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European Journal of Cell Biology Jun 2023The actin cytoskeleton impacts practically every function of a eukaryotic cell. Historically, the best-characterized cytoskeletal activities are in cell morphogenesis,...
The actin cytoskeleton impacts practically every function of a eukaryotic cell. Historically, the best-characterized cytoskeletal activities are in cell morphogenesis, motility, and division. The structural and dynamic properties of the actin cytoskeleton are also crucial for establishing, maintaining, and changing the organization of membrane-bound organelles and other intracellular structures. Such activities are important in nearly all animal cells and tissues, although distinct anatomical regions and physiological systems rely on different regulatory factors. Recent work indicates that the Arp2/3 complex, a broadly expressed actin nucleator, drives actin assembly during several intracellular stress response pathways. These newly described Arp2/3-mediated cytoskeletal rearrangements are coordinated by members of the Wiskott-Aldrich Syndrome Protein (WASP) family of actin nucleation-promoting factors. Thus, the Arp2/3 complex and WASP-family proteins are emerging as crucial players in cytoplasmic and nuclear activities including autophagy, apoptosis, chromatin dynamics, and DNA repair. Characterizations of the functions of the actin assembly machinery in such stress response mechanisms are advancing our understanding of both normal and pathogenic processes, and hold great promise for providing insights into organismal development and interventions for disease.
Topics: Animals; Wiskott-Aldrich Syndrome Protein Family; Actins; Actin-Related Protein 2-3 Complex; Actin Cytoskeleton; Cytoskeleton; Wiskott-Aldrich Syndrome Protein; Actin-Related Protein 3
PubMed: 36907023
DOI: 10.1016/j.ejcb.2023.151301 -
Cell Reports Nov 2022Melanoma is a deadly form of cancer characterized by remarkable therapy resistance. Analyzing the transcriptome of MAPK inhibitor sensitive- and resistant-melanoma, we...
Melanoma is a deadly form of cancer characterized by remarkable therapy resistance. Analyzing the transcriptome of MAPK inhibitor sensitive- and resistant-melanoma, we discovered that APAF-1 is negatively regulated by MITF in resistant tumors. This study identifies the MITF/APAF-1 axis as a molecular driver of MAPK inhibitor resistance. A drug-repositioning screen identified quinacrine and methylbenzethonium as potent activators of apoptosis in a context that mimics drug resistance mediated by APAF-1 inactivation. The compounds showed anti-tumor activity in in vitro and in vivo models, linked to suppression of MITF function. Both drugs profoundly sensitize melanoma cells to MAPK inhibitors, regulating key signaling networks in melanoma, including the MITF/APAF-1 axis. Significant activity of the two compounds in inhibiting specific epigenetic modulators of MITF/APAF-1 expression, such as histone deacetylases, was observed. In summary, we demonstrate that targeting the MITF/APAF-1 axis may overcome resistance and could be exploited as a potential therapeutic approach to treat resistant melanoma.
Topics: Humans; Apoptosis; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Melanoma; Microphthalmia-Associated Transcription Factor; Protein Kinase Inhibitors; Salvage Therapy
PubMed: 36351409
DOI: 10.1016/j.celrep.2022.111601 -
Disease Markers 2022Lung adenocarcinoma (LUAD) is the most common subtype of nonsmall cell lung cancer. Cytochrome c (Cyt c), which is produced from mitochondria, interacts with a protein...
Lung adenocarcinoma (LUAD) is the most common subtype of nonsmall cell lung cancer. Cytochrome c (Cyt c), which is produced from mitochondria, interacts with a protein called Apaf-1 to form the heptameric apoptosome. This heptameric apoptosome then activates the caspase cascade, which ultimately results in the execution of apoptosis. The purpose of our research was to discover a new prognostic model that is based on cytochrome c-related genes (CCRGs) for LUAD patients. Through LASSO regression analysis conducted on the LUAD datasets included in the TCGA datasets, a CCRGs signature was created. The diagnostic accuracy of the multigene signature was verified by an independent source using the GSE31210 and GSE72094 datasets. The GO and KEGG enrichment analysis were performed. In this study, there were 159 differentially expressed CCRGs in the TCGA dataset, while there were 68 differentially expressed CCRGs in the GSE31210 dataset. Additionally, there were 57 genes that overlapped across the two datasets. Using LASSO and Cox regression analysis, a signature consisting of 12 differentially expressed CCRGs was developed from the total of 57 such genes. On the basis of their risk ratings, patients were categorized into high-risk and low-risk categories, with low-risk patients having lower risk scores and a greater likelihood of surviving the disease. Univariate and multivariate analyses both concluded that this signature is an independent risk factor for LUAD. ROC curves demonstrated that this risk signature is capable of accurately predicting the 1-year, 2-year, 3-year, and 5-year survival rates of patients who have LUAD. The infiltration of antigen-presenting cells was higher in the low-risk group, such as aDCs, DCs, pDCs, and iDCs. The expression of multiple immune checkpoints was significantly higher in the low-risk group, such as BTLA, CD28, and CD86. Finally, we showed that the signature can be used to predict the drug sensitivity of already available or under investigational drugs. Overall, patient classification and individualized therapy options may benefit from this study's development of a powerful gene signature with high value for prognostic prediction in LUAD.
