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1

Caspase-2 promotes cytoskeleton protein degradation during apoptotic cell death  

PubMed Central

The caspase family of proteases cleaves large number of proteins resulting in major morphological and biochemical changes during apoptosis. Yet, only a few of these proteins have been reported to selectively cleaved by caspase-2. Numerous observations link caspase-2 to the disruption of the cytoskeleton, although it remains elusive whether any of the cytoskeleton proteins serve as bona fide substrates for caspase-2. Here, we undertook an unbiased proteomic approach to address this question. By differential proteome analysis using two-dimensional gel electrophoresis, we identified four cytoskeleton proteins that were degraded upon treatment with active recombinant caspase-2 in vitro. These proteins were degraded in a caspase-2-dependent manner during apoptosis induced by DNA damage, cytoskeleton disruption or endoplasmic reticulum stress. Hence, degradation of these cytoskeleton proteins was blunted by siRNA targeting of caspase-2 and when caspase-2 activity was pharmacologically inhibited. However, none of these proteins was cleaved directly by caspase-2. Instead, we provide evidence that in cells exposed to apoptotic stimuli, caspase-2 probed these proteins for proteasomal degradation. Taken together, our results depict a new role for caspase-2 in the regulation of the level of cytoskeleton proteins during apoptosis. PMID:24309927

Vakifahmetoglu-Norberg, H; Norberg, E; Perdomo, A B; Olsson, M; Ciccosanti, F; Orrenius, S; Fimia, G M; Piacentini, M; Zhivotovsky, B

2013-01-01

2

Oncogenic ras-induced Down-regulation of Pro-apoptotic Protease Caspase-2 Is Required for Malignant Transformation of Intestinal Epithelial Cells*  

PubMed Central

Resistance of carcinoma cells to anoikis, apoptosis that is normally induced by loss of cell-to-extracellular matrix adhesion, is thought to be essential for the ability of these cells to form primary tumors, invade adjacent tissues, and metastasize to distant organs. Current knowledge about the mechanisms by which cancer cells evade anoikis is far from complete. In an effort to understand these mechanisms, we found that ras, a major oncogene, down-regulates protease caspase-2 (which initiates certain steps of the cellular apoptotic program) in malignant human and rat intestinal epithelial cells. This down-regulation could be reversed by inhibition of a protein kinase Mek, a mediator of Ras signaling. We also found that enforced down-regulation of caspase-2 in nonmalignant intestinal epithelial cells by RNA interference protected them from anoikis. Furthermore, the reversal of the effect of Ras on caspase-2 achieved by the expression of exogenous caspase-2 in detached ras-transformed intestinal epithelial cells promoted well established apoptotic events, such as the release of the pro-apoptotic mitochondrial factors cytochrome c and HtrA2/Omi into the cytoplasm of these cells, significantly enhanced their anoikis susceptibility, and blocked their long term growth in the absence of adhesion to the extracellular matrix. Finally, the blockade of the effect of Ras on caspase-2 substantially suppressed growth of tumors formed by the ras-transformed cells in mice. We conclude that ras-induced down-regulation of caspase-2 represents a novel mechanism by which oncogenic Ras protects malignant intestinal epithelial cells from anoikis, promotes their anchorage-independent growth, and allows them to form tumors in vivo. PMID:21903589

Yoo, Byong Hoon; Wang, Yanfei; Erdogan, Mete; Sasazuki, Takehiko; Shirasawa, Senji; Corcos, Laurent; Sabapathy, Kanaga; Rosen, Kirill V.

2011-01-01

3

CASPASE 2-MEDIATED TUMOR SUPPRESSION INVOLVES SURVIVIN GENE SILENCING  

PubMed Central

One of the pivotal functions of endogenous tumor suppression is to oppose aberrant cell survival, but the molecular requirements of this process are not completely understood. Here, we show that caspase 2, a death effector with largely unknown functions, represses transcription of the survivin gene, a general regulator of cell division and cytoprotection in tumors. This pathway involves caspase 2 proteolytic cleavage of the NF?B activator, RIP1. In turn, loss of RIP1 abolishes transcription of NF?B target genes, including survivin, resulting in deregulated mitotic transitions, enhanced apoptosis, and suppression of tumorigenicity, in vivo. Therefore, caspase 2 functions as an endogenous inhibitor of NF?B-dependent cell survival, and this mechanism may contribute to tumor suppression in humans. PMID:19935698

Guha, Minakshi; Xia, Fang; Raskett, Christopher M.; Altieri, Dario C.

2009-01-01

4

Attenuation of the ELAV1-like protein HuR sensitizes adenocarcinoma cells to the intrinsic apoptotic pathway by increasing the translation of caspase-2L  

PubMed Central

Caspase-2 represents the most conserved member of the caspase family, which exhibits features of both initiator and effector caspases. Using ribonucleoprotein (RNP)-immunoprecipitation assay, we identified the proapoptotic caspase-2L encoding mRNA as a novel target of the ubiquitous RNA-binding protein HuR in DLD-1 colon carcinoma cells. Unexpectedly, crosslinking-RNP and RNA probe pull-down experiments revealed that HuR binds exclusively to the caspase-2-5? untranslated region (UTR) despite that the 3? UTR of the mRNA bears several adenylate- and uridylate-rich elements representing the prototypical HuR binding sites. By using RNAi-mediated loss-of-function approach, we observed that HuR regulates the mRNA and in turn the protein levels of caspase-2 in a negative manner. Silencing of HuR did not affect the stability of caspase-2 mRNA but resulted in an increased redistribution of caspase-2 transcripts from RNP particles to translational active polysomes implicating that HuR exerts a direct repressive effect on caspase-2 translation. Consistently, in vitro translation of a luciferase reporter gene under the control of an upstream caspase-2-5?UTR was strongly impaired after the addition of recombinant HuR, whereas translation of caspase-2 coding region without the 5?UTR is not affected by HuR confirming the functional role of the caspase-2-5?UTR. Functionally, an elevation in caspase-2 level by HuR knockdown correlated with an increased sensitivity of cells to apoptosis induced by staurosporine- and pore-forming toxins as implicated by their significant accumulation in the sub G1 phase and an increase in caspase-2, -3 and poly ADP-ribose polymerase cleavage, respectively. Importantly, HuR knockdown cells remained insensitive toward STS-induced apoptosis if cells were additionally transfected with caspase-2-specific siRNAs. Collectively, our findings support the hypothesis that HuR by acting as an endogenous inhibitor of caspase-2-driven apoptosis may essentially contribute to the antiapoptotic program of adenocarcinoma cells by HuR. PMID:25010987

Winkler, C; Doller, A; Imre, G; Badawi, A; Schmid, T; Schulz, S; Steinmeyer, N; Pfeilschifter, J; Rajalingam, K; Eberhardt, W

2014-01-01

5

Proinflammatory Caspase-2-Mediated Macrophage Cell Death Induced by a Rough Attenuated Brucella suis Strain ? †  

PubMed Central

Brucella spp. are intracellular bacteria that cause an infectious disease called brucellosis in humans and many domestic and wildlife animals. B. suis primarily infects pigs and is pathogenic to humans. The macrophage-Brucella interaction is critical for the establishment of a chronic Brucella infection. Our studies showed that smooth virulent B. suis strain 1330 (S1330) prevented programmed cell death of infected macrophages and rough attenuated B. suis strain VTRS1 (a vaccine candidate) induced strong macrophage cell death. To further investigate the mechanism of VTRS1-induced macrophage cell death, microarrays were used to analyze temporal transcriptional responses of murine macrophage-like J774.A1 cells infected with S1330 or VTRS1. In total 17,685 probe sets were significantly regulated based on the effects of strain, time and their interactions. A miniTUBA dynamic Bayesian network analysis predicted that VTRS1-induced macrophage cell death was mediated by a proinflammatory gene (the tumor necrosis factor alpha [TNF-?] gene), an NF-?B pathway gene (the I?B-? gene), the caspase-2 gene, and several other genes. VTRS1 induced significantly higher levels of transcription of 40 proinflammatory genes than S1330. A Mann-Whitney U test confirmed the proinflammatory response in VTRS1-infected macrophages. Increased production of TNF-? and interleukin 1? (IL-1?) were also detected in the supernatants in VTRS1-infected macrophage cell culture. Hyperphosphorylation of I?B-? was observed in macrophages infected with VTRS1 but not S1330. The important roles of TNF-? and I?B-? in VTRS1-induced macrophage cell death were further confirmed by individual inhibition studies. VTRS1-induced macrophage cell death was significantly inhibited by a caspase-2 inhibitor but not a caspase-1 inhibitor. The role of caspase-2 in regulating the programmed cell death of VTRS1-infected macrophages was confirmed in another study using caspase-2-knockout mice. In summary, VTRS1 induces a proinflammatory, caspase-2- and NF-?B-mediated macrophage cell death. This unique cell death differs from apoptosis, which is not proinflammatory. It is also different from classical pyroptosis, which is caspase-1 mediated. PMID:21464087

Chen, Fang; Ding, Xicheng; Ding, Ying; Xiang, Zuoshuang; Li, Xinna; Ghosh, Debashis; Schurig, Gerhardt G.; Sriranganathan, Nammalwar; Boyle, Stephen M.; He, Yongqun

2011-01-01

6

Additive effects of nicotine and high-fat diet on hepatocellular apoptosis in mice: involvement of caspase 2 and inducible nitric oxide synthase-mediated intrinsic pathway signaling.  

PubMed

Smoking is a major risk factor for diabetes and cardiovascular disease and may contribute to nonalcoholic fatty liver disease (NAFLD). The health risk associated with smoking is exaggerated by obesity and is the leading causes of morbidity and mortality worldwide. We recently demonstrated that combined treatment with nicotine and a high-fat diet (HFD) triggers greater oxidative stress, activates hepatocellular apoptosis, and exacerbates HFD-induced hepatic steatosis. Given that hepatocellular apoptosis plays a pivotal role in the pathogenesis of NAFLD, using this model of exacerbated hepatic steatosis, we elucidated the signal transduction pathways involved in HFD plus nicotine-induced liver cell death. Adult C57BL6 male mice were fed a normal chow diet or HFD with 60% of calories derived from fat and received twice daily IP injections of 0.75?mg/kg BW of nicotine or saline for 10 weeks. High-resolution light microscopy revealed markedly higher lipid accumulation in hepatocytes from mice received HFD plus nicotine, compared to mice on HFD alone. Addition of nicotine to HFD further resulted in an increase in the incidence of hepatocellular apoptosis and was associated with activation of caspase 2, induction of inducible nitric oxide synthase (iNOS), and perturbation of the BAX/BCL-2 ratio. Together, our data indicate the involvement of caspase 2 and iNOS-mediated apoptotic signaling in nicotine plus HFD-induced hepatocellular apoptosis. Targeting the caspase 2-mediated death pathway may have a protective role in development and progression of NAFLD. PMID:24830635

Ivey, R; Desai, M; Green, K; Sinha-Hikim, I; Friedman, T C; Sinha-Hikim, A P

2014-07-01

7

Coenzyme Q10 Rescues Ethanol-induced Corneal Fibroblast Apoptosis through the Inhibition of Caspase-2 Activation*  

PubMed Central

Recent studies indicate that caspase-2 is involved in the early stages of apoptosis, particularly before the occurrence of mitochondrial damage. Here we report the important role of the coenzyme Q10 (CoQ10) on the activity of caspase-2 upstream of mitochondria in ethanol (EtOH)-treated corneal fibroblasts. After EtOH exposure, cells produce excessive reactive oxygen species formation, p53 expression, and most importantly, caspase-2 activation. After the activation of the caspase-2, the cells exhibited hallmarks of apoptotic pathway, such as mitochondrial damage and translocation of Bax and cytochrome c, which were then followed by caspase-3 activation. By pretreating the cells with a cell-permeable, biotinylated pan-caspase inhibitor, we identified caspase-2 as an initiator caspase in EtOH-treated corneal fibroblasts. Loss of caspase-2 inhibited EtOH-induced apoptosis. We further found that caspase-2 acts upstream of mitochondria to mediate EtOH-induced apoptosis. The loss of caspase-2 significantly inhibited EtOH-induced mitochondrial dysfunction, Bax translocation, and cytochrome c release from mitochondria. The pretreatment of CoQ10 prevented EtOH-induced caspase-2 activation and mitochondria-mediated apoptosis. Our data demonstrated that by blocking caspase-2 activity, CoQ10 can protect the cells from mitochondrial membrane change, apoptotic protein translocation, and apoptosis. Taken together, EtOH-induced mitochondria-mediated apoptosis is initiated by caspase-2 activation, which is regulated by CoQ10. PMID:23430247

Chen, Chun-Chen; Liou, Shiow-Wen; Chen, Chi-Chih; Chen, Wen-Chung; Hu, Fung-Rong; Wang, I-Jong; Lin, Shing-Jong

2013-01-01

8

HOXA5Induced Apoptosis in Breast Cancer Cells Is Mediated by Caspases 2 and 8  

Microsoft Academic Search

HOXA5 is a transcriptional factor whose expression is lost in more than 60% of breast carcinomas. Our previous work demonstrated that the overexpression of HOXA5 in MCF7 cells resulted in cell death through a p53-dependent apoptotic pathway. To determine whether p53-independent apoptotic pathways are involved in HOXA5-induced cell death, we engineered a p53-mutant breast cancer cell line, Hs578T, to inducibly

Hexin Chen; Seung Chung; Saraswati Sukumar

2004-01-01

9

Caspase-2 deficiency promotes aberrant DNA-damage response and genetic instability  

PubMed Central

Caspase-2 is an initiator caspase, which has been implicated to function in apoptotic and non-apoptotic signalling pathways, including cell-cycle regulation, DNA-damage signalling and tumour suppression. We previously demonstrated that caspase-2 deficiency enhances E1A/Ras oncogene-induced cell transformation and augments lymphomagenesis in the E?Myc mouse model. Caspase-2?/? mouse embryonic fibroblasts (casp2?/? MEFs) show aberrant cell-cycle checkpoint regulation and a defective apoptotic response following DNA damage. Disruption of cell-cycle checkpoints often leads to genomic instability (GIN), which is a common phenotype of cancer cells and can contribute to cellular transformation. Here we show that caspase-2 deficiency results in increased DNA damage and GIN in proliferating cells. Casp2?/? MEFs readily escape senescence in culture and exhibit increased micronuclei formation and sustained DNA damage during cell culture and following ?-irradiation. Metaphase analyses demonstrated that a lack of caspase-2 is associated with increased aneuploidy in both MEFs and in E?Myc lymphoma cells. In addition, casp2?/? MEFs and lymphoma cells exhibit significantly decreased telomere length. We also noted that loss of caspase-2 leads to defective p53-mediated signalling and decreased trans-activation of p53 target genes upon DNA damage. Our findings suggest that loss of caspase-2 serves as a key function in maintaining genomic integrity, during cell proliferation and following DNA damage. PMID:22498700

Dorstyn, L; Puccini, J; Wilson, C H; Shalini, S; Nicola, M; Moore, S; Kumar, S

2012-01-01

10

Caspase-2 deficiency promotes aberrant DNA-damage response and genetic instability.  

PubMed

Caspase-2 is an initiator caspase, which has been implicated to function in apoptotic and non-apoptotic signalling pathways, including cell-cycle regulation, DNA-damage signalling and tumour suppression. We previously demonstrated that caspase-2 deficiency enhances E1A/Ras oncogene-induced cell transformation and augments lymphomagenesis in the E?Myc mouse model. Caspase-2(-/-) mouse embryonic fibroblasts (casp2(-/-) MEFs) show aberrant cell-cycle checkpoint regulation and a defective apoptotic response following DNA damage. Disruption of cell-cycle checkpoints often leads to genomic instability (GIN), which is a common phenotype of cancer cells and can contribute to cellular transformation. Here we show that caspase-2 deficiency results in increased DNA damage and GIN in proliferating cells. Casp2(-/-) MEFs readily escape senescence in culture and exhibit increased micronuclei formation and sustained DNA damage during cell culture and following ?-irradiation. Metaphase analyses demonstrated that a lack of caspase-2 is associated with increased aneuploidy in both MEFs and in E?Myc lymphoma cells. In addition, casp2(-/-) MEFs and lymphoma cells exhibit significantly decreased telomere length. We also noted that loss of caspase-2 leads to defective p53-mediated signalling and decreased trans-activation of p53 target genes upon DNA damage. Our findings suggest that loss of caspase-2 serves as a key function in maintaining genomic integrity, during cell proliferation and following DNA damage. PMID:22498700

Dorstyn, L; Puccini, J; Wilson, C H; Shalini, S; Nicola, M; Moore, S; Kumar, S

2012-08-01

11

Caspase-2 as a tumour suppressor.  

PubMed

Ever since its discovery 20 years ago, caspase-2 has been enigmatic and its function somewhat controversial. Although many in vitro studies suggested that caspase-2 was important for apoptosis, demonstrating an in vivo cell death role for this caspase has been more problematic, with caspase-2-deficient mice showing limited, tissue-specific cell death defects. Recent results from different laboratories suggest that at least one of its physiological roles in animals is to protect against cellular stress and transformation. As such, loss of caspase-2 augments tumorigenesis in some mouse models of cancer, assigning a tumour suppressor function to this enigmatic caspase. This review focuses on this seemingly non-apoptotic function of caspase-2 as a tumour suppressor and reconciles some of the recent findings in the field. PMID:23811850

Puccini, J; Dorstyn, L; Kumar, S

2013-09-01

12

Caspase-2 as a tumour suppressor  

PubMed Central

Ever since its discovery 20 years ago, caspase-2 has been enigmatic and its function somewhat controversial. Although many in vitro studies suggested that caspase-2 was important for apoptosis, demonstrating an in vivo cell death role for this caspase has been more problematic, with caspase-2-deficient mice showing limited, tissue-specific cell death defects. Recent results from different laboratories suggest that at least one of its physiological roles in animals is to protect against cellular stress and transformation. As such, loss of caspase-2 augments tumorigenesis in some mouse models of cancer, assigning a tumour suppressor function to this enigmatic caspase. This review focuses on this seemingly non-apoptotic function of caspase-2 as a tumour suppressor and reconciles some of the recent findings in the field. PMID:23811850

Puccini, J; Dorstyn, L; Kumar, S

2013-01-01

13

Analysis of the minimal specificity of caspase-2 and identification of Ac-VDTTD-AFC as a caspase-2-selective peptide substrate  

PubMed Central

Caspase-2 is an evolutionarily conserved but enigmatic protease whose biological role remains poorly understood. To date, research into the functions of caspase-2 has been hampered by an absence of reagents that can distinguish its activity from that of the downstream apoptotic caspase, caspase-3. Identification of protein substrates of caspase-2 that are efficiently cleaved within cells may also provide clues to the role of this protease. We used a yeast-based transcriptional reporter system to define the minimal substrate specificity of caspase-2. The resulting profile enabled the identification of candidate novel caspase-2 substrates. Caspase-2 cleaved one of these proteins, the cancer-associated transcription factor Runx1, although with relatively low efficiency. A fluorogenic peptide was derived from the sequence most efficiently cleaved in the context of the transcriptional reporter. This peptide, Ac-VDTTD-AFC, was efficiently cleaved by purified caspase-2 and auto-activating caspase-2 in mammalian cells, and exhibited better selectivity for caspase-2 relative to caspase-3 than reagents that are currently available. We suggest that this reagent, used in parallel with the traditional caspase-3 substrate Ac-DEVD-AFC, will enable researchers to monitor caspase-2 activity in cell lysates and may assist in the determination of stimuli that activate caspase-2 in vivo. PMID:24527765

Kitevska, Tanja; Roberts, Sarah J.; Pantaki-Eimany, Delara; Boyd, Sarah E.; Scott, Fiona L.; Hawkins, Christine J.

2014-01-01

14

Caspase-2: Vestigial Remnant or Master Regulator?  

NSDL National Science Digital Library

Caspase-2, the second mammalian caspase to be identified and the most evolutionarily conserved caspase, has eluded classification. The lack of a profound phenotype in the caspase-2–deficient mouse resulted in decreased interest in caspase-2 for many years. However, advances in the field, including the identification of a potential activation complex and the development of methods to detect active caspase-2, now illuminate our understanding of the function of this caspase. These studies suggest that caspase-2 induces death through two pathways. First, caspase-2 induces cell death independently of the mitochondrial pathway, in a manner similar to that of ced-3, a caspase in Caenorhabditis elegans. Second, caspase-2 also induces cell death upstream of the mitochondrial pathway. The choice of pathway may depend on the type of death stimulus. The placing of caspase-2 upstream and independent of mitochondrial dysfunction provides a potentially new therapeutic target for aberrant cell death.

Carol M. Troy (Departments of Pathology and Neurology;Columbia University College of Physicians and Surgeons REV); Elena M. Ribe (Departments of Pathology and Neurology;Columbia University College of Physicians and Surgeons REV)

2008-09-23

15

Endogenous Zinc Mediates Apoptotic Programmed Cell Death in the Developing Brain  

Microsoft Academic Search

Endogenous zinc can mediate the apoptotic programmed cell death (PCD) in the developing brain. Intensive accumulation of labile\\u000a zinc occurs in almost all neurons undergoing PCD in the developing rat brain. Based on the greater frequency of neurons with\\u000a intensive zinc accumulation compared to apoptotic neurons, it is inferred that cytosolic zinc accumulation precedes apoptotic\\u000a PCD. To determine the role

Eunsil Cho; Jung-Jin Hwang; Seung-Hee Han; Sun Ju Chung; Jae-Young Koh; Joo-Yong Lee

2010-01-01

16

Mitoxantrone-Mediated Apoptotic B16-F1 Cells Induce Specific Antitumor Immune Response  

Microsoft Academic Search

In the process of cell apoptosis induced by specific reagents, calreticulin (CRT) in endoplasmic reticulum is transferred and coated onto the cell membrane. As a sort of specific ligand, the CRT on the surface of apoptotic cells could mediate recognition and clearance of apoptotic cells by phagocytes. In this research we discovered that mitoxantrone could induce apoptosis of mouse melonoma

Chunyu Cao; Yu Han; Yushan Ren; Yanlin Wang

2009-01-01

17

Degradomics reveals that cleavage specificity profiles of caspase-2 and effector caspases are alike.  

