Abstract 1950: Role of Superoxide, Nitric Oxide and Peroxynitrite in Doxorubicin-induced Cell Death in vitro and in vivo

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Partha Mukhopadhyay ◽  
Mohanraj Rajesh ◽  
Sandor Bátkai ◽  
György Haskó ◽  
Csaba Szabo ◽  
...  

Although doxorubicin (DOX) is one of the most potent antitumor agents available, its clinical use is limited because of the risk of severe cardiotoxicity often leading to irreversible congestive heart failure. Apoptotic cell death is a key component in DOX-induced cardiotoxicity, but its trigger(s) and mechanisms are poorly understood. Here, we explore the role of peroxynitrite (a reactive oxidant produced from the diffusion-controlled reaction between nitric oxide and superoxide anion) in DOX-induced cell death. Using a well-established in vivo mouse model of DOX-induced acute heart failure, we demonstrate marked increases in myocardial apoptosis (caspase-3 and 9 gene expression, caspase 3 activity, cytochrome-c release, and TUNEL), iNOS but not eNOS and nNOS expression, 3-nitrotyrosine formation and a decrease in myocardial contractility following DOX treatment. Pre-treatment of mice with peroxynitrite scavengers markedly attenuated DOX-induced myocardial cell death and dysfunction without affecting iNOS expression. DOX induced increased superoxide generation and nitrotyrosine formation in the mitochondria, dissipation of mitochondrial membrane potential, apoptosis (cytochrome-C release, annexin V staining, caspase activation, nuclear fragmentation), and disruption of actin cytoskeleton structure in cardiac-derived H9c2 cells. Selective iNOS inhibitors attenuated DOX-induced apoptosis, without affecting increased mitochondrial superoxide generation, whereas NO donors increased DOX-induced cell death in vitro . The peroxynitrite scavengers FeTMPyP and MnTMPyP markedly reduced both DOX- or peroxynitrite-induced nitrotyrosine formation and cell death in vitro , without affecting DOX-induced increased mitochondrial superoxide formation. Thus, peroxynitrite is a major trigger of DOX-induced apoptosis, and its effective neutralization can be of significant therapeutic benefit.

2009 ◽  
Vol 296 (5) ◽  
pp. H1466-H1483 ◽  
Author(s):  
Partha Mukhopadhyay ◽  
Mohanraj Rajesh ◽  
Sándor Bátkai ◽  
Yoshihiro Kashiwaya ◽  
György Haskó ◽  
...  

Doxorubicin (DOX) is a potent available antitumor agent; however, its clinical use is limited because of its cardiotoxicity. Cell death is a key component in DOX-induced cardiotoxicity, but its mechanisms are elusive. Here, we explore the role of superoxide, nitric oxide (NO), and peroxynitrite in DOX-induced cell death using both in vivo and in vitro models of cardiotoxicity. Western blot analysis, real-time PCR, immunohistochemistry, flow cytometry, fluorescent microscopy, and biochemical assays were used to determine the markers of apoptosis/necrosis and sources of NO and superoxide and their production. Left ventricular function was measured by a pressure-volume system. We demonstrated increases in myocardial apoptosis (caspase-3 cleavage/activity, cytochrome c release, and TUNEL), inducible NO synthase (iNOS) expression, mitochondrial superoxide generation, 3-nitrotyrosine (NT) formation, matrix metalloproteinase (MMP)-2/MMP-9 gene expression, poly(ADP-ribose) polymerase activation [without major changes in NAD(P)H oxidase isoform 1, NAD(P)H oxidase isoform 2, p22 phox, p40 phox, p47 phox, p67 phox, xanthine oxidase, endothelial NOS, and neuronal NOS expression] and decreases in myocardial contractility, catalase, and glutathione peroxidase activities 5 days after DOX treatment to mice. All these effects of DOX were markedly attenuated by peroxynitrite scavengers. Doxorubicin dose dependently increased mitochondrial superoxide and NT generation and apoptosis/necrosis in cardiac-derived H9c2 cells. DOX- or peroxynitrite-induced apoptosis/necrosis positively correlated with intracellular NT formation and could be abolished by peroxynitrite scavengers. DOX-induced cell death and NT formation were also attenuated by selective iNOS inhibitors or in iNOS knockout mice. Various NO donors when coadministered with DOX but not alone dramatically enhanced DOX-induced cell death with concomitant increased NT formation. DOX-induced cell death was also attenuated by cell-permeable SOD but not by cell-permeable catalase, the xanthine oxidase inhibitor allopurinol, or the NADPH oxidase inhibitors apocynine or diphenylene iodonium. Thus, peroxynitrite is a major trigger of DOX-induced cell death both in vivo and in vivo, and the modulation of the pathways leading to its generation or its effective neutralization can be of significant therapeutic benefit.


