Manganese-induced rat pheochromocytoma (PC12) cell death is independent of caspase activation

Apoptosis is triggered by the activation of caspases and characterized by chromatin condensation and nuclear fragmentation (type II nuclear morphology). Necrosis is depicted by a gain in cell volume (oncosis), swelling of organelles, plasma membrane leakage, and subsequent loss of intracellular contents. Although considered as different cell death entities, there is an overlap between apoptosis and necrosis. In this sense, mounting evidence suggests that both processes can be morphological expressions of a common biochemical network known as “apoptosis-necrosis continuum.” To gain insight into the events driving the apoptosis-necrosis continuum, apoptotically proficient cells were screened facing several apoptotic inducers for the absence of type II apoptotic nuclear morphologies. Chelerythrine was selected for further studies based on its cytotoxicity and the lack of apoptotic nuclear alterations. Chelerythrine triggered an early plasma membrane leakage without condensed chromatin aggregates. Ultrastructural analysis revealed that chelerythrine-mediated cytotoxicity was compatible with a necrotic-like type of cell death. Biochemically, chelerythrine induced the activation of caspases. Moreover, the inhibition of caspases prevented chelerythrine-triggered necrotic-like cell death. Compared with staurosporine, chelerythrine induced stronger caspase activation detectable at earlier times. After using a battery of chemicals, we found that high concentrations of thiolic antioxidants fully prevented chelerythrine-driven caspase activation and necrotic-like cell death. Lower amounts of thiolic antioxidants partially prevented chelerythrine-mediated cytotoxicity and allowed cells to display type II apoptotic nuclear morphology correlating with a delay in caspase-3 activation. Altogether, these data support that an early and pronounced activation of caspases can drive cells to undergo a form of necrotic-like regulated cell death.

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Caspase-8 deficiency induces a switch from TLR3 induced apoptosis to lysosomal cell death in neuroblastoma

Scientific Reports ◽

10.1038/s41598-021-89793-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marie-Anaïs Locquet ◽

Gabriel Ichim ◽

Joseph Bisaccia ◽

Aurelie Dutour ◽

Serge Lebecque ◽

...

Keyword(s):

Cell Death ◽

Cancer Cells ◽

Neuroblastoma Cell ◽

Death Receptor ◽

Neuroblastoma Cell Line ◽

Caspase 8 ◽

Caspase Activation ◽

Extrinsic Pathway ◽

Lysosomal Membrane Permeabilization ◽

Induced Apoptosis

AbstractIn cancer cells only, TLR3 acquires death receptor properties by efficiently triggering the extrinsic pathway of apoptosis with Caspase-8 as apical protease. Here, we demonstrate that in the absence of Caspase-8, activation of TLR3 can trigger a form of programmed cell death, which is distinct from classical apoptosis. When TLR3 was activated in the Caspase-8 negative neuroblastoma cell line SH-SY5Y, cell death was accompanied by lysosomal permeabilization. Despite caspases being activated, lysosomal permeabilization as well as cell death were not affected by blocking caspase-activity, positioning lysosomal membrane permeabilization (LMP) upstream of caspase activation. Taken together, our data suggest that LMP with its deadly consequences represents a “default” death mechanism in cancer cells, when Caspase-8 is absent and apoptosis cannot be induced.

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Live-Cell Imaging of Caspase Activation for High-Content Screening

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057109343207 ◽

2009 ◽

Vol 14 (8) ◽

pp. 956-969 ◽

Cited By ~ 31

Author(s):

Christophe Antczak ◽

Toshimitsu Takagi ◽

Christina N. Ramirez ◽

Constantin Radu ◽

Hakim Djaballah

Keyword(s):

Cell Death ◽

Live Cell Imaging ◽

Cell Imaging ◽

Exposure Period ◽

Live Cells ◽

Assay Method ◽

Caspase Activation ◽

Fluorogenic Substrate ◽

Automated Imaging ◽

First Time

Caspases are central to the execution of programmed cell death, and their activation constitutes the biochemical hallmark of apoptosis. In this article, the authors report the successful adaptation of a high-content assay method using the DEVDNucView488™ fluorogenic substrate, and for the first time, they show caspase activation in live cells induced by either drugs or siRNA. The fluorogenic substrate was found to be nontoxic over an exposure period of several days, during which the authors demonstrate automated imaging and quantification of caspase activation of the same cell population as a function of time. Overexpression of the antiapoptotic protein Bcl-XL, alone or in combination with the inhibitor Z-VAD-FMK, attenuated caspase activation in HeLa cells exposed to doxorubicin, etoposide, or cell death siRNA. This method was further validated against 2 well-characterized NSCLC cell lines reported to be sensitive (H3255) or refractory (H2030) to erlotinib, where the authors show a differential time-dependent activation was observed for H3255 and no significant changes in H2030, consistent with their respective chemosensitivity profile. In summary, the results demonstrate the feasibility of using this newly adapted and validated high-content assay to screen chemical or RNAi libraries for the identification of previously uncovered enhancers and suppressors of the apoptotic machinery in live cells. ( Journal of Biomolecular Screening 2009:956-969)

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Reactive oxygen species and caspase activation mediate silica-induced apoptosis in alveolar macrophages

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.280.1.l10 ◽

2001 ◽

Vol 280 (1) ◽

pp. L10-L17 ◽

Cited By ~ 32

Author(s):

Han-Ming Shen ◽

Zhuo Zhang ◽

Qi-Feng Zhang ◽

Choon-Nam Ong

Keyword(s):