PubMed

Caspase-2 is considered an initiator caspase because its long prodomain contains a CARD domain that allows its recruitment and activation in several complexes by homotypic death domain-fold interactions. Because little is known about the function and specificity of caspase-2 and its physiological substrates, we compared the cleavage specificity profile of recombinant human caspase-2 with those of caspase-3 and -7 by analyzing cell lysates using N-terminal COmbined FRActional DIagonal Chromatography (COFRADIC). Substrate analysis of the 68 cleavage sites identified in 61 proteins revealed that the protease specificities of human caspases-2, -3, and -7 largely overlap, revealing the DEVD?G consensus cleavage sequence. We confirmed that Asp(563) in eukaryotic translation initiation factor 4B (eIF4B) is a cleavage site preferred by caspase-2 not only in COFRADIC setup but also upon co-expression in HEK 293T cells. These results demonstrate that activated human caspase-2 shares remarkably overlapping protease specificity with the prototype apoptotic executioner caspases-3 and -7, suggesting that caspase-2 could function as a proapoptotic caspase once released from the activating complex. PMID:22825847

Wejda, Magdalena; Impens, Francis; Takahashi, Nozomi; Van Damme, Petra; Gevaert, Kris; Vandenabeele, Peter

2012-10-01

18

Degradomics Reveals That Cleavage Specificity Profiles of Caspase-2 and Effector Caspases Are Alike*  

PubMed Central

Caspase-2 is considered an initiator caspase because its long prodomain contains a CARD domain that allows its recruitment and activation in several complexes by homotypic death domain-fold interactions. Because little is known about the function and specificity of caspase-2 and its physiological substrates, we compared the cleavage specificity profile of recombinant human caspase-2 with those of caspase-3 and -7 by analyzing cell lysates using N-terminal COmbined FRActional DIagonal Chromatography (COFRADIC). Substrate analysis of the 68 cleavage sites identified in 61 proteins revealed that the protease specificities of human caspases-2, -3, and -7 largely overlap, revealing the DEVD?G consensus cleavage sequence. We confirmed that Asp563 in eukaryotic translation initiation factor 4B (eIF4B) is a cleavage site preferred by caspase-2 not only in COFRADIC setup but also upon co-expression in HEK 293T cells. These results demonstrate that activated human caspase-2 shares remarkably overlapping protease specificity with the prototype apoptotic executioner caspases-3 and -7, suggesting that caspase-2 could function as a proapoptotic caspase once released from the activating complex. PMID:22825847

Wejda, Magdalena; Impens, Francis; Takahashi, Nozomi; Van Damme, Petra; Gevaert, Kris; Vandenabeele, Peter

2012-01-01

19

Transplantation . Author manuscript Mediators involved in the immunomodulatory effects of apoptotic cells  

E-print Network

Transplantation . Author manuscript Page /1 6 Mediators involved in the immunomodulatory effects transplantation1 ô é é INSERM : U645 , Universit de Franche-Comté é , EFS , IFR133 , 1 bd Alexandre Fleming 25020 in experimental transplantation settings. In independent studies, apoptotic cell infusion has been shown to favor

Paris-Sud XI, Université de

20

The PIDDosome, a Protein Complex Implicated in Activation of Caspase2 in Response to Genotoxic Stress  

Microsoft Academic Search

Apoptosis is triggered by activation of initiator caspases upon complex-mediated clustering of the inactive zymogen, as occurs in the caspase-9-activating apoptosome complex. Likewise, caspase-2, which is involved in stress-induced apoptosis, is recruited into a large protein complex, the molecular composition of which remains elusive. We show that activation of caspase-2 occurs in a complex that contains the death domain-containing protein

Antoine Tinel; Jürg Tschopp

2004-01-01

21

Milk fat globule-EGF factor 8 mediates the enhancement of apoptotic cell clearance by glucocorticoids  

PubMed Central

The phagocytic clearance of apoptotic cells is essential to prevent chronic inflammation and autoimmunity. The phosphatidylserine-binding protein milk fat globule-EGF factor 8 (MFG-E8) is a major opsonin for apoptotic cells, and MFG-E8?/? mice spontaneously develop a lupus-like disease. Similar to human systemic lupus erythematosus (SLE), the murine disease is associated with an impaired clearance of apoptotic cells. SLE is routinely treated with glucocorticoids (GCs), whose anti-inflammatory effects are consentaneously attributed to the transrepression of pro-inflammatory cytokines. Here, we show that the GC-mediated transactivation of MFG-E8 expression and the concomitantly enhanced elimination of apoptotic cells constitute a novel aspect in this context. Patients with chronic inflammation receiving high-dose prednisone therapy displayed substantially increased MFG-E8 mRNA levels in circulating monocytes. MFG-E8 induction was dependent on the GC receptor and several GC response elements within the MFG-E8 promoter. Most intriguingly, the inhibition of MFG-E8 induction by RNA interference or genetic knockout strongly reduced or completely abolished the phagocytosis-enhancing effect of GCs in vitro and in vivo. Thus, MFG-E8-dependent promotion of apoptotic cell clearance is a novel anti-inflammatory facet of GC treatment and renders MFG-E8 a prospective target for future therapeutic interventions in SLE. PMID:23832117

Lauber, K; Keppeler, H; Munoz, L E; Koppe, U; Schröder, K; Yamaguchi, H; Krönke, G; Uderhardt, S; Wesselborg, S; Belka, C; Nagata, S; Herrmann, M

2013-01-01

22

Involvement of annexin I in the dexamethasone-mediated upregulation of A549 cells phagocytosis of apoptotic eosinophils.  

PubMed

Phagolysis of apoptotic eosinophils plays an important role in the successful resolution of asthmatic inflammation. However, little is known about underlying mechanisms. Our aim is to investigate whether annexin I is involved in the dexamethasone-mediated enhancement of phagolysis of apoptotic eosinophils by A549 cells. Phagocytosis of apoptotic eosinophils by A549 cells was visualized under laser confocal scanning microscopy. The effect of dexamethasone and TNF-alpha treatment on surface annexin I expression on A549 cells was assayed by Western blot. Eosinophils were purified under sterile conditions from periphery blood of five normal donors. A549 cells were visually assessed for apoptotic eosinophil phagocytosis by microscope. The concentration of interleukin 6 (IL-6), IL-8 and TGF-beta(1) released by A549 cells to the culture supernatants was measured by RIA or ELISA. Dexamethasone upregulated apoptotic eosinophils phagocytosis by A549 cells in a time-dependent manner, which correlated with annexin I surface expression. Annexin I mAb abolished dexamethasone-mediated enhancement of apoptotic eosinophil phagocytosis by A549 cells. Phagocytosis of apoptotic eosinophils did not change IL-6, IL-8 and TGF-beta(1) release from A549 cells. These results suggest that annexin I is involved in upregulating of dexamethasone-mediated phagocytosis of apoptotic eosinophils by A549 cells. Furthermore, the phagocytic clearance of apoptotic eosinophils did not increase proinflammatory responses. PMID:17644190

Wang, Cheng; Wang, Jiong; Guo, Hou-Fu; Liu, Rong-Yu

2007-08-15

23

Hydrogen sulfide-linked sulfhydration of NF-?B mediates its anti-apoptotic actions  

PubMed Central

Summary Nuclear factor ?B (NF-?B) is an anti-apoptotic transcription factor. We show that the anti-apoptotic actions of NF-?B are mediated by hydrogen sulfide (H2S) synthesized by cystathionine gamma-lyase (CSE). TNF? treatment triples H2S generation by stimulating binding of SP1 to the CSE promoter. H2S generated by CSE stimulates DNA binding and gene activation of NF-?B, processes that are abolished in CSE deleted mice. As CSE deletion leads to decreased glutathione levels, resultant oxidative stress may contribute to alterations in CSE mutant mice. H2S acts by sulfhydrating the p65 subunit of NF-?B at cysteine-38, which promotes its binding to the co-activator ribosomal protein S3 (RPS3). Sulfhydration of p65 predominates early following TNF? treatment, then declines and is succeeded by a reciprocal enhancement of p65 nitrosylation. Anti-apoptotic influences of NF-?B, which are markedly diminished in CSE mutant mice. Thus, sulfhydration of NF-?B appears to be a physiologic determinant of its anti-apoptotic transcriptional activity. PMID:22244329

Sen, Nilkantha; Paul, Bindu D.; Gadalla, Moataz M.; Mustafa, Asif K.; Sen, Tanusree; Xu, Risheng; Kim, Seyun; Snyder, Solomon H.

2011-01-01

24

Apoptotic cells induce dendritic cell-mediated suppression via interferon-?-induced IDO  

PubMed Central

Dendritic cells (DC) are sensitive to their local environment and are affected by proximal cell death. This study investigated the modulatory effect of cell death on DC function. Monocyte-derived DC exposed to apoptotic Jurkat or primary T cells failed to induce phenotypic maturation of the DC and were unable to support CD4+ allogeneic T-cell proliferation compared with DC exposed to lipopolysaccharide (LPS) or necrotic cells. Apoptotic cells coincubated with LPS- or necrotic cell-induced mature DC significantly suppressed CD80, CD86 and CD83 and attenuated LPS-induced CD4+ T-cell proliferation. Reduced levels of interleukin-12 (IL-12), IL-10, IL-6, tumour necrosis factor-? and interferon-? (IFN-?) were found to be concomitant with the suppressive activity of apoptotic cells upon DC. Furthermore, intracellular staining confirmed IFN-? expression by DC in association with apoptotic environments. The specific generation of IFN-? by DC within apoptotic environments is suggestive of an anti-inflammatory role by the induction of indoleamine 2,3-dioxygenase (IDO). Both neutralization of IFN-? and IDO blockade demonstrated a role for IFN-? and IDO in the suppression of CD4+ T cells. Moreover, we demonstrate that IDO expression within the DC was found to be IFN-?-dependent. Blocking transforming growth factor-? (TGF-?) also produced a partial release in T-cell proliferation. Our study strongly suggests that apoptosis-induced DC suppression is not an immunological null event and two prime mediators underpinning these functional effects are IFN-?-induced IDO and TGF-?. PMID:18067553

Williams, Charlotte A; Harry, Rachel A; McLeod, Julie D

2008-01-01

25

Modulation of Orphan Nuclear Receptor Nur77-mediated Apoptotic Pathway by Acetylshikonin and Analogs  

PubMed Central

Shikonin derivatives, which are the active components of the medicinal plant Lithospermum erythrorhizon, exhibit many biological effects including apoptosis induction through undefined mechanisms. We recently discovered that orphan nuclear receptor Nur77 migrates from the nucleus to mitochondria, where it binds to Bcl-2 to induce apoptosis. Here, we report that certain shikonin derivatives could modulate the Nur77-Bcl-2 apoptotic pathway by increasing levels of Nur77 protein and promoting its mitochondrial targeting in cancer cells. Structural modification of acetylshikonin resulted in identification of a derivative 5,8-diacetoxyl-6-(1'-Acetoxyl-4'-methyl-3'-pentenyl)-1,4-naphthaquinones (SK07) that exhibited improved efficacy and specificity in activating the pathway. Unlike other Nur77 modulators, shikonins increased levels of Nur77 protein through their posttranscriptional regulation. The apoptotic effect of SK07 was impaired in Nur77 knockout cells and suppressed by co-treatment with leptomycin B (LMB) that inhibited Nur77 cytoplasmic localization. Furthermore, SK07 induced apoptosis in cells expressing the C-terminal half of Nur77 protein but not its N-terminal region. Our data also showed that SK07-induced apoptosis was associated with a Bcl-2 conformational change and Bax activation. Together, our results demonstrate that certain shikonin derivatives act as modulators of the Nur77-mediated apoptotic pathway and identify new shikonin-based lead that targets Nur77 for apoptosis induction. PMID:18974131

Liu, Jie; Zhou, Wen; Li, Shao-Shun; Sun, Zhe; Lin, Bingzhen; Lang, Yuan-Yuan; He, Jia-You; Cao, Xihua; Yan, Tingdong; Wang, Li; Lu, Jiongming; Han, Young-Hoon; Cao, Yu; Zhang, Xiao-kun; Zeng, Jin-Zhang

2008-01-01

26

Mitoxantrone-mediated apoptotic B16-F1 cells induce specific anti-tumor immune response.  

PubMed

In the process of cell apoptosis induced by specific reagents, calreticulin (CRT) in endoplasmic reticulum is transferred and coated onto the cell membrane. As a sort of specific ligand, the CRT on the surface of apoptotic cells could mediate recognition and clearance of apoptotic cells by phagocytes. In this research we discovered that mitoxantrone could induce apoptosis of mouse melonoma B16-F1 tumor cells, accompanied by the membrane translocation and coating of CRT. When mitoxantrone-treated B16-F1 cells were used as antigen to inoculate mice, the mice acquired an ability to suppress proliferation of homologous tumor cells. Splenocytes from these mice showed an increased cytolytic effect on homologous B16-F1 cells but no such effect on non-homologous H22 tumor cells. All these results suggested that mitoxantrone-treated apoptotic B16-F1 cells could be used as a sort of cell vaccine to initiate effective anti-tumor immunoresponse in mice. PMID:20003823

Cao, Chunyu; Han, Yu; Ren, Yushan; Wang, Yanlin

2009-12-01

27

Mitoxantrone-Mediated Apoptotic B16-F1 Cells Induce Specific Anti-tumor Immune Response  

PubMed Central

In the process of cell apoptosis induced by specific reagents, calreticulin (CRT) in endoplasmic reticulum is transferred and coated onto the cell membrane. As a sort of specific ligand, the CRT on the surface of apoptotic cells could mediate recognition and clearance of apoptotic cells by phagocytes. In this research we discovered that mitoxantrone could induce apoptosis of mouse melonoma B16-F1 tumor cells, accompanied by the membrane translocation and coating of CRT. When mitoxantrone-treated B16-F1 cells were used as antigen to inoculate mice, the mice acquired an ability to suppress proliferation of homologous tumor cells. Splenocytes from these mice showed an increased cytolytic effect on homologous B16-F1 cells but no such effect on non-homologous H22 tumor cells. All these results suggested that mitoxantrone-treated apoptotic B16-F1 cells could be used as a sort of cell vaccine to initiate effective anti-tumor immunoresponse in mice. PMID:20003823

Cao, Chunyu; Han, Yu; Ren, Yushan; Wang, Yanlin

2009-01-01

28

Orai1 and STIM1 mediate SOCE and contribute to apoptotic resistance of pancreatic adenocarcinoma.  

PubMed

The store-operated calcium channels (SOCs) represent one of the major calcium-entry pathways in non-excitable cells. SOCs and in particular their major components ORAI1 and STIM1 have been shown to be implicated in a number of physiological and pathological processes such as apoptosis, proliferation and invasion. Here we demonstrate that ORAI1 and STIM1 mediate store-operated calcium entry (SOCE) in pancreatic adenocarcinoma cell lines. We show that both ORAI1 and STIM1 play pro-survival anti-apoptotic role in pancreatic adenocarcinoma cell lines, as siRNA-mediated knockdown of ORAI1 and/or STIM1 increases apoptosis induced by chemotherapy drugs 5-fluorouracil (5-FU) or gemcitabine. We also demonstrate that both 5-FU and gemcitabine treatments increase SOCE in Panc1 pancreatic adenocarcinoma cell line via upregulation of ORAI1 and STIM1. Altogether our results reveal the novel calcium-dependent mechanism of action of the chemotherapy drugs 5-FU and gemcitabine and emphasize the anti-apoptotic role of ORAI1 and STIM1 in pancreatic adenocarcinoma cells. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau. PMID:24583265

Kondratska, Kateryna; Kondratskyi, Artem; Yassine, Maya; Lemonnier, Loic; Lepage, Gilbert; Morabito, Angela; Skryma, Roman; Prevarskaya, Natalia

2014-10-01

29

Caspase mediated enhanced apoptotic action of cyclophosphamide- and resveratrol-treated MCF-7 cells.  

PubMed

Cyclophosphamide (CPA) is a widely used chemotherapeutic drug for neoplasias. It is a DNA and protein alkylating agent having a broad spectrum of activity against a variety of neoplasms including breast cancer. The therapeutic effectiveness of CPA is limited by the high-dose hematopoietic, renal, and cardiac toxicity that accompanies the systemic distribution of liver-derived activated drug metabolites. The present study examines the potential of combining resveratrol (RES) with CPA and aims to increase the understanding of the mechanism of cell killing. Interestingly, we found that RES significantly enhances the caspase-mediated cytotoxic activity of CPA on MCF-7 cells in vitro. RES at 50 microM decreases the IC(50) value of CPA from 10 to 5 mM. FACS data reveals CPA or RES alone mediated G0/G1 and S phase arrest, while the combination of these drugs released both the arrests and results in an increase in the sub G0/G1 peak. Additional analyses indicated the significant up-regulation (P = 0.001) of tumor suppressor p53 and p53-regulated pro-apoptotic Bax and Fas in MCF-7 cells following CPA treatment in combination with RES, which may contribute to the enhancement of the antitumor effect of CPA. Furthermore, downregulation of anti-apoptotic Bcl-2 (P = 0.001) was observed in MCF-7 cells treated with CPA with or without RES when compared to untreated MCF-7. These results suggest the possibility of a new combination chemotherapeutic regimen leading to improvements in the treatment of breast cancer. PMID:19372630

Singh, Neetu; Nigam, Manisha; Ranjan, Vishal; Sharma, Ramesh; Balapure, Anil Kumar; Rath, Srikanta Kumar

2009-04-01

30

Activation of p53-regulated pro-apoptotic signaling pathways in PrP-mediated myopathy  

PubMed Central

Background We have reported that doxycycline-induced over-expression of wild type prion protein (PrP) in skeletal muscles of Tg(HQK) mice is sufficient to cause a primary myopathy with no signs of peripheral neuropathy. The preferential accumulation of the truncated PrP C1 fragment was closely correlated with these myopathic changes. In this study we use gene expression profiling to explore the temporal program of molecular changes underlying the PrP-mediated myopathy. Results We used DNA microarrays, and confirmatory real-time PCR and Western blot analysis to demonstrate deregulation of a large number of genes in the course of the progressive myopathy in the skeletal muscles of doxycycline-treated Tg(HQK) mice. These include the down-regulation of genes coding for the myofibrillar proteins and transcription factor MEF2c, and up-regulation of genes for lysosomal proteins that is concomitant with increased lysosomal activity in the skeletal muscles. Significantly, there was prominent up-regulation of p53 and p53-regulated genes involved in cell cycle arrest and promotion of apoptosis that paralleled the initiation and progression of the muscle pathology. Conclusion The data provides the first in vivo evidence that directly links p53 to a wild type PrP-mediated disease. It is evident that several mechanistic features contribute to the myopathy observed in PrP over-expressing mice and that p53-related apoptotic pathways appear to play a major role. PMID:19400950

Liang, Jingjing; Parchaliuk, Debra; Medina, Sarah; Sorensen, Garrett; Landry, Laura; Huang, Shenghai; Wang, Meiling; Kong, Qingzhong; Booth, Stephanie A

2009-01-01

31

Impaired antioxidant defence and accumulation of oxidative stress in caspase-2-deficient mice.  

PubMed

Caspase-2 has been implicated in apoptosis and in non-apoptotic processes such as cell cycle regulation, tumor suppression and ageing. Using caspase-2 knockout (casp2(-/-)) mice, we show here that the putative anti-ageing role of this caspase is due in part to its involvement in the stress response pathway. The old casp2(-/-) mice show increased cellular levels of oxidized proteins, lipid peroxides and DNA damage, suggesting enhanced oxidative stress. Furthermore, murine embryonic fibroblasts from casp2(-/-) mice showed increased reactive oxygen species generation when challenged with pro-oxidants. Reduced activities of antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were observed in the old casp2(-/-) mice. Interestingly, in the old casp2(-/-) animals expression of FoxO1 and FoxO3a was significantly reduced, whereas p21 levels and the number of senescent hepatocytes were elevated. In contrast to young wild-type mice, the casp2(-/-) animals fed an on ethanol-based diet failed to show enhanced GSH-Px and SOD activities. Thus, caspase-2, most likely via FoxO transcription factors, regulates the oxidative stress response in vivo. PMID:22343713

Shalini, S; Dorstyn, L; Wilson, C; Puccini, J; Ho, L; Kumar, S

2012-08-01

32

Impaired antioxidant defence and accumulation of oxidative stress in caspase-2-deficient mice  

PubMed Central

Caspase-2 has been implicated in apoptosis and in non-apoptotic processes such as cell cycle regulation, tumor suppression and ageing. Using caspase-2 knockout (casp2?/?) mice, we show here that the putative anti-ageing role of this caspase is due in part to its involvement in the stress response pathway. The old casp2?/? mice show increased cellular levels of oxidized proteins, lipid peroxides and DNA damage, suggesting enhanced oxidative stress. Furthermore, murine embryonic fibroblasts from casp2?/? mice showed increased reactive oxygen species generation when challenged with pro-oxidants. Reduced activities of antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were observed in the old casp2?/? mice. Interestingly, in the old casp2?/? animals expression of FoxO1 and FoxO3a was significantly reduced, whereas p21 levels and the number of senescent hepatocytes were elevated. In contrast to young wild-type mice, the casp2?/? animals fed an on ethanol-based diet failed to show enhanced GSH-Px and SOD activities. Thus, caspase-2, most likely via FoxO transcription factors, regulates the oxidative stress response in vivo. PMID:22343713

Shalini, S; Dorstyn, L; Wilson, C; Puccini, J; Ho, L; Kumar, S

2012-01-01

33

Role of Apoptotic Proteins in REC-2006 Mediated Radiation Protection in Hepatoma Cell Lines.  

PubMed

The present study was carried out to evaluate the role of apoptotic proteins in REC-2006-mediated radiation protection in hepatoma cell lines. REC-2006 treatment 2?h before irradiation strongly inhibited the cleavage of ATM and PARP-1 in HepG2 cells. The expression of nuclear apoptosis inducing factor (AIF) was found to be more inhibited (~17%) in HepG2 cells in REC-2006 + radiation-treated group. More inhibition (~33%) of cytochrome c was observed in HepG2 cells upon REC-2006 treatment 2?h prior irradiation. Similarly, significantly more (P<.05) inhibition of Apaf-1, caspase-9 and caspase-3 was observed in REC-2006 + radition-treated group in HepG2 cells. REC-2006 treatment restored the expression of ICAD in HepG2 cells; however, no restoration was observed in Hep3B cells. Lower nuclear to cytoplasmic CAD ratio was observed in HepG2 cells (~0.6) as compared with Hep3B cells (~1.2) in REC-2006 + radiation-treated group. In conclusion, REC-2006 rendered higher protection in HepG2 cells by inhibiting the expression and translocation of AIF, inhibiting the cleavage of ATM and PARP-1, restoring the expression of ICAD, inhibiting the release of cytochrome c and thus modulating the expression of Apaf-1 caspase-9 and activity of caspase-3. PMID:21799693

Singh, Pankaj Kumar; Kumar, Raj; Sharma, Ashok; Arora, Rajesh; Chawla, Raman; Jain, Swatantra Kumar; Tripathi, Rajendra Prasad; Sharma, Rakesh Kumar

2011-01-01

34

KAISO, a critical regulator of p53-mediated transcription of CDKN1A and apoptotic genes.  

