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Cell Sep 2022Drug-tolerant persister cells (persisters) evade apoptosis upon targeted and conventional cancer therapies and represent a major non-genetic barrier to effective cancer...
Drug-tolerant persister cells (persisters) evade apoptosis upon targeted and conventional cancer therapies and represent a major non-genetic barrier to effective cancer treatment. Here, we show that cells that survive treatment with pro-apoptotic BH3 mimetics display a persister phenotype that includes colonization and metastasis in vivo and increased sensitivity toward ferroptosis by GPX4 inhibition. We found that sublethal mitochondrial outer membrane permeabilization (MOMP) and holocytochrome c release are key requirements for the generation of the persister phenotype. The generation of persisters is independent of apoptosome formation and caspase activation, but instead, cytosolic cytochrome c induces the activation of heme-regulated inhibitor (HRI) kinase and engagement of the integrated stress response (ISR) with the consequent synthesis of ATF4, all of which are required for the persister phenotype. Our results reveal that sublethal cytochrome c release couples sublethal MOMP to caspase-independent initiation of an ATF4-dependent, drug-tolerant persister phenotype.
Topics: Animals; Apoptosis; Carrier Proteins; Caspases; Cytochromes c; Drug Resistance, Neoplasm; Humans; Mice; Mitochondria; Neoplasms
PubMed: 36055199
DOI: 10.1016/j.cell.2022.07.025 -
Nature Reviews. Immunology Jun 2013Inflammasomes are key signalling platforms that detect pathogenic microorganisms and sterile stressors, and that activate the highly pro-inflammatory cytokines... (Review)
Review
Inflammasomes are key signalling platforms that detect pathogenic microorganisms and sterile stressors, and that activate the highly pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18. In this Review, we discuss the complex regulatory mechanisms that facilitate a balanced but effective inflammasome-mediated immune response, and we highlight the similarities to another molecular signalling platform - the apoptosome - that monitors cellular health. Extracellular regulatory mechanisms are discussed, as well as the intracellular control of inflammasome assembly, for example, via ion fluxes, free radicals and autophagy.
Topics: Autophagy; Carrier Proteins; Humans; Inflammasomes; Inflammation Mediators; Interleukin-18; Interleukin-1beta; Models, Immunological; NLR Family, Pyrin Domain-Containing 3 Protein; Receptors, Interleukin-1; Signal Transduction
PubMed: 23702978
DOI: 10.1038/nri3452 -
Molecular Cell Mar 2002Caspases are central components of the machinery responsible for apoptosis. Recent structural and biochemical studies on procaspases, IAPs, Smac/DIABLO, and apoptosome... (Review)
Review
Caspases are central components of the machinery responsible for apoptosis. Recent structural and biochemical studies on procaspases, IAPs, Smac/DIABLO, and apoptosome have revealed a conserved mechanism of caspase activation and inhibition. This article reviews these latest advances and presents our current understanding of caspase regulation during apoptosis.
Topics: Animals; Apoptosis; Binding Sites; Caspase Inhibitors; Caspases; Enzyme Activation; Inhibitor of Apoptosis Proteins; Insect Proteins; Models, Biological; Models, Molecular; Protein Conformation; Protein Precursors; Protein Structure, Tertiary; Proteins
PubMed: 11931755
DOI: 10.1016/s1097-2765(02)00482-3 -
Genes To Cells : Devoted To Molecular &... Nov 1998Apoptosis is an essential physiological process for the selective elimination of cells, which is involved in a variety of biological events. The Bcl-2 family is the best... (Review)
Review
Apoptosis is an essential physiological process for the selective elimination of cells, which is involved in a variety of biological events. The Bcl-2 family is the best characterized protein family involved in the regulation of apoptotic cell death, consisting of anti-apoptotic and pro-apoptotic members. The anti-apoptotic members of this family, such as Bcl-2 and Bcl-XL, prevent apoptosis either by sequestering proforms of death-driving cysteine proteases called caspases (a complex called the apoptosome) or by preventing the release of mitochondrial apoptogenic factors such as cytochrome c and AIF (apoptosis-inducing factor) into the cytoplasm. After entering the cytoplasm, cytochrome c and AIF directly activate caspases that cleave a set of cellular proteins to cause apoptotic changes. In contrast, pro-apoptotic members of this family, such as Bax and Bak, trigger the release of caspases from death antagonists via heterodimerization and also by inducing the release of mitochondrial apoptogenic factors into the cytoplasm via acting on mitochondrial permeability transition pore, thereby leading to caspase activation. Thus, the Bcl-2 family of proteins acts as a critical life-death decision point within the common pathway of apoptosis.
Topics: Animals; Apoptosis; Caenorhabditis elegans; Mitochondria; Organelles; Protein Binding; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-bcl-2
PubMed: 9990505
DOI: 10.1046/j.1365-2443.1998.00223.x -
Nature Communications Apr 2019Gasdermin E (GSDME/DFNA5) cleavage by caspase-3 liberates the GSDME-N domain, which mediates pyroptosis by forming pores in the plasma membrane. Here we show that...
