed Central

Gonçalves, A. P.; Monteiro, João; Lucchi, Chiara; Kowbel, David J.; Cordeiro, J. M.; Correia-de-Sá, Paulo; Rigden, Daniel J.; Glass, N. L.; Videira, Arnaldo

2014-01-01

Alterations in the intracellular levels of calcium are a common response to cell death stimuli in animals and fungi and, particularly, in the Neurospora crassa response to staurosporine. We highlight the importance of the extracellular availability of Ca2+ for this response. Limitation of the ion in the culture medium further sensitizes cells to the drug and results in increased accumulation of reactive oxygen species (ROS). Conversely, an approximately 30-fold excess of external Ca2+ leads to increased drug tolerance and lower ROS generation. In line with this, distinct staurosporine-induced cytosolic Ca2+ signaling profiles were observed in the absence or presence of excessive external Ca2+. High-throughput RNA sequencing revealed that different concentrations of extracellular Ca2+ define distinct transcriptional programs. Our transcriptional profiling also pointed to two putative novel Ca2+-binding proteins, encoded by the NCU08524 and NCU06607 genes, and provides a reference dataset for future investigations on the role of Ca2+ in fungal biology. PMID:28357255

Targeting the upstream transcriptional activator of PD-L1 as an alternative strategy in melanoma therapy.

PubMed

Zhu, Bo; Tang, Liming; Chen, Shuyang; Yin, Chengqian; Peng, Shiguang; Li, Xin; Liu, Tongzheng; Liu, Wei; Han, Changpeng; Stawski, Lukasz; Xu, Zhi-Xiang; Zhou, Guangbiao; Chen, Xiang; Gao, Xiumei; Goding, Colin R; Xu, Nan; Cui, Rutao; Cao, Peng

2018-05-22

Programmed cell death ligand 1 (PD-L1) interacts with programmed cell death protein-1 (PD-1) as an immune checkpoint. Reactivating the immune response by inhibiting PD-L1 using therapeutic antibodies provides substantial clinical benefits in many, though not all, melanoma patients. However, transcriptional suppression of PD-L1 expression as an alternative therapeutic anti-melanoma strategy has not been exploited. Here we provide biochemical evidence demonstrating that ultraviolet radiation (UVR) induction of PD-L1 in skin is directly controlled by nuclear factor E2-related transcription factor 2 (NRF2). Depletion of NRF2 significantly induces tumor infiltration by both CD8 + and CD4 + T cells to suppress melanoma progression, and combining NRF2 inhibition with anti-PD-1 treatment enhanced its anti-tumor function. Our studies identify a critical and targetable PD-L1 upstream regulator and provide an alternative strategy to inhibit the PD-1/PD-L1 signaling in melanoma treatment.

Autophagy, programmed cell death and reactive oxygen species in sexual reproduction in plants.

PubMed

Kurusu, Takamitsu; Kuchitsu, Kazuyuki

2017-05-01

Autophagy is one of the major cellular processes of recycling of proteins, metabolites and intracellular organelles, and plays crucial roles in the regulation of innate immunity, stress responses and programmed cell death (PCD) in many eukaryotes. It is also essential in development and sexual reproduction in many animals. In plants, although autophagy-deficient mutants of Arabidopsis thaliana show phenotypes in abiotic and biotic stress responses, their life cycle seems normal and thus little had been known until recently about the roles of autophagy in development and reproduction. Rice mutants defective in autophagy show sporophytic male sterility and immature pollens, indicating crucial roles of autophagy during pollen maturation. Enzymatic production of reactive oxygen species (ROS) by respiratory burst oxidase homologues (Rbohs) play multiple roles in regulating anther development, pollen tube elongation and fertilization. Significance of autophagy and ROS in the regulation of PCD of transient cells during plant sexual reproduction is discussed in comparison with animals.

Immune checkpoint blockade: the role of PD-1-PD-L axis in lymphoid malignancies

PubMed Central

Ilcus, Cristina; Bagacean, Cristina; Tempescul, Adrian; Popescu, Cristian; Parvu, Andrada; Cenariu, Mihai; Bocsan, Corina; Zdrenghea, Mihnea

2017-01-01

The co-inhibitory receptor programmed cell death (PD)-1, expressed by immune effector cells, is credited with a protective role for normal tissue during immune responses, by limiting the extent of effector activation. Its presently known ligands, programmed death ligands (PD-Ls) 1 and 2, are expressed by a variety of cells including cancer cells, suggesting a role for these molecules as an immune evasion mechanism. Blocking of the PD-1-PD-L signaling axis has recently been shown to be effective and was clinically approved in relapsed/refractory tumors such as malignant melanoma and lung cancer, but also classical Hodgkin’s lymphoma. A plethora of trials exploring PD-1 blockade in cancer are ongoing. Here, we review the role of PD-1 signaling in lymphoid malignancies, and the latest results of trials investigating PD-1 or PD-L1 blocking agents in this group of diseases. Early phase studies proved very promising, leading to the clinical approval of a PD-1 blocking agent in Hodgkin’s lymphoma, and Phase III clinical studies are either planned or ongoing in most lymphoid malignancies. PMID:28496333

Advances in immunotherapy for non-small cell lung cancer.

PubMed

Reckamp, Karen L

2015-12-01

In most patients, lung cancer presents as advanced disease with metastases to lymph nodes and/or distant organs, and survival is poor. Lung cancer is also a highly immune-suppressing malignancy with numerous methods to evade antitumor immune responses, including deficiencies in antigen processing and presentation, release of immunomodulatory cytokines, and inhibition of T-cell activation. Advances in understanding the complex interactions of the immune system and cancer have led to novel therapies that promote T-cell activation at the tumor site, resulting in prolonged clinical benefit. Immune checkpoint inhibitors, specifically programmed death receptor 1 pathway antibodies, have demonstrated impressively durable responses and improved survival in patients with non-small cell lung cancer. This article will review the recent progress made in immunotherapy for lung cancer with data from trials evaluating programmed death receptor 1 and cytotoxic T-lymphocyte-associated protein 4 monoclonal antibodies in addition to cancer vaccines. The review will focus on studies that have been published and the latest randomized trials exploring immune therapy in lung cancer. These results form the framework for a new direction in the treatment of lung cancer toward immunotherapy.

Involvement of Alveolar Epithelial Cell Necroptosis in IPF Pathogenesis.

PubMed

Lee, Ji-Min; Yoshida, Masahiro; Kim, Mi-So; Lee, June-Hyuk; Baek, Ae-Rin; Jang, An Soo; Kim, Do Jin; Minagawa, Shunsuke; Chin, Su Sie; Park, Choon-Sik; Araya, Jun; Kuwano, Kazuyoshi; Park, Sung Woo

2018-02-14

Alveolar epithelial cell (AEC) injury leading to cell death is involved in the process of fibrosis development during idiopathic pulmonary fibrosis (IPF). Among regulated/programmed cell death, the excessive apoptosis of AECs has been widely implicated in IPF pathogenesis. Necroptosis is a type of regulated/programmed necrosis. A multiprotein complex composed of receptor-interacting protein kinase-1 and -3 (RIPK1/3) plays a key regulatory role in initiating necroptosis. Although necroptosis participates in disease pathogeneses through the release of damage-associated molecular patterns (DAMPs), its association with IPF progression remains elusive. In this study, we attempted to illuminate the involvement of RIPK3-regulated necroptosis in IPF pathogenesis. IPF lung tissues were used to detect necroptosis, and the role of RIPK3 was determined using cell culturing models of AECs. Lung fibrosis models of bleomycin (BLM) treatment were also used. RIPK3 expression levels were increased in IPF lungs and both apoptosis and necroptosis were detected mainly in AECs. Necrostatin-1 and RIPK3 knockdown experiments in AECs revealed the participation of necroptosis in BLM and hydrogen peroxide-induced cell death. BLM treatment induced RIPK3 expression in AECs and increased High Mobility Group Box 1 (HMGB1) and interleukin 1β (IL-1β) levels in mouse lungs. The efficient attenuation of BLM-induced lung inflammation and fibrosis was determined in RIPK3 knockout mice and by necrostatin-1 with a concomitant reduction in HMGB1 and IL-1β. RIPK3-regulated necroptosis in AECs is involved in the mechanism of lung fibrosis development through the release of DAMPs as part of the pathogenic sequence of IPF.

The Enemy within: Innate Surveillance-Mediated Cell Death, the Common Mechanism of Neurodegenerative Disease

PubMed Central

Richards, Robert I.; Robertson, Sarah A.; O'Keefe, Louise V.; Fornarino, Dani; Scott, Andrew; Lardelli, Michael; Baune, Bernhard T.

2016-01-01

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 innate-mediated damage in neural tissues, and renders innate surveillance mediated cell death a plausible common pathogenic pathway responsible for neurodegenerative diseases, in both familial and sporadic forms. Here we have assembled evidence in favor of the hypothesis that neurodegenerative disease is the cumulative result of chronic activation of the innate surveillance pathway, triggered by endogenous or environmental danger or damage associated molecular patterns in a progressively expanding cascade of inflammation, tissue damage and cell death. PMID:27242399

Cell proliferation and apoptosis during histogenesis of the guinea pig and rabbit cerebellar cortex.

PubMed

Lossi, Laura; Coli, Alessandra; Giannessi, Elisabetta; Stornelli, Maria Rita; Marroni, Paolo

2002-01-01

Cell proliferation and apoptosis are essential for development of the nervous system. In this study we have investigated the histogenesis of the cerebellar cortex in guinea pig (a precocial species) and rabbit (an altricial species) at different stages of pregnancy and postnatal life. Proliferating cells were identified after labeling with antibodies against the proliferating cell nuclear antigen (PCNA) and/or the Ki-67 antigen. Apoptotic cells were visualized in situ by the TUNEL method and by immunodetection of cleaved caspase 3 and 9. In guinea pigs, both proliferating and apoptotic cells were detected during pre-natal life (E0-E40). Conversely, cell proliferation and apoptosis in rabbits were temporally restricted to early postnatal weeks (P0-P20). In both species cell proliferation was mainly linked to differentiation and migration of the granule cells. In both species, the majority of cells undergoing programmed cell death likely corresponded to granule cells. They were mainly detected in the external granular layer, and were by far more common than previously reported in other locations of the postnatal brain. This study shows that apoptosis is a shared process of cell death during cerebellar development in both altricial and precocial animals, and that there is a direct spatial and temporal correlation between cell proliferation and death in two mammals with different time tables in cerebellar maturation.

Strategic disruption of nuclear pores structure, integrity and barrier for nuclear apoptosis.

PubMed

Shahin, Victor

2017-08-01

Apoptosis is a programmed cell death playing key roles in physiology and pathophysiology of multi cellular organisms. Its nuclear manifestation requires transmission of the death signals across the nuclear pore complexes (NPCs). In strategic sequential steps apoptotic factors disrupt NPCs structure, integrity and barrier ultimately leading to nuclear breakdown. The present review reflects on these steps. Copyright © 2017 Elsevier Ltd. All rights reserved.

The plant metacaspase AtMC1 in pathogen-triggered programmed cell death and aging: functional linkage with autophagy

PubMed Central

Coll, N S; Smidler, A; Puigvert, M; Popa, C; Valls, M; Dangl, J L

2014-01-01

Autophagy is a major nutrient recycling mechanism in plants. However, its functional connection with programmed cell death (PCD) is a topic of active debate and remains not well understood. Our previous studies established the plant metacaspase AtMC1 as a positive regulator of pathogen-triggered PCD. Here, we explored the linkage between plant autophagy and AtMC1 function in the context of pathogen-triggered PCD and aging. We observed that autophagy acts as a positive regulator of pathogen-triggered PCD in a parallel pathway to AtMC1. In addition, we unveiled an additional, pro-survival homeostatic function of AtMC1 in aging plants that acts in parallel to a similar pro-survival function of autophagy. This novel pro-survival role of AtMC1 may be functionally related to its prodomain-mediated aggregate localization and potential clearance, in agreement with recent findings using the single budding yeast metacaspase YCA1. We propose a unifying model whereby autophagy and AtMC1 are part of parallel pathways, both positively regulating HR cell death in young plants, when these functions are not masked by the cumulative stresses of aging, and negatively regulating senescence in older plants. PMID:24786830

Found in Translation: How Preclinical Research Is Guiding the Clinical Development of the BCL2-Selective Inhibitor Venetoclax.

PubMed

Leverson, Joel D; Sampath, Deepak; Souers, Andrew J; Rosenberg, Saul H; Fairbrother, Wayne J; Amiot, Martine; Konopleva, Marina; Letai, Anthony

2017-12-01

Since the discovery of apoptosis as a form of programmed cell death, targeting the apoptosis pathway to induce cancer cell death has been a high-priority goal for cancer therapy. After decades of effort, drug-discovery scientists have succeeded in generating small-molecule inhibitors of antiapoptotic BCL2 family proteins. Innovative medicinal chemistry and structure-based drug design, coupled with a strong fundamental understanding of BCL2 biology, were essential to the development of BH3 mimetics such as the BCL2-selective inhibitor venetoclax. We review a number of preclinical studies that have deepened our understanding of BCL2 biology and facilitated the clinical development of venetoclax. Significance: Basic research into the pathways governing programmed cell death have paved the way for the discovery of apoptosis-inducing agents such as venetoclax, a BCL2-selective inhibitor that was recently approved by the FDA and the European Medicines Agency. Preclinical studies aimed at identifying BCL2-dependent tumor types have translated well into the clinic thus far and will likely continue to inform the clinical development of venetoclax and other BCL2 family inhibitors. Cancer Discov; 7(12); 1376-93. ©2017 AACR. ©2017 American Association for Cancer Research.