Topics: Adenocarcinoma of Lung; Apoptosomes; CD28 Antigens; Carcinoma, Non-Small-Cell Lung; Caspases; Cytochromes c; Drugs, Investigational; Humans; Lung Neoplasms; Prognosis
PubMed: 36225197
DOI: 10.1155/2022/8809956 -
Redox Biology Nov 2022Nutritional pancreatic atrophy (NPA) is a classical Se/vitamin E deficiency disease of chicks. To reveal molecular mechanisms of its pathogenesis, we fed day-old chicks...
Nutritional pancreatic atrophy (NPA) is a classical Se/vitamin E deficiency disease of chicks. To reveal molecular mechanisms of its pathogenesis, we fed day-old chicks a practical, low-Se diet (14 μg Se/kg), and replicated the typical symptoms of NPA including vesiculated mitochondria, cytoplasmic vacuoles, and hyaline bodies in acinar cells of chicks as early as day 18. Target pathway analyses illustrated a > 90% depletion (P < 0.05) of glutathione peroxidase 4 (GPX4) protein and up-regulated apoptotic signaling (cytochrome C/caspase 9/caspase 3) in the pancreas and(or) acinar cells of Se deficient chicks compared with Se-adequate chicks. Subsequently, we overexpressed and suppressed GPX4 expression in the pancreatic acinar cells and observed an inverse (P < 0.05) relationship between the GPX4 production and apoptotic signaling and cell death. Applying pull down and mass spectrometry, we unveiled that GPX4 bound prothymosin alpha (ProTalpha) to inhibit formation of apoptosome in the pancreatic acinar cells. Destroying this novel protein-protein interaction by silencing either gene expression accelerated HO-induced apoptosis in the cells. In the end, we applied GPX4 shRNA to silence GPX4 expression in chick embryo and confirmed the physiological relevance of the GPX4 role and mechanism shown ex vivo and in the acinar cells. Altogether, our results indicated that GPX4 depletion in Se-deficient chicks acted as a major contributor to their development of NPA due to the lost binding of GPX4 to ProTalpha and its subsequent inhibition on the cytochrome c/caspase 9/caspase 3 cascade in the acinar cells. Our findings not only provide a novel molecular mechanism for explaining pathogenesis of NPA but also reveal a completely new cellular pathway in regulating apoptosis by selenoproteins.
PubMed: 36162257
DOI: 10.1016/j.redox.2022.102482 -
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 -
Journal of Personalized Medicine Aug 2022To adapt to the tumor environment or to escape chemotherapy, cancer cells rapidly reprogram their metabolism. The hallmark biochemical phenotype of cancer cells is the... (Review)
Review
To adapt to the tumor environment or to escape chemotherapy, cancer cells rapidly reprogram their metabolism. The hallmark biochemical phenotype of cancer cells is the shift in metabolic reprogramming towards aerobic glycolysis. It was thought that this metabolic shift to glycolysis alone was sufficient for cancer cells to meet their heightened energy and metabolic demands for proliferation and survival. Recent studies, however, show that cancer cells rely on glutamine, lipid, and mitochondrial metabolism for energy. Oncogenes and scavenging pathways control many of these metabolic changes, and several metabolic and tumorigenic pathways are post-transcriptionally regulated by microRNA (miRNAs). Genes that are directly or indirectly responsible for energy production in cells are either negatively or positively regulated by miRNAs. Therefore, some miRNAs play an oncogenic role by regulating the metabolic shift that occurs in cancer cells. Additionally, miRNAs can regulate mitochondrial calcium stores and energy metabolism, thus promoting cancer cell survival, cell growth, and metastasis. In the electron transport chain (ETC), miRNAs enhance the activity of apoptosis-inducing factor (AIF) and cytochrome c, and these apoptosome proteins are directed towards the ETC rather than to the apoptotic pathway. This review will highlight how miRNAs regulate the enzymes, signaling pathways, and transcription factors of cancer cell metabolism and mitochondrial calcium import/export pathways. The review will also focus on the metabolic reprogramming of cancer cells to promote survival, proliferation, growth, and metastasis with an emphasis on the therapeutic potential of miRNAs for cancer treatment.
PubMed: 36013278
DOI: 10.3390/jpm12081329 -
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 Discovery Apr 2022Oxidative stress is a state in which the accumulation of reactive oxygen species exceeds the capacity of cellular antioxidant systems. Both apoptosis and necrosis are...