PubMed

An unresolved issue in genotoxic stress response is identification of induced regulatory proteins and how these activate tumor suppressor p53 to determine appropriate cell responses. Transcription factor KAISO was previously described to repress transcription following binding to methylated DNA. In this study, we show that KAISO is induced by DNA damage in p53-expressing cells and then interacts with the p53-p300 complex to increase acetylation of p53 K320 and K382 residues, although decreasing K381 acetylation. Moreover, the p53 with this particular acetylation pattern shows increased DNA binding and potently induces cell cycle arrest and apoptosis by activating transcription of CDKN1A (cyclin-dependent kinase inhibitor 1) and various apoptotic genes. Analogously, in Kaiso KO mouse embryonic fibroblast cells, p53-to-promoter binding and up-regulation of p21 and apoptosis gene expression is significantly compromised. KAISO may therefore be a critical regulator of p53-mediated cell cycle arrest and apoptosis in response to various genotoxic stresses in mammalian cells. PMID:25288747

Koh, Dong-In; Han, Dohyun; Ryu, Hoon; Choi, Won-Il; Jeon, Bu-Nam; Kim, Min-Kyeong; Kim, Youngsoo; Kim, Jin Young; Parry, Lee; Clarke, Alan R; Reynolds, Albert B; Hur, Man-Wook

2014-10-21

35

Titanium dioxide induces apoptotic cell death through reactive oxygen species-mediated Fas upregulation and Bax activation  

PubMed Central

Background Titanium dioxide (TiO2) has been widely used in many areas, including biomedicine, cosmetics, and environmental engineering. Recently, it has become evident that some TiO2 particles have a considerable cytotoxic effect in normal human cells. However, the molecular basis for the cytotoxicity of TiO2 has yet to be defined. Methods and results In this study, we demonstrated that combined treatment with TiO2 nanoparticles sized less than 100 nm and ultraviolet A irradiation induces apoptotic cell death through reactive oxygen species-dependent upregulation of Fas and conformational activation of Bax in normal human cells. Treatment with P25 TiO2 nanoparticles with a hydrodynamic size distribution centered around 70 nm (TiO2P25–70) together with ultraviolet A irradiation-induced caspase-dependent apoptotic cell death, accompanied by transcriptional upregulation of the death receptor, Fas, and conformational activation of Bax. In line with these results, knockdown of either Fas or Bax with specific siRNA significantly inhibited TiO2-induced apoptotic cell death. Moreover, inhibition of reactive oxygen species with an antioxidant, N-acetyl-L-cysteine, clearly suppressed upregulation of Fas, conformational activation of Bax, and subsequent apoptotic cell death in response to combination treatment using TiO2P25–70 and ultraviolet A irradiation. Conclusion These results indicate that sub-100 nm sized TiO2 treatment under ultraviolet A irradiation induces apoptotic cell death through reactive oxygen species-mediated upregulation of the death receptor, Fas, and activation of the preapoptotic protein, Bax. Elucidating the molecular mechanisms by which nanosized particles induce activation of cell death signaling pathways would be critical for the development of prevention strategies to minimize the cytotoxicity of nanomaterials. PMID:22419868

Yoo, Ki-Chun; Yoon, Chang-Hwan; Kwon, Dongwook; Hyun, Kyung-Hwan; Woo, Soo Jung; Kim, Rae-Kwon; Lim, Eun-Jung; Suh, Yongjoon; Kim, Min-Jung; Yoon, Tae Hyun; Lee, Su-Jae

2012-01-01

36

Beneficial Effects of Astragaloside IV for Hair Loss via Inhibition of Fas/Fas L-Mediated Apoptotic Signaling  

PubMed Central

Apoptosis with premature termination of hair follicle growth induces several types of hair loss and is one of the crucial factors of hair loss. Astragaloside IV, which is a major component of Astragalus membranaceus, is a cycloartane triterpene saponin. Although an anti-apoptotic effect of Astragaloside IV has been reported, its effects against hair loss have not been investigated. To explore the underlying mechanisms of Astragaloside IV on apoptotic signaling in hair follicle, the dorsal skin of depilated C57BL/6 mice was topically treated with 1 and 100 ?M Astragaloside IV for 14 days. In Astragaloside IV-treated group, TUNEL-positive cells were reduced. We found that Astragaloside IV blocked the procaspase-8, resulting in the inhibition of caspase-3 and procaspase-9 activities. The changes were accompanied with down-regulation of Bax and p53, and up-regulation of Bcl-2 and Bcl-xL by Astragaloside IV treatment. In addition, activation of NF-?B and phosphorylation of I?B-? were inhibited, along with decreases in three MAPKs: ERK, SAPK/JNK and p38 by Astragaloside IV. The expressions of KGF, p21, TNF-? and IL-1?, which are keratinocyte terminal differentiation markers associated with catagen, were modulated by treatment with Astragaloside IV. These results demonstrated that Astragaloside IV is concerned with blocking the Fas/Fas L-mediated apoptotic pathway, which would be an alternative therapy for hair loss. PMID:24676213

Kim, Mi Hye; Kim, Sung-Hoon; Yang, Woong Mo

2014-01-01

37

Caspase-2 Is Upregulated after Sciatic Nerve Transection and Its Inhibition Protects Dorsal Root Ganglion Neurons from Apoptosis after Serum Withdrawal  

PubMed Central

Sciatic nerve (SN) transection-induced apoptosis of dorsal root ganglion neurons (DRGN) is one factor determining the efficacy of peripheral axonal regeneration and the return of sensation. Here, we tested the hypothesis that caspase-2 (CASP2) orchestrates apoptosis of axotomised DRGN both in vivo and in vitro by disrupting the local neurotrophic supply to DRGN. We observed significantly elevated levels of cleaved CASP2 (C-CASP2), compared to cleaved caspase-3 (C-CASP3), within TUNEL+DRGN and DRG glia (satellite and Schwann cells) after SN transection. A serum withdrawal cell culture model, which induced 40% apoptotic death in DRGN and 60% in glia, was used to model DRGN loss after neurotrophic factor withdrawal. Elevated C-CASP2 and TUNEL were observed in both DRGN and DRG glia, with C-CASP2 localisation shifting from the cytosol to the nucleus, a required step for induction of direct CASP2-mediated apoptosis. Furthermore, siRNA-mediated downregulation of CASP2 protected 50% of DRGN from apoptosis after serum withdrawal, while downregulation of CASP3 had no effect on DRGN or DRG glia survival. We conclude that CASP2 orchestrates the death of SN-axotomised DRGN directly and also indirectly through loss of DRG glia and their local neurotrophic factor support. Accordingly, inhibiting CASP2 expression is a potential therapy for improving both the SN regeneration response and peripheral sensory recovery. PMID:23451279

Vigneswara, Vasanthy; Berry, Martin

2013-01-01

38

Exposure to Apoptotic Activated CD4+ T Cells Induces Maturation and APOBEC3G- Mediated Inhibition of HIV1 Infection in Dendritic Cells  

Microsoft Academic Search

Dendritic cells (DCs) are activated by signaling via pathogen-specific receptors or exposure to inflammatory mediators. Here we show that co-culturing DCs with apoptotic HIV-infected activated CD4+ T cells (ApoInf) or apoptotic uninfected activated CD4+ T cells (ApoAct) induced expression of co-stimulatory molecules and cytokine release. In addition, we measured a reduced HIV infection rate in DCs after co-culture with ApoAct.

Venkatramanan Mohanram; Ulrika Johansson; Annette E. Sköld; Joshua Fink; Sushil Kumar Pathak; Barbro Mäkitalo; Lilian Walther-Jallow; Anna-Lena Spetz

2011-01-01

39

Notch1 signaling promotes survival of glioblastoma cells via EGFR-mediated induction of anti-apoptotic Mcl-1.  

PubMed

The Notch1-mediated signaling pathway has a central role in the maintenance of neural stem cells and contributes to growth and progression of glioblastomas, the most frequent malignant brain tumors in adults. Here, we demonstrate that the Notch1 receptor promotes survival of glioblastoma cells by regulation of the anti-apoptotic Mcl-1 protein. Notch1-dependent regulation of Mcl-1 occurs cell type dependent at a transcriptional or post-translational level and is mediated by the induction of epidermal growth factor receptor (EGFR). Inhibition of the Notch1 pathway overcomes apoptosis resistance and sensitizes glioblastoma cells to apoptosis induced by ionizing radiation, the death ligand TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) or the Bcl-2/Bcl-XL inhibitor ABT-737. In conclusion, targeting Notch1 might represent a promising novel strategy in the treatment of glioblastomas. PMID:22249262

Fassl, A; Tagscherer, K E; Richter, J; Berriel Diaz, M; Alcantara Llaguno, S R; Campos, B; Kopitz, J; Herold-Mende, C; Herzig, S; Schmidt, M H H; Parada, L F; Wiestler, O D; Roth, W

2012-11-01

40

Integrin ?PS3/??-mediated phagocytosis of apoptotic cells and bacteria in Drosophila.  

PubMed

Integrins exert a variety of cellular functions as heterodimers of two transmembrane subunits named ? and ?. Integrin ??, a ?-subunit of Drosophila integrin, is involved in the phagocytosis of apoptotic cells and bacteria. Here, we searched for an ?-subunit that forms a complex and cooperates with ??. Examinations of RNAi-treated animals suggested that ?PS3, but not any of four other ?-subunits, is required for the effective phagocytosis of apoptotic cells in Drosophila embryos. The mutation of ?PS3-encoding scb, deficiency, insertion of P-element, or alteration of nucleotide sequences, brought about a reduction in the level of phagocytosis. The defect in phagocytosis by deficiency was reverted by the forced expression of scb. Furthermore, flies in which the expression of both ?PS3 and ?? was inhibited by RNAi showed a level of phagocytosis almost equal to that observed in flies with RNAi for either subunit alone. A loss of ?PS3 also decreased the activity of larval hemocytes in the phagocytosis of Staphylococcus aureus. Finally, a co-immunoprecipitation analysis using a Drosophila cell line treated with a chemical cross-linker suggested a physical association between ?PS3 and ??. These results collectively indicated that integrin ?PS3/?? serves as a receptor in the phagocytosis of apoptotic cells and bacteria by Drosophila phagocytes. PMID:23426364

Nonaka, Saori; Nagaosa, Kaz; Mori, Toshinobu; Shiratsuchi, Akiko; Nakanishi, Yoshinobu

2013-04-12

41

Cracking the cytotoxicity code: apoptotic induction of 10-acetylirciformonin B is mediated through ROS generation and mitochondrial dysfunction.  

PubMed

A marine furanoterpenoid derivative, 10-acetylirciformonin B (10AB), was found to inhibit the proliferation of leukemia, hepatoma, and colon cancer cell lines, with selective and significant potency against leukemia cells. It induced DNA damage and apoptosis in leukemia HL 60 cells. To fully understand the mechanism behind the 10AB apoptotic induction against HL 60 cells, we extended our previous findings and further explored the precise molecular targets of 10AB. We found that the use of 10AB increased apoptosis by 8.9%-87.6% and caused disruption of mitochondrial membrane potential (MMP) by 15.2%-95.2% in a dose-dependent manner, as demonstrated by annexin-V/PI and JC-1 staining assays, respectively. Moreover, our findings indicated that the pretreatment of HL 60 cells with N-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger, diminished MMP disruption and apoptosis induced by 10AB, suggesting that ROS overproduction plays a crucial rule in the cytotoxic activity of 10AB. The results of a cell-free system assay indicated that 10AB could act as a topoisomerase catalytic inhibitor through the inhibition of topoisomerase II?. On the protein level, the expression of the anti-apoptotic proteins Bcl-xL and Bcl-2, caspase inhibitors XIAP and survivin, as well as hexokinase II were inhibited by the use of 10AB. On the other hand, the expression of the pro-apoptotic protein Bax was increased after 10AB treatment. Taken together, our results suggest that 10AB-induced apoptosis is mediated through the overproduction of ROS and the disruption of mitochondrial metabolism. PMID:24857964

Shih, Huei-Chuan; El-Shazly, Mohamed; Juan, Yung-Shun; Chang, Chao-Yuan; Su, Jui-Hsin; Chen, Yu-Cheng; Shih, Shou-Ping; Chen, Huei-Mei; Wu, Yang-Chang; Lu, Mei-Chin

2014-05-01

42

Cracking the Cytotoxicity Code: Apoptotic Induction of 10-Acetylirciformonin B is Mediated through ROS Generation and Mitochondrial Dysfunction  

PubMed Central

A marine furanoterpenoid derivative, 10-acetylirciformonin B (10AB), was found to inhibit the proliferation of leukemia, hepatoma, and colon cancer cell lines, with selective and significant potency against leukemia cells. It induced DNA damage and apoptosis in leukemia HL 60 cells. To fully understand the mechanism behind the 10AB apoptotic induction against HL 60 cells, we extended our previous findings and further explored the precise molecular targets of 10AB. We found that the use of 10AB increased apoptosis by 8.9%–87.6% and caused disruption of mitochondrial membrane potential (MMP) by 15.2%–95.2% in a dose-dependent manner, as demonstrated by annexin-V/PI and JC-1 staining assays, respectively. Moreover, our findings indicated that the pretreatment of HL 60 cells with N-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger, diminished MMP disruption and apoptosis induced by 10AB, suggesting that ROS overproduction plays a crucial rule in the cytotoxic activity of 10AB. The results of a cell-free system assay indicated that 10AB could act as a topoisomerase catalytic inhibitor through the inhibition of topoisomerase II?. On the protein level, the expression of the anti-apoptotic proteins Bcl-xL and Bcl-2, caspase inhibitors XIAP and survivin, as well as hexokinase II were inhibited by the use of 10AB. On the other hand, the expression of the pro-apoptotic protein Bax was increased after 10AB treatment. Taken together, our results suggest that 10AB-induced apoptosis is mediated through the overproduction of ROS and the disruption of mitochondrial metabolism. PMID:24857964

Shih, Huei-Chuan; El-Shazly, Mohamed; Juan, Yung-Shun; Chang, Chao-Yuan; Su, Jui-Hsin; Chen, Yu-Cheng; Shih, Shou-Ping; Chen, Huei-Mei; Wu, Yang-Chang; Lu, Mei-Chin

2014-01-01

43

Peptidoglycan from Staphylococcus aureus has an anti-apoptotic effect in HaCaT keratinocytes mediated by the production of the cellular inhibitor of apoptosis protein-2.  

PubMed

Colonization of epithelium by microorganisms leads to inflammatory responses. In some cases an anti-apoptotic response involving the cellular inhibitor of apoptosis protein-2 (cIAP-2) also occurs. Although strong expression of cIAP-2 has been observed in lesional skin from psoriatic patients and in HaCaT keratinocytes treated with peptidoglycan (PGN) from Staphylococcus aureus, anti-apoptotic responses induced in the skin by cIAP-2 have seldom been studied. In this study, the effect of PGN on TNF-?-induced apoptotic HaCaT keratinocytes was assessed. Morphological analysis, quantification of cells with DNA fragmentation and active caspase-3 detection was performed to assess apoptotic cell death. Greater LL-37 and cIAP-2 production was found in keratinocytes stimulated with PGN than in non-treated cells (P < 0.05). In comparison with cells treated with TNF-? only, a significant reduction in apoptotic cell death was observed when HaCaT were pretreated with PGN before inducing apoptosis with TNF-? (P < 0.05). In addition, an inhibitor of cIAP-2 activity (LCL161) stopped the PGN effect. These findings show that PGN from S. aureus has an anti-apoptotic effect in keratinocytes mediated by cIAP-2 production, suggesting that this anti-apoptotic activity could favor proliferation of keratinocytes in psoriasis. PMID:24372854

Vázquez-Sánchez, Ernesto Antonio; Rodríguez-Romero, Magdalena; Sánchez-Torres, Luvia Enid; Rodríguez-Martínez, Sandra; Cancino-Diaz, Juan Carlos; Rodríguez-Cortes, Octavio; García-López, Eduardo Stalin; Cancino-Diaz, Mario Eugenio

2014-02-01

44

TGF?1 increases microglia-mediated engulfment of apoptotic cells via upregulation of the milk fat globule-EGF factor 8.  

PubMed

Milk fat globule-epidermal growth factor-factor 8 (Mfge8) has been described as an essential molecule during microglia-mediated clearance of apoptotic cells via binding to phosphatidylserine residues and subsequent phagocytosis. Impaired uptake of apoptotic cells by microglia results in prolonged inflammatory responses and damage of healthy cells. Although the mechanisms of Mfge8-mediated engulfment of apoptotic cells are well understood, endogenous or exogenous factors that regulate Mfge8 expression remain elusive. Here, we describe that TGF?1 increases the expression of Mfge8 and enhances the engulfment of apoptotic cells by primary mouse microglia in a Mfge8-dependent manner. Further, apoptotic cells are capable of increasing microglial TGF? expression and release and shift the microglia phenotype toward alternative activation. Moreover, we provide evidence that Mfge8 expression is differentially regulated in microglia after classical and alternative activation and that Mfge8 is not able to exert direct antiinflammatory effects on LPS-treated primary microglia. Together, these results underline the importance of TGF?1 as a regulatory factor for microglia and suggest that increased TGF?1 expression in models of neurodegeneration might be involved in clearance of apoptotic cells via regulation of Mfge8 expression. GLIA 2015;63:142-153. PMID:25130376

Spittau, Björn; Rilka, Jennifer; Steinfath, Elsa; Zöller, Tanja; Krieglstein, Kerstin

2015-01-01

45

A knockout of the caspase 2 gene produces increased resistance of the nigrostriatal dopaminergic pathway to MPTP-induced toxicity  

PubMed Central

This study investigated the effect of a knockout of the caspase 2 gene on the sensitivity of murine nigral dopaminergic neurons to 1-methyl-4-1,2,3,6-tetrahydropyridine (MPTP)-induced toxicity. Female wild type (WT), heterozygous caspase 2 NL (HET) and homozygous caspase 2 null (NL) mice were treated with cumulative dosages of 0, 10, 15 or 20 mg/kg MPTP free base. Without MPTP treatment, one week later dopamine (DA) levels were not significantly different in HET or NL versus WT mice. Twenty mg/kg MPTP reduced striatal DA in WT and HET (p<0.01) but not NL mice. This same MPTP dosage regimen also induced a significantly greater decrease in tyrosine hydroxylase immunopositive (TH+) protein in striata of WT compared to NL mice (p<0.001). Subsequently, WT and NL mice were treated daily with 20 mg/kg MPTP for 3 days and 25 mg/kg MPTP for 2 additional days, and TH+ neurons in the substantia nigra (SN) were estimated using unbiased stereology. When compared to untreated WT, the numbers of TH+ neurons were significantly lower in the SN of untreated NL mice (p<0.05). Treatment with the MPTP regimen significantly reduced TH+ neurons in WT mice but not NL mice. In primary mesencephalic cultures both the cell bodies and the neuronal processes of TH immunopositive (TH+) neurons from NL embryos were significantly (p<0.001) more resistant to 10µM MPP+ compared to WT. Following MPP+ treatment, features of apoptotic cell death were also significantly (p<0.001) more prevalent in nuclei of TH+ neurons in cultures prepared from WT versus NL mouse pups. These results suggest that caspase 2 may play a role in modulating the MPTP-induced damage to the nigrostriatal dopaminergic system. PMID:21419766

Tiwari, Meenakshi; Herman, Brian; Morgan, William W.

2011-01-01

46

MPYS, a Novel Membrane Tetraspanner, Is Associated with Major Histocompatibility Complex Class II and Mediates Transduction of Apoptotic Signals ? †  

PubMed Central

Although the best-defined function of type II major histocompatibility complex (MHC-II) is presentation of antigenic peptides to T lymphocytes, these molecules can also transduce signals leading alternatively to cell activation or apoptotic death. MHC-II is a heterodimer of two transmembrane proteins, each containing a short cytoplasmic tail that is dispensable for transduction of death signals. This suggests the function of an undefined MHC-II-associated transducer in signaling the death response. Here we describe a novel plasma membrane tetraspanner (MPYS) that is associated with MHC-II and mediates its transduction of death signals. MPYS is unusual among tetraspanners in containing an extended C-terminal cytoplasmic tail (?140 amino acids) with multiple embedded signaling motifs. MPYS is tyrosine phosphorylated upon MHC-II aggregation and associates with inositol lipid and tyrosine phosphatases. Finally, MHC class II-mediated cell death signaling requires MPYS-dependent activation of the extracellular signal-regulated kinase signaling pathway. PMID:18559423

Jin, Lei; Waterman, Paul M.; Jonscher, Karen R.; Short, Cindy M.; Reisdorph, Nichole A.; Cambier, John C.

2008-01-01

47

Reduced IRE1? mediates apoptotic cell death by disrupting calcium homeostasis via the InsP3 receptor  

PubMed Central

The endoplasmic reticulum (ER) is not only a home for folding and posttranslational modifications of secretory proteins but also a reservoir for intracellular Ca2+. Perturbation of ER homeostasis contributes to the pathogenesis of various neurodegenerative diseases, such as Alzheimer's and Parkinson diseases. One key regulator that underlies cell survival and Ca2+ homeostasis during ER stress responses is inositol-requiring enzyme 1? (IRE1?). Despite extensive studies on this ER membrane-associated protein, little is known about the molecular mechanisms by which excessive ER stress triggers cell death and Ca2+ dysregulation via the IRE1?-dependent signaling pathway. In this study, we show that inactivation of IRE1? by RNA interference increases cytosolic Ca2+ concentration in SH-SY5Y cells, leading to cell death. This dysregulation is caused by an accelerated ER-to-cytosolic efflux of Ca2+ through the InsP3 receptor (InsP3R). The Ca2+ efflux in IRE1?-deficient cells correlates with dissociation of the Ca2+-binding InsP3R inhibitor CIB1 and increased complex formation of CIB1 with the pro-apoptotic kinase ASK1, which otherwise remains inactivated in the IRE1?–TRAF2–ASK1 complex. The increased cytosolic concentration of Ca2+ induces mitochondrial production of reactive oxygen species (ROS), in particular superoxide, resulting in severe mitochondrial abnormalities, such as fragmentation and depolarization of membrane potential. These Ca2+ dysregulation-induced mitochondrial abnormalities and cell death in IRE1?-deficient cells can be blocked by depleting ROS or inhibiting Ca2+ influx into the mitochondria. These results demonstrate the importance of IRE1? in Ca2+ homeostasis and cell survival during ER stress and reveal a previously unknown Ca2+-mediated cell death signaling between the IRE1?–InsP3R pathway in the ER and the redox-dependent apoptotic pathway in the mitochondrion. PMID:24743743

Son, S M; Byun, J; Roh, S-E; Kim, S J; Mook-Jung, I

2014-01-01

48

Elevated Levels of Uterine Anti-Apoptotic Signaling May Activate NFKB and Potentially Confer Resistance to Caspase 3-Mediated Apoptotic Cell Death During Pregnancy in Mice1  

PubMed Central

Preserving the uterus in a state of relative quiescence is vital to the maintenance of a successful pregnancy. Elevated cytoplasmic levels of uterine caspase 3 during pregnancy have been proposed as a potential regulator of uterine quiescence through direct targeting and disabling of the uterine contractile architecture. However, despite highly elevated levels of uterine caspase 3 during pregnancy, there is minimal evidence of apoptosis. This current study defines the mechanism whereby the pregnant uterine myocyte may harness the tocolytic activity of active caspases while avoiding apoptotic cell death. Using the pregnant mouse model, we have analyzed the uterus for changes in pro- and antiapoptotic signaling patterns associated with the advancing stages of pregnancy. Briefly, we have found that members of the IAP family, such as SURVIVIN and XIAP, and the Bcl2 family members, such as MCL1, are elevated in the uterine myocyte during late gestation. The IAP family members are the only endogenous inhibitors of active caspase 3, and MCL1 limits activation of caspase 3 by suppressing proapoptotic signaling. Elevated XIAP levels partner with SURVIVIN, resulting in increased levels of the antiapoptotic MCL1 via NFKB activation; these together have the potential to limit both the activity and level of active caspase 3 in the pregnant uterus as term approaches. We propose that modification of these antiapoptotic signaling partners allows the pregnant uterus to escape the apoptotic action of elevated active caspase 3 levels but also functions to limit the levels of active uterine caspase 3 near term. PMID:21566000

Jeyasuria, Pancharatnam; Subedi, Kalpana; Suresh, Arvind; Condon, Jennifer C.