A high-content phenotypic screen reveals the disruptive potency of quinacrine and 3',4'-dichlorobenzamil on the digestive vacuole of Plasmodium falciparum.

PubMed

Lee, Yan Quan; Goh, Amanda S P; Ch'ng, Jun Hong; Nosten, François H; Preiser, Peter Rainer; Pervaiz, Shazib; Yadav, Sanjiv Kumar; Tan, Kevin S W

2014-01-01

Plasmodium falciparum is the etiological agent of malignant malaria and has been shown to exhibit features resembling programmed cell death. This is triggered upon treatment with low micromolar doses of chloroquine or other lysosomotrophic compounds and is associated with leakage of the digestive vacuole contents. In order to exploit this cell death pathway, we developed a high-content screening method to select compounds that can disrupt the parasite vacuole, as measured by the leakage of intravacuolar Ca(2+). This assay uses the ImageStream 100, an imaging-capable flow cytometer, to assess the distribution of the fluorescent calcium probe Fluo-4. We obtained two hits from a small library of 25 test compounds, quinacrine and 3',4'-dichlorobenzamil. The ability of these compounds to permeabilize the digestive vacuole in laboratory strains and clinical isolates was validated by confocal microscopy. The hits could induce programmed cell death features in both chloroquine-sensitive and -resistant laboratory strains. Quinacrine was effective at inhibiting field isolates in a 48-h reinvasion assay regardless of artemisinin clearance status. We therefore present as proof of concept a phenotypic screening method with the potential to provide mechanistic insights to the activity of antimalarial drugs.

The Molecular Ecophysiology of Programmed Cell Death in Marine Phytoplankton

NASA Astrophysics Data System (ADS)

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.

Involvement of Programmed Cell Death in Neurotoxicity of Metallic Nanoparticles: Recent Advances and Future Perspectives

NASA Astrophysics Data System (ADS)

Song, Bin; Zhou, Ting; Liu, Jia; Shao, LongQuan

2016-11-01

The widespread application of metallic nanoparticles (NPs) or NP-based products has increased the risk of exposure to NPs in humans. The brain is an important organ that is more susceptible to exogenous stimuli. Moreover, any impairment to the brain is irreversible. Recently, several in vivo studies have found that metallic NPs can be absorbed into the animal body and then translocated into the brain, mainly through the blood-brain barrier and olfactory pathway after systemic administration. Furthermore, metallic NPs can cross the placental barrier to accumulate in the fetal brain, causing developmental neurotoxicity on exposure during pregnancy. Therefore, metallic NPs become a big threat to the brain. However, the mechanisms underlying the neurotoxicity of metallic NPs remain unclear. Programmed cell death (PCD), which is different from necrosis, is defined as active cell death and is regulated by certain genes. PCD can be mainly classified into apoptosis, autophagy, necroptosis, and pyroptosis. It is involved in brain development, neurodegenerative disorders, psychiatric disorders, and brain injury. Given the pivotal role of PCD in neurological functions, we reviewed relevant articles and tried to summarize the recent advances and future perspectives of PCD involvement in the neurotoxicity of metallic NPs, with the purpose of comprehensively understanding the neurotoxic mechanisms of NPs.

The proteases HtrA2/Omi and UCH-L1 regulate TNF-induced necroptosis

PubMed Central

2013-01-01

Background In apoptosis, proteolysis by caspases is the primary mechanism for both initiation and execution of programmed cell death (PCD). In contrast, the impact of proteolysis on the regulation and execution of caspase-independent forms of PCD (programmed necrosis, necroptosis) is only marginally understood. Likewise, the identity of the involved proteases has remained largely obscure. Here, we have investigated the impact of proteases in TNF-induced necroptosis. Results The serine protease inhibitor TPKC protected from TNF-induced necroptosis in multiple murine and human cells systems whereas inhibitors of metalloproteinases or calpain/cysteine and cathepsin proteases had no effect. A screen for proteins labeled by a fluorescent TPCK derivative in necroptotic cells identified HtrA2/Omi (a serine protease previously implicated in PCD) as a promising candidate. Demonstrating its functional impact, pharmacological inhibition or genetic deletion of HtrA2/Omi protected from TNF-induced necroptosis. Unlike in apoptosis, HtrA2/Omi did not cleave another protease, ubiquitin C-terminal hydrolase (UCH-L1) during TNF-induced necroptosis, but rather induced monoubiquitination indicative for UCH-L1 activation. Correspondingly, pharmacologic or RNA interference-mediated inhibition of UCH-L1 protected from TNF-induced necroptosis. We found that UCH-L1 is a mediator of caspase-independent, non-apoptotic cell death also in diseased kidney podocytes by measuring cleavage of the protein PARP-1, caspase activity, cell death and cell morphology. Indicating a role of TNF in this process, podocytes with stably downregulated UCH-L1 proved resistant to TNF-induced necroptosis. Conclusions The proteases HtrA2/Omi and UCH-L1 represent two key components of TNF-induced necroptosis, validating the relevance of proteolysis not only for apoptosis, but also for caspase-independent PCD. Since UCH-L1 clearly contributes to the non-apoptotic death of podocytes, interference with the necroptotic properties of HtrA2/Omi and UCH-L1 may prove beneficial for the treatment of patients, e.g. in kidney failure. PMID:24090154

Mille modis morimur: We die in a thousand ways.

PubMed

Banfalvi, Gaspar

2017-02-01

Dying cells subjected to apoptotic programs are engulfed by neighboring cells or by professional phagocytes, without inflammation or immunological reactions in the tissue where apoptosis takes place. Apoptotic cells release danger-associated project signals to their neighbours, through different molecular patterns, stimulate antigen production and immune responses. Microenvironmental effects with several functional consequences indicate that cell death is a complex process and may take place in several ways. This idea is expressed by the title of the Special Issue and by the title of the guest editorial "Mille modis morimur" meaning that not only multicellular organisms, but also single cells may die in a thousand ways. This idea is demonstrated by the papers serving as examples for cell death. Apoptosis was induced by clary sage oil in Candida cells. Heavy metal (Gd) induced cell motility and apoptosis was found in mammalian cells. RNA oxidation enhanced the reversion frequency of apoptosis in yeast mutants. The frequency of apoptotic micronucleus formation increased in a concentration-dependent manner by methotrexate. The antioxidant coenzyme Q10 protected renal proximal tubule cells against nicotine-induced apoptosis. The synergy of 2-deoxy-D-glucose combined with berberine induced lysosome/autophagy. The mitochondrial apoptotic pathway could be regulated by glucocorticoid receptor in collaboration with Bcl-2 family proteins in developing T cells. Cylindrospermopsin induced biochemical changes led to apoptosis in plants. Mechanisms of stress seriously impacted the risk of apoptosis. Transcriptional control of apoptotic cell clearance was achieved by macrophage nuclear receptors. Finally, the clinical aspects of apoptosis-induced lymphopenia were reviewed in sepsis and other severe injuries. These examples not only support the view of many ways of cell death, but predict further potential ways to induce or reduce the risk of cell death.

c-FLIP is involved in erythropoietin-mediated protection of erythroid-differentiated cells from TNF-alpha-induced apoptosis.

PubMed

Vittori, Daniela; Vota, Daiana; Callero, Mariana; Chamorro, María E; Nesse, Alcira

2010-05-04

The TNF-alpha (tumour necrosis factor) affects a wide range of biological activities, such as cell proliferation and apoptosis. Cell life or death responses to this cytokine might depend on cell conditions. This study focused on the modulation of factors that would affect the sensitivity of erythroid-differentiated cells to TNF-alpha. Hemin-differentiated K562 cells showed higher sensitivity to TNF-induced apoptosis than undifferentiated cells. At the same time, hemin-induced erythroid differentiation reduced c-FLIP (cellular FLICE-inhibitory protein) expression. However, this negative effect was prevented by prior treatment with Epo (erythropoietin), which allowed the cell line to maintain c-FLIP levels. On the other hand, erythroid-differentiated UT-7 cells - dependent on Epo for survival - showed resistance to TNF-alpha pro-apoptotic action. Only after the inhibition of PI3K (phosphatidylinositol-3 kinase)-mediated pathways, which was accompanied by negative c-FLIP modulation and increased erythroid differentiation, were UT-7 cells sensitive to TNF-alpha-triggered apoptosis. In summary, erythroid differentiation might deregulate the balance between growth promotion and death signals induced by TNF-alpha, depending on cell type and environmental conditions. The role of c-FLIP seemed to be critical in the protection of erythroid-differentiated cells from apoptosis or in the determination of their sensitivity to TNF-mediated programmed cell death. Epo, which for the first time was found to be involved in the prevention of c-FLIP down-regulation, proved to have an anti-apoptotic effect against the pro-inflammatory factor. The identification of signals related to cell life/death switching would have significant implications in the control of proliferative diseases and would contribute to the understanding of mechanisms underlying the anaemia associated with inflammatory processes.

Atezolizumab: A novel PD-L1 inhibitor in cancer therapy with a focus in bladder and non-small cell lung cancers.

PubMed

Krishnamurthy, A; Jimeno, A

2017-04-01

In recent years, immunotherapy has come to the forefront as a major development in cancer treatment. Evasion of the immune system by tumor cells has been identified as one of the hallmarks of cancer and multiple therapies have been developed to counter this process. Programmed cell death 1 ligand 1 (PD-L1), a ligand to programmed cell death protein 1 (PD-1), is expressed by many cancer cells and the binding of PD-L1 to PD-1 results in the suppression of T-cell-mediated immune response against cancer cells. Atezolizumab is a monoclonal antibody that binds to PD-L1 and blocks its interaction with PD-1, thereby enhancing T-cell activity against tumor cells. Atezolizumab has been shown to be well tolerated with no dose-limiting toxicities in phase I trials. Atezolizumab was approved by the U.S. Food and Drug Administration in 2016 for the treatment of platinum-resistant metastatic non-small cell lung cancer (NSCLC) and urothelial cancer based on phase II and preliminary phase III studies that have shown significant improvement in objective response rate and median overall survival. There are 117 ongoing clinical trials of atezolizumab currently. Given its efficacy in NSCLC and urothelial carcinoma, atezolizumab holds much potential in the future of cancer therapeutics. Copyright 2017 Clarivate Analytics.

Inhibition of Ced-3/ICE-related Proteases Does Not Prevent Cell Death Induced by Oncogenes, DNA Damage, or the Bcl-2 Homologue Bak

PubMed Central

McCarthy, Nicola J.; Whyte, Moira K.B.; Gilbert, Christopher S.; Evan, Gerard I.

1997-01-01

There is increasing evidence for a central role in mammalian apoptosis of the interleukin-1β– converting enzyme (ICE) family of cysteine proteases, homologues of the product of the nematode “death” gene, ced-3. Ced-3 is thought to act as an executor rather than a regulator of programmed cell death in the nematode. However, it is not known whether mammalian ICE-related proteases (IRPs) are involved in the execution or the regulation of mammalian apoptosis. Moreover, an absolute requirement for one or more IRPs for mammalian apoptosis has yet to be established. We have used two cell-permeable inhibitors of IRPs, Z-Val-Ala-Asp.fluoromethylketone (ZVAD.fmk) and t-butoxy carbonyl-Asp.fluoromethylketone (BD.fmk), to demonstrate a critical role for IRPs in mammalian apoptosis induced by several disparate mechanisms (deregulated oncogene expression, ectopic expression of the Bcl-2 relative Bak, and DNA damage–induced cell death). In all instances, ZVAD.fmk and BD.fmk treatment inhibits characteristic biochemical and morphological events associated with apoptosis, including cleavage of nuclear lamins and poly-(ADP-ribose) polymerase, chromatin condensation and nucleosome laddering, and external display of phosphatidylserine. However, neither ZVAD.fmk nor BD.fmk inhibits the onset of apoptosis, as characterized by the onset of surface blebbing; rather, both act to delay completion of the program once initiated. In complete contrast, IGF-I and Bcl-2 delay the onset of apoptosis but have no effect on the kinetics of the program once initiated. Our data indicate that IRPs constitute part of the execution machinery of mammalian apoptosis induced by deregulated oncogenes, DNA damage, or Bak but that they act after the point at which cells become committed to apoptosis or can be rescued by survival factors. Moreover, all such blocked cells have lost proliferative potential and all eventually die by a process involving cytoplasmic blebbing. PMID:9008715

A Comprehensive Analysis of Programmed Cell Death Ligand-1 Expression With the Clone SP142 Antibody in Non-Small-Cell Lung Cancer Patients.

PubMed

Takada, Kazuki; Toyokawa, Gouji; Okamoto, Tatsuro; Shimokawa, Mototsugu; Kozuma, Yuka; Matsubara, Taichi; Haratake, Naoki; Akamine, Takaki; Takamori, Shinkichi; Katsura, Masakazu; Shoji, Fumihiro; Oda, Yoshinao; Maehara, Yoshihiko

2017-09-01

Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) have been identified as novel targets for immunotherapy, with anti-PD-1 therapy currently the standard treatment for non-small-cell lung cancer (NSCLC) patients after the failure of first-line chemotherapy treatment. The recent phase II POPLAR and phase III OAK studies showed that atezolizumab, a representative PD-L1 inhibitor, exhibited a survival benefit compared with standard therapy in patients with NSCLC. We examined PD-L1 expression in NSCLC using the clone SP142 of POPLAR and OAK studies. PD-L1 expression in 499 surgically resected NSCLC patients was evaluated using immunohistochemistry using SP142. We set cutoff values as 1%, 5%, 10%, and 50%. The samples from 189 (37.9%), 119 (23.8%), 71 (14.2%), and 39 (7.8%) patients were positive for PD-L1 expression at cutoff values of 1%, 5%, 10%, and 50%, respectively. Fisher exact tests showed that PD-L1 positivity was significantly associated with male sex, smoking, advanced stage, the presence of vascular invasion, squamous cell carcinoma, and wild type epidermal growth factor receptor gene mutation status at all cutoff values. Univariate and multivariate survival analyses revealed that PD-L1-positive patients had a worse prognosis than PD-L1-negative patients only at the 1% cutoff value. Forest plot analyses showed that the 1% cutoff provided a more sensitive value for the prediction of postoperative prognosis. PD-L1 expression varied greatly according to different cutoff values. This study might be a useful reference to understand the results of POPLAR and OAK studies and to select patients likely to benefit from atezolizumab. Copyright © 2017 Elsevier Inc. All rights reserved.