Oxidative stress is a state in which the accumulation of reactive oxygen species exceeds the capacity of cellular antioxidant systems. Both apoptosis and necrosis are observed under oxidative stress, and we have reported that these two forms of cell death are induced in HO-stimulated HeLa cells depending on the concentration of HO. Weak HO stimulation induces apoptosis, while strong HO stimulation induces necrosis. However, the detailed mechanisms controlling the switching between these forms of cell death depending on the level of oxidative stress remain elusive. Here, we found that NAD metabolism is a key factor in determining the form of cell death in HO-stimulated HeLa cells. Under both weak and strong HO stimulation, intracellular nicotinamide adenine dinucleotide (NAD) was depleted to a similar extent by poly (ADP-ribose) (PAR) polymerase 1 (PARP1)-dependent consumption. However, the intracellular NAD concentration recovered under weak HO stimulation but not under strong HO stimulation. NAD recovery was mediated by nicotinamide (NAM) phosphoribosyltransferase (NAMPT)-dependent synthesis via the NAD salvage pathway, which was suggested to be impaired only under strong HO stimulation. Furthermore, downstream of NAD, the dynamics of the intracellular ATP concentration paralleled those of NAD, and ATP-dependent caspase-9 activation via apoptosome formation was thus impaired under strong HO stimulation. Collectively, these findings suggest that NAD dynamics balanced by PARP1-dependent consumption and NAMPT-dependent production are important to determine the form of cell death activated under oxidative stress.
PubMed: 35410407
DOI: 10.1038/s41420-022-01007-3 -
Frontiers in Cell and Developmental... 2021Programmed cell death (PCD) in animals mainly refers to lytic and non-lytic forms. Disruption and integrity of the plasma membrane are considered as hallmarks of lytic... (Review)
Review
Programmed cell death (PCD) in animals mainly refers to lytic and non-lytic forms. Disruption and integrity of the plasma membrane are considered as hallmarks of lytic and apoptotic cell death, respectively. These lytic cell death programs can prevent the hosts from microbial pathogens. The key to our understanding of these cases is pattern recognition receptors, such as TLRs in animals and LRR-RLKs in plants, and nod-like receptors (NLRs). Herein, we emphatically discuss the biochemical and structural studies that have clarified the anti-apoptotic and pro-apoptotic functions of Bcl-2 family proteins during intrinsic apoptosis and how caspase-8 among apoptosis, necroptosis, and pyroptosis sets the switchable threshold and integrates innate immune signaling, and that have compared the similarity and distinctness of the apoptosome, necroptosome, and inflammasome. We recapitulate that the necroptotic MLKL pore, pyroptotic gasdermin pore, HR-inducing resistosome, and mitochondrial Bcl-2 family all can form ion channels, which all directly boost membrane disruption. Comparing the conservation and unique aspects of PCD including ferrroptosis among bacteria, animals, and plants, the commonly shared immune domains including TIR-like, gasdermin-like, caspase-like, and MLKL/CC-like domains act as arsenal modules to restructure the diverse architecture to commit PCD suicide upon stresses/stimuli for host community.
PubMed: 35223864
DOI: 10.3389/fcell.2021.790117 -
Current Issues in Molecular Biology Nov 2021Hepatitis C virus (HCV)-induced liver disease contributes to chronic hepatitis. The immune factors identified in HCV include changes in the innate and adaptive immune...
Hepatitis C virus (HCV)-induced liver disease contributes to chronic hepatitis. The immune factors identified in HCV include changes in the innate and adaptive immune system. The inflammatory mediators, known as "inflammasome", are a consequence of the metabolic products of cells and commensal or pathogenic bacteria and viruses. The only effective strategy to prevent disease progression is eradication of the viral infection. Immune cells play a pivotal role during liver inflammation, triggering fibrogenesis. The present paper discusses the potential role of markers in cell death and the inflammatory cascade leading to the severity of liver damage. We aim to present the clinical parameters and laboratory data in a cohort of 88 HCV-infected non-cirrhotic and 25 HCV cirrhotic patients, to determine the characteristic light microscopic (LM) and transmission electron microscopic (TEM) changes in their liver biopsies and to present the link between the severity of liver damage and the serum levels of cytokines and caspases. A matched HCV non-infected cohort was used for the comparison of serum inflammatory markers. We compared the inflammation in HCV individuals with a control group of 280 healthy individuals. We correlated the changes in inflammatory markers in different stages of the disease and the histology. We concluded that the serum levels of cytokine, chemokine, and cleaved caspase markers reveal the inflammatory status in HCV. Based upon the information provided by the changes in biomarkers the clinician can monitor the severity of HCV-induced liver damage. New oral well-tolerated treatment regimens for chronic hepatitis C patients can achieve cure rates of over 90%. Therefore, using the noninvasive biomarkers to monitor the evolution of the liver damage is an effective personalized medicine procedure to establish the severity of liver injury and its repair.
Topics: Apoptosis; Biomarkers; Case-Control Studies; Cell Death; Cytokines; Disease Susceptibility; Hepacivirus; Hepatitis C; Humans; Inflammation Mediators; Liver
PubMed: 34889885
DOI: 10.3390/cimb43030139