2011-01-01

49

CREB mediates the insulinotropic and anti-apoptotic effects of GLP-1 signaling in adult mouse ?-cells  

PubMed Central

Objective Glucagon-like peptide-1 (GLP-1) plays a major role in pancreatic ?-cell function and survival by increasing cytoplasmic cAMP levels, which are thought to affect transcription through activation of the basic leucine zipper (bZIP) transcription factor CREB. Here, we test CREB function in the adult ?-cell through inducible gene deletion. Methods We employed cell type-specific and inducible gene ablation to determine CREB function in pancreatic ?-cells in mice. Results By ablating CREB acutely in mature ?-cells in tamoxifen-treated CrebloxP/loxP;Pdx1-CreERT2 mice, we show that CREB has little impact on ?-cell turnover, in contrast to what had been postulated previously. Rather, CREB is required for GLP-1 to elicit its full effects on stimulating glucose-induced insulin secretion and protection from cytokine-induced apoptosis. Mechanistically, we find that CREB regulates expression of the pro-apoptotic gene p21 (Cdkn1a) in ?-cells, thus demonstrating that CREB is essential to mediating this critical aspect of GLP-1 receptor signaling. Conclusions In sum, our studies using conditional gene deletion put into question current notions about the importance of CREB in regulating ?-cell function and mass. However, we reveal an important role for CREB in the ?-cell response to GLP-1 receptor signaling, further validating CREB as a therapeutic target for diabetes. PMID:25379405

Shin, Soona; Le Lay, John; Everett, Logan J.; Gupta, Rana; Rafiq, Kiran; Kaestner, Klaus H.

2014-01-01

50

Critical roles of cellular glutathione homeostasis and jnk activation in andrographolide-mediated apoptotic cell death in human hepatoma cells.  

PubMed

Andrographolide (ANDRO), isolated from the traditional herbal medicine Andrographis paniculata, is reported to have the potential therapeutic effects for hepatocellular carcinoma (HCC) in our previous reports. Here, we investigated the mechanism of ANDRO-mediated apoptotic cell death, focusing on the involvement of cellular reduced glutathione (GSH) homeostasis and c-Jun NH(2) -Terminal kinase (JNK). Buthionine sulfoximine (BSO), an inhibitor of cellular GSH biosynthesis, significantly augmented ANDRO-induced cytotoxicity in hepatoma Hep3B and HepG2 cells. BSO depleted cellular GSH, and augmented ANDRO-induced apoptosis, inhibition of colony formation and JNK activation in Hep3B cells. All these effects could be reversed by GSH monoethyl ester (GSH.EE), whose deacetylation replenishes cellular GSH. BSO also augmented ANDRO-induced activation of apoptosis signal-regulating kinase 1 (ASK1), mitogen-activated protein kinase kinase-4 (MKK4) and c-Jun, which are all up-stream or down-stream signals of JNK. Further results showed that JNK inhibitor SP600125 and 420116 both reversed ANDRO-induced cytotoxicity, and SP600125 also decreased ANDRO-increased intracellular GSH and GCL activity. Finally, we showed that in nude mice bearing xenografted Hep3B tumors, BSO improved the inhibition of tumor growth by ANDRO. Taken together, our results suggest that there is a crosstalk between JNK activation and cellular GSH homeostasis, and ANDRO targets this to induce cytotoxicity in hepatoma cells. PMID:21319226

Ji, Lili; Shen, Kaikai; Jiang, Ping; Morahan, Grant; Wang, Zhengtao

2011-08-01

51

IgG Autoantibodies Against Deposited C3 Inhibit Macrophage-Mediated Apoptotic Cell Engulfment in Systemic Autoimmunity1  

PubMed Central

Defective clearance of apoptotic cells has been shown in systemic lupus erythematosus (SLE) and is postulated to enhance autoimmune responses by increasing access to intracellular autoantigens. Until now, research has emphasized inherited rather than acquired impairment of apoptotic cell engulfment in the pathogenesis of SLE. Here, we confirm previous results that efficient removal of apoptotic cells (efferocytosis) is bolstered in the presence of wild type mouse serum, through the C3 deposition on the apoptotic cell surface. In contrast, sera from three mouse models of SLE, MerKD, MRLlpr and NZBWF1, did not support and in fact actively inhibited apoptotic cell uptake. IgG autoantibodies were responsible for the inhibition, through the blockade of C3 recognition by macrophages. Consistent with this, IgG removal reversed the inhibitory activity within autoimmune serum and purified autoimmune IgG blocked both the detection of C3 on apoptotic cells and C3-dependent efferocytosis. Sera from SLE patients demonstrated elevated anti-C3b IgG that blocked detection of C3 on apoptotic cells, activity that was not found in healthy controls or patients with rheumatoid arthritis, nor in mice prior to the onset of autoimmunity. We propose that the suppression of apoptotic cell disposal by antibodies against deposited C3 may contribute to increasing severity and/or exacerbations in SLE. PMID:21813769

Kenyon, Karla D.; Cole, Caroline; Crawford, Fran; Kappler, John W.; Thurman, Joshua M.; Bratton, Donna L.; Boackle, Susan A.; Henson, Peter M.

2011-01-01

52

Aplidin™ induces the mitochondrial apoptotic pathway via oxidative stress-mediated JNK and p38 activation and protein kinase C ?  

Microsoft Academic Search

Aplidin™, a new antitumoural drug presently in phase II clinical trials, has shown both in vitro and in vivo activity against human cancer cells. Aplidin™ effectively inhibits cell viability by triggering a canonical apoptotic program resulting in alterations in cell morphology, caspase activation, and chromatin fragmentation. Pro-apoptotic concentrations of Aplidin™ induce early oxidative stress, which results in a rapid and

Luis F García-Fernández; Alejandro Losada; Victoria Alcaide; Alberto M Álvarez; Ana Cuadrado; Laura González; Keiko Nakayama; Keiichi I Nakayama; José María Fernández-Sousa; Alberto Muñoz; José María Sánchez-Puelles

2002-01-01

53

Loss of caspase-2 augments lymphomagenesis and enhances genomic instability in Atm-deficient mice.  

PubMed

Caspase-2, the most evolutionarily conserved member of the caspase family, has been shown to be involved in apoptosis induced by various stimuli. Our recent work indicates that caspase-2 has putative functions in tumor suppression and protection against cellular stress. As such, the loss of caspase-2 enhances lymphomagenesis in Eµ-Myc transgenic mice, and caspase-2 KO (Casp2(-/-)) mice show characteristics of premature aging. However, the extent and specificity of caspase-2 function in tumor suppression is currently unclear. To further investigate this, ataxia telangiectasia mutated KO (Atm(-/-)) mice, which develop spontaneous thymic lymphomas, were used to generate Atm(-/-)Casp2(-/-) mice. Initial characterization revealed that caspase-2 deficiency enhanced growth retardation and caused synthetic perinatal lethality in Atm(-/-) mice. A comparison of tumor susceptibility demonstrated that Atm(-/-)Casp2(-/-) mice developed tumors with a dramatically increased incidence compared with Atm(-/-) mice. Atm(-/-)Casp2(-/-) tumor cells displayed an increased proliferative capacity and extensive aneuploidy that coincided with elevated oxidative damage. Furthermore, splenic and thymic T cells derived from premalignant Atm(-/-)Casp2(-/-) mice also showed increased levels of aneuploidy. These observations suggest that the tumor suppressor activity of caspase-2 is linked to its function in the maintenance of genomic stability and suppression of oxidative damage. Given that ATM and caspase-2 are important components of the DNA damage and antioxidant defense systems, which are essential for the maintenance of genomic stability, these proteins may synergistically function in tumor suppression by regulating these processes. PMID:24248351

Puccini, Joseph; Shalini, Sonia; Voss, Anne K; Gatei, Magtouf; Wilson, Claire H; Hiwase, Devendra K; Lavin, Martin F; Dorstyn, Loretta; Kumar, Sharad

2013-12-01

54

Loss of caspase-2 augments lymphomagenesis and enhances genomic instability in Atm-deficient mice  

PubMed Central

Caspase-2, the most evolutionarily conserved member of the caspase family, has been shown to be involved in apoptosis induced by various stimuli. Our recent work indicates that caspase-2 has putative functions in tumor suppression and protection against cellular stress. As such, the loss of caspase-2 enhances lymphomagenesis in Eµ-Myc transgenic mice, and caspase-2 KO (Casp2?/?) mice show characteristics of premature aging. However, the extent and specificity of caspase-2 function in tumor suppression is currently unclear. To further investigate this, ataxia telangiectasia mutated KO (Atm?/?) mice, which develop spontaneous thymic lymphomas, were used to generate Atm?/?Casp2?/? mice. Initial characterization revealed that caspase-2 deficiency enhanced growth retardation and caused synthetic perinatal lethality in Atm?/? mice. A comparison of tumor susceptibility demonstrated that Atm?/?Casp2?/? mice developed tumors with a dramatically increased incidence compared with Atm?/? mice. Atm?/?Casp2?/? tumor cells displayed an increased proliferative capacity and extensive aneuploidy that coincided with elevated oxidative damage. Furthermore, splenic and thymic T cells derived from premalignant Atm?/?Casp2?/? mice also showed increased levels of aneuploidy. These observations suggest that the tumor suppressor activity of caspase-2 is linked to its function in the maintenance of genomic stability and suppression of oxidative damage. Given that ATM and caspase-2 are important components of the DNA damage and antioxidant defense systems, which are essential for the maintenance of genomic stability, these proteins may synergistically function in tumor suppression by regulating these processes. PMID:24248351

Puccini, Joseph; Shalini, Sonia; Voss, Anne K.; Gatei, Magtouf; Wilson, Claire H.; Hiwase, Devendra K.; Lavin, Martin F.; Dorstyn, Loretta; Kumar, Sharad

2013-01-01

55

Caspase-2 is involved in cell death induction by taxanes in breast cancer cells  

PubMed Central

Background We studied the role of caspase-2 in apoptosis induction by taxanes (paclitaxel, novel taxane SB-T-1216) in breast cancer cells using SK-BR-3 (nonfunctional p53, functional caspase-3) and MCF-7 (functional p53, nonfunctional caspase-3) cell lines. Results Both taxanes induced apoptosis in SK-BR-3 as well as MCF-7 cells. Caspase-2 activity in SK-BR-3 cells increased approximately 15-fold within 48 h after the application of both taxanes at the death-inducing concentration (100 nM). In MCF-7 cells, caspase-2 activity increased approximately 11-fold within 60 h after the application of taxanes (300 nM). Caspase-2 activation was confirmed by decreasing levels of procaspase-2, increasing levels of cleaved caspase-2 and the cleavage of caspase-2 substrate golgin-160. The inhibition of caspase-2 expression using siRNA increased the number of surviving cells more than 2-fold in MCF-7 cells, and at least 4-fold in SK-BR-3 cells, 96 h after the application of death-inducing concentration of taxanes. The inhibition of caspase-2 expression also resulted in decreased cleavage of initiator caspases (caspase-8, caspase-9) as well as executioner caspases (caspase-3, caspase-7) in both cell lines after the application of taxanes. In control cells, caspase-2 seemed to be mainly localized in the nucleus. After the application of taxanes, it was released from the nucleus to the cytosol, due to the long-term disintegration of the nuclear envelope, in both cell lines. Taxane application led to some formation of PIDDosome complex in both cell lines within 24 h after the application. After taxane application, p21WAF1/CIP1 expression was only induced in MCF-7 cells with functional p53. However, taxane application did not result in a significant increase of PIDD expression in either SK-BR-3 or MCF-7 cells. The inhibition of RAIDD expression using siRNA did not affect the number of surviving SK-BR-3 and MCF-7 cells after taxane application at all. Conclusion Caspase-2 is required, at least partially, for apoptosis induction by taxanes in tested breast cancer cells. We suggest that caspase-2 plays the role of an apical caspase in these cells. Caspase-2 seems to be activated via other mechanism than PIDDosome formation. It follows the release of caspase-2 from the nucleus to the cytosol. PMID:23672670

2013-01-01

56

Macrophage ADAM17 deficiency augments CD36-dependent apoptotic cell uptake and the linked anti-inflammatory phenotype.  

E-print Network

??Rationale: Phagocytosis of apoptotic cells (efferocytosis) is mediated by apoptotic cell receptors and is essential for resolution of inflammation. In chronic inflammation, apoptotic cell clearance… (more)

Driscoll, Will

2013-01-01

57

Estrogen receptor-alpha 36 mediates the anti-apoptotic effect of estradiol in triple negative breast cancer cells via a membrane-associated mechanism.  

PubMed

17?-Estradiol can promote the growth and development of several estrogen receptor (ER)-negative breast cancers. The effects are rapid and non-genomic, suggesting that a membrane-associated ER is involved. ER?36 has been shown to mediate rapid, non-genomic, membrane-associated effects of 17?-estradiol in several cancer cell lines, including triple negative HCC38 breast cancer cells. Moreover, the effect is anti-apoptotic. The aim of this study was to determine if ER?36 mediates this anti-apoptotic effect, and to elucidate the mechanism involved. Taxol was used to induce apoptosis in HCC38 cells, and the effect of 17?-estradiol pre-treatment was determined. Antibodies to ER?36, signal pathway inhibitors, ER?36 deletion mutants, and ER?36-silencing were used prior to these treatments to determine the role of ER?36 in these effects and to determine which signaling molecules were involved. We found that the anti-apoptotic effect of 17?-estradiol in HCC38 breast cancer cells is in fact mediated by membrane-associated ER?36. We also showed that this signaling occurs through a pathway that requires PLD, LPA, and PI3K; G?s and calcium signaling may also be involved. In addition, dynamic palmitoylation is required for the membrane-associated effect of 17?-estradiol. Exon 9 of ER?36, a unique exon to ER?36 not found in other identified splice variants of ER? with previously unknown function, is necessary for these effects. This study provides a working model for a mechanism by which estradiol promotes anti-apoptosis through membrane-associated ER?36, suggesting that ER?36 may be a potential membrane target for drug design against breast cancer, particularly triple negative breast cancer. PMID:25108195

Chaudhri, Reyhaan A; Hadadi, Agreen; Lobachev, Kirill S; Schwartz, Zvi; Boyan, Barbara D

2014-11-01

58

The roles of JNK and apoptotic signaling pathways in PEITC-mediated responses in human HT29 colon adenocarcinoma cells  

Microsoft Academic Search

Abstract Phenethyl isothiocyanate (PEITC) is a ,potential chemopreventive ,agent that is present naturally in widely consumed vegetables, especially in watercress. It has been extensively investigated for its anticancer activities against lung, forestomach and esophageal tumorigenesis. Here we investigated the pro-apoptotic effect of PEITC in HT-

Rong Hu; Bok Ryang Kim; Chi Chen; Vidya Hebbar; A.-N. Tony Kong

2003-01-01

59

Impaired Clearance of Early Apoptotic Cells Mediated by Inhibitory IgG Antibodies in Patients with Primary Sjögren's Syndrome  

PubMed Central

Objectives Deficient efferocytosis (i.e. phagocytic clearance of apoptotic cells) has been frequently reported in systemic lupus erythematosus (SLE). Todate, patients with primary Sjögren's syndrome (SS) have not been assessed for phagocytosis of apoptotic cells (ApoCell-phagocytosis) and of particulate targets (microbeads, MB-phagocytosis). Design ApoCell-phagocytosis and MB-phagocytosis were comparatively assessed by flow cytometry in peripheral blood specimens and monocyte-derived macrophage (MDM) preparations from healthy blood donors (HBD) and consecutive SS, SLE and rheumatoid arthritis (RA) patients. Cross-admixture ApoCell-phagocytosis experiments were also performed using phagocytes from HBD or patients, and apoptotic cells pretreated with whole sera or purified serum IgG derived from patients or HBD. Results Compared to HBD, approximately half of SS and SLE patients studied (but not RA) manifested significantly reduced ApoCell-phagocytosis (p<0.001) and MB-phagocytosis (p<0.003) by blood-borne phagocytes that correlated inversely with disease activity (p?0.004). In cross-admixture assays, healthy monocytes showed significantly reduced ApoCell-phagocytosis when fed with apoptotic cells that were pretreated with sera or purified serum IgG preparations from SS and SLE patients (p<0.0001, compared to those from HBD or RA). Such aberrant effect of the SS and SLE sera and IgG preparations correlated linearly with their content of IgG antibodies against apoptotic cells (p?0.0001). Phagocytic dysfunction maybe also present in certain SS and SLE patients, as supported by deficient capacity of MDM for ApoCell-phagocytosis and MB-phagocytosis under patients' serum-free conditions. Conclusion Similarly to SLE, efferocytosis is frequently impaired in SS and is primarily due to the presence of inhibitory IgG anti-ApoCell antibodies and secondarily to phagocytes' dysfunction. PMID:25396412

Manoussakis, Menelaos N.; Fragoulis, George E.; Vakrakou, Aigli G.; Moutsopoulos, Haralampos M.

2014-01-01

60

Regulation of CRADD-caspase 2 cascade by histone deacetylase 1 in gastric cancer  

PubMed Central

CRADD, also referred as RAIDD, is an adaptor protein that could interact with both caspase 2 and RIP that can promote apoptosis once activated. HDAC inhibitors are promising anti-cancer agents by inducing apoptosis of various cancer cells. In this study, we found that CRADD was induced by TSA (trichostatin A) to activate caspase 2-dependent apoptosis. CRADD was downregulated in gastric cancer and the restoration of its expression suppressed the viability of gastric cancer cells. HDAC1 was responsible for its downregulation in gastric cancer since HDAC1 siRNA upregulated CRADD expression and HDAC1 directly bound to the promoter of CRADD. Therefore, the high expression of HDAC1 can downregulate CRADD to confer gastric cancer cells the resistance to caspase 2-dependent apoptosis. HDAC inhibitors, potential anti-cancer drugs under investigation, can promote caspase 2-dependent apoptosis by inducing the expression of CRADD. PMID:25360218

Shen, Qi; Tang, Wanfen; Sun, Jie; Feng, Lifeng; Jin, Hongchuan; Wang, Xian

2014-01-01

61

Tip60 HAT Activity Mediates APP Induced Lethality and Apoptotic Cell Death in the CNS of a Drosophila Alzheimer's Disease Model  

PubMed Central

Histone acetylation of chromatin promotes dynamic transcriptional responses in neurons that influence neuroplasticity critical for cognitive ability. It has been demonstrated that Tip60 histone acetyltransferase (HAT) activity is involved in the transcriptional regulation of genes enriched for neuronal function as well as the control of synaptic plasticity. Accordingly, Tip60 has been implicated in the neurodegenerative disorder Alzheimer's disease (AD) via transcriptional regulatory complex formation with the AD linked amyloid precursor protein (APP) intracellular domain (AICD). As such, inappropriate complex formation may contribute to AD-linked neurodegeneration by misregulation of target genes involved in neurogenesis; however, a direct and causative epigenetic based role for Tip60 HAT activity in this process during neuronal development in vivo remains unclear. Here, we demonstrate that nervous system specific loss of Tip60 HAT activity enhances APP mediated lethality and neuronal apoptotic cell death in the central nervous system (CNS) of a transgenic AD fly model while remarkably, overexpression of Tip60 diminishes these defects. Notably, all of these effects are dependent upon the C-terminus of APP that is required for transcriptional regulatory complex formation with Tip60. Importantly, we show that the expression of certain AD linked Tip60 gene targets critical for regulating apoptotic pathways are modified in the presence of APP. Our results are the first to demonstrate a functional interaction between Tip60 and APP in mediating nervous system development and apoptotic neuronal cell death in the CNS of an AD fly model in vivo, and support a novel neuroprotective role for Tip60 HAT activity in AD neurodegenerative pathology. PMID:22848598

Pirooznia, Sheila K.; Chiu, Kellie; Koduri, Sravanthi; Elefant, Felice

2012-01-01

62

Biliverdin reductase/bilirubin mediates the anti-apoptotic effect of hypoxia in pulmonary arterial smooth muscle cells through ERK1/2 pathway  

SciTech Connect

Inhibition of pulmonary arterial smooth muscle cell (PASMC) apoptosis induced by hypoxia plays an important role in pulmonary arterial remodeling leading to aggravate hypoxic pulmonary arterial hypertension. However, the mechanisms of hypoxia acting on PASMC apoptosis remain exclusive. Biliverdin reductase (BVR) has many essential biologic roles in physiological and pathological processes. Nevertheless, it is unclear whether the hypoxia-induced inhibition on PASMC apoptosis is mediated by BVR. In the present work, we found BVR majorly localized in PASMCs and was up-regulated in levels of protein and mRNA by hypoxia. Then we studied the contribution of BVR to anti-apoptotic response of hypoxia in PASMCs. Our results showed that siBVR, blocking generation of bilirubin, reversed the effect of hypoxia on enhancing cell survival and apoptotic protein (Bcl-2, procasepase-9, procasepase-3) expression, preventing nuclear shrinkage, DNA fragmentation and mitochondrial depolarization in starved PASMCs, which were recovered by exogenous bilirubin. Moreover, the inhibitory effect of bilirubin on PASMC apoptosis under hypoxic condition was blocked by the inhibitor of ERK1/2 pathway. Taken together, our data indicate that BVR contributes to the inhibitory process of hypoxia on PASMC apoptosis, which is mediated by bilirubin through ERK1/2 pathway. Highlights: • BVR expresses in PASMC and is up-regulated by hypoxia in protein and mRNA levels. • BVR/bilirubin contribute to the inhibitive process of hypoxia on PASMC apoptosis. • Bilirubin protects PASMC from apoptosis under hypoxia via ERK1/2 pathway.

Song, Shasha [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Wang, Shuang [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Biopharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150081 (China); Ma, Jun; Yao, Lan; Xing, Hao; Zhang, Lei; Liao, Lin [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Zhu, Daling, E-mail: dalingz@yahoo.com [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Biopharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150081 (China)

2013-08-01

63

Canarypox Virus-Induced Maturation of Dendritic Cells Is Mediated by Apoptotic Cell Death and Tumor Necrosis Factor Alpha Secretion  

PubMed Central

Recombinant avipox viruses are being widely evaluated as vaccines. To address how these viruses, which replicate poorly in mammalian cells, might be immunogenic, we studied how canarypox virus (ALVAC) interacts with primate antigen-presenting dendritic cells (DCs). When human and rhesus macaque monocyte-derived DCs were exposed to recombinant ALVAC, immature DCs were most susceptible to infection. However, many of the infected cells underwent apoptotic cell death, and dying infected cells were engulfed by uninfected DCs. Furthermore, a subset of DCs matured in the ALVAC-exposed DC cultures. DC maturation coincided with tumor necrosis factor alpha (TNF-?) secretion and was significantly blocked in the presence of anti-TNF-? antibodies. Interestingly, inhibition of apoptosis with a caspase 3 inhibitor also reduced some of the maturation induced by exposure to ALVAC. This indicates that both TNF-? and the presence of primarily apoptotic cells contributed to DC maturation. Therefore, infection of immature primate DCs with ALVAC results in apoptotic death of infected cells, which can be internalized by noninfected DCs driving DC maturation in the presence of the TNF-? secreted concomitantly by exposed cells. This suggests an important mechanism that may influence the immunogenicity of avipox virus vectors. PMID:11070033

Ignatius, Ralf; Marovich, Mary; Mehlhop, Erin; Villamide, Loreley; Mahnke, Karsten; Cox, William I.; Isdell, Frank; Frankel, Sarah S.; Mascola, John R.; Steinman, Ralph M.; Pope, Melissa

2000-01-01

64

Enhancement in efferocytosis of oxidized low-density lipoprotein-induced apoptotic RAW264.7 cells through Sirt1-mediated autophagy.  