PD-1 expression by tumor-associated macrophages inhibits phagocytosis and tumor immunity

PubMed Central

Gordon, Sydney R.; Maute, Roy L.; Dulken, Ben W.; Hutter, Gregor; George, Benson M.; McCracken, Melissa N.; Gupta, Rohit; Tsai, Jonathan M.; Sinha, Rahul; Corey, Daniel; Ring, Aaron M.; Connolly, Andrew J.; Weissman, Irving L.

2017-01-01

Programmed cell death protein 1 (PD-1) is an immune checkpoint receptor that is upregulated on activated T cells to induce immune tolerance.1,2 Tumor cells frequently overexpress the ligand for PD-1, programmed cell death ligand 1 (PD-L1), facilitating escape from the immune system.3,4 Monoclonal antibodies blocking PD-1/PD-L1 have shown remarkable clinical efficacy in patients with a variety of cancers, including melanoma, colorectal cancer, non-small cell lung cancer, and Hodgkin’s lymphoma.5–9 Although it is well-established that PD-1/PD-L1 blockade activates T cells, little is known about the role that this pathway may have on tumor-associated macrophages (TAMs). Here we show that both mouse and human TAMs express PD-1. TAM PD-1 expression increases over time in mouse models, and with increasing disease stage in primary human cancers. TAM PD-1 expression negatively correlates with phagocytic potency against tumor cells, and blockade of PD-1/PD-L1 in vivo increases macrophage phagocytosis, reduces tumor growth, and lengthens survival in mouse models of cancer in a macrophage-dependent fashion. Our results suggest that PD-1/PD-L1 therapies may also function through a direct effect on macrophages, with significant implications for treatment with these agents. PMID:28514441

Advances in cancer immunology and cancer immunotherapy.

PubMed

Voena, Claudia; Chiarle, Roberto

2016-02-01

After decades of setbacks, cancer immunology is living its Golden Age. Recent advances in cancer immunology have provided new therapeutic approaches to treat cancer. The objective clinical response observed in patients treated with antibodies that block the immune checkpoints, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell-death protein 1 (PD-1)/programmed cell-death 1 ligand 1 (PD-L1) pathways, has led to their FDA approval for the treatment of melanoma in 2011 and in 2014, respectively. The anti-PD-1 antibody nivolumab has received the FDA-approval in March 2015 for squamous lung cancer treatment. In addition, antibodies targeting PD-1 or PD-L1 have demonstrated their efficacy and safety in additional tumors, including non-small cell lung carcinoma (NSCLC), renal cell carcinoma (RCC), bladder cancer, and Hodgkin's lymphoma. Almost at the same time, the field of adoptive cell transfer has exploded. The chimeric antigen receptor (CAR) T technology has provided strong evidence of efficacy in the treatment of B cell malignancies, and different T cell based treatments are currently under investigation for different types of tumors. In this review we will discuss the latest advances in cancer immunology and immunotherapy as well as new treatments now under development in the clinic and potential strategies that have shown promising results in preclinical models.

What a Shock: No Apoptosis without Heat Shock Protein 90α | Center for Cancer Research

Cancer.gov

Apoptosis, also known as programmed cell death, consists of a series of reactions designed to systematically chop up a cell and its contents. The process is used to eliminate specific cells during development or to remove old or damaged cells without harming any surrounding cells. Since cancer cells can develop mechanisms to avoid apoptosis, researchers may be able to identify new targets to combat cancer by better understanding the details of the apoptotic process.

Clostridium perfringens beta-toxin induces necrostatin-inhibitable, calpain-dependent necrosis in primary porcine endothelial cells.

PubMed

Autheman, Delphine; Wyder, Marianne; Popoff, Michel; D'Herde, Katharina; Christen, Stephan; Posthaus, Horst

2013-01-01

Clostridium perfringens β-toxin (CPB) is a β-barrel pore-forming toxin and an essential virulence factor of C. perfringens type C strains, which cause fatal hemorrhagic enteritis in animals and humans. We have previously shown that CPB is bound to endothelial cells within the intestine of affected pigs and humans, and that CPB is highly toxic to primary porcine endothelial cells (pEC) in vitro. The objective of the present study was to investigate the type of cell death induced by CPB in these cells, and to study potential host cell mechanisms involved in this process. CPB rapidly induced lactate dehydrogenase (LDH) release, propidium iodide uptake, ATP depletion, potassium efflux, a marked rise in intracellular calcium [Ca(2+)]i, release of high-mobility group protein B1 (HMGB1), and caused ultrastructural changes characteristic of necrotic cell death. Despite a certain level of caspase-3 activation, no appreciable DNA fragmentation was detected. CPB-induced LDH release and propidium iodide uptake were inhibited by necrostatin-1 and the two dissimilar calpain inhibitors PD150606 and calpeptin. Likewise, inhibition of potassium efflux, chelation of intracellular calcium and treatment of pEC with cyclosporin A also significantly inhibited CPB-induced LDH release. Our results demonstrate that rCPB primarily induces necrotic cell death in pEC, and that necrotic cell death is not merely a passive event caused by toxin-induced membrane disruption, but is propagated by host cell-dependent biochemical pathways activated by the rise in intracellular calcium and inhibitable by necrostatin-1, consistent with the emerging concept of programmed necrosis ("necroptosis").

MYC and EGR1 synergize to trigger tumor cell death by controlling NOXA and BIM transcription upon treatment with the proteasome inhibitor bortezomib

PubMed Central

Wirth, Matthias; Stojanovic, Natasa; Christian, Jan; Paul, Mariel C.; Stauber, Roland H.; Schmid, Roland M.; Häcker, Georg; Krämer, Oliver H.; Saur, Dieter; Schneider, Günter

2014-01-01

The c-MYC (MYC afterward) oncogene is well known for driving numerous oncogenic programs. However, MYC can also induce apoptosis and this function of MYC warrants further clarification. We report here that a clinically relevant proteasome inhibitor significantly increases MYC protein levels and that endogenous MYC is necessary for the induction of apoptosis. This kind of MYC-induced cell death is mediated by enhanced expression of the pro-apoptotic BCL2 family members NOXA and BIM. Quantitative promoter-scanning chromatin immunoprecipitations (qChIP) further revealed binding of MYC to the promoters of NOXA and BIM upon proteasome inhibition, correlating with increased transcription. Both promoters are further characterized by the presence of tri-methylated lysine 4 of histone H3, marking active chromatin. We provide evidence that in our apoptosis models cell death occurs independently of p53 or ARF. Furthermore, we demonstrate that recruitment of MYC to the NOXA as well as to the BIM gene promoters depends on MYC's interaction with the zinc finger transcription factor EGR1 and an EGR1-binding site in both promoters. Our study uncovers a novel molecular mechanism by showing that the functional cooperation of MYC with EGR1 is required for bortezomib-induced cell death. This observation may be important for novel therapeutic strategies engaging the inherent pro-death function of MYC. PMID:25147211

Comparative analysis of programmed cell death pathways in filamentous fungi.

PubMed

Fedorova, Natalie D; Badger, Jonathan H; Robson, Geoff D; Wortman, Jennifer R; Nierman, William C

2005-12-08

Fungi can undergo autophagic- or apoptotic-type programmed cell death (PCD) on exposure to antifungal agents, developmental signals, and stress factors. Filamentous fungi can also exhibit a form of cell death called heterokaryon incompatibility (HI) triggered by fusion between two genetically incompatible individuals. With the availability of recently sequenced genomes of Aspergillus fumigatus and several related species, we were able to define putative components of fungi-specific death pathways and the ancestral core apoptotic machinery shared by all fungi and metazoa. Phylogenetic profiling of HI-associated proteins from four Aspergilli and seven other fungal species revealed lineage-specific protein families, orphan genes, and core genes conserved across all fungi and metazoa. The Aspergilli-specific domain architectures include NACHT family NTPases, which may function as key integrators of stress and nutrient availability signals. They are often found fused to putative effector domains such as Pfs, SesB/LipA, and a newly identified domain, HET-s/LopB. Many putative HI inducers and mediators are specific to filamentous fungi and not found in unicellular yeasts. In addition to their role in HI, several of them appear to be involved in regulation of cell cycle, development and sexual differentiation. Finally, the Aspergilli possess many putative downstream components of the mammalian apoptotic machinery including several proteins not found in the model yeast, Saccharomyces cerevisiae. Our analysis identified more than 100 putative PCD associated genes in the Aspergilli, which may help expand the range of currently available treatments for aspergillosis and other invasive fungal diseases. The list includes species-specific protein families as well as conserved core components of the ancestral PCD machinery shared by fungi and metazoa.

A lysigenic programmed cell death-dependent process shapes schizogenously formed aerenchyma in the stems of the waterweed Egeria densa

PubMed Central

Bartoli, G.; Forino, L. M. C.; Durante, M.; Tagliasacchi, A. M.

2015-01-01

Background and Aims Plant adaptation to submergence can include the formation of prominent aerenchyma to facilitate gas exchange. The aim of this study was to characterize the differentiation of the constitutive aerenchyma in the stem of the aquatic macrophyte Egeria densa (Hydrocharitaceae) and to verify if any form of cell death might be involved. Methods Plants were collected from a pool in a botanical garden. Aerenchyma differentiation and apoptotic hallmarks were investigated by light microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay coupled with genomic DNA extraction and gel electrophoresis (DNA laddering assay). Cell viability and the occurrence of peroxides and nitric oxide (NO) were determined histochemically using specific fluorogenic probes. Key Results Aerenchyma differentiation started from a hexagonally packed pre-aerenchymatic tissue and, following a basipetal and centripetal developmental pattern, produced a honeycomb arrangement. After an early schizogenous differentiation process, a late lysigenous programmed cell death- (PCD) dependent mechanism occurred. This was characterized by a number of typical apoptotic hallmarks, including DNA fragmentation, chromatin condensation, apoptotic-like bodies, partial cell wall lysis and plasmolysis. In addition, local increases in H2O2 and NO were observed and quantified. Conclusions The differentiation of cortical aerenchyma in the stem of E. densa is a complex process, consisting of a combination of an early schizogenous differentiation mechanism and a late lysigenous PCD-dependent process. The PCD remodels the architecture of the gas spaces previously formed schizogenously, and also results in a reduction of O2-consuming cells and in recycling of material derived from the lysigenic dismantling of the cells. PMID:26002256

A lysigenic programmed cell death-dependent process shapes schizogenously formed aerenchyma in the stems of the waterweed Egeria densa.

PubMed

Bartoli, G; Forino, L M C; Durante, M; Tagliasacchi, A M

2015-07-01

Plant adaptation to submergence can include the formation of prominent aerenchyma to facilitate gas exchange. The aim of this study was to characterize the differentiation of the constitutive aerenchyma in the stem of the aquatic macrophyte Egeria densa (Hydrocharitaceae) and to verify if any form of cell death might be involved. Plants were collected from a pool in a botanical garden. Aerenchyma differentiation and apoptotic hallmarks were investigated by light microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay coupled with genomic DNA extraction and gel electrophoresis (DNA laddering assay). Cell viability and the occurrence of peroxides and nitric oxide (NO) were determined histochemically using specific fluorogenic probes. Aerenchyma differentiation started from a hexagonally packed pre-aerenchymatic tissue and, following a basipetal and centripetal developmental pattern, produced a honeycomb arrangement. After an early schizogenous differentiation process, a late lysigenous programmed cell death- (PCD) dependent mechanism occurred. This was characterized by a number of typical apoptotic hallmarks, including DNA fragmentation, chromatin condensation, apoptotic-like bodies, partial cell wall lysis and plasmolysis. In addition, local increases in H2O2 and NO were observed and quantified. The differentiation of cortical aerenchyma in the stem of E. densa is a complex process, consisting of a combination of an early schizogenous differentiation mechanism and a late lysigenous PCD-dependent process. The PCD remodels the architecture of the gas spaces previously formed schizogenously, and also results in a reduction of O2-consuming cells and in recycling of material derived from the lysigenic dismantling of the cells. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Inflammation promotes oral squamous carcinoma immune evasion via induced programmed death ligand-1 surface expression.