2005 ◽  
Vol 25 (5) ◽  
pp. 2000-2013 ◽  
Author(s):  
Niklas Finnberg ◽  
Joshua J. Gruber ◽  
Peiwen Fei ◽  
Dorothea Rudolph ◽  
Anka Bric ◽  
...  

ABSTRACT DR5 (also called TRAIL receptor 2 and KILLER) is an apoptosis-inducing membrane receptor for tumor necrosis factor-related apoptosis-inducing ligand (also called TRAIL and Apo2 ligand). DR5 is a transcriptional target of p53, and its overexpression induces cell death in vitro. However, the in vivo biology of DR5 has remained largely unexplored. To better understand the role of DR5 in development and in adult tissues, we have created a knockout mouse lacking DR5. This mouse is viable and develops normally with the exception of having an enlarged thymus. We show that DR5 is not expressed in developing embryos but is present in the decidua and chorion early in development. DR5-null mouse embryo fibroblasts expressing E1A are resistant to treatment with TRAIL, suggesting that DR5 may be the primary proapoptotic receptor for TRAIL in the mouse. When exposed to ionizing radiation, DR5-null tissues exhibit reduced amounts of apoptosis compared to wild-type thymus, spleen, Peyer's patches, and the white matter of the brain. In the ileum, colon, and stomach, DR5 deficiency was associated with a subtle phenotype of radiation-induced cell death. These results indicate that DR5 has a limited role during embryogenesis and early stages of development but plays an organ-specific role in the response to DNA-damaging stimuli.


2004 ◽  
Vol 15 (6) ◽  
pp. 2804-2818 ◽  
Author(s):  
Gabriela Paroni ◽  
Michela Mizzau ◽  
Clare Henderson ◽  
Giannino Del Sal ◽  
Claudio Schneider ◽  
...  

Histone deacetylases (HDACs) are important regulators of gene expression as part of transcriptional corepressor complexes. Here, we demonstrate that caspases can repress the activity of the myocyte enhancer factor (MEF)2C transcription factor by regulating HDAC4 processing. Cleavage of HDAC4 occurs at Asp 289 and disjoins the carboxy-terminal fragment, localized into the cytoplasm, from the amino-terminal fragment, which accumulates into the nucleus. In the nucleus, the caspase-generated fragment of HDAC4 is able to trigger cytochrome c release from mitochondria and cell death in a caspase-9–dependent manner. The caspase-cleaved amino-terminal fragment of HDAC4 acts as a strong repressor of the transcription factor MEF2C, independently from the HDAC domain. Removal of amino acids 166–289 from the caspase-cleaved fragment of HDAC4 abrogates its ability to repress MEF2 transcription and to induce cell death. Caspase-2 and caspase-3 cleave HDAC4 in vitro and caspase-3 is critical for HDAC4 cleavage in vivo during UV-induced apoptosis. After UV irradiation, GFP-HDAC4 translocates into the nucleus coincidentally/immediately before the retraction response, but clearly before nuclear fragmentation. Together, our data indicate that caspases could specifically modulate gene repression and apoptosis through the proteolyic processing of HDAC4.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1446
Author(s):  
Tingting Jin ◽  
Jun Lin ◽  
Yingchao Gong ◽  
Xukun Bi ◽  
Shasha Hu ◽  
...  