PubMed

Macrophages play a key role in atherosclerotic plaque formation and rupture. These phagocytic cells are important in the scavenging of modified lipoproteins, unwanted or dead cells and cellular debris through efferocytosis. Sirtuin1 (Sirt1), a member of the conserved sirtuin family and a key regulator in the progression of atherosclerosis exerts protective effects by regulating autophagy, a well-known survival mechanism. Inhibition of autophagy may also result in defective efferocytosis. This study aimed to investigate the effect of Sirt1 on the efferocytosis of oxidized low-density lipoprotein (ox-LDL)-induced apoptotic RAW264.7 cells through upregulation of autophagy. The apoptotic cells were incubated with high and low concentrations of Sirt1 activator resveratrol (RSV) and Sirt1 inhibitor nicotinamide (NAM) as well as autophagy inhibitor 3-methyl-adenine (3-MA) + low concentration RSV. Apoptosis was determined by flow cytometry (FCM) of annexin-V/propidium iodide (AV/PI) dual staining. Total proteins were extracted and protein levels were detected through western blot analysis. The ox-LDL uptake and efferocytosis of apoptotic RAW264.7 cells were detected by oil red O staining and calculation of the phagocytic index of apoptotic RAW264.7 cells. The expression of Sirt1 and autophagy marker proteins was simultaneously increased with the stimulation of low concentration RSV (all P<0.05) and decreased in low and high NAM groups (all P<0.05), compared with the control group. Efferocytosis was highest in the low concentration RSV group (P<0.001) and relatively lower in the low and high concentration NAM groups (both P<0.05) compared with the control group, which was similar to the change in the expression of Sirt1 and autophagy marker proteins. The results showed that the efferocytosis of apoptotic RAW264.7 cells was significantly improved with the upregulation of Sirt1?mediated autophagy. Therefore, Sirt1 may serve as a novel therapeutic target for the treatment of atherosclerosis. PMID:24378473

Liu, Baoxin; Zhang, Buchun; Guo, Rong; Li, Shuang; Xu, Yawei

2014-03-01

65

Enhancement in efferocytosis of oxidized low-density lipoprotein-induced apoptotic RAW264.7 cells through Sirt1-mediated autophagy  

PubMed Central

Macrophages play a key role in atherosclerotic plaque formation and rupture. These phagocytic cells are important in the scavenging of modified lipoproteins, unwanted or dead cells and cellular debris through efferocytosis. Sirtuin1 (Sirt1), a member of the conserved sirtuin family and a key regulator in the progression of atherosclerosis exerts protective effects by regulating autophagy, a well-known survival mechanism. Inhibition of autophagy may also result in defective efferocytosis. This study aimed to investigate the effect of Sirt1 on the efferocytosis of oxidized low-density lipoprotein (ox-LDL)-induced apoptotic RAW264.7 cells through upregulation of autophagy. The apoptotic cells were incubated with high and low concentrations of Sirt1 activator resveratrol (RSV) and Sirt1 inhibitor nicotinamide (NAM) as well as autophagy inhibitor 3-methyladenine (3-MA) + low concentration RSV. Apoptosis was determined by flow cytometry (FCM) of annexin-V/propidium iodide (AV/PI) dual staining. Total proteins were extracted and protein levels were detected through western blot analysis. The ox-LDL uptake and efferocytosis of apoptotic RAW264.7 cells were detected by oil red O staining and calculation of the phagocytic index of apoptotic RAW264.7 cells. The expression of Sirt1 and autophagy marker proteins was simultaneously increased with the stimulation of low concentration RSV (all P<0.05) and decreased in low and high NAM groups (all P<0.05), compared with the control group. Efferocytosis was highest in the low concentration RSV group (P<0.001) and relatively lower in the low and high concentration NAM groups (both P<0.05) compared with the control group, which was similar to the change in the expression of Sirt1 and autophagy marker proteins. The results showed that the efferocytosis of apoptotic RAW264.7 cells was significantly improved with the upregulation of Sirt1-mediated autophagy. Therefore, Sirt1 may serve as a novel therapeutic target for the treatment of atherosclerosis. PMID:24378473

LIU, BAOXIN; ZHANG, BUCHUN; GUO, RONG; LI, SHUANG; XU, YAWEI

2014-01-01

66

Caspase-2 Short Isoform Interacts with Membrane-Associated Cytoskeleton Proteins to Inhibit Apoptosis  

PubMed Central

Caspase-2 (casp-2) is the most conserved caspase across species, and is one of the initiator caspases activated by various stimuli. The casp-2 gene produces several alternative splicing isoforms. It is believed that the long isoform, casp-2L, promotes apoptosis, whereas the short isoform, casp-2S, inhibits apoptosis. The actual effect of casp-2S on apoptosis is still controversial, however, and the underlying mechanism for casp-2S-mediated apoptosis inhibition is unclear. Here, we analyzed the effects of casp-2S on DNA damage induced apoptosis through “gain-of-function” and “loss-of-function” strategies in ovarian cancer cell lines. We clearly demonstrated that the over-expression of casp-2S inhibited, and the knockdown of casp-2S promoted, the cisplatin-induced apoptosis of ovarian cancer cells. To explore the mechanism by which casp-2S mediates apoptosis inhibition, we analyzed the proteins which interact with casp-2S in cells by using immunoprecipitation (IP) and mass spectrometry. We have identified two cytoskeleton proteins, Fodrin and ?-Actinin 4, which interact with FLAG-tagged casp-2S in HeLa cells and confirmed this interaction through reciprocal IP. We further demonstrated that casp-2S (i) is responsible for inhibiting DNA damage-induced cytoplasmic Fodrin cleavage independent of cellular p53 status, and (ii) prevents cisplatin-induced membrane blebbing. Taken together, our data suggests that casp-2S affects cellular apoptosis through its interaction with membrane-associated cytoskeletal Fodrin protein. PMID:23840868

Han, Chunhua; Zhao, Ran; Kroger, John; Qu, Meihua; Wani, Altaf A.; Wang, Qi-En

2013-01-01

67

Do plants mediate their anti-diabetic effects through anti-oxidant and anti-apoptotic actions? an in vitro assay of 3 Indian medicinal plants  

PubMed Central

Background Both experimental and clinical studies suggest that oxidative stress plays a major role in the pathogenesis of both types of diabetes mellitus. This oxidative stress leads to ?-cell destruction by apoptosis. Hence exploring agents modulating oxidative stress is an effective strategy in the treatment of both Type I and Type II diabetes. Plants are a major source of anti-oxidants and exert protective effects against oxidative stress in biological systems. Phyllanthus emblica, Curcuma longa and Tinospora cordifolia are three such plants widely used in Ayurveda for their anti-hyperglycemic activity. Additionally their anti-oxidant properties have been scientifically validated in various experimental in vitro and in vivo models. Hence the present in vitro study was planned to assess whether the anti-hyperglycemic effects of the hydro-alcoholic extracts of Phyllanthus emblica (Pe) and Curcuma longa (Cl) and aqueous extract of Tinospora cordifolia (Tc) are mediated through their antioxidant and/or anti-apoptotic property in a streptozotocin induced stress model. Methods RINm5F cell line was used as a model of pancreatic ?-cells against stress induced by streptozotocin (2 mM). Non-toxic concentrations of the plant extracts were identified using MTT assay. Lipid peroxidation through MDA release, modulation of apoptosis and insulin release were the variables measured to assess streptozotocin induced damage and protection afforded by the plant extracts. Results All 3 plants extracts significantly inhibited MDA release from RIN cells indicating protective effect against STZ induced oxidative damage. They also exhibited a dose dependent anti-apoptotic effect as seen by a decrease in the sub G0 population in response to STZ. None of the plant extracts affected insulin secretion from the cells to a great extent. Conclusion The present study thus demonstrated that the protective effect of the selected medicinal plants against oxidative stress induced by STZ in vitro, which was exerted through their anti-oxidant and anti-apoptotic actions. PMID:24093976

2013-01-01

68

Mangiferin attenuates diabetic nephropathy by inhibiting oxidative stress mediated signaling cascade, TNF? related and mitochondrial dependent apoptotic pathways in streptozotocin-induced diabetic rats.  

PubMed

Oxidative stress plays a crucial role in the progression of diabetic nephropathy in hyperglycemic conditions. It has already been reported that mangiferin, a natural C-glucosyl xanthone and polyhydroxy polyphenol compound protects kidneys from diabetic nephropathy. However, little is known about the mechanism of its beneficial action in this pathophysiology. The present study, therefore, examines the detailed mechanism of the beneficial action of mangiferin on STZ-induced diabetic nephropathy in Wister rats as the working model. A significant increase in plasma glucose level, kidney to body weight ratio, glomerular hypertrophy and hydropic changes as well as enhanced nephrotoxicity related markers (BUN, plasma creatinine, uric acid and urinary albumin) were observed in the experimental animals. Furthermore, increased oxidative stress related parameters, increased ROS production and decreased the intracellular antioxidant defenses were detected in the kidney. Studies on the oxidative stress mediated signaling cascades in diabetic nephropathy demonstrated that PKC isoforms (PKC?, PKC? and PKC?), MAPKs (p38, JNK and ERK1/2), transcription factor (NF-?B) and TGF-?1 pathways were involved in this pathophysiology. Besides, TNF? was released in this hyperglycemic condition, which in turn activated caspase 8, cleaved Bid to tBid and finally the mitochorndia-dependent apoptotic pathway. In addition, oxidative stress also disturbed the proapoptotic-antiapoptotic (Bax and Bcl-2) balance and activated mitochorndia-dependent apoptosis via caspase 9, caspase 3 and PARP cleavage. Mangiferin treatment, post to hyperglycemia, successfully inhibited all of these changes and protected the cells from apoptotic death. PMID:25233093

Pal, Pabitra Bikash; Sinha, Krishnendu; Sil, Parames C

2014-01-01

69

LPS/CD14 activation triggers SGLT-1-mediated glucose uptake and cell rescue in intestinal epithelial cells via early apoptotic signals upstream of caspase-3.  

PubMed

Recent findings indicate that enhanced glucose uptake protects enterocytes from excessive apoptosis and barrier defects induced by LPS exposure. The aim of this study was to characterize the mechanisms responsible for increased sodium-dependent glucose cotransporter (SGLT)-1 activity in enterocytes challenged with LPS. SGLT-1-transfected Caco-2 cells were incubated with LPS in high glucose media. LPS increased SGLT-1 activity in dose- and time-dependent fashion, and is due to increased V(max) of the cotransporter. Elevated apical expression of SGLT-1 was also demonstrated. This LPS-induced effect was colchicine-inhibitable, suggesting microtubule-dependent translocation of SGLT-1 onto apical surface. Immunofluorescence staining showed expression of CD14 on the apical surface, but no TLR-4, on these cells. Neutralizing anti-CD14 decreased the LPS-induced upregulation of SGLT-1 activity, whereas anti-TLR-4 had no effect. Pharmacological studies indicated that signaling for LPS-mediated SGLT-1 glucose uptake depends on caspase-8 and -9 activation, but occurs independently of caspase-3. The findings describe a novel feedback mechanism within the apoptotic signaling pathway for SGLT-1-dependent cytoprotection. The observation suggests a new function for CD14 on enterocytes, involving the induction of the caspase-dependent SGLT-1 activity, which ultimately leads to cell rescue. The understanding of these signaling events may shed light on enterocytic cytoprotection and homeostasis mechanism upon pro-apoptotic challenges. PMID:16860318

Yu, Linda C H; Turner, Jerrold R; Buret, Andre G

2006-10-15

70

Correlation of glucocorticoid-mediated E4BP4 upregulation with altered expression of pro- and anti-apoptotic genes in CEM human lymphoblastic leukemia cells.  

PubMed

In Caenorhabditiselegans, motorneuron apoptosis is regulated via a ces-2-ces-1-egl-1 pathway. We tested whether human CEM lymphoblastic leukemia cells undergo apoptosis via an analogous pathway. We have previously shown that E4BP4, a ces-2 ortholog, mediates glucocorticoid (GC)-dependent upregulation of BIM, an egl-1 ortholog, in GC-sensitive CEM C7-14 cells and in CEM C1-15mE#3 cells, which are sensitized to GCs by ectopic expression of E4BP4. In the present study, we demonstrate that the human ces-1 orthologs, SLUG and SNAIL, are not significantly repressed in correlation with E4BP4 expression. Expression of E4BP4 homologs, the PAR family genes, especially HLF, encoding a known anti-apoptotic factor, was inverse to that of E4BP4 and BIM. Expression of pro- and anti-apoptotic genes in CEM cells was analyzed via an apoptosis PCR Array. We identified BIRC3 and BIM as genes whose expression paralleled that of E4BP4, while FASLG, TRAF4, BCL2A1, BCL2L1, BCL2L2 and CD40LG as genes whose expression was opposite to that of E4BP4. PMID:25101525

Beach, Jessica A; Nary, Laura J; Hovanessian, Rebeka; Medh, Rheem D

2014-08-29

71

Mangiferin Attenuates Diabetic Nephropathy by Inhibiting Oxidative Stress Mediated Signaling Cascade, TNF? Related and Mitochondrial Dependent Apoptotic Pathways in Streptozotocin-Induced Diabetic Rats  

PubMed Central

Oxidative stress plays a crucial role in the progression of diabetic nephropathy in hyperglycemic conditions. It has already been reported that mangiferin, a natural C-glucosyl xanthone and polyhydroxy polyphenol compound protects kidneys from diabetic nephropathy. However, little is known about the mechanism of its beneficial action in this pathophysiology. The present study, therefore, examines the detailed mechanism of the beneficial action of mangiferin on STZ-induced diabetic nephropathy in Wister rats as the working model. A significant increase in plasma glucose level, kidney to body weight ratio, glomerular hypertrophy and hydropic changes as well as enhanced nephrotoxicity related markers (BUN, plasma creatinine, uric acid and urinary albumin) were observed in the experimental animals. Furthermore, increased oxidative stress related parameters, increased ROS production and decreased the intracellular antioxidant defenses were detected in the kidney. Studies on the oxidative stress mediated signaling cascades in diabetic nephropathy demonstrated that PKC isoforms (PKC?, PKC? and PKC?), MAPKs (p38, JNK and ERK1/2), transcription factor (NF-?B) and TGF-?1 pathways were involved in this pathophysiology. Besides, TNF? was released in this hyperglycemic condition, which in turn activated caspase 8, cleaved Bid to tBid and finally the mitochorndia-dependent apoptotic pathway. In addition, oxidative stress also disturbed the proapoptotic-antiapoptotic (Bax and Bcl-2) balance and activated mitochorndia-dependent apoptosis via caspase 9, caspase 3 and PARP cleavage. Mangiferin treatment, post to hyperglycemia, successfully inhibited all of these changes and protected the cells from apoptotic death. PMID:25233093

Pal, Pabitra Bikash; Sinha, Krishnendu; Sil, Parames C.

2014-01-01

72

Tumour-mediated TRAIL-Receptor expression indicates effective apoptotic depletion of infiltrating CD8+ immune cells in clinical colorectal cancer.  

PubMed

Expression of apoptosis-related proteins on tumour cells has been shown in several experimental models to be an efficient mechanism for a counterattack against host anti-tumour immune responses in solid tumours. Here we provide a clinical evidence for such a tumour immune escape mechanism by demonstrating tumour to T cell-directed death receptor signalling (TRAIL/TRAIL-Receptor (TRAIL-R)) in colorectal cancer (CRC). In a series of patients with CRC and completed 5-year follow up, we investigated apoptosis and expression levels of apoptosis-related proteins. Gene and protein profiles in the tumours demonstrated intratumoural upregulated gene expression for Fas, Fas-L, TRAIL, TRAIL-R and TNF-alpha (RT-qPCR). Levels of terminaldeoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick-end labelling (TUNEL)-positive events were positively correlated with TRAIL-R1-expression on tumour infiltrating immune cells. Among the immune cells, preferentially CD8+ T cells were found to express TRAIL-R1 while serial immunostaining in the same patient tumours showed abundant apoptotic (TUNEL-positive) immune cells. In conclusion, our results in tumour samples from CRC patients suggest TRAIL-R1-mediated apoptotic depletion of infiltrating immune cells (CD8+) in response to TRAIL expression by the tumour itself. This supports the notion of an efficient escape from tumour immune response and thus evasion from the attack of activated CD8+ T cells. These findings may enhance our understanding of tumour progression in CRC and might be helpful for the development of TRAIL and its death receptor-based therapy. PMID:20580220

Grimm, Martin; Kim, Mia; Rosenwald, Andreas; von Raden, Burkhard H A; von Rahden, Burkhard; Tsaur, Igor; Meier, Eva; Heemann, Uwe; Germer, Christoph-Thomas; Gasser, Martin; Waaga-Gasser, Ana Maria

2010-08-01

73

Rac1 signaling protects monocytic AML cells expressing the MLL-AF9 oncogene from caspase-mediated apoptotic death.  

PubMed

We investigated the relevance of signaling mechanisms regulated by the Ras-homologous GTPase Rac1 for survival of acute myeloid leukemia (AML) cells harbouring the MLL-AF9 oncogene due to t(9;11)(p21;q23) translocation. Monocytic MLL-AF9 expressing cells (MM6, THP-1) were hypersensitive to both small-molecule inhibitors targeting Rac1 (EHT 1864, NSC 23766) (IC50EHT ~12.5 ?M) and lipid lowering drugs (lovastatin, atorvastatin) (IC50Lova ~7.5 ?M) as compared to acute myelocytic leukemia (NOMO-1, HL60) and T cell leukemia (Jurkat) cells (IC50EHT >30 ?M; IC50Lova >25 ?M). Hypersensitivity of monocytic cells following Rac1 inhibition resulted from caspase-driven apoptosis as shown by profound activation of caspase-8,-9,-7,-3 and substantial (~90 %) decrease in protein expression of pro-survival factors (survivin, XIAP, p-Akt). Apoptotic death was preceded by S139-posphorylation of histone H2AX (?H2AX), a prototypical surrogate marker of DNA double-strand breaks (DSBs). Taken together, abrogation of Rac1 signaling causes DSBs in acute monocytic leukemia cells harbouring the MLL-AF9 oncogene, which, together with downregulation of survivin, XIAP and p-Akt, results in massive induction of caspase-driven apoptotic death. Apparently, Rac1 signaling is required for maintaining genetic stability and maintaining survival in specific subtypes of AML. Hence, targeting of Rac1 is considered a promising novel strategy to induce lethality in MLL-AF9 expressing AML. PMID:23624644

Hinterleitner, C; Huelsenbeck, J; Henninger, C; Wartlick, F; Schorr, A; Kaina, B; Fritz, G

2013-08-01

74

Caspase-2 Maintains Bone Homeostasis by Inducing Apoptosis of Oxidatively-Damaged Osteoclasts  

PubMed Central

Osteoporosis is a silent disease, characterized by a porous bone micro-structure that enhances risk for fractures and associated disabilities. Senile, or age-related osteoporosis (SO), affects both men and women, resulting in increased morbidity and mortality. However, cellular and molecular mechanisms underlying senile osteoporosis are not fully known. Recent studies implicate the accumulation of reactive oxygen species (ROS) and increased oxidative stress as key factors in SO. Herein, we show that loss of caspase-2, a cysteine aspartate protease involved in oxidative stress-induced apoptosis, results in total body and femoral bone loss in aged mice (20% decrease in bone mineral density), and an increase in bone fragility (30% decrease in fracture strength). Importantly, we demonstrate that genetic ablation or selective inhibition of caspase-2 using zVDVAD-fmk results in increased numbers of bone-resorbing osteoclasts and enhanced tartrate-resistant acid phosphatase (TRAP) activity. Conversely, transfection of osteoclast precursors with wild type caspase-2 but not an enzymatic mutant, results in a decrease in TRAP activity. We demonstrate that caspase-2 expression is induced in osteoclasts treated with oxidants such as hydrogen peroxide and that loss of caspase-2 enhances resistance to oxidants, as measured by TRAP activity, and decreases oxidative stress-induced apoptosis of osteoclasts. Moreover, oxidative stress, quantified by assessment of the lipid peroxidation marker, 4-HNE, is increased in Casp2-/- bone, perhaps due to a decrease in antioxidant enzymes such as SOD2. Taken together, our data point to a critical and novel role for caspase-2 in maintaining bone homeostasis by modulating ROS levels and osteoclast apoptosis during conditions of enhanced oxidative stress that occur during aging. PMID:24691516

Sharma, Ramaswamy; Callaway, Danielle; Vanegas, Difernando; Bendele, Michelle; Lopez-Cruzan, Marisa; Horn, Diane; Guda, Teja; Fajardo, Roberto; Abboud-Werner, Sherry; Herman, Brian

2014-01-01

75

LBH589, a deacetylase inhibitor, induces apoptosis in adult T-cell leukemia/lymphoma cells via activation of a novel RAIDD-caspase-2 pathway  

PubMed Central

Adult T-cell leukemia/lymphoma (ATLL), an aggressive neoplasm etiologically associated with human T-lymphotropic virus type-1 (HTLV-1), is resistant to treatment. In this study, we examined the effects of a new inhibitor of deacetylase enzymes, LBH589, on ATLL cells. LBH589 effectively induced apoptosis in ATLL-related cell lines and primary ATLL cells and reduced the size of tumors inoculated in SCID mice. Analyses, including with a DNA microarray, revealed that neither death receptors nor p53 pathways contributed to the apoptosis. Instead, LBH589 activated an intrinsic pathway through the activation of caspase-2. Furthermore, small interfering RNA experiments targeting caspase-2, caspase-9, RAIDD, p53-induced protein with a death domain (PIDD) and RIPK1 (RIP) indicated that activation of RAIDD is crucial and an event initiating this pathway. In addition, LBH589 caused a marked decrease in levels of factors involved in ATLL cell proliferation and invasion such as CCR4, IL-2R and HTLV-1 HBZ-SI, a spliced form of the HTLV-1 basic zipper factor HBZ. In conclusion, we showed that LBH589 is a strong inducer of apoptosis in ATLL cells and uncovered a novel apoptotic pathway initiated by activation of RAIDD. PMID:21242994

Hasegawa, H; Yamada, Y; Tsukasaki, K; Mori, N; Tsuruda, K; Sasaki, D; Usui, T; Osaka, A; Atogami, S; Ishikawa, C; Machijima, Y; Sawada, S; Hayashi, T; Miyazaki, Y; Kamihira, S

2011-01-01

76

Nitric oxide mediates coral bleaching through an apoptotic-like cell death pathway: evidence from a model sea anemone-dinoflagellate symbiosis.  