PubMed

Lu, Wanlu; Lu, Libing; Feng, Yun; Chen, Jiao; Li, Yan; Kong, Xiangli; Chen, Sixiu; Li, Xiaoyu; Chen, Qianming; Zhang, Ping

2013-05-01

The association between inflammation and cancer provides a new target for tumor biotherapy. The inflammatory cells and molecules within the tumor microenvironment have decisive dual roles in antitumor immunity and immune evasion. In the present study, phytohemagglutinin (PHA) was used to stimulate peripheral blood mononuclear cells (PBMCs) to simulate the tumor inflammatory microenvironment. The effect of immune cells and inflammatory cytokines on the surface expression of programmed cell death-1 ligand 1 (PD-L1) and tumor immune evasion was investigated using flow cytometry (FCM) and an in vivo xenotransplantation model. Based on the data, PHA-activated, but not resting, immune cells were able to promote the surface expression of PD-L1 in Tca8113 oral squamous carcinoma cells via the secretion of inflammatory cytokines, but not by cell-cell contact. The majority of the inflammatory cytokines had no significant effect on the proliferation, cell cycle progression and apoptosis of the Tca8113 cells, although they each induced the expression of PD-L1 in a dose-dependent manner. In total, 99% of the Tca8113 cells expressed PD-L1 following treatment with the supernatant of PHA-stimulated PBMCs. The PHA-supernatant pretreated Tca8113 cells unusually induced Tca8113 antigen-specific CD8 + T cell apoptosis in vitro and the evasion of antigen-specific T cell attraction in a nude mouse tumor-bearing model. These results indicate a new mechanism for the promotion of tumor immune evasion by the tumor inflammatory microenvironment.

Inflammation promotes oral squamous carcinoma immune evasion via induced programmed death ligand-1 surface expression

PubMed Central

LU, WANLU; LU, LIBING; FENG, YUN; CHEN, JIAO; LI, YAN; KONG, XIANGLI; CHEN, SIXIU; LI, XIAOYU; CHEN, QIANMING; ZHANG, PING

2013-01-01

The association between inflammation and cancer provides a new target for tumor biotherapy. The inflammatory cells and molecules within the tumor microenvironment have decisive dual roles in antitumor immunity and immune evasion. In the present study, phytohemagglutinin (PHA) was used to stimulate peripheral blood mononuclear cells (PBMCs) to simulate the tumor inflammatory microenvironment. The effect of immune cells and inflammatory cytokines on the surface expression of programmed cell death-1 ligand 1 (PD-L1) and tumor immune evasion was investigated using flow cytometry (FCM) and an in vivo xenotransplantation model. Based on the data, PHA-activated, but not resting, immune cells were able to promote the surface expression of PD-L1 in Tca8113 oral squamous carcinoma cells via the secretion of inflammatory cytokines, but not by cell-cell contact. The majority of the inflammatory cytokines had no significant effect on the proliferation, cell cycle progression and apoptosis of the Tca8113 cells, although they each induced the expression of PD-L1 in a dose-dependent manner. In total, 99% of the Tca8113 cells expressed PD-L1 following treatment with the supernatant of PHA-stimulated PBMCs. The PHA-supernatant pretreated Tca8113 cells unusually induced Tca8113 antigen-specific CD8+ T cell apoptosis in vitro and the evasion of antigen-specific T cell attraction in a nude mouse tumor-bearing model. These results indicate a new mechanism for the promotion of tumor immune evasion by the tumor inflammatory microenvironment PMID:23761816

Fish oil-derived lipid emulsion induces RIP1-dependent and caspase 8-licensed necroptosis in IEC-6 cells through overproduction of reactive oxygen species.

PubMed

Yan, Jun-Kai; Yan, Wei-Hui; Cai, Wei

2018-06-23

Excessive cell death of enterocytes has been demonstrated to be partially associated with the intravenously-administrated lipid emulsions (LEs) during parenteral nutrition (PN) support. However, as a new generation of LE, the effect of fish oil-derived lipid emulsion (FOLE) on the death of enterocytes remains elusive. Intestinal epithelial cells (IEC-6 cell line) were treated with FOLE (0.25-1%) for 24 h. Cell survival was measured by CCK-8 assay, and morphological changes were monitored by time-lapse live cell imaging. The expression of receptor-interacting protein 1/3 (RIP1/3) and caspase 8 was assessed by westernblot, and the formation of necrosome (characterized by the assembly of RIP1/3 complex along with the dissociation of caspase 8) was examined by immunoprecipitation. Additionally, the production of intracellular reactive oxygen species (ROS) was detected by using a ROS detection kit with an oxidation-sensitive probe (DCFH-DA). FOLE dose-dependently induced non-apoptotic, but programmed necroctic cell death (necroptosis) within 4-8 h after treatment. The assembly of RIP1/3 complex along with the dissociation of caspase 8 from RIP1 was observed in FOLE-treated cells. Moreover, FOLE-induced cell death was significantly alleviated by inhibiting RIP1, and was further aggravated by inhibiting caspase 8. In addition, prior to cell death the accumulation of intracellular ROS was significantly increased in FOLE-treated cells (increased by approximately 5-fold versus control, p < 0.001), which could be attenuated by inhibiting RIP1 (decreased by approximately 35% versus FOLE, p < 0.05). FOLE induces RIP1-dependent and caspase 8-licensed necroptosis through overproduction of ROS in vitro. Our findings may provide novel insights into the clinical applications of FOLE during PN support.

Distinct p300-Responsive Mechanisms Promote Caspase-Dependent Apoptosis by Human T-Cell Lymphotropic Virus Type 1 Tax Protein

PubMed Central

Nicot, Christophe; Harrod, Robert

2000-01-01

The dysregulation of cellular apoptosis pathways has emerged as a critical early event associated with the development of many types of human cancers. Numerous viral and cellular oncogenes, aside from their inherent transforming properties, are known to induce programmed cell death, consistent with the hypothesis that genetic defects are required to support tumor survival. Here, we report that nuclear expression of the CREB-binding protein (CBP)/p300-binding domain of the human T-cell lymphotropic virus type 1 (HTLV-1) transactivator, Tax, triggers an apoptotic death-inducing signal during short-term clonal analyses, as well as in transient cell death assays. Coexpression of the antiapoptotic factor Bcl-2 increased serum stimulation; incubation with the chemical caspase inhibitor z-Val-Ala-dl-Asp fluoromethylketone antagonized Tax-induced cell death. The CBP/p300-binding defective Tax mutants K88A and V89A exhibited markedly reduced cytotoxic effects compared to the wild-type Tax protein. Importantly, nuclear expression of the minimal CBP/p300-binding peptide of Tax induced apoptosis in the absence of Tax-dependent transcriptional activities, while its K88A counterpart did not cause cell death. Further, Tax-mediated apoptosis was effectively prevented by ectopic expression of the p300 coactivator. We also report that activation of the NF-κB transcription pathway by Tax, under growth arrest conditions, results in apoptosis that occurs independent of direct Tax coactivator effects. Our results allude to a novel pivotal role for the transcriptional coactivator p300 in determining cell fate and raise the possibility that dysregulated coactivator usage may pose an early barrier to transformation that must be selectively overcome as a prerequisite for the initiation of neoplasia. PMID:11046153

Distinct p300-responsive mechanisms promote caspase-dependent apoptosis by human T-cell lymphotropic virus type 1 Tax protein.

PubMed

Nicot, C; Harrod, R

2000-11-01

The dysregulation of cellular apoptosis pathways has emerged as a critical early event associated with the development of many types of human cancers. Numerous viral and cellular oncogenes, aside from their inherent transforming properties, are known to induce programmed cell death, consistent with the hypothesis that genetic defects are required to support tumor survival. Here, we report that nuclear expression of the CREB-binding protein (CBP)/p300-binding domain of the human T-cell lymphotropic virus type 1 (HTLV-1) transactivator, Tax, triggers an apoptotic death-inducing signal during short-term clonal analyses, as well as in transient cell death assays. Coexpression of the antiapoptotic factor Bcl-2 increased serum stimulation; incubation with the chemical caspase inhibitor z-Val-Ala-DL-Asp fluoromethylketone antagonized Tax-induced cell death. The CBP/p300-binding defective Tax mutants K88A and V89A exhibited markedly reduced cytotoxic effects compared to the wild-type Tax protein. Importantly, nuclear expression of the minimal CBP/p300-binding peptide of Tax induced apoptosis in the absence of Tax-dependent transcriptional activities, while its K88A counterpart did not cause cell death. Further, Tax-mediated apoptosis was effectively prevented by ectopic expression of the p300 coactivator. We also report that activation of the NF-kappaB transcription pathway by Tax, under growth arrest conditions, results in apoptosis that occurs independent of direct Tax coactivator effects. Our results allude to a novel pivotal role for the transcriptional coactivator p300 in determining cell fate and raise the possibility that dysregulated coactivator usage may pose an early barrier to transformation that must be selectively overcome as a prerequisite for the initiation of neoplasia.

Phenotypic and Molecular Analysis of Mes-3, a Maternal-Effect Gene Required for Proliferation and Viability of the Germ Line in C. Elegans

PubMed Central

Paulsen, J. E.; Capowski, E. E.; Strome, S.

1995-01-01

mes-3 is one of four maternal-effect sterile genes that encode maternal components required for normal postembryonic development of the germ line in Caenorhabditis elegans. mes-3 mutant mothers produce sterile progeny, which contain few germ cells and no gametes. This terminal phenotype reflects two problems: reduced proliferation of the germ line and germ cell death. Both the appearance of the dying germ cells and the results of genetic tests indicate that germ cells in mes-3 animals undergo a necrotic-like death, not programmed cell death. The few germ cells that appear healthy in mes-3 worms do not differentiate into gametes, even after elimination of the signaling pathway that normally maintains the undifferentiated population of germ cells. Thus, mes-3 encodes a maternally supplied product that is required both for proliferation of the germ line and for maintenance of viable germ cells that are competent to differentiate into gametes. Cloning and molecular characterization of mes-3 revealed that it is the upstream gene in an operon. The genes in the operon display parallel expression patterns; transcripts are present throughout development and are not restricted to germ-line tissue. Both mes-3 and the downstream gene in the operon encode novel proteins. PMID:8601481

Dihydroartemisinin induces endothelial cell anoikis through the activation of the JNK signaling pathway

PubMed Central

Zhang, Jiao; Guo, Ling; Zhou, Xia; Dong, Fengyun; Li, Liqun; Cheng, Zuowang; Xu, Yinghua; Liang, Jiyong; Xie, Qi; Liu, Ju

2016-01-01

Angiogenesis is required for the growth and metastasis of solid tumors. The anti-malarial agent dihydroartemisinin (DHA) demonstrates potent anti-angiogenic activity, but the underlying molecular mechanisms are not yet fully understood. During the process of angiogenesis, endothelial cells migrating from existing capillaries may undergo programmed cell death after detaching from the extracellular matrix, a process that is defined as anchorage-dependent apoptosis or anoikis. In the present study, DHA-induced cell death was compared in human umbilical vein endothelial cells (HUVECs) cultured in suspension and attached to culture plates. In suspended HUVECs, the cell viability was decreased and apoptosis was increased with the treatment of 50 µM DHA for 5 h, while the same treatment did not affect the attached HUVECs. In addition, 50 µM DHA increased the phosphorylation of c-Jun N-terminal kinase (JNK) in suspended HUVECs, but not in attached HUVECs, for up to 5 h of treatment. The JNK inhibitor, SP600125, reversed DHA-induced cell death in suspended HUVECs, suggesting that the JNK pathway may mediate DHA-induced endothelial cell anoikis. The data from the present study indicates a novel mechanism for understanding the anti-angiogenic effects of DHA, which may be used as a component for chemotherapy. PMID:27602117

The pathway of cell dismantling during programmed cell death in lace plant (Aponogeton madagascariensis) leaves.

PubMed

Wertman, Jaime; Lord, Christina En; Dauphinee, Adrian N; Gunawardena, Arunika Hlan

2012-07-25

Developmentally regulated programmed cell death (PCD) is the controlled death of cells that occurs throughout the life cycle of both plants and animals. The lace plant (Aponogeton madagascariensis) forms perforations between longitudinal and transverse veins in spaces known as areoles, via developmental PCD; cell death begins in the center of these areoles and develops towards the margin, creating a gradient of PCD. This gradient was examined using both long- and short-term live cell imaging, in addition to histochemical staining, in order to establish the order of cellular events that occur during PCD. The first visible change observed was the reduction in anthocyanin pigmentation, followed by initial chloroplast changes and the bundling of actin microfilaments. At this stage, an increased number of transvacuolar strands (TVS) was evident. Perhaps concurrently with this, increased numbers of vesicles, small mitochondrial aggregates, and perinuclear accumulation of both chloroplasts and mitochondria were observed. The invagination of the tonoplast membrane and the presence of vesicles, both containing organelle materials, suggested evidence for both micro- and macro-autophagy, respectively. Mitochondrial aggregates, as well as individual chloroplasts were subsequently seen undergoing Brownian motion in the vacuole. Following these changes, fragmentation of nuclear DNA, breakdown of actin microfilaments and early cell wall changes were detected. The vacuole then swelled, causing nuclear displacement towards the plasma membrane (PM) and tonoplast rupture followed closely, indicating mega-autophagy. Subsequent to tonoplast rupture, cessation of Brownian motion occurred, as well as the loss of mitochondrial membrane potential (ΔΨm), nuclear shrinkage and PM collapse. Timing from tonoplast rupture to PM collapse was approximately 20 minutes. The entire process from initial chlorophyll reduction to PM collapse took approximately 48 hours. Approximately six hours following PM collapse, cell wall disappearance began and was nearly complete within 24 hours. Results showed that a consistent sequence of events occurred during the remodelling of lace plant leaves, which provides an excellent system to study developmental PCD in vivo. These findings can be used to compare and contrast with other developmental PCD examples in plants.

Sevoflurane post-conditioning protects primary rat cortical neurons against oxygen-glucose deprivation/resuscitation via down-regulation in mitochondrial apoptosis axis of Bid, Bim, Puma-Bax and Bak mediated by Erk1/2.