Gasdermin E (GSDME/DFNA5) cleavage by caspase-3 liberates the GSDME-N domain, which mediates pyroptosis by forming pores in the plasma membrane. Here we show that GSDME-N also permeabilizes the mitochondrial membrane, releasing cytochrome c and activating the apoptosome. Cytochrome c release and caspase-3 activation in response to intrinsic and extrinsic apoptotic stimuli are significantly reduced in GSDME-deficient cells comparing with wild type cells. GSDME deficiency also accelerates cell growth in culture and in a mouse model of melanoma. Phosphomimetic mutation of the highly conserved phosphorylatable Thr6 residue of GSDME, inhibits its pore-forming activity, thus uncovering a potential mechanism by which GSDME might be regulated. Like GSDME-N, inflammasome-generated gasdermin D-N (GSDMD-N), can also permeabilize the mitochondria linking inflammasome activation to downstream activation of the apoptosome. Collectively, our results point to a role of gasdermin proteins in targeting the mitochondria to promote cytochrome c release to augment the mitochondrial apoptotic pathway.
Topics: Animals; Caspase 3; Cytochromes c; Fibroblasts; Gene Knockout Techniques; HEK293 Cells; HeLa Cells; Humans; Inflammasomes; Macrophages; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondria; Mitochondrial Membranes; Mutation; Phosphorylation; Primary Cell Culture; Protein Domains; Pyroptosis; Receptors, Estrogen; Skin Neoplasms; Threonine
PubMed: 30976076
DOI: 10.1038/s41467-019-09397-2 -
Advanced Science (Weinheim,... Oct 2022Chemotherapeutics remain the first choice for advanced gastric cancers (GCs). However, drug resistance and unavoidable severe toxicity lead to chemotherapy failure and...
Chemotherapeutics remain the first choice for advanced gastric cancers (GCs). However, drug resistance and unavoidable severe toxicity lead to chemotherapy failure and poor prognosis. Long noncoding RNAs (lncRNAs) play critical roles in tumor progression in many cancers, including GC. Here, through RNA screening, an apoptotic protease-activating factor 1 (APAF1)-binding lncRNA (ABL) that is significantly elevated in cancerous GC tissues and an independent prognostic factor for GC patients is identified. Moreover, ABL overexpression inhibits GC cell apoptosis and promotes GC cell survival and multidrug resistance in GC xenograft and organoid models. Mechanistically, ABL directly binds to the RNA-binding protein IGF2BP1 via its KH1/2 domain, and then IGF2BP1 further recognizes the METTL3-mediated m6A modification on ABL, which maintains ABL stability. In addition, ABL can bind to the WD1/WD2 domain of APAF1, which competitively prevent cytochrome c from interacting with APAF1, blocking apoptosome assembly and caspase-9/3 activation; these events lead to resistance to cell death in GC cells. Intriguingly, targeting ABL using encapsulated liposomal siRNA can significantly enhance the sensitivity of GC cells to chemotherapy. Collectively, the results suggest that ABL can be a potential prognostic biomarker and therapeutic target in GC.
Topics: Apoptosis; Apoptosomes; Apoptotic Protease-Activating Factor 1; Biomarkers; Caspase 9; Cytochromes c; Drug Resistance, Multiple; Humans; Methyltransferases; RNA, Long Noncoding; RNA, Small Interfering; Stomach Neoplasms
PubMed: 35975461
DOI: 10.1002/advs.202201889 -
Cell Death and Differentiation Jul 2018The apoptosome is a platform that activates apical procaspases in response to intrinsic cell death signals. Biochemical and structural studies in the past two decades... (Review)
Review
The apoptosome is a platform that activates apical procaspases in response to intrinsic cell death signals. Biochemical and structural studies in the past two decades have extended our understanding of apoptosome composition and structure, while illuminating the requirements for initiator procaspase activation. A number of studies have now provided high-resolution structures for apoptosomes from C. elegans (CED-4), D. melanogaster (Dark), and H. sapiens (Apaf-1), which define critical protein interfaces, including intra and interdomain interactions. This work also reveals interactions of apoptosomes with their respective initiator caspases, CED-3, Dronc and procaspase-9. Structures of the human apoptosome have defined the requirements for cytochrome c binding, which triggers the conversion of inactive Apaf-1 molecules to an extended, assembly competent state. While recent data have provided a detailed understanding of apoptosome formation and procaspase activation, they also highlight important evolutionary differences with functional implications for caspase activation. Comparison of the CARD/CARD disks and apoptosomes formed by CED-4, Dark and Apaf-1. Cartoons of the active states of the CARD-CARD disks, illustrating the two CED-4 CARD tetrameric ring layers (CED4a and CED4b; top row) and the binding of 8 Dronc CARDs and between 3-4 pc-9 CARDs, to the Dark and Apaf-1 CARD disk respectively (middle and lower rows). Ribbon diagrams of the active CED-4, Dark and Apaf-1 apoptosomes are shown (right column).