PubMed

Coral bleaching (involving the loss of symbiotic algae from the cnidarian host) is a major threat to coral reefs and appears to be mediated at the cellular level by nitric oxide (NO). In this study, we examined the specific role of NO in bleaching using the sea anemone Aiptasia pulchella, a model system for the study of corals. Exposure of A. pulchella to high-temperature shock (26-33°C over <1 h) or an NO donor (S-nitrosoglutathione) resulted in significant increases in host caspase-like enzyme activity. These responses were reflected in the intensities of bleaching, which were significantly higher in heat- or NO-treated specimens than in controls maintained in seawater at 26°C. Notably, the inhibition of caspase-like activity prevented bleaching even in the presence of an NO donor or at elevated temperature. The additional use of an NO scavenger controlled for effects mediated by agents other than NO. We also exposed A. pulchella to a more ecologically relevant treatment (an increase from 26 to 33°C over 6-7 d). Again, host NO synthesis correlated with the activation of caspase-like enzyme activity. Therefore, we conclude that NO's involvement in cnidarian bleaching arises through the regulation of host apoptotic pathways. PMID:23934282

Hawkins, Thomas D; Bradley, Benjamin J; Davy, Simon K

2013-12-01

77

Non-conventional apoptotic response to ionising radiation mediated by N-methyl D-aspartate receptors in immature neuronal cells  

PubMed Central

During cortical development, N-methyl D-aspartate (NMDA) receptors are highly involved in neuronal maturation and synapse establishment. Their implication in the phenomenon of excitotoxicity has been extensively described in several neurodegenerative diseases due to the permissive entry of Ca2+ ions and massive accumulation in the intracellular compartment, which is highly toxic to cells. Ionising radiation is also a source of stress to the cells, particularly immature neurons. Their capacity to induce cell death has been described for various cell types either by directly damaging the DNA or indirectly through the generation of reactive oxygen species responsible for the activation of a battery of stress response effectors leading in certain cases, to cell death. In this study, in order to determine whether a link exists between NMDA receptors-mediated excitotoxicity and radiation-induced cell death, we evaluated radiation-induced cell death in vitro and in vivo in maturing neurons during the fetal period. Cell death induction was assessed by TUNEL, caspase-3 activity and DNA ladder assays, with or without the administration of dizocilpine (MK-801), a non-competitive NMDA receptor antagonist which blocks neuronal Ca2+ influx. To further investigate the possible involvement of Ca2+-dependent enzyme activation, known to occur at high Ca2+ concentrations, we examined the protective effect of a calpain inhibitor on cell death induced by radiation. Doses ranging from 0.2 to 0.6 Gy of X-rays elicited a clear apoptotic response that was prevented by the injection of dizocilpine (MK-801) or calpain inhibitor. These data demonstrate the involvement of NMDA receptors in radiation-induced neuronal death by the activation of downstream effectors, including calpain-related pathways. An increased apoptotic process elicited by radiation, occurring independently of the normal developmental scheme, may eliminate post-mitotic but immature neuronal cells and deeply impair the establishment of the neuronal network, which in the case of cortical development is critical for cognitive capacities. PMID:23338045

SAMARI, NADA; DE SAINT-GEORGES, LOUIS; PANI, GIUSEPPE; BAATOUT, SARAH; LEYNS, LUC; BENOTMANE, MOHAMMED ABDERRAFI

2013-01-01

78

Astragaloside IV inhibits doxorubicin-induced cardiomyocyte apoptosis mediated by mitochondrial apoptotic pathway via activating the PI3K/Akt pathway.  

PubMed

Doxorubicin (DOX) is a widely used antitumor drug whose application is seriously limited by its cardiotoxicity. Mitochondria-mediated cardiomyocyte apoptosis plays a critical role in DOX-induced cardiotoxicity (DIC). The aim of the present study was to investigate the protective effect of astragaloside IV (3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-cycloastragenol, AS-IV), a pure saponin isolated from Astragalus membranaceus, against DOX-induced cardiomyocyte apoptosis in primary cultured neonatal rat cardiomyocytes. Immunocytochemistry and Microculture Tetrazolium (MTT) assays showed that AS-IV significantly reduced DOX-induced cardiomyocyte loss. Additionally, AS-IV markedly ameliorated DOX-caused cardiomyocyte dysfunction via restoring the beating cell ratio and beating rate in cardiomyocytes. Furthermore, AS-IV substantially reduced the mitochondrial reactive oxygen species (ROS) production and lactate dehydrogenase (LDH), creatine kinase-MB isoenzyme (CK-MB) and cytochrome c (CytC) release, and restored the reduced ATP level, succinate dehydrogenase (SDH) and ATP synthase activities induced by DOX, suggesting that AS-IV significantly attenuated DOX-induced mitochondrial damage and dysfunction. It was further observed that DOX-induced cardiomyocyte apoptosis, as qualitatively evaluated by Hoechst 33258 staining and accurately quantified by flow cytometry, was markedly inhibited by AS-IV. Western blot analysis manifested that AS-IV significantly inhibited the activation of mitochondrial apoptotic pathway (MAP) via inducing the phosphorylation of Akt and Bad. Furthermore, phosphatidylinositol 3-kinase (PI3K) inhibitor 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) remarkably inhibited the anti-apoptotic effect of AS-IV. Moreover, AS-IV didn't compromise the antitumor activity of DOX. Taken together, our findings indicate that AS-IV ameliorates DIC, and this beneficial effect appears to be dependent on the activation of the PI3K/Akt pathway. Thus, AS-IV may hold promise as an efficient cardioprotective agent against DIC. PMID:24390491

Jia, Yuanyuan; Zuo, Daiying; Li, Zengqiang; Liu, Hanmo; Dai, Zhengning; Cai, Jiayi; Pang, Lili; Wu, Yingliang

2014-01-01

79

Temozolomide-mediated DNA methylation in human myeloid precursor cells:differential involvement of intrinsic and extrinsic apoptotic pathways  

PubMed Central

Purpose An understanding of how hematopoietic cells respond to therapy that causes myelosuppression will help develop approaches to prevent this potentially life-threatening toxicity. The goal of this study was to determine how human myeloid precursor cells (MP) respond to temozolomide (TMZ)-induced DNA damage. Experimental Design We developed an ex vivo primary human MP cells model system to investigate the involvement of cell-death pathways using a known myelosuppressive regimen of O6-benzylguanine (6BG) and TMZ. Results Exposure to 6BG/TMZ led to increases in p53, p21, ?-H2AX, and mitochondrial DNA damage. Increases in mitochondrial membrane depolarization correlated with increased caspase-9 and caspase-3 activities following 6BG/TMZ treatment. These events correlated with decreases in activated AKT, downregulation of the DNA repair protein O6methylguanine-DNA methyltransferase (MGMT), and increased cell death. During MP cell expansion, FAS/CD95/APO1(FAS) expression increased over time and was present on ~100% of the cells following exposure to 6BG/TMZ. While c-flipshort, an endogenous inhibitor of FAS-mediated signaling, was decreased in 6BG/TMZ-treated versus control, 6BG-, or TMZ alone-treated cells, there were no changes in caspase-8 activity. Additionally, there were no changes in the extent of cell death in MP cells exposed to 6BG/TMZ in the presence of neutralizing or agonistic anti-FAS antibodies, indicating that FAS-mediated signaling was not operative. Conclusions In human MP cells, 6BG/TMZ-initiated apoptosis occurred by intrinsic, mitochondrial-mediated and not extrinsic, FAS-mediated apoptosis. Human MP cells represent a clinically relevant model system for gaining insight into how hematopoietic cells respond to chemotherapeutics and offer an approach for selecting effective chemotherapeutic regimens with limited hematopoietic toxicity. PMID:23536437

Wang, Haiyan; Cai, Shanbao; Ernstberger, Aaron; Bailey, Barbara J.; Wang, Michael Z.; Cai, Wenjing; Goebel, W. Scott; Czader, Magdalena B.; Crean, Colin; Suvannasankhah, Attaya; Shokolenkoc, Inna; Wilson, Glenn L.; Baluyut, Arthur R.; Mayo, Lindsey D.; Pollok, Karen E.

2013-01-01

80

Cadmium induces apoptotic cell death in WI 38 cells via caspase-dependent Bid cleavage and calpain-mediated mitochondrial Bax cleavage by Bcl-2-independent pathway.  

PubMed

Previous reports have demonstrated that cadmium (Cd) may induce cell death via apoptosis, but the mechanism responsible for cellular death is not clear. In this study, we investigated the signaling pathways implicated in Cd-induced apoptosis in lung epithelial fibroblast (WI 38) cells. Apoptotic features were observed using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, propidium iodide staining and DNA laddering. A treatment of cadmium caused the caspase-8-dependent Bid cleavage, the release of cytochrome c (Cyt c), activation of caspase-9 and -3, and PARP cleavage. A caspase-8 specific inhibitor prevented the Bid cleavage, caspase-3 activation and cell death. Alternatively, we observed that full-length Bax was cleaved into 18-kDa fragment (p18/Bax); this was initiated after 12 h and by 36 h the full-length Bax protein was totally cleaved to the p18/Bax, which caused a drastic release of Cyt c from mitochondria. The p18/Bax was detected exclusively in the mitochondrial fraction, and it originated from mitochondrial full-length Bax, but not from the cytosol full-length Bax. Cd also induced the activation of the mitochondrial 30-kDa small subunit of calpain that was preceded by Bax cleavage. Cd induced the upregulation of Bcl-2 and the degradation of p53 protein. N-acetyl cysteine effectively inhibited the Cd-induced DeltaPsim reduction, indicating ROS acts upstream of mitochondrial membrane depolarization. Taken together, our results suggest that Cd-induced apoptosis was thought to be mediated at least two pathways; caspase-dependent Bid cleavage, and the other is calpain-mediated mitochondrial Bax cleavage. Moreover, we found that the function of Bid and Bax was not dependent of Bcl-2, and that ROS can also contribute in the Cd-induced cell death. PMID:15450950

Oh, Seon-Hee; Lee, Byung-Hoon; Lim, Sung-Chul

2004-11-01

81

Apoptotic sensitivity of colon cancer cells to histone deacetylase inhibitors is mediated by an Sp1/Sp3-activated transcriptional program involving immediate-early gene induction.  

PubMed

Histone deacetylase inhibitors (HDACi) induce growth arrest and apoptosis in colon cancer cells and are being considered for colon cancer therapy. The underlying mechanism of action of these effects is poorly defined with both transcription-dependent and -independent mechanisms implicated. We screened a panel of 30 colon cancer cell lines for sensitivity to HDACi-induced apoptosis and correlated the differences with gene expression patterns induced by HDACi in the five most sensitive and resistant lines. A robust and reproducible transcriptional response involving coordinate induction of multiple immediate-early (fos, jun, egr1, egr3, atf3, arc, nr4a1) and stress response genes (Ndrg4, Mt1B, Mt1E, Mt1F, Mt1H) was selectively induced in HDACi sensitive cells. Notably, a significant percentage of these genes were basally repressed in colon tumors. Bioinformatics analysis revealed that the promoter regions of the HDACi-induced genes were enriched for KLF4/Sp1/Sp3 transcription factor binding sites. Altering KLF4 levels failed to modulate apoptosis or transcriptional responses to HDACi treatment. In contrast, HDACi preferentially stimulated the activity of Spl/Sp3 and blocking their action attenuated both the transcriptional and apoptotic responses to HDACi treatment. Our findings link HDACi-induced apoptosis to activation of a Spl/Sp3-mediated response that involves derepression of a transcriptional network basally repressed in colon cancer. PMID:20068171

Wilson, Andrew J; Chueh, Anderly C; Tögel, Lars; Corner, Georgia A; Ahmed, Naseem; Goel, Sanjay; Byun, Do-Sun; Nasser, Shannon; Houston, Michele A; Jhawer, Minaxi; Smartt, Helena J M; Murray, Lucas B; Nicholas, Courtney; Heerdt, Barbara G; Arango, Diego; Augenlicht, Leonard H; Mariadason, John M

2010-01-15

82

A novel polysaccharide from Ganoderma atrum exerts antitumor activity by activating mitochondria-mediated apoptotic pathway and boosting the immune system.  

PubMed

Ganoderma is a precious health-care edible medicinal fungus in China. A novel Ganoderma atrum polysaccharide (PSG-1) is the main bioactive component. We investigated the antitumor effect and molecular mechanisms of PSG-1. It exhibited no significant effect on cell proliferation directly. In contrast, administration of PSG-1 markedly suppressed tumor growth in CT26 tumor-bearing mice. It was observed that PSG-1 caused apoptosis in CT26 cells. Apoptosis was associated with loss of mitochondrial membrane potential, enhancement of mitochondrial cytochrome c release and intracellular ROS production, elevation of p53 and Bax expression, downregulation of Bcl-2, and the activation of caspase-9 and -3. Moreover, PSG-1 enhanced immune organ index and promoted lymphocyte proliferation as well as cytokine levels in serum. Taken together, our data indicate that PSG-1 has potential antitumor activity in vivo by inducing apoptosis via mitochondria-mediated apoptotic pathway and enhances host immune system function. Therefore, PSG-1 could be a safe and effective antitumor, bioactive agent or functional food. PMID:24506418

Zhang, Shenshen; Nie, Shaoping; Huang, Danfei; Feng, Yanling; Xie, Mingyong

2014-02-19

83

Chloroplastic NADPH oxidase-like activity-mediated perpetual hydrogen peroxide generation in the chloroplast induces apoptotic-like death of Brassica napus leaf protoplasts.  

PubMed

Despite extensive research over the past years, regeneration from protoplasts has been observed in only a limited number of plant species. Protoplasts undergo complex metabolic modification during their isolation. The isolation of protoplasts induces reactive oxygen species (ROS) generation in Brassica napus leaf protoplasts. The present study was conducted to provide new insight into the mechanism of ROS generation in B. napus leaf protoplasts. In vivo localization of H(2)O(2) and enzymes involved in H(2)O(2) generation and detoxification, molecular antioxidant-ascorbate and its redox state and lipid peroxidation were investigated in the leaf and isolated protoplasts. Incubating leaf strips in the macerating enzyme (ME) for different duration (3, 6, and 12 h) induced accumulation of H(2)O(2) and malondialdehyde (lipid peroxidation, an index of membrane damage) in protoplasts. The level of H(2)O(2) was highest just after protoplast isolation and subsequently decreased during culture. Superoxide generating NADPH oxidase (NOX)-like activity was enhanced, whereas superoxide dismutase (SOD) and ascorbate peroxidase (APX) decreased in the protoplasts compared to leaves. Diaminobenzidine peroxidase (DAB-POD) activity was also lower in the protoplasts compared to leaves. Total ascorbate content, ascorbate to dehydroascorbate ratio (redox state), were enhanced in the protoplasts compared to leaves. Higher activity of NOX-like enzyme and weakening in the activity of antioxidant enzymes (SOD, APX, and DAB-POD) in protoplasts resulted in excessive accumulation of H(2)O(2) in chloroplasts of protoplasts. Chloroplastic NADPH oxidase-like activity mediated perpetual H(2)O(2) generation probably induced apoptotic-like cell death of B. napus leaf protoplasts as indicated by parallel DNA laddering and decreased mitochondrial membrane potential. PMID:21853253

Tewari, Rajesh Kumar; Watanabe, Daisuke; Watanabe, Masami

2012-01-01

84

Neuroprotection by NGF and BDNF Against Neurotoxin-Exerted Apoptotic Death in Neural Stem Cells Are Mediated Through Trk Receptors, Activating PI3Kinase and MAPK Pathways  

Microsoft Academic Search

Neural stem cells (NSC) undergo apoptotic cell death during development of nervous system and in adult. However, little is\\u000a known about the biochemical regulation of neuroprotection by neurotrophin in these cells. In this report, we demonstrate that\\u000a Staurosporine (STS) and Etoposide (ETS) induced apoptotic cell death of NSC by a mechanism requiring Caspase 3 activation,\\u000a poly (ADP-ribose) polymerase and Lamin

Nga Nguyen; Sang Bae Lee; Yung Song Lee; Kyung-Hoon Lee; Jee-Yin Ahn

2009-01-01

85

Brain angiogenesis inhibitor 1 is expressed by gastric phagocytes during infection with Helicobacter pylori and mediates the recognition and engulfment of human apoptotic gastric epithelial cells.  

PubMed

After Helicobacter pylori infection in humans, gastric epithelial cells (GECs) undergo apoptosis due to stimulation by the bacteria or inflammatory cytokines. In this study, we assessed the expression and function of brain angiogenesis inhibitor 1 (BAI1) in the engulfment of apoptotic GECs using human tissue and cells. After induction of apoptosis by H. pylori or camptothecin, there was a 5-fold increase in the binding of apoptotic GECs to THP-1 cells or peripheral blood monocyte-derived macrophages as assayed by confocal microscopy or conventional and imaging flow cytometry. Binding was impaired 95% by pretreating apoptotic cells with annexin V, underscoring the requirement for phosphatidylserine recognition. The phosphatidylserine receptor BAI1 was expressed in human gastric biopsy specimens and gastric phagocytes. To confirm the role of BAI1 in apoptotic cell clearance, the functional domain of BAI1 was used as a competitive inhibitor or BAI1 expression was inhibited by small interfering RNA. Both approaches decreased binding and engulfment >40%. Exposing THP-1 cells to apoptotic cells inhibited IL-6 production from 1340 to <364 pg/ml; however, this decrease was independent of phagocytosis. We conclude that recognition of apoptotic cells by BAI1 contributes to their clearance in the human gastric mucosa and this is associated with anti-inflammatory effects. PMID:24509909

Das, Soumita; Sarkar, Arup; Ryan, Kieran A; Fox, Sarah; Berger, Alice H; Juncadella, Ignacio J; Bimczok, Diane; Smythies, Lesley E; Harris, Paul R; Ravichandran, Kodi S; Crowe, Sheila E; Smith, Phillip D; Ernst, Peter B

2014-05-01

86

Human chorionic gonadotropin suppresses human breast cancer cell growth directly via p53-mediated mitochondrial apoptotic pathway and indirectly via ovarian steroid secretion.  

PubMed

The tumor-suppressive effects of human chorionic gonadotropin (hCG) against human breast cancer cells were examined. In cell viability assays, hCG inhibited the growth of three human breast cancer cell lines (estrogen receptor (ER)-positive KPL-1 and MCF-7, and ER-negative MKL-F cells), and the growth inhibition activity of hCG was most pronounced against KPL-1 cells (luteinizing hormone/chorionic gonadotropin receptor (LHCGR)-positive and luminal-A subtype). In hCG-treated KPL-1 cells, immunoblotting analysis revealed the expression of tumor suppressor protein p53 peaking at 12 h following treatment, followed by cleavage of caspase-9 and caspase-3 at 24 h and 48 h, respectively. KPL-1-transplanted athymic mice were divided into 3 groups: a sham-treated group that received an inoculation of KPL-1 cells at 6 weeks of age followed by daily intraperitoneal (i.p.) injection of saline; an in vitro hCG-treated KPL-1 group that received an inoculation of KPL-1 cells pre-treated with 100 IU/ml hCG in vitro for 48 h at 6 weeks of age, followed by daily i.p. injection of saline; and an in vivo hCG-treated group that received an KPL-1 cell inoculation at 6 weeks of age, followed by daily i.p. injection of 100 IU hCG. The daily injections of saline or hCG continued until the end of the experiment when mice reached 11 weeks of age. KPL-1 tumor growth was retarded in in vitro and in vivo hCG-treated mice compared to sham-treated controls, and the final tumor volume and tumor weight tended to be suppressed in the in vitro hCG-treated group and were significantly suppressed in the in vivo hCG-treated group. In vivo 100-IU hCG injections for 5 weeks elevated serum estradiol levels (35.7 vs. 23.5 pg/ml); thus, the mechanisms of hCG action may be directly coordinated via the p53-mediated mitochondrial apoptotic pathway and indirectly through ovarian steroid secretion that elevates estrogen levels. It is thus concluded that hCG may be an attractive agent for treating human breast cancer expressing both LHCGR and ER. PMID:24596382

Yuri, Takashi; Kinoshita, Yuichi; Emoto, Yuko; Yoshizawa, Katsuhiko; Tsubura, Airo

2014-03-01

87

A Novel Herbal Medicine, KIOM-C, Induces Autophagic and Apoptotic Cell Death Mediated by Activation of JNK and Reactive Oxygen Species in HT1080 Human Fibrosarcoma Cells  

PubMed Central

KIOM-C was recently demonstrated to have anti-metastatic activity in highly malignant cancer cells via suppression of NF-?B-mediated MMP-9 activity. In addition, it was reported to be effective for clearance of the influenza virus by increasing production of anti-viral cytokines, such as TNF-? and IFN-?, and efficacious in the treatment of pigs suffering from porcine circovirus-associated disease (PCVAD). In this study, we investigated whether KIOM-C induces cancer cell death and elucidated the underlying anti-cancer mechanisms. In addition, we examined whether KIOM-C oral administration suppresses in vivo tumor growth of HT1080 cells in athymic nude mice. We initially found that KIOM-C at concentrations of 500 and 1000 µg/ml caused dose- and time-dependent cell death in cancer cells, but not normal hepatocytes, to approximately 50% of control levels. At the early stage of KIOM-C treatment (12 h), cells were arrested in G1 phase, which was accompanied by up-regulation of p21 and p27, down-regulation of cyclin D1, and subsequent increases in apoptotic and autophagic cells. Following KIOM-C treatment, the extent of caspase-3 activation, PARP cleavage, Beclin-1 expression, and LC3-II conversion was remarkably up-regulated, but p62 expression was down-regulated. Phosphorylation of AMPK, ULK, JNK, c-jun, and p53 was increased significantly in response to KIOM-C treatment. The levels of intracellular ROS and CHOP expression were also increased. In particular, the JNK-specific inhibitor SP600125 blocked KIOM-C-induced ROS generation and CHOP expression almost completely, which consequently almost completely rescued cell death, indicating that JNK activation plays a critical role in KIOM-C-induced cell death. Furthermore, daily oral administration of 85 and 170 mg/kg KIOM-C efficiently suppressed the tumorigenic growth of HT1080 cells, without systemic toxicity. These results collectively suggest that KIOM-C efficiently induces cancer cell death by both autophagy and apoptosis via activation of JNK signaling pathways, and KIOM-C represents a safe and potent herbal therapy for treating malignancies. PMID:24878898

Kim, Aeyung; Im, Minju; Yim, Nam-Hui; Kim, Taesoo; Ma, Jin Yeul

2014-01-01

88

Heme oxygenase and nitric oxide synthase mediate cooling-associated protection against TNF--induced microcirculatory dysfunction and apoptotic cell death  

Microsoft Academic Search

Local cooling protects against TNF-- induced injury by attenuating inflammation-associated microcirculatory dysfunction and leukocytic response. Mechanisms of protection, however, are not fully un- derstood. We studied whether the metabolites of the HO and NOS pathway, exerting potent vasodilatory, antioxidant, and anti-apoptotic properties, are involved in tissue cryoprotection. In animals pretreated with L-NAME or SnPP-IX, cooling-associated abrogation of TNF--induced microcirculatory dysfunction

MICHAELA AMON; MICHAEL D. MENGER; BRIGITTE VOLLMAR

89

Taurine protects HK-2 cells from oxidized LDL-induced cytotoxicity via the ROS-mediated mitochondrial and p53-related apoptotic pathways.  