PubMed

Zhang, Li-Min; Zhao, Xiao-Chun; Sun, Wen-Bo; Li, Rui; Jiang, Xiao-Jing

2015-10-15

Temporal post-conditioning helps provide neuroprotection against brain injury secondary to ischemia-reperfusion and is considered an effective intervention, but the exact mechanism of sevoflurane post-conditioning is unclear. The essential axis involves activator Bid, Bim, Puma (BH3s), Bax, and Bak; activates the mitochondrial death program; and might be involved in a cell death signal. Extracellular signal-related kinases 1/2 (Erk1/2) play a pivotal role in cell growth and proliferation. We hypothesized that sevoflurane post-conditioning might inhibit Bid, Bim, Puma, Bax, and Bak expression and is activated by phosphor-Erk1/2 to decrease neuronal death. To test this hypothesis, we exposed primary cortical neuron cultures to oxygen-glucose deprivation for 1h, along with resuscitation for 24h (OGD/R). MTT assays, propidium iodide uptake (PI), JC-1 fluorescence, and Western blot indicated the following: decreased cell viability (P<0.05); increased cell death (P<0.05); decreased mitochondrial membrane potential (P<0.05); and decreased Bid, Bim, Puma, Bax, and Bak expression with OGD/R exposure. Inhibition of Erk1/2 phosphorylation could attenuate sevoflurane post-conditioning that mediated an increase in neuronal viability and mitochondrial membrane potential, as well as a decrease in cell death and Bid, Bim, Puma, Bax, and Bak expression after OGD/R treatment. The results demonstrated that sevoflurane post-conditioning caused a marked decrease in cortical neuronal death secondary to OGD/R exposure through the downregulation of the mitochondrial apoptosis axis involving Bid, Bim, Puma, Bax, and Bak that was mediated by the phosphorylation/activation of Erk1/2. Copyright © 2015 Elsevier B.V. All rights reserved.

Simulation of spread and control of lesions in brain.

PubMed

Thamattoor Raman, Krishna Mohan

2012-01-01

A simulation model for the spread and control of lesions in the brain is constructed using a planar network (graph) representation for the central nervous system (CNS). The model is inspired by the lesion structures observed in the case of multiple sclerosis (MS), a chronic disease of the CNS. The initial lesion site is at the center of a unit square and spreads outwards based on the success rate in damaging edges (axons) of the network. The damaged edges send out alarm signals which, at appropriate intensity levels, generate programmed cell death. Depending on the extent and timing of the programmed cell death, the lesion may get controlled or aggravated akin to the control of wild fires by burning of peripheral vegetation. The parameter phase space of the model shows smooth transition from uncontrolled situation to controlled situation. The simulations show that the model is capable of generating a wide variety of lesion growth and arrest scenarios.

Mechanisms of immune evasion and current status of checkpoint inhibitors in non-small cell lung cancer.

PubMed

Qin, Angel; Coffey, David G; Warren, Edus H; Ramnath, Nithya

2016-09-01

In the past several years, immunotherapy has emerged as a viable treatment option for patients with advanced non-small cell lung cancer (NSCLC) without actionable driver mutations that have progressed on standard chemotherapy. We are also beginning to understand the methods of immune evasion employed by NSCLC which likely contribute to the 20% response rate to immunotherapy. It is also yet unclear what tumor or patient factors predict response to immunotherapy. The objectives of this review are (1) review the immunogenicity of NSCLC (2) describe the mechanisms of immune evasion (3) summarize efforts to target the anti-program death-1 (PD-1) and anti-program death-ligand 1(PD-L1) pathway (4) outline determinants of response to PD-1/PD-L1 therapy and (5) discuss potential future areas for research. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Radiation therapy and PD-1/PD-L1 blockade: the clinical development of an evolving anticancer combination.

PubMed

Gong, Jun; Le, Thang Q; Massarelli, Erminia; Hendifar, Andrew E; Tuli, Richard

2018-06-04

Several inhibitors of programmed cell death-1 (PD-1) and programmed death ligand-1 (PD-L1) have been approved as a form of immunotherapy for multiple cancers. Ionizing radiation therapy (RT) has been shown to enhance the priming and effector phases of the antitumor T-cell response rendering it an attractive therapy to combine with PD-1/PD-L1 inhibitors. Preclinical data support the rational combination of the 2 modalities and has paved way for the clinical development of the combination across a spectrum of cancers. In this review, we highlight the preclinical and clinical development of combined RT and PD-1/PD-L1 blockade to date. In addition to a comprehensive evaluation of available safety and efficacy data, we discuss important points of consideration in clinical trial design for this promising combination.

On Programmed Cell Death in Plasmodium falciparum: Status Quo

PubMed Central

Engelbrecht, Dewaldt; Durand, Pierre Marcel; Coetzer, Thérèsa Louise

2012-01-01

Conflicting arguments and results exist regarding the occurrence and phenotype of programmed cell death (PCD) in the malaria parasite Plasmodium falciparum. Inconsistencies relate mainly to the number and type of PCD markers assessed and the different methodologies used in the studies. In this paper, we provide a comprehensive overview of the current state of knowledge and empirical evidence for PCD in the intraerythrocytic stages of P. falciparum. We consider possible reasons for discrepancies in the data and offer suggestions towards more standardised investigation methods in this field. Furthermore, we present genomic evidence for PCD machinery in P. falciparum. We discuss the potential adaptive or nonadaptive role of PCD in the parasite life cycle and its possible exploitation in the development of novel drug targets. Lastly, we pose pertinent unanswered questions concerning the PCD phenomenon in P. falciparum to provide future direction. PMID:22287973

Oxidative damage and cell-programmed death induced in Zea mays L. by allelochemical stress.

PubMed

Ciniglia, Claudia; Mastrobuoni, Francesco; Scortichini, Marco; Petriccione, Milena

2015-05-01

The allelochemical stress on Zea mays was analyzed by using walnut husk washing waters (WHWW), a by-product of Juglans regia post-harvest process, which possesses strong allelopathic potential and phytotoxic effects. Oxidative damage and cell-programmed death were induced by WHWW in roots of maize seedlings. Treatment induced ROS burst, with excess of H2O2 content. Enzymatic activities of catalase were strongly increased during the first hours of exposure. The excess in malonildialdehyde following exposure to WHWW confirmed that oxidative stress severely damaged maize roots. Membrane alteration caused a decrease in NADPH oxidase activity along with DNA damage as confirmed by DNA laddering. The DNA instability was also assessed through sequence-related amplified polymorphism assay, thus suggesting the danger of walnut processing by-product and focusing the attention on the necessity of an efficient treatment of WHWW.

NK Cells Restrain Spontaneous Antitumor CD8+ T Cell Priming through PD-1/PD-L1 Interactions with Dendritic Cells.

PubMed

Iraolagoitia, Ximena L Raffo; Spallanzani, Raul G; Torres, Nicolás I; Araya, Romina E; Ziblat, Andrea; Domaica, Carolina I; Sierra, Jessica M; Nuñez, Sol Y; Secchiari, Florencia; Gajewski, Thomas F; Zwirner, Norberto W; Fuertes, Mercedes B

2016-08-01

Despite the classical function of NK cells in the elimination of tumor and of virus-infected cells, evidence for a regulatory role for NK cells has been emerging in different models of autoimmunity, transplantation, and viral infections. However, this role has not been fully explored in the context of a growing tumor. In this article, we show that NK cells can limit spontaneous cross-priming of tumor Ag-specific CD8(+) T cells, leading to reduced memory responses. After challenge with MC57 cells transduced to express the model Ag SIY (MC57.SIY), NK cell-depleted mice exhibited a significantly higher frequency of SIY-specific CD8(+) T cells, with enhanced IFN-γ production and cytotoxic capability. Depletion of NK cells resulted in a CD8(+) T cell population skewed toward an effector memory T phenotype that was associated with enhanced recall responses and delayed tumor growth after a secondary tumor challenge with B16.SIY cells. Dendritic cells (DCs) from NK cell-depleted tumor-bearing mice exhibited a more mature phenotype. Interestingly, tumor-infiltrating and tumor-draining lymph node NK cells displayed an upregulated expression of the inhibitory molecule programmed death ligand 1 that, through interaction with programmed death-1 expressed on DCs, limited DC activation, explaining their reduced ability to induce tumor-specific CD8(+) T cell priming. Our results suggest that NK cells can, in certain contexts, have an inhibitory effect on antitumor immunity, a finding with implications for immunotherapy in the clinic. Copyright © 2016 by The American Association of Immunologists, Inc.

Effects of Gravity on Cell Movement and Development

NASA Technical Reports Server (NTRS)

Wang, Yu-Li

2002-01-01

The main purpose of this project was to understand how the migration and growth of cultured cells respond to mechanical forces. We have made significant progress on all the proposed aims. The most important discoveries are that changes in the environmental mechanical input, such as during space flight, can induce profound changes in cell migration, growth, and programmed cell death. In addition, using genetically engineered cells, we have gained important insight into the molecular mechanism underlying such mechanosensing processes. The results are summarized.

Immunotherapy of chronic hepatitis C virus infection with antibodies against programmed cell death-1 (PD-1).

PubMed

Fuller, Michael J; Callendret, Benoit; Zhu, Baogong; Freeman, Gordon J; Hasselschwert, Dana L; Satterfield, William; Sharpe, Arlene H; Dustin, Lynn B; Rice, Charles M; Grakoui, Arash; Ahmed, Rafi; Walker, Christopher M

2013-09-10

Hepatitis C virus (HCV) persistence is facilitated by exhaustion of CD8+ T cells that express the inhibitory receptor programmed cell death 1 (PD-1). Blockade of PD-1 signaling improves in vitro proliferation of HCV-specific T lymphocytes, but whether antiviral function can be restored in infected individuals is unknown. To address this question, chimpanzees with persistent HCV infection were treated with anti-PD-1 antibodies. A significant reduction in HCV viremia was observed in one of three treated animals without apparent hepatocellular injury. Viremia rebounded in the responder animal when antibody treatment was discontinued. Control of HCV replication was associated with restoration of intrahepatic CD4+ and CD8+ T-cell immunity against multiple HCV proteins. The responder animal had a history of broader T-cell immunity to multiple HCV proteins than the two chimpanzees that did not respond to PD-1 therapy. The results suggest that successful PD-1 blockade likely requires a critical threshold of preexisting virus-specific T cells in liver and warrants consideration of therapeutic vaccination strategies in combination with PD-1 blockade to broaden narrow responses. Anti-PD-1 immunotherapy may also facilitate control of other persistent viruses, notably the hepatitis B virus where options for long-term control of virus replication are limited.

Development and characterization of monoclonal antibodies against canine PD-1 and PD-L1.

PubMed

Nemoto, Yuki; Shosu, Kazuha; Okuda, Masaru; Noguchi, Shunsuke; Mizuno, Takuya

2018-04-01

Recent research has focused on immunotherapy, particularly with regard to cancer treatment. Programmed death-1 and programmed death ligand 1 (PD-1/PD-L1) pathway blockade is a central topic of the promising immunotherapy field. In veterinary medicine, observations of the PD-1/PD-L1 pathway, including the relationship between immune cells and diseases, have increased. In this study, monoclonal antibodies specific to canine PD-1 and PD-L1 were developed, and the antibodies against PD-1 and PD-L1 bind to PD-1 and PD-L1 overexpressing cells, respectively. Additionally, each antibody interfered with the interaction between PD-1 and PD-L1. The expression of PD-1 and PD-L1 was detected on activated T cells from canine peripheral blood mononuclear cells (PBMC), and, remarkably, was the first recorded instance of PD-L1 expression on canine immature dendritic cells. Production of IFN-γ by activated T cells increased significantly when incubated with anti-PD-1 antibody alone and with both anti-PD-1 and anti-PD-L1 antibodies, revealing the functional effects of the antibodies. The antibodies will be useful for research on immune systems and may be the first passive immunotherapy approach in canine cancer patients. Copyright © 2018 Elsevier B.V. All rights reserved.

Photodynamic Cancer Therapy—Recent Advances

NASA Astrophysics Data System (ADS)

Abrahamse, Heidi

2011-09-01

The basic principle of the photodynamic effect was discovered over a hundred years ago leading to the pioneering work on PDT in Europe. It was only during the 1980s, however, when "photoradiation therapy" was investigated as a possible treatment modality for cancer. Photodynamic therapy (PDT) is a photochemotherapeutic process which requires the use of a photosensitizer (PS) that, upon entry into a cancer cell is targeted by laser irradiation to initiate a series of events that contribute to cell death. PSs are light-sensitive dyes activated by a light source at a specific wavelength and can be classified as first or second generation PSs based on its origin and synthetic pathway. The principle of PS activation lies in a photochemical reaction resulting from excitation of the PS producing singlet oxygen which in turn reacts and damages cell organelles and biomolecules required for cell function and ultimately leading to cell destruction. Several first and second generation PSs have been studied in several different cancer types in the quest to optimize treatment. PSs including haematoporphyrin derivative (HpD), aminolevulinic acid (ALA), chlorins, bacteriochlorins, phthalocyanines, naphthalocyanines, pheophorbiedes and purpurins all require selective uptake and retention by cancer cells prior to activation by a light source and subsequent cell death induction. Photodynamic diagnosis (PDD) is based on the fluorescence effect exhibited by PSs upon irradiation and is often used concurrently with PDT to detect and locate tumours. Both laser and light emitting diodes (LED) have been used for PDT depending on the location of the tumour. Internal cancers more often require the use of laser light delivery using fibre optics as delivery system while external PDT often make use of LEDs. Normal cells have a lower uptake of the PS in comparison to tumour cells, however the acute cytotoxic effect of the compound on the recovery rate of normal cells is not known. Subcellular localization of PS is of vital importance when cell death mechanism is identified. Programmed cell death (PCD) viz. apoptosis, necrosis and autophagy have all been identified as inducible cell death mechanisms during PDT. While apoptosis is probably the preferred cell death mechanism, understanding the molecular differences and identifying the cross-talk between these mechanisms are crucial to the development of new PSs aimed at improving the killing efficiency and overall effectiveness of PDT as a cancer treatment modality. This paper reviews the process of PDT cancer therapy, the available PSs, their effectiveness for different cancers as well as the cell death mechanisms identified during PDT of different cancers associated with specific PSs.