Both calcium-independent phospholipase A2 beta (iPLA2β) and endoplasmic reticulum (ER) stress regulate important pathophysiological processes including inflammation, calcium homeostasis and apoptosis. However, their roles in ischemic heart disease are poorly understood. Here, we show that the expression of iPLA2β is increased during myocardial ischemia/reperfusion (I/R) injury, concomitant with the induction of ER stress and the upregulation of cell death. We further show that the levels of iPLA2β in serum collected from acute myocardial infarction (AMI) patients and in samples collected from both in vivo and in vitro I/R injury models are significantly elevated. Further, iPLA2β knockout mice and siRNA mediated iPLA2β knockdown are employed to evaluate the ER stress and cell apoptosis during I/R injury. Additionally, cell surface protein biotinylation and immunofluorescence assays are used to trace and locate iPLA2β. Our data demonstrate the increase of iPLA2β augments ER stress and enhances cardiomyocyte apoptosis during I/R injury in vitro and in vivo. Inhibition of iPLA2β ameliorates ER stress and decreases cell death. Mechanistically, iPLA2β promotes ER stress and apoptosis by translocating to ER upon myocardial I/R injury. Together, our study suggests iPLA2β contributes to ER stress-induced apoptosis during myocardial I/R injury, which may serve as a potential therapeutic target against ischemic heart disease.


2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Lan Jin ◽  
Yunhe Chen ◽  
Dan Cheng ◽  
Zhikai He ◽  
Xinyi Shi ◽  
...  

AbstractColorectal cancer (CRC) is one of the most aggressive and lethal cancers. The role of autophagy in the pathobiology of CRC is intricate, with opposing functions manifested in different cellular contexts. The Yes-associated protein (YAP), a transcriptional coactivator inactivated by the Hippo tumor-suppressor pathway, functions as an oncoprotein in a variety of cancers. In this study, we found that YAP could negatively regulate autophagy in CRC cells, and consequently, promote tumor progression of CRC in vitro and in vivo. Mechanistically, YAP interacts with TEAD forming a complex to upregulate the transcription of the apoptosis-inhibitory protein Bcl-2, which may subsequently facilitate cell survival by suppressing autophagy-related cell death; silencing Bcl-2 expression could alleviate YAP-induced autophagy inhibition without affecting YAP expression. Collectively, our data provide evidence for YAP/Bcl-2 as a potential therapeutic target for drug exploration against CRC.


Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 376
Author(s):  
Chantal B. Lucini ◽  
Ralf J. Braun

In the last decade, pieces of evidence for TDP-43-mediated mitochondrial dysfunction in neurodegenerative diseases have accumulated. In patient samples, in vitro and in vivo models have shown mitochondrial accumulation of TDP-43, concomitantly with hallmarks of mitochondrial destabilization, such as increased production of reactive oxygen species (ROS), reduced level of oxidative phosphorylation (OXPHOS), and mitochondrial membrane permeabilization. Incidences of TDP-43-dependent cell death, which depends on mitochondrial DNA (mtDNA) content, is increased upon ageing. However, the molecular pathways behind mitochondrion-dependent cell death in TDP-43 proteinopathies remained unclear. In this review, we discuss the role of TDP-43 in mitochondria, as well as in mitochondrion-dependent cell death. This review includes the recent discovery of the TDP-43-dependent activation of the innate immunity cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) pathway. Unravelling cell death mechanisms upon TDP-43 accumulation in mitochondria may open up new opportunities in TDP-43 proteinopathy research.


Marine Drugs ◽  
2018 ◽  
Vol 16 (9) ◽  
pp. 325 ◽  
Author(s):  
Xiaojuan Li ◽  
Yunping Tang ◽  
Fangmiao Yu ◽  
Yu Sun ◽  
Fangfang Huang ◽  
...  