PubMed

Oxidized LDL (oxLDL) induces a pro-oxidative environment and promotes apoptosis, causing the progression of renal diseases in humans. Taurine is a semi-essential amino acid in mammals and has been shown to be a potent endogenous antioxidant. The kidney plays a pivotal role in maintaining the balance of taurine. However, the mechanisms underlying the protective effects of taurine against oxLDL-induced injury in renal epithelial cells have not been clarified. In the present study, we investigated the anti-apoptotic effects of taurine on human proximal tubular epithelial (HK-2) cells exposed to oxLDL and explored the related mechanisms. We observed that oxLDL increased the contents of ROS and of malondialdehyde (MDA), which is a lipid peroxidation by-product that acts as an indicator of the cellular oxidation status. In addition, oxLDL induced cell death and apoptosis in HK-2 cells. Pretreatment with taurine at 100?M significantly attenuated the oxLDL-induced cytotoxicity. We determined that oxLDL triggered the phosphorylation of ERK and, in turn, the activation of p53 and other apoptosis-related events, including calcium accumulation, destabilization of the mitochondrial permeability and disruption of the balance between pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins. The malfunctions induced by oxLDL were effectively blocked by taurine. Thus, our results suggested that taurine exhibits potential therapeutic activity by preventing oxLDL-induced nephrotoxicity. The inhibition of oxLDL-induced epithelial apoptosis by taurine was at least partially due to its anti-oxidant activity and its ability to modulate the ERK and p53 apoptotic pathways. PMID:25018059

Chang, Chun-Yu; Shen, Chao-Yu; Kang, Chao-Kai; Sher, Yuh-Pyng; Sheu, Wayne H-H; Chang, Chia-Che; Lee, Tsung-Han

2014-09-15

90

Houttuynia cordata Thunb extract modulates G0/G1 arrest and Fas/CD95-mediated death receptor apoptotic cell death in human lung cancer A549 cells  

PubMed Central

Background Houttuynia cordata Thunb (HCT) is commonly used in Taiwan and other Asian countries as an anti-inflammatory, antibacterial and antiviral herbal medicine. In this study, we investigated the anti-human lung cancer activity and growth inhibition mechanisms of HCT in human lung cancer A549 cells. Results In order to investigate effects of HCT on A549 cells, MTT assay was used to evaluate cell viability. Flow cytometry was employed for cell cycle analysis, DAPI staining, and the Comet assay was used for DNA fragmentation and DNA condensation. Western blot analysis was used to analyze cell cycle and apoptotic related protein levels. HCT induced morphological changes including cell shrinkage and rounding. HCT increased the G0/G1 and Sub-G1 cell (apoptosis) populations and HCT increased DNA fragmentation and DNA condensation as revealed by DAPI staining and the Comet assay. HCT induced activation of caspase-8 and caspase-3. Fas/CD95 protein levels were increased in HCT-treated A549 cells. The G0/G1 phase and apoptotic related protein levels of cyclin D1, cyclin A, CDK 4 and CDK 2 were decreased, and p27, caspase-8 and caspase-3 were increased in A549 cells after HCT treatment. Conclusions The results demonstrated that HCT-induced G0/G1 phase arrest and Fas/CD95-dependent apoptotic cell death in A549 cells PMID:23506616

2013-01-01

91

HSF1-mediated BAG3 expression attenuates apoptosis in 4-hydroxynonenal-treated colon cancer cells via stabilization of anti-apoptotic Bcl-2 proteins.  

PubMed

4-Hydroxynonenal (HNE) is a pro-apoptotic electrophile generated during the spontaneous decomposition of oxidized lipids. We have previously shown that HNE activates the transcription factor, heat shock factor 1 (HSF1), and promotes cytoprotective heat shock gene expression and that silencing HSF1 sensitizes the colon cancer cell line RKO to HNE-induced apoptosis. Here we report a reduction in the anti-apoptotic proteins Bcl-X(L), Mcl-1, and Bcl-2 in HSF1-silenced RKO cells, and we examine the underlying mechanism. To investigate the regulation of the Bcl-2 family by HSF1, microarray analysis of gene expression was performed. We observed that the Hsp70 co-chaperone, BAG3 (Bcl-2-associated athanogene domain 3), is strongly induced by HNE in control but not in HSF1-silenced colon cancer cells. Silencing BAG3 expression with small interfering RNA caused a dramatic reduction in Bcl-X(L), Mcl-1, and Bcl-2 protein levels in colon cancer cells and increased apoptosis, similar to the effect of silencing HSF1. Also, immunoprecipitation experiments indicate specific interactions between BAG3, Hsp70, and the Bcl-2 family member, Bcl-X(L). Overall, our data reveal that BAG3 is HSF1-inducible and has a unique role facilitating cancer cell survival during pro-apoptotic stress by stabilizing the level of Bcl-2 family proteins. PMID:19179333

Jacobs, Aaron T; Marnett, Lawrence J

2009-04-01

92

The HIV protease inhibitor ritonavir synergizes with butyrate for induction of apoptotic cell death and mediates expression of heme oxygenase-1 in DLD-1 colon carcinoma cells.  

PubMed

The protease inhibitor ritonavir is an integral part of current antiretroviral therapy targeting human immunodeficiency virus. Recent studies demonstrate that ritonavir induces apoptotic cell death with high efficiency in lymphoblastoid cell lines. Moreover, ritonavir can suppress activation of the transcription factor nuclear factor-kappaB and is an inhibitor of interleukin-1beta and tumor necrosis factor-alpha production in peripheral blood mononuclear cells. Thus, ritonavir appears to have anti-inflammatory properties. In the present study, we investigated in DLD-1 colon carcinoma cell effects of ritonavir on apoptotic cell death and expression of heme oxygenase-1 (HO-1), an anti-inflammatory enzyme that may be critically involved in the modulation of colonic inflammation. Compared to unstimulated control, ritonavir resulted in a moderate increase in the rate of apoptotic cell death as observed after 20 h of incubation. Notably, ritonavir potently synergized with the short-chain fatty acid butyrate for induction of caspase-3-dependent apoptosis in DLD-1 cells. Ritonavir enhanced mRNA and protein expression of HO-1 in DLD-1 cells. Ritonavir-induced HO-1 protein was suppressed by SB203580 or SB202190 and preceded by immediate upregulation of cellular c-Fos and c-Jun protein levels. This process was associated with induction of activator protein-1 as detected by electrophoretic mobility shift analysis. The present data suggest that ritonavir has the potential to curb colon carcinogenesis by reducing cell growth via mechanisms that include apoptosis and by simultaneously modulating colonic inflammation via induction of anti-inflammatory HO-1. PMID:15504750

Mühl, Heiko; Paulukat, Jens; Höfler, Sonja; Hellmuth, Markus; Franzen, Rochus; Pfeilschifter, Josef

2004-12-01

93

Characterization of fenofibrate-mediated anti-proliferative pro-apoptotic effects on high-grade gliomas and anti-invasive effects on glioma stem cells.  

PubMed

Glioblastoma is the most common, and at the same time, most aggressive type of high-grade glioma (HGG). The prognosis of glioblastoma patients treated with standard therapy including surgery, temozolomide and radiation therapy remains poor. Peroxisome proliferator-activated receptor-? (PPAR?) agonists are in widespread clinical use for the treatment of hyperlipidemia. Recent evidence has suggested a potential role in various cancers including glioblastoma. In this study, we characterized the effects of PPAR? agonist, fenofibrate, directly on HGG cells and glioma stem cells (GSC). Fenofibrate exhibited dose-dependent p53-independent anti-proliferative effects on HGG starting at 25 ?M and pro-apoptotic effects starting at 50 ?M, suggesting that the anti-proliferative actions are present only at 25 ?M. PPAR? was expressed in all HGG cell lines. Inhibition of PPAR? with specific inhibitor GW6471 did not affect either proliferation or apoptosis suggesting that these are PPAR?-independent effects. Fenofibrate treatment of HGG cells robustly diminished the expression of key signaling pathways, including NF-?B and cyclin D1. Phosphorylation of Akt was also diminished, with no change in total Akt. Effects on apoptotic signaling molecules, Bax and Bcl-xL, had a trend towards pro-apoptotic effects. With respect to GSC, fenofibrate treatment at 25 ?M significantly decreased invasion in association with a decrease in CD133 and Oct4 expression. Overall, results support consideration of fenofibrate as an anti-glioma agent and establish its potential as an adjunct treatment strategy for HGG. Translation to the clinical setting could be rapid given its current use as a clinical agent and its low toxicity profile. PMID:24493576

Binello, Emanuela; Mormone, Elisabetta; Emdad, Luni; Kothari, Harini; Germano, Isabelle M

2014-04-01

94

Quercetin enhances apoptotic effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in ovarian cancer cells through reactive oxygen species (ROS) mediated CCAAT enhancer-binding protein homologous protein (CHOP)-death receptor 5 pathway.  

PubMed

Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has shown efficacy in a phase 2 clinical trial, development of resistance to TRAIL by tumor cells is a major roadblock. We investigated whether quercetin, a flavonoid, can sensitize human ovarian cancer cells to TRAIL. Results indicate that quercetin sensitized cancer cells to TRAIL. The quercetin induced expression of death receptor DR5 but did not affect expression of DR4 in cancer cells. The induction of DR5 was mediated through activation of JNK and through upregulation of a transcription factor CCAAT enhancer-binding protein homologous protein (CHOP); as silencing of these signaling molecules abrogated the effect of quercetin. Upregulation of DR5 was mediated through the generation of reactive oxygen species (ROS), as ROS scavengers reduced the effect of quercetin on JNK activation, CHOP upregulation, DR induction, TRAIL sensitization, downregulated the expression of cell survival proteins and upregulated the proapoptotic proteins. Furthermore, quercetin enhances TRAIL mediated inhibition of tumor growth of human SKOV-3 xenograft was associated with induction of apoptosis, activation of caspase-3, CHOP and DR5. Overall, our data suggest that quercetin enhances apoptotic death of ovarian cancer cells to TRAIL through upregulation of CHOP-induced DR5 expression following ROS mediated endoplasmic reticulum-stress. PMID:24612139

Yi, Liu; Zongyuan, Yang; Cheng, Gong; Lingyun, Zhang; Guilian, Yu; Wei, Gong

2014-05-01

95

The roles of endoplasmic reticulum stress and mitochondrial apoptotic signaling pathway in quercetin-mediated cell death of human prostate cancer PC-3 cells.  

PubMed

Prostate cancer has its highest incidence and is becoming a major concern. Many studies have shown that traditional Chinese medicine exhibited antitumor responses. Quercetin, a natural polyphenolic compound, has been shown to induce apoptosis in many human cancer cell lines. Although numerous evidences show multiple possible signaling pathways of quercetin in apoptosis, there is no report to address the role of endoplasmic reticulum (ER) stress in quercetin-induced apoptosis in PC-3 cells. The purpose of this study was to investigate the effects of quercetin on the induction of the apoptotic pathway in human prostate cancer PC-3 cells. Cells were treated with quercetin for 24 and 48 h and at various doses (50-200 ?M), and cell morphology and viability decreased significantly in dose-dependent manners. Flow cytometric assay indicated that quercetin at 150 ?M caused G0/G1 phase arrest (31.4-49.7%) and sub-G1 phase cells (19.77%) for 36 h treatment and this effect is a time-dependent manner. Western blotting analysis indicated that quercetin induces the G0/G1 phase arrest via decreasing the levels of CDK2, cyclins E, and D proteins. Quercetin also stimulated the protein expression of ATF, GRP78, and GADD153 which is a hall marker of ER stress. Furthermore, PC-3 cells after incubation with quercetin for 48 h showed an apoptotic cell death and DNA damage which are confirmed by DAPI and Comet assays, leading to decrease the antiapoptotic Bcl-2 protein and level of ??m , and increase the proapoptotic Bax protein and the activations of caspase-3, -8, and -9. Moreover, quercetin promoted the trafficking of AIF protein released from mitochondria to nuclei. These data suggest that quercetin may induce apoptosis by direct activation of caspase cascade through mitochondrial pathway and ER stress in PC-3 cells. PMID:22431435

Liu, Kuo-Ching; Yen, Chun-Yi; Wu, Rick Sai-Chuen; Yang, Jai-Sing; Lu, Hsu-Feng; Lu, Kung-Wen; Lo, Chyi; Chen, Hung-Yi; Tang, Nou-Ying; Wu, Chih-Chung; Chung, Jing-Gung

2014-04-01

96

Translocation of a Bak C-Terminus Mutant from Cytosol to Mitochondria to Mediate Cytochrome c Release: Implications for Bak and Bax Apoptotic Function  

PubMed Central

Background One of two proapoptotic Bcl-2 proteins, Bak or Bax, is required to permeabilize the mitochondrial outer membrane during apoptosis. While Bax is mostly cytosolic and translocates to mitochondria following an apoptotic stimulus, Bak is constitutively integrated within the outer membrane. Membrane anchorage occurs via a C-terminal transmembrane domain that has been studied in Bax but not in Bak, therefore what governs their distinct subcellular distribution is uncertain. In addition, whether the distinct subcellular distributions of Bak and Bax contributes to their differential regulation during apoptosis remains unclear. Methodology/Principal Findings To gain insight into Bak and Bax targeting to mitochondria, elements of the Bak C-terminus were mutated, or swapped with those of Bax. Truncation of the C-terminal six residues (C-segment) or substitution of three basic residues within the C-segment destabilized Bak. Replacing the Bak C-segment with that from Bax rescued stability and function, but unexpectedly resulted in a semi-cytosolic protein, termed Bak/BaxCS. When in the cytosol, both Bax and Bak/BaxCS sequestered their hydrophobic transmembrane domains in their hydrophobic surface groove. Upon apoptotic signalling, Bak/BaxCS translocated to the mitochondrial outer membrane, inserted its transmembrane domain, oligomerized, and released cytochrome c. Despite this Bax-like subcellular distribution, Bak/BaxCS retained Bak-like regulation following targeting of Mcl-1. Conclusions/Significance Residues in the C-segment of Bak and of Bax contribute to their distinct subcellular localizations. That a semi-cytosolic form of Bak, Bak/BaxCS, could translocate to mitochondria and release cytochrome c indicates that Bak and Bax share a conserved mode of activation. In addition, the differential regulation of Bak and Bax by Mcl-1 is predominantly independent of the initial subcellular localizations of Bak and Bax. PMID:22442658

Ferrer, Pedro Eitz; Frederick, Paul; Gulbis, Jacqueline M.

2012-01-01

97

Recognition ligands on apoptotic cells: a perspective  

Microsoft Academic Search

The process of apoptosis includes crit- ically important changes on the cell surface that lead to its recognition and removal. The recogni- tion also generates a number of other local tissue responses including suppression of inflammation and immunity. It is surprising that the ligands gen- erated on the apoptotic cell, which mediates these effects, have received relatively little attention. Some

Shyra J. Gardai; Donna L. Bratton; Carole Anne Ogden; Peter M. Henson

2006-01-01

98

Clearance of apoptotic corpses  

Microsoft Academic Search

Apoptotic corpses can be engulfed and cleared by many other cell types in addition to ‘professional’ phagocytes such as macrophage.\\u000a Studies of several organisms have contributed to the understanding of apoptotic corpse engulfment. Two partially redundant\\u000a engulfment pathways have been characterized that act even in non-professional phagocytes to promote corpse engulfment. This\\u000a review summarizes some recent progress in signaling by

John F. Fullard; Abhijit Kale; Nicholas E. Baker

2009-01-01

99

Phenethyl Isothiocyanate (PEITC) Inhibits the Growth of Human Oral Squamous Carcinoma HSC-3 Cells through G(0)/G(1) Phase Arrest and Mitochondria-Mediated Apoptotic Cell Death.  

PubMed

Phenethyl isothiocyanate (PEITC), an effective anticancer and chemopreventive agent, has been reported to inhibit cancer cell growth through cell-cycle arrest and induction of apoptotic events in various human cancer cells models. However, whether PEITC inhibits human oral squamous cell carcinoma HSC-3 cell growth and its underlying mechanisms is still not well elucidated. In the present study, we evaluated the inhibitory effects of PEITC in HSC-3 cells and examined PEITC-modulated cell-cycle arrest and apoptosis. The contrast-phase and flow cytometric assays were used for examining cell morphological changes and viability, respectively. The changes of cell-cycle and apoptosis-associated protein levels were determined utilizing Western blotting in HSC-3 cells after exposure to PEITC. Our results indicated that PEITC effectively inhibited the HSC-3 cells' growth and caused apoptosis. PEITC induced G(0)/G(1) phase arrest through the effects of associated protein such as p53, p21, p17, CDK2 and cyclin E, and it triggered apoptosis through promotion of Bax and Bid expression and reduction of Bcl-2, leading to decrease the levels of mitochondrial membrane potential (??(m)), and followed the releases of cytochrome c, AIF and Endo G then for causing apoptosis in HSC-3 cells. These results suggest that PEITC could be an antitumor compound for oral cancer therapy. PMID:22919418

Chen, Po-Yuan; Lin, Kai-Chun; Lin, Jing-Pin; Tang, Nou-Ying; Yang, Jai-Sing; Lu, Kung-Wen; Chung, Jing-Gung

2012-01-01

100

dapk1, encoding an activator of a p19ARF-p53-mediated apoptotic checkpoint, is a transcription target of p53.  

PubMed

The p53 tumour suppressor functions as a transcriptional activator, and several p53-inducible genes that play a critical proapoptotic role have been described. Moreover, p53 regulates the expression of various proteins participating in autoregulatory feedback loops, including proteins that negatively control p53 stability (Mdm2 and Pirh2) or modulate stress-induced phosphorylation of p53 on Ser-46 (p53DINP1 or Wip1), a key event for p53-induced apoptosis. Here, we describe a new systematic analysis of p53 targets using oligonucleotide chips, and report the identification of dapk1 as a novel p53 target. We demonstrate that dapk1 mRNA levels increase in a p53-dependent manner in various cellular settings. Both human and mouse dapk1 genomic loci contain DNA sequences that bind p53 in vitro and in vivo. Since dapk1 encodes a serine/threonine kinase previously shown to suppress oncogene-induced transformation by activating a p19ARF/p53-dependent apoptotic checkpoint, our results suggest that Dapk1 participates in a new positive feedback loop controlling p53 activation and apoptosis. PMID:15608685

Martoriati, Alain; Doumont, Gilles; Alcalay, Myriam; Bellefroid, Eric; Pelicci, Pier Giuseppe; Marine, Jean-Christophe

2005-02-17

101

The anti-apoptotic effect of IGF-1 on tissue resident stem cells is mediated via PI3-kinase dependent secreted frizzled related protein 2 (Sfrp2) release  

SciTech Connect

Previous studies suggest that IGF-1 may be used as an adjuvant to stem cell transfer in order to improve cell engraftment in ischemic tissue. In the current study, we investigated the effect of IGF-1 on serum deprivation and hypoxia induced stem cell apoptosis and the possible mechanisms involved. Exposure of adipose tissue derived stem cells (ASCs) to serum deprivation and hypoxia resulted in significant apoptosis in ASC which is partially prevented by IGF-1. IGF-1's anti-apoptotic effect was abolished in ASCs transfected with Sfrp2 siRNA but not by the control siRNA. Using Western blot analysis, we demonstrated that serum deprivation and hypoxia reduced the expression of nuclear {beta}-catenin, which is reversed by IGF-1. IGF-1's effect on {beta}-catenin expression was abolished by the presence of PI3-kinase inhibitor LY294002 or in ASCs transfected with Sfrp2 siRNA. These results suggest that IGF-1, through the release of the Sfrp2, contributes to cell survival by stabilizing {beta}-catenin.

Gehmert, Sebastian; Sadat, Sanga; Song Yaohua; Yan Yasheng [Department of Molecular Pathology, University of Texas M.D. Anderson Cancer Center, SCRB2, Box 951, 7435 Fannin Street, Houston, TX 77030 (United States); Alt, Eckhard [Department of Molecular Pathology, University of Texas M.D. Anderson Cancer Center, SCRB2, Box 951, 7435 Fannin Street, Houston, TX 77030 (United States)], E-mail: ealt@mdanderson.org

2008-07-11

102

In the absence of cellular poly (A) binding protein, the glycolytic enzyme GAPDH translocated to the cell nucleus and activated the GAPDH mediated apoptotic pathway by enhancing acetylation and serine 46 phosphorylation of p53  

SciTech Connect

Highlights: {yields} PABP knock down and cell apoptosis. {yields} Nuclear translocation of GAPDH in PABP depleted cells. {yields} Role of p53 in apoptosis of PABP depleted cells. {yields} Bax translocation and cytochrome C release and caspase 3 activation following PABP depletion. {yields} Association of p53 with Bcl2 and Bax. -- Abstract: The cytoplasmic poly (A) binding protein (PABP) interacts with 3' poly (A) tract of eukaryotic mRNA and is important for both translation and stability of mRNA. Previously, we have shown that depletion of PABP by siRNA prevents protein synthesis and consequently leads to cell death through apoptosis. In the present investigation, we studied the mechanism of cell apoptosis. We show that in the absence of PABP, the glycolytic enzyme GAPDH translocated to the cell nucleus and activated the GAPDH mediated apoptotic pathway by enhancing acetylation and serine 46 phosphorylation of p53. As a result, p53 translocated to the mitochondria to initiate Bax mediated apoptosis.

Thangima Zannat, Mst.; Bhattacharjee, Rumpa B. [Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada)] [Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Bag, Jnanankur, E-mail: jbag@uoguelph.ca [Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada)] [Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada)

2011-06-03

103

Folate Deficiency Triggers an Oxidative-Nitrosative Stress-Mediated Apoptotic Cell Death and Impedes Insulin Biosynthesis in RINm5F Pancreatic Islet ?-Cells: Relevant to the Pathogenesis of Diabetes  

PubMed Central

It has been postulated that folic acid (folate) deficiency (FD) may be a risk factor for the pathogenesis of a variety of oxidative stress-triggered chronic degenerative diseases including diabetes, however, the direct evidence to lend support to this hypothesis is scanty. For this reason, we set out to study if FD can trigger the apoptotic events in an insulin-producing pancreatic RINm5F islet ? cells. When these cells were cultivated under FD condition, a time-dependent growth impediment was observed and the demise of these cells was demonstrated to be apoptotic in nature proceeding through a mitochondria-dependent pathway. In addition to evoke oxidative stress, FD condition could also trigger nitrosative stress through a NF-?B-dependent iNOS-mediated overproduction of nitric oxide (NO). The latter compound could then trigger depletion of endoplasmic reticulum (ER) calcium (Ca2+) store leading to cytosolic Ca2+ overload and caused ER stress as evidence by the activation of CHOP expression. Furthermore, FD-induced apoptosis of RINm5F cells was found to be correlated with a time-dependent depletion of intracellular gluthathione (GSH) and a severe down-regulation of Bcl-2 expression. Along the same vein, we also demonstrated that FD could severely impede RINm5F cells to synthesize insulin and their abilities to secret insulin in response to glucose stimulation were appreciably hampered. Even more importantly, we found that folate replenishment could not restore the ability of RINm5F cells to resynthesize insulin. Taken together, our data provide strong evidence to support the hypothesis that FD is a legitimate risk factor for the pathogenesis of diabetes. PMID:24223745

Wang, Yu-Huei; Chen, Chia-Hui; Mau, Shin-Yi; Ho, Chun-Te; Chang, Pey-Jium; Liu, Tsan-Zon; Chen, Ching-Hsein

2013-01-01

104

Apoptotic cells subjected to cold/warming exposure disorganize apoptotic microtubule network and undergo secondary necrosis.  