Photodynamic Cancer Therapy - Recent Advances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abrahamse, Heidi

The basic principle of the photodynamic effect was discovered over a hundred years ago leading to the pioneering work on PDT in Europe. It was only during the 1980s, however, when 'photoradiation therapy' was investigated as a possible treatment modality for cancer. Photodynamic therapy (PDT) is a photochemotherapeutic process which requires the use of a photosensitizer (PS) that, upon entry into a cancer cell is targeted by laser irradiation to initiate a series of events that contribute to cell death. PSs are light-sensitive dyes activated by a light source at a specific wavelength and can be classified as first ormore » second generation PSs based on its origin and synthetic pathway. The principle of PS activation lies in a photochemical reaction resulting from excitation of the PS producing singlet oxygen which in turn reacts and damages cell organelles and biomolecules required for cell function and ultimately leading to cell destruction. Several first and second generation PSs have been studied in several different cancer types in the quest to optimize treatment. PSs including haematoporphyrin derivative (HpD), aminolevulinic acid (ALA), chlorins, bacteriochlorins, phthalocyanines, naphthalocyanines, pheophorbiedes and purpurins all require selective uptake and retention by cancer cells prior to activation by a light source and subsequent cell death induction. Photodynamic diagnosis (PDD) is based on the fluorescence effect exhibited by PSs upon irradiation and is often used concurrently with PDT to detect and locate tumours. Both laser and light emitting diodes (LED) have been used for PDT depending on the location of the tumour. Internal cancers more often require the use of laser light delivery using fibre optics as delivery system while external PDT often make use of LEDs. Normal cells have a lower uptake of the PS in comparison to tumour cells, however the acute cytotoxic effect of the compound on the recovery rate of normal cells is not known. Subcellular localization of PS is of vital importance when cell death mechanism is identified. Programmed cell death (PCD) viz. apoptosis, necrosis and autophagy have all been identified as inducible cell death mechanisms during PDT. While apoptosis is probably the preferred cell death mechanism, understanding the molecular differences and identifying the cross-talk between these mechanisms are crucial to the development of new PSs aimed at improving the killing efficiency and overall effectiveness of PDT as a cancer treatment modality. This paper reviews the process of PDT cancer therapy, the available PSs, their effectiveness for different cancers as well as the cell death mechanisms identified during PDT of different cancers associated with specific PSs.« less

Therapeutic strategies of drug repositioning targeting autophagy to induce cancer cell death: from pathophysiology to treatment.

PubMed

Yoshida, Go J

2017-03-09

The 2016 Nobel Prize in Physiology or Medicine was awarded to the researcher that discovered autophagy, which is an evolutionally conserved catabolic process which degrades cytoplasmic constituents and organelles in the lysosome. Autophagy plays a crucial role in both normal tissue homeostasis and tumor development and is necessary for cancer cells to adapt efficiently to an unfavorable tumor microenvironment characterized by hypo-nutrient conditions. This protein degradation process leads to amino acid recycling, which provides sufficient amino acid substrates for cellular survival and proliferation. Autophagy is constitutively activated in cancer cells due to the deregulation of PI3K/Akt/mTOR signaling pathway, which enables them to adapt to hypo-nutrient microenvironment and exhibit the robust proliferation at the pre-metastatic niche. That is why just the activation of autophagy with mTOR inhibitor often fails in vain. In contrast, disturbance of autophagy-lysosome flux leads to endoplasmic reticulum (ER) stress and an unfolded protein response (UPR), which finally leads to increased apoptotic cell death in the tumor tissue. Accumulating evidence suggests that autophagy has a close relationship with programmed cell death, while uncontrolled autophagy itself often induces autophagic cell death in tumor cells. Autophagic cell death was originally defined as cell death accompanied by large-scale autophagic vacuolization of the cytoplasm. However, autophagy is a "double-edged sword" for cancer cells as it can either promote or suppress the survival and proliferation in the tumor microenvironment. Furthermore, several studies of drug re-positioning suggest that "conventional" agents used to treat diseases other than cancer can have antitumor therapeutic effects by activating/suppressing autophagy. Because of ever increasing failure rates and high cost associated with anticancer drug development, this therapeutic development strategy has attracted increasing attention because the safety profiles of these medicines are well known. Antimalarial agents such as artemisinin and disease-modifying antirheumatic drug (DMARD) are the typical examples of drug re-positioning which affect the autophagy regulation for the therapeutic use. This review article focuses on recent advances in some of the novel therapeutic strategies that target autophagy with a view to treating/preventing malignant neoplasms.

Apigenin inhibits the inducible expression of programmed death ligand 1 by human and mouse mammary carcinoma cells.

PubMed

Coombs, Melanie R Power; Harrison, Megan E; Hoskin, David W

2016-10-01

Programmed death ligand 1 (PD-L1) is expressed by many cancer cell types, as well as by activated T cells and antigen-presenting cells. Constitutive and inducible PD-L1 expression contributes to immune evasion by breast cancer (BC) cells. We show here that the dietary phytochemical apigenin inhibited interferon (IFN)-γ-induced PD-L1 upregulation by triple-negative MDA-MB-468 BC cells, HER2(+) SK-BR-3 BC cells, and 4T1 mouse mammary carcinoma cells, as well as human mammary epithelial cells, but did not affect constitutive PD-L1 expression by triple-negative MDA-MB-231 BC cells. IFN-β-induced expression of PD-L1 by MDA-MB-468 cells was also inhibited by apigenin. In addition, luteolin, the major metabolite of apigenin, inhibited IFN-γ-induced PD-L1 expression by MDA-MB-468 cells. Apigenin-mediated inhibition of IFN-γ-induced PD-L1 expression by MDA-MB-468 and 4T1 cells was associated with reduced phosphorylation of STAT1, which was early and transient at Tyr701 and sustained at Ser727. Apigenin-mediated inhibition of IFN-γ-induced PD-L1 expression by MDA-MB-468 cells also increased proliferation and interleukin-2 synthesis by PD-1-expressing Jurkat T cells that were co-cultured with MDA-MB-468 cells. Apigenin therefore has the potential to increase the vulnerability of BC cells to T cell-mediated anti-tumor immune responses. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The HDAC6/8/10 inhibitor TH34 induces DNA damage-mediated cell death in human high-grade neuroblastoma cell lines.

PubMed

Kolbinger, Fiona R; Koeneke, Emily; Ridinger, Johannes; Heimburg, Tino; Müller, Michael; Bayer, Theresa; Sippl, Wolfgang; Jung, Manfred; Gunkel, Nikolas; Miller, Aubry K; Westermann, Frank; Witt, Olaf; Oehme, Ina

2018-06-09

High histone deacetylase (HDAC) 8 and HDAC10 expression levels have been identified as predictors of exceptionally poor outcomes in neuroblastoma, the most common extracranial solid tumor in childhood. HDAC8 inhibition synergizes with retinoic acid treatment to induce neuroblast maturation in vitro and to inhibit neuroblastoma xenograft growth in vivo. HDAC10 inhibition increases intracellular accumulation of chemotherapeutics through interference with lysosomal homeostasis, ultimately leading to cell death in cultured neuroblastoma cells. So far, no HDAC inhibitor covering HDAC8 and HDAC10 at micromolar concentrations without inhibiting HDACs 1, 2 and 3 has been described. Here, we introduce TH34 (3-(N-benzylamino)-4-methylbenzhydroxamic acid), a novel HDAC6/8/10 inhibitor for neuroblastoma therapy. TH34 is well-tolerated by non-transformed human skin fibroblasts at concentrations up to 25 µM and modestly impairs colony growth in medulloblastoma cell lines, but specifically induces caspase-dependent programmed cell death in a concentration-dependent manner in several human neuroblastoma cell lines. In addition to the induction of DNA double-strand breaks, HDAC6/8/10 inhibition also leads to mitotic aberrations and cell-cycle arrest. Neuroblastoma cells display elevated levels of neuronal differentiation markers, mirrored by formation of neurite-like outgrowths under maintained TH34 treatment. Eventually, after long-term treatment, all neuroblastoma cells undergo cell death. The combination of TH34 with plasma-achievable concentrations of retinoic acid, a drug applied in neuroblastoma therapy, synergistically inhibits colony growth (combination index (CI) < 0.1 for 10 µM of each). In summary, our study supports using selective HDAC inhibitors as targeted antineoplastic agents and underlines the therapeutic potential of selective HDAC6/8/10 inhibition in high-grade neuroblastoma.

Tomato Ribonuclease LX with the Functional Endoplasmic Reticulum Retention Motif HDEF Is Expressed during Programmed Cell Death Processes, Including Xylem Differentiation, Germination, and Senescence1

PubMed Central

Lehmann, Karin; Hause, Bettina; Altmann, Dorit; Köck, Margret

2001-01-01

We have studied the subcellular localization of the acid S-like ribonuclease (RNase) LX in tomato (Lycopersicon esculentum Mill.) cells using a combination of biochemical and immunological methods. It was found that the enzyme, unexpectedly excluded from highly purified vacuoles, accumulates in the endoplasmic reticulum. The evidence that RNase LX is a resident of the endoplasmic reticulum (ER) is supported by an independent approach showing that the C-terminal peptide HDEF of RNase LX acts as an alternative ER retention signal in plants. For functional testing, the cellular distribution of chimeric protein constructs based on a marker protein, Brazil nut (Bertholletia excelsa) 2S albumin, was analyzed immunochemically in transgenic tobacco (Nicotiana tabacum) plants. Here, we report that the peptide motif is necessary and sufficient to accumulate 2S albumin constructs of both vacuolar and extracellular final destinations in the ER. We have shown immunochemically that RNase LX is specifically expressed during endosperm mobilization and leaf and flower senescence. Using immunofluorescence, RNase LX protein was detected in immature tracheary elements, suggesting a function in xylem differentiation. These results support a physiological function of RNase LX in selective cell death processes that are also thought to involve programmed cell death. It is assumed that RNase LX accumulates in an ER-derived compartment and is released by membrane disruption into the cytoplasma of those cells that are intended to undergo autolysis. These processes are accompanied by degradation of cellular components supporting a metabolic recycling function of the intracellular RNase LX. PMID:11598219

Pyroptosis and Apoptosis Pathways Engage in Bidirectional Crosstalk in Monocytes and Macrophages.

PubMed

Taabazuing, Cornelius Y; Okondo, Marian C; Bachovchin, Daniel A

2017-04-20

Pyroptosis is a lytic form of programmed cell death mediated by the inflammatory caspase-1, -4, and -5. We recently discovered that small-molecule inhibitors of the serine peptidases DPP8 and DPP9 (DPP8/9) induce pro-caspase-1-dependent pyroptosis in monocytes and macrophages. Notably, DPP8/9 inhibitors, unlike microbial agents, absolutely require caspase-1 to induce cell death. Therefore, DPP8/9 inhibitors are useful probes to study caspase-1 in cells. Here, we show that, in the absence of the pyroptosis-mediating substrate gasdermin D (GSDMD), caspase-1 activates caspase-3 and -7 and induces apoptosis, demonstrating that GSDMD is the only caspase-1 substrate that induces pyroptosis. Conversely, we found that, during apoptosis, caspase-3/-7 specifically block pyroptosis by cleaving GSDMD at a distinct site from the inflammatory caspases that inactivates the protein. Overall, this work reveals bidirectional crosstalk between apoptosis and pyroptosis in monocytes and macrophages, further illuminating the complex interplay between cell death pathways in the innate immune system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Patterning C. elegans: homeotic cluster genes, cell fates and cell migrations.

PubMed

Salser, S J; Kenyon, C

1994-05-01

Despite its simple body form, the nematode C. elegans expresses homeotic cluster genes similar to those of insects and vertebrates in the patterning of many cell types and tissues along the anteroposterior axis. In the ventral nerve cord, these genes program spatial patterns of cell death, fusion, division and neurotransmitter production; in migrating cells they regulate the direction and extent of movement. Nematode development permits an analysis at the cellular level of how homeotic cluster genes interact to specify cell fates, and how cell behavior can be regulated to assemble an organism.

Inhibition of KSP by ARRY-520 Induces Cell Cycle Block and Cell Death via the Mitochondrial Pathway in AML Cells

PubMed Central

Carter, Bing Z.; Mak, Duncan H.; Woessner, Richard; Gross, Stefan; Schober, Wendy D.; Estrov, Zeev; Kantarjian, Hagop; Andreeff, Michael

2013-01-01

Kinesin spindle protein (KSP), a microtubule-associated motor protein essential for cell cycle progression, is overexpressed in many cancers and a potential anti-tumor target. We found that inhibition of KSP by a selective inhibitor, ARRY-520, blocked cell cycle progression, leading to apoptosis in acute myeloid leukemia cell lines which express high levels of KSP. Knockdown of p53, overexpression of XIAP, and mutation in caspase-8 did not significantly affect sensitivity to ARRY-520, suggesting that the response is independent of p53, XIAP, and the extrinsic apoptotic pathway. Although ARRY-520 induced mitotic arrest in both HL-60 and Bcl-2-overexpressing HL-60Bcl-2 cells, cell death was blunted in HL-60Bcl-2 cells, suggesting that the apoptotic program is executed through the mitochondrial pathway. Accordingly, inhibition of Bcl-2 by ABT-737 was synergistic with ARRY-520 in HL-60Bcl-2 cells. Furthermore, ARRY-520 increased Bim protein levels prior to caspase activation in HL-60 cells. ARRY-520 significantly inhibited tumor growth of xenografts in SCID mice and inhibited AML blast but not normal colony formation, supporting a critical role for KSP in proliferation of leukemic progenitor cells. These results demonstrate that ARRY-520 potently induces cell cycle block and subsequent death in leukemic cells via the mitochondrial pathway and has potential to eradicate AML progenitor cells. PMID:19458629

Necroptosis in cardiovascular disease - a new therapeutic target.