We investigated the antitumor mechanism of Anthopleura anjunae oligopeptide (AAP-H, YVPGP) in prostate cancer DU-145 cells in vitro and in vivo. Results indicated that AAP-H was nontoxic and exhibited antitumor activities. Cell cycle analysis indicated that AAP-H may arrest DU-145 cells in the S phase. The role of the phosphatidylinositol 3-kinase/protein kinase B/mammalian rapamycin target protein (PI3K/AKT/mTOR) signaling pathway in the antitumor mechanism of APP-H was investigated. Results showed that AAP-H treatment led to dose-dependent reduction in the levels of p-AKT (Ser473), p-PI3K (p85), and p-mTOR (Ser2448), whereas t-AKT and t-PI3K levels remained unaltered compared to the untreated DU-145 cells. Inhibition of PI3K/AKT/mTOR signaling pathway in the DU-145 cells by employing inhibitor LY294002 (10 μM) or rapamycin (20 nM) effectively attenuated AAP-H-induced phosphorylation of AKT and mTOR. At the same time, inhibitor addition further elevated AAP-H-induced cleaved-caspase-3 levels. Furthermore, the effect of AAP-H on tumor growth and the role of the PI3K/AKT/mTOR signaling pathway in nude mouse model were also investigated. Immunohistochemical analysis showed that activated AKT, PI3K, and mTOR levels were reduced in DU-145 xenografts. Western blotting showed that AAP-H treatment resulted in dose-dependent reduction in p-AKT (Ser473), p-PI3K (p85), and p-mTOR (Ser2448) levels, whereas t-AKT and t-PI3K levels remained unaltered. Similarly, Bcl-xL levels decreased, whereas that of Bax increased after AAP-H treatment. AAP-H also increased initiator (caspase 8 and 9) and executor caspase (caspase 3 and 7) levels. Therefore, the antitumor mechanism of APP-H on DU-145 cells may involve regulation of the PI3K/AKT/mTOR signaling pathway, which eventually promotes apoptosis via mitochondrial and death receptor pathways. Thus, the hydrophobic oligopeptide (YVPGP) can be developed as an adjuvant for the prevention or treatment of prostate cancer in the future.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fengjie Jiang ◽  
Xiaozhu Tang ◽  
Chao Tang ◽  
Zhen Hua ◽  
Mengying Ke ◽  
...  

AbstractN6-methyladenosine (m6A) modification is the most prevalent modification in eukaryotic RNAs while accumulating studies suggest that m6A aberrant expression plays an important role in cancer. HNRNPA2B1 is a m6A reader which binds to nascent RNA and thus affects a perplexing array of RNA metabolism exquisitely. Despite unveiled facets that HNRNPA2B1 is deregulated in several tumors and facilitates tumor growth, a clear role of HNRNPA2B1 in multiple myeloma (MM) remains elusive. Herein, we analyzed the function and the regulatory mechanism of HNRNPA2B1 in MM. We found that HNRNPA2B1 was elevated in MM patients and negatively correlated with favorable prognosis. The depletion of HNRNPA2B1 in MM cells inhibited cell proliferation and induced apoptosis. On the contrary, the overexpression of HNRNPA2B1 promoted cell proliferation in vitro and in vivo. Mechanistic studies revealed that HNRNPA2B1 recognized the m6A sites of ILF3 and enhanced the stability of ILF3 mRNA transcripts, while AKT3 downregulation by siRNA abrogated the cellular proliferation induced by HNRNPA2B1 overexpression. Additionally, the expression of HNRNPA2B1, ILF3 and AKT3 was positively associated with each other in MM tissues tested by immunohistochemistry. In summary, our study highlights that HNRNPA2B1 potentially acts as a therapeutic target of MM through regulating AKT3 expression mediated by ILF3-dependent pattern.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 14-15
Author(s):  
Sara El Hoss ◽  
Sylvie Cochet ◽  
Auria Godard ◽  
Hongxia Yan ◽  
Michaël Dussiot ◽  
...  