Topics: Animals; Apoptosomes; Apoptotic Protease-Activating Factor 1; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Caspase 9; Drosophila Proteins; Drosophila melanogaster; Humans
PubMed: 29765111
DOI: 10.1038/s41418-017-0025-z -
Life Science Alliance Sep 2023In , onset of programmed cell death is marked with the activation of CED-3, a process that requires assembly of the CED-4 apoptosome. Activated CED-3 forms a holoenzyme...
In , onset of programmed cell death is marked with the activation of CED-3, a process that requires assembly of the CED-4 apoptosome. Activated CED-3 forms a holoenzyme with the CED-4 apoptosome to cleave a wide range of substrates, leading to irreversible cell death. Despite decades of investigations, the underlying mechanism of CED-4-facilitated CED-3 activation remains elusive. Here, we report cryo-EM structures of the CED-4 apoptosome and three distinct CED-4/CED-3 complexes that mimic different activation stages for CED-3. In addition to the previously reported octamer in crystal structures, CED-4, alone or in complex with CED-3, exists in multiple oligomeric states. Supported by biochemical analyses, we show that the conserved CARD-CARD interaction promotes CED-3 activation, and initiation of programmed cell death is regulated by the dynamic organization of the CED-4 apoptosome.
Topics: Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Apoptosomes; Apoptosis
PubMed: 37402593
DOI: 10.26508/lsa.202302056 -
Archives of Biochemistry and Biophysics Mar 2018Apaf-1 is a cytosolic multi-domain protein in the apoptosis regulatory network. When cytochrome c releases from mitochondria; it binds to WD-40 repeats of Apaf-1...
Apaf-1 is a cytosolic multi-domain protein in the apoptosis regulatory network. When cytochrome c releases from mitochondria; it binds to WD-40 repeats of Apaf-1 molecule and induces oligomerization of Apaf-1. Here in, a split luciferase assay was used to compare apoptosome formation in cell-free and cell-based systems. This assay uses Apaf-1 tagged with either N-terminal fragment or C-terminal fragment of P. pyralis luciferase. In cell based-system, the apoptosome formation is induced inside the cells which express Apaf-1 tagged with complementary fragments of luciferase while in cell-free system, the apoptosome formation is induced in extracts of the cells. In cell-free system, cytochrome c dependent luciferase activity was observed with full length Apaf-1. However, luciferase activity due to apoptosome formation was much higher in cell based system compared to cell-free system. The truncated Apaf-1 which lacks WD-40 repeats (ΔApaf-1) interacted with endogenous Apaf-1 in a different fashion compared to native form as confirmed by different retention time of eluate in gel filtration and binding to affinity column. The interactions between endogenous Apaf-1 and ΔApaf-1 is stronger than its interaction with native exogenous Apaf-1 as indicated by dominant negative effect of ΔApaf-1 on caspase-3 processing.
Topics: Apoptosis; Apoptosomes; Apoptotic Protease-Activating Factor 1; Biopolymers; Caspase 3; Caspase 9; Cell-Free System; Chromatography, Affinity; Chromatography, Gel; Enzyme Activation; HEK293 Cells; Humans; Luciferases; Protein Binding; Proteolysis; WD40 Repeats
PubMed: 29410086
DOI: 10.1016/j.abb.2018.01.017 -
Current Osteoporosis Reports Jun 2021In this review, we describe the biology of extracellular vesicles (EV) and how they contribute to bone-associated cancers. (Review)
Review
PURPOSE OF REVIEW
In this review, we describe the biology of extracellular vesicles (EV) and how they contribute to bone-associated cancers.
RECENT FINDINGS
Crosstalk between tumor and bone has been demonstrated to promote tumor and metastatic progression. In addition to direct cell-to-cell contact and soluble factors, such as cytokines, EVs mediate crosstalk between tumor and bone. EVs are composed of a heterogenous group of membrane-delineated vesicles of varying size range, mechanisms of formation, and content. These include apoptotic bodies, microvesicles, large oncosomes, and exosomes. EVs derived from primary tumors have been shown to alter bone remodeling and create formation of a pre-metastatic niche that favors development of bone metastasis. Similarly, EVs from marrow stromal cells have been shown to promote tumor progression. Additionally, EVs can act as therapeutic delivery vehicles due to their low immunogenicity and targeting specificity. EVs play critical roles in intercellular communication. Multiple classes of EVs exist based on size on mechanism of formation. In addition to a role in pathophysiology, EVs can be exploited as therapeutic delivery vehicles.
Topics: Bone Neoplasms; Cell Communication; Disease Progression; Extracellular Vesicles; Humans; Signal Transduction; Tumor Microenvironment
PubMed: 33638774
DOI: 10.1007/s11914-021-00668-w