PubMed

Gupta, Kartik; Phan, Noel; Wang, Qiwei; Liu, Bo

2018-05-01

Contrary to the apoptosis-necrosis binary view of cell death, recent experimental evidence demonstrates that several forms of necrosis, represented by necroptosis, are regulated or programmed in nature. Multiple death stimuli known to be associated with cardiovascular disease are capable of causing either apoptosis or necroptosis. Whether a cell dies from apoptosis or necroptosis has distinct consequences on inflammation. It is known that apoptosis, a non-lytic form of death mediated by the caspase family of proteases, does not generally evoke an immune response. Necroptosis, on the other hand, is a lytic form of cell death. Due to the rapid loss of plasma membrane integrity, cells dying from necroptosis release proinflammatory intracellular contents and subsequently cause inflammation. Our review delineates various genetic and biochemical evidence that demonstrates a compelling role of necroptosis in the pathogenesis and/or progression of cardiovascular disease including myocardial infarction, atherosclerosis, and aortic aneurysm. Through recent studies of necroptosis in cardiovascular diseases, we attempt to discuss the role of necroptosis in vascular inflammation as well as the potential of necroptosis inhibitors in future clinical management of cardiovascular events. Inhibiting necroptosis in the vasculature has an overall protective role and necroptosis may represent a new therapeutic target to prevent the development and progression of cardiovascular diseases. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Caenorhabditis elegans mucolipin-like gene cup-5 is essential for viability and regulates lysosomes in multiple cell types.

PubMed

Hersh, Bradley M; Hartwieg, Erika; Horvitz, H Robert

2002-04-02

The misregulation of programmed cell death, or apoptosis, contributes to the pathogenesis of many diseases. We used Nomarski microscopy to screen for mutants containing refractile cell corpses in a C. elegans strain in which all programmed cell death is blocked and such corpses are absent. We isolated a mutant strain that accumulates refractile bodies resembling irregular cell corpses. We rescued this mutant phenotype with the C. elegans mucolipidosis type IV (ML-IV) homolog, the recently identified cup-5 (coelomocyte-uptake defective) gene. ML-IV is a human autosomal recessive lysosomal storage disease characterized by psychomotor retardation and ophthalmological abnormalities. Our null mutations in cup-5 cause maternal-effect lethality. In addition, cup-5 mutants contain excess lysosomes in many and possibly all cell types and contain lamellar structures similar to those observed in ML-IV cell lines. The human ML-IV gene is capable of rescuing both the maternal-effect lethality and the lysosome-accumulation abnormality of cup-5 mutants. cup-5 mutants seem to contain excess apoptotic cells as detected by staining with terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling. We suggest that the increased apoptosis seen in cup-5 mutants is a secondary consequence of the lysosomal defect, and that abnormalities in apoptosis may be associated with human lysosomal storage disorders.

Virus-induced apoptosis and phosphorylation form of metacaspase in the marine coccolithophorid Emiliania huxleyi.

PubMed

Liu, Jingwen; Cai, Weicong; Fang, Xian; Wang, Xueting; Li, Guiling

2018-04-01

Lytic viral infection and programmed cell death (PCD) are thought to represent two distinct death mechanisms in phytoplankton, unicellular photoautotrophs that drift with ocean currents. PCD (apoptosis) is mainly brought about by the activation of caspases, a protease family with unique substrate selectivity. Here, we demonstrated that virus infection induced apoptosis of marine coccolithophorid Emiliania huxleyi BOF92 involving activation of metacaspase. E. huxleyi cells exhibited cell death process akin to that of apoptosis when exposed to virus infection. We observed typical hallmarks of apoptosis including cell shrinkage, associated nuclear morphological changes and DNA fragmentation. Immunoblotting revealed that antibody against human active-caspase-3 shared epitopes with a protein of ≈ 23 kDa; whose pattern of expression correlated with the onset of cell death. Moreover, analysis on two-dimensional gel electrophoresis revealed that two spots of active caspase-3 co-migrated with the different isoelectric points. Phosphatase treatment of cytosolic extracts containing active caspases-3 showed a mobility shift, suggesting that phosphorylated form of this enzyme might be present in the extracts. Computational prediction of phosphorylation sites based on the amino acid sequence of E. huxleyi metacaspase showed multiple phosphorylated sites for serine, threonine and tyrosine residues. This is the first report showing that phosphorylation modification of metacaspase in E. huxleyi might be required for certain biochemical and morphological changes during virus induced apoptosis.

Dynamic metabolic exchange governs a marine algal-bacterial interaction.

PubMed

Segev, Einat; Wyche, Thomas P; Kim, Ki Hyun; Petersen, Jörn; Ellebrandt, Claire; Vlamakis, Hera; Barteneva, Natasha; Paulson, Joseph N; Chai, Liraz; Clardy, Jon; Kolter, Roberto

2016-11-18

Emiliania huxleyi is a model coccolithophore micro-alga that generates vast blooms in the ocean. Bacteria are not considered among the major factors influencing coccolithophore physiology. Here we show through a laboratory model system that the bacterium Phaeobacter inhibens , a well-studied member of the Roseobacter group, intimately interacts with E. huxleyi. While attached to the algal cell, bacteria initially promote algal growth but ultimately kill their algal host. Both algal growth enhancement and algal death are driven by the bacterially-produced phytohormone indole-3-acetic acid. Bacterial production of indole-3-acetic acid and attachment to algae are significantly increased by tryptophan, which is exuded from the algal cell. Algal death triggered by bacteria involves activation of pathways unique to oxidative stress response and programmed cell death. Our observations suggest that bacteria greatly influence the physiology and metabolism of E. huxleyi. Coccolithophore-bacteria interactions should be further studied in the environment to determine whether they impact micro-algal population dynamics on a global scale.

(Re-)programming of subtype specific cardiomyocytes.

PubMed

Hausburg, Frauke; Jung, Julia Jeannine; Hoch, Matti; Wolfien, Markus; Yavari, Arash; Rimmbach, Christian; David, Robert

2017-10-01

Adult cardiomyocytes (CMs) possess a highly restricted intrinsic regenerative potential - a major barrier to the effective treatment of a range of chronic degenerative cardiac disorders characterized by cellular loss and/or irreversible dysfunction and which underlies the majority of deaths in developed countries. Both stem cell programming and direct cell reprogramming hold promise as novel, potentially curative approaches to address this therapeutic challenge. The advent of induced pluripotent stem cells (iPSCs) has introduced a second pluripotent stem cell source besides embryonic stem cells (ESCs), enabling even autologous cardiomyocyte production. In addition, the recent achievement of directly reprogramming somatic cells into cardiomyocytes is likely to become of great importance. In either case, different clinical scenarios will require the generation of highly pure, specific cardiac cellular-subtypes. In this review, we discuss these themes as related to the cardiovascular stem cell and programming field, including a focus on the emergent topic of pacemaker cell generation for the development of biological pacemakers and in vitro drug testing. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis and evaluation of a radiolabeled bis-zinc(II)-cyclen complex as a potential probe for in vivo imaging of cell death.

PubMed

Wang, Hongliang; Wu, Zhifang; Li, Sijin; Hu, Kongzhen; Tang, Ganghua

2017-04-01

The exposition of phosphatidylserine (PS) from the cell membrane is associated with most cell death programs (apoptosis, necrosis, autophagy, mitotic catastrophe, etc.), which makes PS an attractive target for overall cell death imaging. To this end, zinc(II) macrocycle coordination complexes with cyclic polyamine units as low-molecular-weight annexin mimics have a selective affinity for biomembrane surfaces enriched with PS, and are therefore useful for detection of cell death. In the present study, a 11 C-labeled zinc(II)-bis(cyclen) complex ( 11 C-CyclenZn2) was prepared and evaluated as a new positron emission tomography (PET) probe for cell death imaging. 11 C-CyclenZn2 was synthesized by methylation of its precursor, 4-methoxy-2,5-di-[10-methyl-1,4,7,10-tetraazacyclododecane-1,4,7-tricarboxylic acid tri-tert-butyl ester] phenol (Boc-Cyclen2) with 11 C-methyl triflate as a prosthetic group in acetone, deprotection by hydrolysis in aqueous HCl solution, and chelation with zinc nitrate. The cell death imaging capability of 11 C-CyclenZn2 was evaluated using in vitro cell uptake assays with camptothecin-treated PC-3 cells, biodistribution studies, and in vivo PET imaging in Kunming mice bearing S-180 fibrosarcoma. Starting from 11 C-methyl triflate, the total preparation time for 11 C-CyclenZn2 was ~40 min, with an uncorrected radiochemical yield of 12 ± 3% (based on 11 C-CH 3 OTf, n = 10), a radiochemical purity of greater than 95%, and the specific activity of 0.75-1.01 GBq/μmol. The cell death binding specificity of 11 C-CyclenZn2 was demonstrated by significantly different uptake rates in camptothecin-treated and control PC-3 cells in vitro. Inhibition experiments for 18 F-radiofluorinated Annexin V binding to apoptotic/necrotic cells illustrated the necessity of zinc ions for zinc(II)-bis(cyclen) complexation in binding cell death, and zinc(II)-bis(cyclen) complexe and Annexin V had not identical binding pattern with apoptosis/necrosis cells. Biodistribution studies of 11 C-CyclenZn2 revealed a fast clearance from blood, low uptake rates in brain and muscle tissue, and high uptake rates in liver and kidney, which provide the main metabolic route. PET imaging using 11 C-CyclenZn2 revealed that cyclophosphamide-treated mice (CP-treated group) exhibited a significant increase of uptake rate in the tumor at 60 min postinjection, compared with control mice (Control group). The results indicate that the ability of 11 C-CyclenZn2 to detect cell death is comparable to Annexin V, and it has potential as a PET tracer for noninvasive evaluation and monitoring of anti-tumor chemotherapy.

PDT: death pathways

NASA Astrophysics Data System (ADS)

Kessel, David

2007-02-01

Cellular targets of photodynamic therapy include mitochondria, lysosomes, the endoplasmic reticulum (ER) and the plasma membrane. PDT can evoke necrosis, autophagy and apoptosis, or combinations of these, depending on the PDT dose, the site(s) of photodamage and the cellular phenotype. It has been established that loss of viability occurs even when the apoptotic program is inhibited. Studies assessing effects of ER or mitochondrial photodamage, involving loss of Bcl-2 function, indicate that low-dose PDT elicited a rapid autophagic response in L1210 cells. This was attributed to the ability of autophagy to recycle photodamaged organelles, and there was partial protection from loss of viability. This effect was not observed in L1210/Atg7, where autophagy was silenced. At higher PDT doses, apoptotic cells were observed within 60 min in both cell lines, but more so in L1210. The ability of L1210 cells to undergo autophagy did not offer protection from cell death at the higher PDT dose. Previous studies had indicated that autophagy can contribute to cell death, since L1210 cells that do not undergo an initial apoptotic response often contain multiple autophagic vacuoles 24 hr later. With L1210/Atg7, apoptosis alone may account for the loss of viability at an LD 90 PDT dose.

Predictors of Survival among Adult Ethiopian Patients in the National ART Program at Seven University Teaching Hospitals: A Prospective Cohort Study.

PubMed

Fekade, Daniel; Weldegebreal, Teklu; Teklu, Alula M; Damen, Melake; Abdella, Saro; Baraki, Nega; Belayhun, Bekele; Berhan, Eyoel; Kebede, Amha; Assefa, Yibeltal

2017-02-01

In Ethiopia, the publicly funded antiretroviral treatment (ART) program was started in 2005. Two hundred seventy-five thousand patients were enrolled in the national ART program by 2012. However, there is limited data on mortality and predictors of death among adult patients in the ART program. The study aimed to estimate mortality and risk factors for death among adult, ART-naïve patients, started in the national ART program from January 2009 to July 2013. Multi-site, prospective, observational cohort study of adult, age > 18 years, ART-naïve patients, started in the national ART program at seven university-affiliated hospitals from January 2009 - July 2013. Kaplan-Meier and Cox regression analyses were used to estimate survival and determine risk factors for death. A total of 976 patients, 594 females (60.9 %), were enrolled into the study. Median age of the cohort was 33years. The median CD4 count at start of ART was 144 cells/µl (interquartile range (IQR) 78-205), and 34.2% (330/965) had CD4 < 100. Sixty-three percent (536/851) had viral load greater than 5 log copies/ml (IQR 4.7-5.7) at base line. One hundred and one deaths were recorded during follow-up period, all-cause mortality rate 10.3%; 5.4 deaths/100 person years of observation, 95% confidence interval 4.4-6.5. Seventy percent of the deaths occurred within six months of starting ART. Cox regression analyses showed that the following measures independently predicted mortality: age >51 years, (Adjusted Hazard Ratio (AHR) 4.01, P=0.003), WHO stages III&IV, (AHR 1.76, p = 0.025), CD4 count, <100, (AHR 2.36, p =0.006), and viral load >5 log copies /ml (CHR 1.71, p = 0.037). There is high early on- ART mortality in patients presenting with advanced immunodeficiency. Detecting cases and initiating ART before onset of advanced immunodeficiency might improve survival.