Sickle cell disease (SCD) is an autosomal hereditary recessive disorder caused by a point mutation in the β globin gene resulting in a Glu-to-Val substitution at the 6th position of the β globin protein. The resulting abnormal hemoglobin (HbS) polymerizes under hypoxic conditions driving red blood cell (RBC) sickling (Pauling et al., 1949). While pathobiology of circulating RBCs has been extensively analyzed in SCD, erythropoiesis is surprisingly poorly documented. In β-thalassemia, ineffective erythropoiesis is characterized by high levels of apoptotic erythroblasts during the late stages of terminal differentiation, due to an accumulation of free β-globin chains (Arlet et al., 2016). Ineffective erythropoiesis is the major cause of anemia in β-thalassemia patients. In contrast, a marked decrease in life span of circulating red cells, a feature of sickle red cells, is considered to be the major determinant of chronic anemia in SCD. It is generally surmised that ineffective erythropoiesis contributes little to anemia. The bone marrow environment has been well documented to be hypoxic (0.1 to 6% O2) (Mantel et al., 2015). As hypoxia induces HbS polymerization, we hypothesized that cell death may occur in vivo because of HbS polymer formation in the late stages of differentiation characterized by high intracellular hemoglobin concentration. In the present study, using both in vitro and in vivo derived human erythroblasts we assessed the extent of ineffective erythropoiesis in SCD. We explored the mechanistic basis of the ineffective erythropoiesis in SCD using biochemical, cellular and imaging techniques. In vitro erythroid differentiation using CD34+ cells isolated from SCD patients and from healthy donors was performed. A 2-phase erythroid differentiation protocol was used and cultures were performed at two different oxygen conditions, i.e. normoxia and partial hypoxia (5% O2). We found that hypoxia induces cell death of sickle erythroblasts starting at the polychromatic stage, positively selecting cells with high levels of fetal hemoglobin (HbF). This inference was supported by flow cytometry data showing higher percentages of dead cells within the non-F-cell population as compared to the F-cell population for SCD cells. Moreover, SCD dead cells showed higher levels of chaperon protein HSP70 in the cytoplasm than live cells, while no difference was detected between both subpopulations for control cells, suggesting that cell death of SCD erythroblasts was probably due to HSP70 cytoplasmic sequestration. This was supported by western-blot experiments showing less HSP70 in the nucleus of SCD erythroblasts under hypoxia, associated with decreased levels of GATA-1. At the molecular level, HSP70 was co-immunoprecipitated with HbS under hypoxia indicating that both proteins were in the same complex and suggesting interaction between HSP70 and HbS polymers in the cyotplasm. Importantly, we confirm these results in vivo by showing that in bone marrow of SCD patients (n = 5) cell loss occurs during terminal erythroid differentiation, with a significant drop in the cell count between the polychromatic and the orthochromatic stages (Figure 1). In order to specifically address the role of HbF in cell survival, we used a CRISPR-Cas9 approach to mimic the effect of hereditary persistence of fetal hemoglobin (HPFH). CD34+ cells were transfected either with a gRNA targeting the LRF binding site (-197) or a gRNA targeting an unrelated locus (AAVS1) (Weber, Frati, et al. 2020). As expected, the disruption of the LRF binding site resulted in HbF induction as shown by higher %F-cells compared to AAVS1 control. These higher levels of F-cells resulted in decreased apoptosis, under both normoxic and hypoxic conditions, clearly demonstrating the positive and selective effect of HbF on SCD cell survival (Figure 2). In summary, our study shows that HbF has a dual beneficial effect in SCD by conferring a preferential survival of F-cells in the circulation and by decreasing ineffective erythropoiesis. These findings thus bring new insights into the role of HbF in modulating clinical severity of anemia in SCD by both regulating red cell production and red cell destruction. Disclosures No relevant conflicts of interest to declare.


2000 ◽  
Vol 192 (7) ◽  
pp. 1035-1046 ◽  
Author(s):  
Veronika Jesenberger ◽  
Katarzyna J. Procyk ◽  
Junying Yuan ◽  
Siegfried Reipert ◽  
Manuela Baccarini

The enterobacterial pathogen Salmonella induces phagocyte apoptosis in vitro and in vivo. These bacteria use a specialized type III secretion system to export a virulence factor, SipB, which directly activates the host's apoptotic machinery by targeting caspase-1. Caspase-1 is not involved in most apoptotic processes but plays a major role in cytokine maturation. We show that caspase-1–deficient macrophages undergo apoptosis within 4–6 h of infection with invasive bacteria. This process requires SipB, implying that this protein can initiate the apoptotic machinery by regulating components distinct from caspase-1. Invasive Salmonella typhimurium targets caspase-2 simultaneously with, but independently of, caspase-1. Besides caspase-2, the caspase-1–independent pathway involves the activation of caspase-3, -6, and -8 and the release of cytochrome c from mitochondria, none of which occurs during caspase-1–dependent apoptosis. By using caspase-2 knockout macrophages and chemical inhibition, we establish a role for caspase-2 in both caspase-1–dependent and –independent apoptosis. Particularly, activation of caspase-1 during fast Salmonella-induced apoptosis partially relies on caspase-2. The ability of Salmonella to induce caspase-1–independent macrophage apoptosis may play a role in situations in which activation of this protease is either prevented or uncoupled from the induction of apoptosis.


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