Reactive Oxygen Species ◽

Cell Death ◽

Alveolar Macrophages ◽

Caspase 3 ◽

Reactive Oxygen ◽

Parp Cleavage ◽

Oxygen Species ◽

Caspase Activation ◽

Caspase 9 ◽

Induced Apoptosis

Alveolar macrophages (AMs) are the principal target cells of silica and occupy a key position in the pathogenesis of silica-related diseases. Silica has been found to induce apoptosis in AMs, whereas its underlying mechanisms involving the initiation and execution of apoptosis are largely unknown. The main objective of the present study was to examine the form of cell death caused by silica and the mechanisms involved. Silica-induced apoptosis in AMs was evaluated by terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling assay and cell cycle/DNA content analysis. The elevated level of reactive oxygen species (ROS), caspase-9 and caspase-3 activation, and poly(ADP-ribose) polymerase (PARP) cleavage in silica-treated AMs were also determined. The results showed that there was a temporal pattern of apoptotic events in silica-treated AMs, starting with ROS formation and followed by caspase-9 and caspase-3 activation, PARP cleavage, and DNA fragmentation. Silica-induced apoptosis was significantly attenuated by a caspase-3 inhibitor, N-acetyl-Asp-Glu-Val-Asp aldehyde, and ebselen, a potent antioxidant. These findings suggest that apoptosis is an important form of cell death caused by silica exposure in which the elevated ROS level that results from silica exposure may act as an initiator, leading to caspase activation and PARP cleavage to execute the apoptotic process.

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Internucleosomal DNA cleavage and neuronal cell survival/death

The Journal of Cell Biology ◽

10.1083/jcb.122.3.523 ◽

1993 ◽

Vol 122 (3) ◽

pp. 523-532 ◽

Cited By ~ 129

Author(s):

A Batistatou ◽

LA Greene

Keyword(s):

Cell Death ◽

Cell Survival ◽

Pc12 Cells ◽

Dna Fragmentation ◽

Cell Cultures ◽

Pc12 Cell ◽

Dna Cleavage ◽

Sympathetic Neurons ◽

Term Survival ◽

Serum Withdrawal

Serum-free PC12 cell cultures have been used to study the mechanisms of neuronal death after neurotrophic factor deprivation. We previously reported that PC12 cells undergo "apoptotic" internucleosomal DNA cleavage after withdrawal of trophic support. Here, we have used a sensitive method to detect PC12 cell DNA fragmentation within three hrs of serum removal and have exploited this assay to examine several aspects regarding the mechanisms of neuronal survival/death. Major advantages of this assay are that it permits acute experiments to be performed well before other manifest signs of cell death and under conditions that cannot be applied chronically. We find that this apopotic DNA fragmentation is distinct from the random DNA degradation that occurs during necrotic death. Major observations include the following: (a) There is a good correlation between the ability of trophic substances to promote PC12 cell survival and to inhibit early DNA fragmentation. (b) Phorbol ester, an activator of PKC, acutely suppresses DNA fragmentation, but does not promote long-term survival or inhibition of endonuclease activity when applied chronically due to its downregulation of PKC. (c) Cells undergoing apoptosis within 3 h of serum withdrawal have a "commitment point" of only 1.0-1.5 h beyond which they can no longer be rescued by NGF. (d) Aurin, a non-carboxylic analog of the endonuclease inhibitor ATA, also inhibits DNA fragmentation and promotes short-term survival of PC12 cells. (e) Macromolecular synthesis is not required for DNA fragmentation or for NGF to prevent this event. (f) Extracellular Ca2+ is not required for internucleosomal DNA cleavage caused by serum withdrawal or for suppression of this by NGF. (g) DNA fragmentation can also be detected in cultures of rat sympathetic neurons as early as 10 h after removal of NGF. As in PC12 cell cultures, this precedes morphological signs of cell death.

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Dynamics of in vivo ASC speck formation

The Journal of Cell Biology ◽

10.1083/jcb.201703103 ◽

2017 ◽

Vol 216 (9) ◽

pp. 2891-2909 ◽

Cited By ~ 19

Author(s):

Paola Kuri ◽

Nicole L. Schieber ◽

Thomas Thumberger ◽

Joachim Wittbrodt ◽

Yannick Schwab ◽

...

Keyword(s):

Electron Microscopy ◽

Cell Death ◽

Light And Electron Microscopy ◽

Three Dimensional ◽

Inflammasome Activation ◽

Caspase Activation ◽

Endogenous Gene ◽

Pyrin Domain ◽

Effector Caspase

Activated danger or pathogen sensors trigger assembly of the inflammasome adaptor ASC into specks, large signaling platforms considered hallmarks of inflammasome activation. Because a lack of in vivo tools has prevented the study of endogenous ASC dynamics, we generated a live ASC reporter through CRISPR/Cas9 tagging of the endogenous gene in zebrafish. We see strong ASC expression in the skin and other epithelia that act as barriers to insult. A toxic stimulus triggered speck formation and rapid pyroptosis in keratinocytes in vivo. Macrophages engulfed and digested that speck-containing, pyroptotic debris. A three-dimensional, ultrastructural reconstruction, based on correlative light and electron microscopy of the in vivo assembled specks revealed a compact network of highly intercrossed filaments, whereas pyrin domain (PYD) or caspase activation and recruitment domain alone formed filamentous aggregates. The effector caspase is recruited through PYD, whose overexpression induced pyroptosis but only after substantial delay. Therefore, formation of a single, compact speck and rapid cell-death induction in vivo requires a full-length ASC.

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