The pro-angiogenic cytokine pleiotrophin potentiates cardiomyocyte apoptosis through inhibition of endogenous AKT/PKB activity.

PubMed

Li, Jinliang; Wei, Hong; Chesley, Alan; Moon, Chanil; Krawczyk, Melissa; Volkova, Maria; Ziman, Bruce; Margulies, Kenneth B; Talan, Mark; Crow, Michael T; Boheler, Kenneth R

2007-11-30

Pleiotrophin is a development-regulated cytokine and growth factor that can promote angiogenesis, cell proliferation, or differentiation, and it has been reported to have neovasculogenic effects in damaged heart. Developmentally, it is prominently expressed in fetal and neonatal hearts, but it is minimally expressed in normal adult heart. Conversely, we show in a rat model of myocardial infarction and in human dilated cardiomyopathy that pleiotrophin is markedly up-regulated. To elucidate the effects of pleiotrophin on cardiac contractile cells, we employed primary cultures of rat neonatal and adult cardiomyocytes. We show that pleiotrophin is released from cardiomyocytes in vitro in response to hypoxia and that the addition of recombinant pleiotrophin promotes caspase-mediated genomic DNA fragmentation in a dose- and time-dependent manner. Functionally, it potentiates the apoptotic response of neonatal cardiomyocytes to hypoxic stress and to ultraviolet irradiation and of adult cardiomyocytes to hypoxia-reoxygenation. Moreover, UV-induced apoptosis in neonatal cardiomyocytes can be partially inhibited by small interfering RNA-mediated knockdown of endogenous pleiotrophin. Mechanistically, pleiotrophin antagonizes IGF-1 associated Ser-473 phosphorylation of AKT/PKB, and it concomitantly decreases both BAD and GSK3beta phosphorylation. Adenoviral expression of constitutively active AKT and lithium chloride-mediated inhibition of GSK3beta reduce the potentiated programmed cell death elicited by pleiotrophin. These latter data indicate that pleiotrophin potentiates cardiomyocyte cell death, at least partially, through inhibition of AKT signaling. In conclusion, we have uncovered a novel function for pleiotrophin on heart cells following injury. It fosters cardiomyocyte programmed cell death in response to pro-apoptotic stress, which may be critical to myocardial injury repair.

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

PubMed

Galluzzi, Lorenzo; Vitale, Ilio; Aaronson, Stuart A; Abrams, John M; Adam, Dieter; Agostinis, Patrizia; Alnemri, Emad S; Altucci, Lucia; Amelio, Ivano; Andrews, David W; Annicchiarico-Petruzzelli, Margherita; Antonov, Alexey V; Arama, Eli; Baehrecke, Eric H; Barlev, Nickolai A; Bazan, Nicolas G; Bernassola, Francesca; Bertrand, Mathieu J M; Bianchi, Katiuscia; Blagosklonny, Mikhail V; Blomgren, Klas; Borner, Christoph; Boya, Patricia; Brenner, Catherine; Campanella, Michelangelo; Candi, Eleonora; Carmona-Gutierrez, Didac; Cecconi, Francesco; Chan, Francis K-M; Chandel, Navdeep S; Cheng, Emily H; Chipuk, Jerry E; Cidlowski, John A; Ciechanover, Aaron; Cohen, Gerald M; Conrad, Marcus; Cubillos-Ruiz, Juan R; Czabotar, Peter E; D'Angiolella, Vincenzo; Dawson, Ted M; Dawson, Valina L; De Laurenzi, Vincenzo; De Maria, Ruggero; Debatin, Klaus-Michael; DeBerardinis, Ralph J; Deshmukh, Mohanish; Di Daniele, Nicola; Di Virgilio, Francesco; Dixit, Vishva M; Dixon, Scott J; Duckett, Colin S; Dynlacht, Brian D; El-Deiry, Wafik S; Elrod, John W; Fimia, Gian Maria; Fulda, Simone; García-Sáez, Ana J; Garg, Abhishek D; Garrido, Carmen; Gavathiotis, Evripidis; Golstein, Pierre; Gottlieb, Eyal; Green, Douglas R; Greene, Lloyd A; Gronemeyer, Hinrich; Gross, Atan; Hajnoczky, Gyorgy; Hardwick, J Marie; Harris, Isaac S; Hengartner, Michael O; Hetz, Claudio; Ichijo, Hidenori; Jäättelä, Marja; Joseph, Bertrand; Jost, Philipp J; Juin, Philippe P; Kaiser, William J; Karin, Michael; Kaufmann, Thomas; Kepp, Oliver; Kimchi, Adi; Kitsis, Richard N; Klionsky, Daniel J; Knight, Richard A; Kumar, Sharad; Lee, Sam W; Lemasters, John J; Levine, Beth; Linkermann, Andreas; Lipton, Stuart A; Lockshin, Richard A; López-Otín, Carlos; Lowe, Scott W; Luedde, Tom; Lugli, Enrico; MacFarlane, Marion; Madeo, Frank; Malewicz, Michal; Malorni, Walter; Manic, Gwenola; Marine, Jean-Christophe; Martin, Seamus J; Martinou, Jean-Claude; Medema, Jan Paul; Mehlen, Patrick; Meier, Pascal; Melino, Sonia; Miao, Edward A; Molkentin, Jeffery D; Moll, Ute M; Muñoz-Pinedo, Cristina; Nagata, Shigekazu; Nuñez, Gabriel; Oberst, Andrew; Oren, Moshe; Overholtzer, Michael; Pagano, Michele; Panaretakis, Theocharis; Pasparakis, Manolis; Penninger, Josef M; Pereira, David M; Pervaiz, Shazib; Peter, Marcus E; Piacentini, Mauro; Pinton, Paolo; Prehn, Jochen H M; Puthalakath, Hamsa; Rabinovich, Gabriel A; Rehm, Markus; Rizzuto, Rosario; Rodrigues, Cecilia M P; Rubinsztein, David C; Rudel, Thomas; Ryan, Kevin M; Sayan, Emre; Scorrano, Luca; Shao, Feng; Shi, Yufang; Silke, John; Simon, Hans-Uwe; Sistigu, Antonella; Stockwell, Brent R; Strasser, Andreas; Szabadkai, Gyorgy; Tait, Stephen W G; Tang, Daolin; Tavernarakis, Nektarios; Thorburn, Andrew; Tsujimoto, Yoshihide; Turk, Boris; Vanden Berghe, Tom; Vandenabeele, Peter; Vander Heiden, Matthew G; Villunger, Andreas; Virgin, Herbert W; Vousden, Karen H; Vucic, Domagoj; Wagner, Erwin F; Walczak, Henning; Wallach, David; Wang, Ying; Wells, James A; Wood, Will; Yuan, Junying; Zakeri, Zahra; Zhivotovsky, Boris; Zitvogel, Laurence; Melino, Gerry; Kroemer, Guido

2018-03-01

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field.

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

PubMed

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 level, and also by filling in gaps detailing plant apoptotic factors not yet amalgamated within the literature. Copyright © 2012 Elsevier GmbH. All rights reserved.

Stem cell fusion as an ultimate line of defense against xenobiotics.

PubMed

Padron Velazquez, Julio Lazaro

2006-01-01

There are several indications that the potential of stem cells to fuse with somatic cells is extremely high and, what's more exciting, in some instances goes as far as reprogramming and/or rescuing altered cells. It remains unclear, however, how frequent this mechanism is and what patho-physiological role it might play in nature. A plausible hypothesis, discussed in this paper, suggests that stem cell niches might provide a safeguard for the intact genome and epigenome. By fusing with somatic de-differentiated cells, stem cells might consent epigenetic reprogramming and/or genetic recovery of genes which otherwise could drive altered cells to malignancy. If the many sophisticated mechanisms of metabolism, cell repair, programmed cell death and tissue regeneration should fail, stem cells might represent a final attempt to recover dedifferentiated cells to avoid inflowing in cancer. In the current reappraisal of the different mechanisms of defense against xenobiotics, even the incidence of cancer itself is considered an evolving mechanism which, through a kind of programmed death of individuals exhibiting defective mutations, favors advancement of the phenotypes which adapt best. Additionally, with regard to the mechanisms of transmitting somatic mutations, based on stem cells' capacity to migrate and to fuse, here it is speculated that stem cells might be capable of carrying acquired somatic mutations from peripheral tissues to the gonads, and transmit that information into the germinal line. If appropriately demonstrated, these mechanisms might delineate a novel therapeutic area to be explored. The use of stem cells to reprogram/recover irreversibly damaged cells or to transmit beneficial mutations might be a valuable therapeutic approach in the future.

Adenovirus-mediated suppression of HMGI(Y) protein synthesis as potential therapy of human malignant neoplasias

PubMed Central

Scala, Stefania; Portella, Giuseppe; Fedele, Monica; Chiappetta, Gennaro; Fusco, Alfredo

2000-01-01

High mobility group I (HMGI) proteins are overexpressed in several human malignant tumors. We previously demonstrated that inhibition of HMGI synthesis prevents thyroid cell transformation. Here, we report that an adenovirus carrying the HMGI(Y) gene in an antisense orientation (Ad-Yas) induced programmed cell death of two human thyroid anaplastic carcinoma cell lines (ARO and FB-1), but not normal thyroid cells. The Ad-Yas virus led to death of lung, colon, and breast carcinoma cells. A control adenovirus carrying the lacZ gene did not inhibit the growth of either normal or neoplastic cells. Ad-Yas treatment of tumors induced in athymic mice by ARO cells caused a drastic reduction in tumor size. Therefore, suppression of HMGI(Y) protein synthesis by an HMGI(Y) antisense adenoviral vector may be a useful treatment strategy in a variety of human malignant neoplasias, in which HMGI(Y) gene overexpression is a general event. PMID:10759549

Heat stress induces different forms of cell death in sea anemones and their endosymbiotic algae depending on temperature and duration.

PubMed

Dunn, S R; Thomason, J C; Le Tissier, M D A; Bythell, J C

2004-11-01

Bleaching of reef building corals and other symbiotic cnidarians due to the loss of their dinoflagellate algal symbionts (=zooxanthellae), and/or their photosynthetic pigments, is a common sign of environmental stress. Mass bleaching events are becoming an increasingly important cause of mortality and reef degradation on a global scale, linked by many to global climate change. However, the cellular mechanisms of stress-induced bleaching remain largely unresolved. In this study, the frequency of apoptosis-like and necrosis-like cell death was determined in the symbiotic sea anemone Aiptasia sp. using criteria that had previously been validated for this symbiosis as indicators of programmed cell death (PCD) and necrosis. Results indicate that PCD and necrosis occur simultaneously in both host tissues and zooxanthellae subject to environmentally relevant doses of heat stress. Frequency of PCD in the anemone endoderm increased within minutes of treatment. Peak rates of apoptosis-like cell death in the host were coincident with the timing of loss of zooxanthellae during bleaching. The proportion of apoptosis-like host cells subsequently declined while cell necrosis increased. In the zooxanthellae, both apoptosis-like and necrosis-like activity increased throughout the duration of the experiment (6 days), dependent on temperature dose. A stress-mediated PCD pathway is an important part of the thermal stress response in the sea anemone symbiosis and this study suggests that PCD may play different roles in different components of the symbiosis during bleaching.

5-Fluorouracil-induced apoptosis in cultured oral cancer cells.

PubMed

Tong, D; Poot, M; Hu, D; Oda, D

2000-03-01

Chemotherapy is commonly used to treat advanced oral squamous cell carcinoma (SCC) and is known to kill cancer cells through apoptosis. Our hypothesis states that 5-fluorouracil (5FU) also kills cultured oral epithelial cells through programmed cell death or apoptosis. Cultured oral cancer cells were exposed to an optimum dose of 20 mg/ml of 5FU. Cells were analyzed for changes in cell cycle distribution and induction of cell death including apoptosis. Normal control, human papilloma virus-immortalized (PP), ATCC SCC cell line (CA1) and two primary oral SCC cell lines (CA3 and -4) were studied. Inhibition of apoptosis by a pan-caspase inhibitor was used. SYTO 11 flow cytometry showed increased apoptosis in all 5FU-treated cell cultures compared to untreated controls. The results show biological variation in apoptotic response. CA1 had the lowest apoptotic rate of the cancer cell lines at 1.5%. Next lowest was CA3, followed by CA4 and PP. In addition, alteration in the G1 and S phase fractions were found. Untreated CA1 showed 28% G1, 53% S compared to 43% G1, and 40% S of treated. We investigated the pathway of apoptosis using the pan-caspase inhibitor IDN-1529 by methylthiazolyl diphenyl tetrazolium bromide (MTT) colorimetric analysis. Results showed mild inhibition of cell death when cells were incubated with 50 microM IDN-1529 for 24 h. This suggests a probable caspase-dependent apoptotic pathway. In conclusion, our data suggest that 5FU induces oral cancer cell death through apoptosis and that biological variation exists between normal and cancer cells and between different types of cancer cells themselves. Our data indicate that cultures of a useful in vitro model for chemosensitivity assays are possible. Our results also suggest a caspase-dependent pathway for chemocytotoxicity in oral SCC.

Apoptosis-Like Death, an Extreme SOS Response in Escherichia coli

PubMed Central

Erental, Ariel; Kalderon, Ziva; Saada, Ann; Smith, Yoav

2014-01-01

ABSTRACT 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. PMID:25028428