PubMed

Apoptotic microtubule network (AMN) is organized during apoptosis, forming a cortical structure beneath the plasma membrane which plays a critical role in preserving cell morphology and plasma membrane integrity. The aim of this study was to examine the effect of cold/warming exposure on apoptotic microtubules and plasma membrane integrity during the execution phase of apoptosis. We demonstrated in camptothecin-induced apoptotic H460 cells that cold/warming exposure disorganized apoptotic microtubules and allowed the access of active caspases to the cellular cortex and the cleavage of essential proteins in the preservation of plasma membrane permeability. Cleavage of cellular cortex and plasma membrane proteins, such as ?-spectrin, paxilin, focal adhesion kinase and calcium ATPase pump (PMCA-4) involved in cell calcium extrusion resulted in increased plasma permeability and calcium overload leading apoptotic cells to secondary necrosis. The essential role of caspase-mediated cleavage in this process was demonstrated because the addition of the pan-caspase inhibitor z-VAD during cold/warming exposure that induces AMN depolymerization avoided the cleavage of cortical and plasma membrane proteins and prevented apoptotic cells to undergo secondary necrosis. Likewise, apoptotic microtubules stabilization by taxol during cold/warming exposure also prevented cellular cortex and plasma membrane protein cleavage and secondary necrosis. Furthermore, microtubules stabilization or caspase inhibition during cold/warming exposure was also critical for proper phosphatidylserine externalization and apoptotic cell clearance by macrophages. These results indicate that cold/warming exposure of apoptotic cells induces secondary necrosis which can be prevented by both, microtubule stabilization or caspase inhibition. PMID:25027509

Oropesa-Ávila, Manuel; Fernández-Vega, Alejandro; de la Mata, Mario; Garrido-Maraver, Juan; Cotán, David; Paz, Marina Villanueva; Pavón, Ana Delgado; Cordero, Mario D; Alcocer-Gómez, Elizabet; de Lavera, Isabel; Lema, Rafael; Zaderenko, Ana Paula; Sánchez-Alcázar, José A

2014-09-01

105

Regulation of HA14-1 mediated oxidative stress, toxic response, and autophagy by curcumin to enhance apoptotic activity in human embryonic kidney cells.  

PubMed

An alteration in susceptibility to apoptosis not only contributes to promotion of malignancy but can also enhance drug resistance in response to anticancer therapies. HA14-1 is a small molecule which has the potential of inducing apoptosis in cancerous cells. HA14-1 manifests an antagonistic effect on antiapoptotic protein Bcl-2 and consequently induces cell death in various cancerous cell lines. However, it is also known to generate ROS and toxic response in the cells upon decomposition. Elevated level of ROS is responsible for oxidative stress and other pathological consequences, if not metabolized properly. The aim of the present study was to examine the synergistic effect of curcumin in promoting apoptosis by regulating the HA14-1 mediated ROS generation, toxicity, oxidative stress, and autophagy in human embryonic kidney cells. Our study demonstrates that curcumin efficiently scavenges HA14-1 mediated generation of ROS and toxic response resulting in augmentation of apoptosis in HEK 293T cells by promoting inhibition of antiapoptotic proteins and process of autophagy. Thus curcumin along with HA14-1 regulates cell proliferation by disruption of the antiapoptotic signaling mechanism. This approach could serve as a promising strategy for therapeutic potential to overcome their adverse effects. PMID:23559532

Ranjan, Kishu; Sharma, Anupama; Surolia, Avadhesha; Pathak, Chandramani

2014-01-01

106

Transcriptomic Analysis Unveils Correlations between Regulative Apoptotic Caspases and Genes of Cholesterol Homeostasis in Human Brain  

PubMed Central

Regulative circuits controlling expression of genes involved in the same biological processes are frequently interconnected. These circuits operate to coordinate the expression of multiple genes and also to compensate dysfunctions in specific elements of the network. Caspases are cysteine-proteases with key roles in the execution phase of apoptosis. Silencing of caspase-2 expression in cultured glioblastoma cells allows the up-regulation of a limited number of genes, among which some are related to cholesterol homeostasis. Lysosomal Acid Lipase A (LIPA) was up-regulated in two different cell lines in response to caspase-2 down-regulation and cells silenced for caspase-2 exhibit reduced cholesterol staining in the lipid droplets. We expanded this observation by large-scale analysis of mRNA expression. All caspases were analyzed in terms of co-expression in comparison with 166 genes involved in cholesterol homeostasis. In the brain, hierarchical clustering has revealed that the expression of regulative apoptotic caspases (CASP2, CASP8 CASP9, CASP10) and of the inflammatory CASP1 is linked to several genes involved in cholesterol homeostasis. These correlations resulted in altered GBM (Glioblastoma Multiforme), in particular for CASP1. We have also demonstrated that these correlations are tissue specific being reduced (CASP9 and CASP10) or different (CASP2) in the liver. For some caspases (CASP1, CASP6 and CASP7) these correlations could be related to brain aging. PMID:25330190

Picco, Raffaella; Tomasella, Andrea; Fogolari, Federico; Brancolini, Claudio

2014-01-01

107

CRK adaptor protein expression is required for efficient replication of avian influenza A viruses and controls JNK-mediated apoptotic responses.  

PubMed

The non-structural protein 1 (A/NS1) of influenza A viruses (IAV) harbours several src-homology domain (SH) binding motifs that are required for interaction with cellular proteins. The SH3 binding motif at aa212-217 [PPLPPK] of A/NS1 was shown to be essential for binding to the cellular adaptor proteins CRK and CRKL. Both regulate diverse cellular effector pathways, including activation of the MAP-kinase JNK that in turn mediates antiviral responses to IAV infection. By studying functional consequences of A/NS1-CRK interaction we show here that A/NS1 binding to CRK contributes to suppression of the antiviral-acting JNK-ATF2 pathway. However, only IAV that encode an A/NS1-protein harbouring the CRK/CRKL SH3 binding motif PPLPPK were attenuated upon downregulation of CRKI/II and CRKL, but not of CRKII alone. The PPLPPK site-harbouring candidate strains could be discriminated from other strains by a pronounced viral activation of the JNK-ATF2 signalling module that was even further boosted upon knock-down of CRKI/II. Interestingly, this enhanced JNK activation did not alter type-I IFN-expression, but rather resulted in increased levels of virus-induced cell death. Our results imply that binding capacity of A/NS1 to CRK/CRKL has evolved in virus strains that over-induce the antiviral acting JNK-ATF2 signalling module and helps to suppress the detrimental apoptosis promoting action of this pathway. PMID:20088952

Hrincius, Eike R; Wixler, Viktor; Wolff, Thorsten; Wagner, Ralf; Ludwig, Stephan; Ehrhardt, Christina

2010-06-01

108

Induction of apoptosis and apoptotic mediators in Balb/C splenic lymphocytes by dietary n-3 and n-6 fatty acids.  

PubMed

The present study was designed to investigate the effect of dietary n-6 and n-3 polyunsaturated fatty acids (PUFA) on anti-CD3 and anti-Fas antibody-induced apoptosis and its mediators in mouse spleen cells. Nutritionally adequate semipurified diets containing either 5% w/w corn oil (n-6 PUFA) or fish oil (n-3 PUFA) were fed to weanling female Balb/C mice, and 24 wk later mice were sacrificed. In n-3 PUFA-fed mice, serum and splenocyte lipid peroxides were increased by 20 and 28.3% respectively, compared to n-6 PUFA-fed mice. Further, serum vitamin E levels were decreased by 50% in the n-3 PUFA-fed group, whereas higher anti-Fas- and anti-CD3-induced apoptosis (65 and 66%) and necrosis (17 and 25%), compared to the n-6 PUFA-fed group, were found when measured with Annexin V and propidium iodide staining, respectively. In addition, decreased Bcl-2 and increased Fas-ligand (Fas-L) also were observed in the n-3 PUFA-fed group compared to the n-6 PUFA-fed group. No difference in the ratio of splenocyte subsets nor their Fas expression was observed between the n-3 PUFA-fed and n-6 PUFA-fed groups, whereas decreased proliferation of splenocytes was found in n-3 PUFA-fed mice compared to n-6 PUFA-fed mice. In conclusion, our results indicate that dietary n-3 PUFA induces higher apoptosis by increasing the generation of lipid peroxides and elevating Fas-L expression along with decreasing Bcl-2 expression. A reduced proliferative response of immune cells also was observed in n-3 PUFA-fed mice. PMID:10574656

Avula, C P; Zaman, A K; Lawrence, R; Fernandes, G

1999-09-01

109

A sustained deficiency of mitochondrial respiratory complex III induces an apoptotic cell death through the p53-mediated inhibition of pro-survival activities of the activating transcription factor 4.  

PubMed

Generation of energy in mitochondria is subjected to physiological regulation at many levels, and its malfunction may result in mitochondrial diseases. Mitochondrial dysfunction is associated with different environmental influences or certain genetic conditions, and can be artificially induced by inhibitors acting at different steps of the mitochondrial electron transport chain (ETC). We found that a short-term (5?h) inhibition of ETC complex III with myxothiazol results in the phosphorylation of translation initiation factor eIF2? and upregulation of mRNA for the activating transcription factor 4 (ATF4) and several ATF4-regulated genes. The changes are characteristic for the adaptive integrated stress response (ISR), which is known to be triggered by unfolded proteins, nutrient and metabolic deficiency, and mitochondrial dysfunctions. However, after a prolonged incubation with myxothiazol (13-17?h), levels of ATF4 mRNA and ATF4-regulated transcripts were found substantially suppressed. The suppression was dependent on the p53 response, which is triggered by the impairment of the complex III-dependent de novo biosynthesis of pyrimidines by mitochondrial dihydroorotate dehydrogenase. The initial adaptive induction of ATF4/ISR acted to promote viability of cells by attenuating apoptosis. In contrast, the induction of p53 upon a sustained inhibition of ETC complex III produced a pro-apoptotic effect, which was additionally stimulated by the p53-mediated abrogation of the pro-survival activities of the ISR. Interestingly, a sustained inhibition of ETC complex I by piericidine did not induce the p53 response and stably maintained the pro-survival activation of ATF4/ISR. We conclude that a downregulation of mitochondrial ETC generally induces adaptive pro-survival responses, which are specifically abrogated by the suicidal p53 response triggered by the genetic risks of the pyrimidine nucleotide deficiency. PMID:25375376

Evstafieva, A G; Garaeva, A A; Khutornenko, A A; Klepikova, A V; Logacheva, M D; Penin, A A; Novakovsky, G E; Kovaleva, I E; Chumakov, P M

2014-01-01

110

Topological Transitions in Mitochondrial Membranes controlled by Apoptotic Proteins  

NASA Astrophysics Data System (ADS)

The Bcl-2 family comprises pro-apoptotic proteins, capable of permeabilizing the mitochondrial membrane, and anti-apoptotic members interacting in an antagonistic fashion to regulate programmed cell death (apoptosis). They offer potential therapeutic targets to re-engage cellular suicide in tumor cells but the extensive network of implicated protein-protein interactions has impeded full understanding of the decision pathway. We show, using synchrotron x-ray diffraction, that pro-apoptotic proteins interact with mitochondrial-like model membranes to generate saddle-splay (negative Gaussian) curvature topologically required for pore formation, while anti-apoptotic proteins can deactivate curvature generation by molecules drastically different from Bcl-2 family members and offer evidence for membrane-curvature mediated interactions general enough to affect very disparate systems.

Hwee Lai, Ghee; Sanders, Lori K.; Mishra, Abhijit; Schmidt, Nathan W.; Wong, Gerard C. L.; Ivashyna, Olena; Schlesinger, Paul H.

2010-03-01

111

P2X7 Receptor-mediated Scavenger Activity of Mononuclear Phagocytes toward Non-opsonized Particles and Apoptotic Cells Is Inhibited by Serum Glycoproteins but Remains Active in Cerebrospinal Fluid*  

PubMed Central

Rapid phagocytosis of non-opsonized particles including apoptotic cells is an important process that involves direct recognition of the target by multiple scavenger receptors including P2X7 on the phagocyte surface. Using a real-time phagocytosis assay, we studied the effect of serum proteins on this phagocytic process. Inclusion of 1–5% serum completely abolished phagocytosis of non-opsonized YG beads by human monocytes. Inhibition was reversed by pretreatment of serum with 1–10 mm tetraethylenepentamine, a copper/zinc chelator. Inhibitory proteins from the serum were determined as negatively charged glycoproteins (pI < 6) with molecular masses between 100 and 300 kDa. A glycoprotein-rich inhibitory fraction of serum not only abolished YG bead uptake but also inhibited phagocytosis of apoptotic lymphocytes or neuronal cells by human monocyte-derived macrophages. Three copper- and/or zinc-containing serum glycoproteins, ceruloplasmin, serum amyloid P-component, and amyloid precursor protein, were identified, and the purified proteins were shown to inhibit the phagocytosis of beads by monocytes as well as phagocytosis of apoptotic neuronal cells by macrophages. Human adult cerebrospinal fluid, which contains very little glycoprotein, had no inhibitory effect on phagocytosis of either beads or apoptotic cells. These data suggest for the first time that metal-interacting glycoproteins present within serum are able to inhibit the scavenger activity of mononuclear phagocytes toward insoluble debris and apoptotic cells. PMID:22461619

Gu, Ben J.; Duce, James A.; Valova, Valentina A.; Wong, Bruce; Bush, Ashley I.; Petrou, Steven; Wiley, James S.

2012-01-01

112

Apoptotic markers in protozoan parasites  

Microsoft Academic Search

The execution of the apoptotic death program in metazoans is characterized by a sequence of morphological and biochemical changes that include cell shrinkage, presentation of phosphatidylserine at the cell surface, mitochondrial alterations, chromatin condensation, nuclear fragmentation, membrane blebbing and the formation of apoptotic bodies. Methodologies for measuring apoptosis are based on these markers. Except for membrane blebbing and formation of

Antonio Jiménez-Ruiz; Juan Fernando Alzate; Ewan Thomas MacLeod; Carsten Günter Kurt Lüder; Nicolas Fasel; Hilary Hurd

2010-01-01

113

Assembly of the Bak Apoptotic Pore  

PubMed Central

Bak and Bax are the essential effectors of the intrinsic pathway of apoptosis. Following an apoptotic stimulus, both undergo significant changes in conformation that facilitates their self-association to form pores in the mitochondrial outer membrane. However, the molecular structures of Bak and Bax oligomeric pores remain elusive. To characterize how Bak forms pores during apoptosis, we investigated its oligomerization under native conditions using blue native PAGE. We report that, in a healthy cell, inactive Bak is either monomeric or in a large complex involving VDAC2. Following an apoptotic stimulus, activated Bak forms BH3:groove homodimers that represent the basic stable oligomeric unit. These dimers multimerize to higher-order oligomers via a labile interface independent of both the BH3 domain and groove. Linkage of the ?6:?6 interface is sufficient to stabilize higher-order Bak oligomers on native PAGE, suggesting an important role in the Bak oligomeric pore. Mutagenesis of the ?6 helix disrupted apoptotic function because a chimera of Bak with the ?6 derived from Bcl-2 could be activated by truncated Bid (tBid) and could form BH3:groove homodimers but could not form high molecular weight oligomers or mediate cell death. An ?6 peptide could block Bak function but did so upstream of dimerization, potentially implicating ?6 as a site for activation by BH3-only proteins. Our examination of native Bak oligomers indicates that the Bak apoptotic pore forms by the multimerization of BH3:groove homodimers and reveals that Bak ?6 is not only important for Bak oligomerization and function but may also be involved in how Bak is activated by BH3-only proteins. PMID:23893415

Ma, Stephen; Hockings, Colin; Anwari, Khatira; Kratina, Tobias; Fennell, Stephanie; Lazarou, Michael; Ryan, Michael T.; Kluck, Ruth M.; Dewson, Grant

2013-01-01

114

Viral Subversion of Apoptotic Enzymes: Escape from Death Row*  

PubMed Central

To prolong cell viability and facilitate replication, viruses have evolved multiple mechanisms to inhibit the host apoptotic response. Cellular proteases such as caspases and serine proteases are instrumental in promoting apoptosis. Thus, these enzymes are logical targets for virus-mediated modulation to suppress cell death. Four major classes of viral inhibitors antagonize caspase function: serpins, p35 family members, inhibitor of apoptosis proteins, and viral FLICE-inhibitory proteins. Viruses also subvert activity of the serine proteases, granzyme B and HtrA2/Omi, to avoid cell death. The combined efforts of viruses to suppress apoptosis suggest that this response should be avoided at all costs. However, some viruses utilize caspases during replication to aid virus protein maturation, progeny release, or both. Hence, a multifaceted relationship exists between viruses and the apoptotic response they induce. Examination of these interactions contributes to our understanding of both virus pathogenesis and the regulation of apoptotic enzymes in normal cellular functions. PMID:18729734

Best, Sonja M.

2008-01-01

115

H. pylori Infection Inhibits Phagocyte Clearance of Apoptotic Gastric Epithelial Cells  

PubMed Central

Increased apoptotic death of gastric epithelial cells is a hallmark of H. pylori infection, and altered epithelial cell turnover is an important contributor to gastric carcinogenesis. To address the fate of apoptotic gastric epithelial cells and their role in H. pylori mucosal disease, we investigated phagocyte clearance of apoptotic gastric epithelial cells in H. pylori infection. Human gastric mononuclear phagocytes were analyzed for their ability to take up apoptotic epithelial cells in vivo using immunofluorescence analysis. We then used primary human gastric epithelial cells induced to undergo apoptosis by exposure to live H. pylori to study apoptotic cell uptake by autologous monocyte-derived macrophages. We show that HLA-DR+ mononuclear phagocytes in human gastric mucosa contain cytokeratin-positive and TUNEL-positive apoptotic epithelial cell material, indicating that gastric phagocytes are involved in apoptotic epithelial cell clearance. We further show that H. pylori both increased apoptosis in primary gastric epithelial cells and decreased phagocytosis of the apoptotic epithelial cells by autologous monocyte-derived macrophages. Reduced macrophage clearance of apoptotic cells was mediated in part by H. pylori-induced macrophage TNF-?, which was expressed at higher levels in H. pylori-infected, compared to uninfected, gastric mucosa. Importantly, we show that H. pylori-infected gastric mucosa contained significantly higher numbers of apoptotic epithelial cells and higher levels of non-phagocytosed TUNEL-positive apoptotic material, consistent with a defect in apoptotic cell clearance. Thus, as shown in other autoimmune and chronic inflammatory diseases, insufficient phagocyte clearance may contribute to the chronic and self-perpetuating inflammation in human H. pylori infection. PMID:23686492

Bimczok, Diane; Smythies, Lesley E.; Waites, Ken B.; Grams, Jayleen M.; Stahl, Richard D.; Mannon, Peter J.; Peter, Shajan; Wilcox, C. Mel; Harris, Paul R.; Das, Soumita; Ernst, Peter B.; Smith, Phillip D.

2013-01-01

116

Dual-Targeting Pro-apoptotic Peptide for Programmed Cancer Cell Death via Specific Mitochondria Damage  

PubMed Central

Mitochondria are vital organelles to eukaryotic cells. Damage to mitochondria will cause irreversible cell death or apoptosis. In this report, we aim at programmed cancer cell death via specific mitochondrial damage. Herein, a functionalized pro-apoptotic peptide demonstrates a dual-targeting capability using folic acid (FA) (targeting agent I) and triphenylphosphonium (TPP) cation (targeting agent II). FA is a cancer-targeting agent, which can increase the cellular uptake of the pro-apoptotic peptide via receptor-mediated endocytosis. And the TPP cation is the mitochondrial targeting agent, which specifically delivers the pro-apoptotic peptide to its particular subcellular mitochondria after internalized by cancer cells. Then the pro-apoptotic peptide accumulates in mitochondria and causes its serious damage. This dual-targeting strategy has the potential to effectively transport the pro-apoptotic peptide to targeted cancer cell mitochondria, inducing mitochondrial dysfunction and triggering the mitochondria-dependent apoptosis to efficiently eliminate cancer cells. PMID:24336626

Chen, Wei-Hai; Xu, Xiao-Ding; Luo, Guo-Feng; Jia, Hui-Zhen; Lei, Qi; Cheng, Si-Xue; Zhuo, Ren-Xi; Zhang, Xian-Zheng

2013-01-01

117

c-Met Overexpression Contributes to the Acquired Apoptotic Resistance of Nonadherent Ovarian Cancer Cells through a Cross Talk Mediated by Phosphatidylinositol 3-Kinase and Extracellular Signal-Regulated Kinase 1/212  

PubMed Central

Ovarian cancer is the most lethal gynecologic cancer mainly because of widespread peritoneal dissemination and malignant ascites. Key to this is the capacity of tumor cells to escape suspension-induced apoptosis (anoikis), which also underlies their resistance to chemotherapy. Here, we used a nonadherent cell culture model to investigate the molecular mechanisms of apoptotic resistance of ovarian cancer cells that may mimic the chemoresistance found in solid tumors. We found that ovarian cancer cells acquired a remarkable resistance to anoikis and apoptosis induced by exposure to clinically relevant doses of two front-line chemotherapeutic drugs cisplatin and paclitaxel when grown in three-dimensional than monolayer cultures. Inhibition of the hepatocyte growth factor (HGF) receptor c-Met, which is frequently overexpressed in ovarian cancer, by a specific inhibitor or small interfering RNA blocked the acquired anoikis resistance and restored chemosensitivity in three-dimensional not in two-dimensional cultures. These effects were found to be dependent on both phosphatidylinositol 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK) 1/2 signaling pathways. Inhibitors of PI3K/Akt abrogated ERK1/2 activation and its associated anoikis resistance in response to HGF, suggesting a signaling relay between these two pathways. Furthermore, we identified a central role of Ras as a mechanism of this cross talk. Interestingly, Ras did not lie upstream of PI3K/Akt, whereas PI3K/Akt signaling to ERK1/2 involved Ras. These findings shed new light on the apoptotic resistance mechanism of nonadherent ovarian cancer ascites cells and may have important clinical implications. PMID:20126471

Tang, Maggie K S; Zhou, Hong Y; Yam, Judy W P; Wong, Alice S T

2010-01-01

118

Identification of TLT2 as an engulfment receptor for apoptotic cells  

PubMed Central

Clearance of apoptotic cells (efferocytosis) is critical to the homeostasis of immune system by restraining inflammation and autoimmune response to intracellular antigens released from dying cells. Toll-like receptors (TLRs) mediated innate immunity plays important role in pathogen clearance and in regulation of adaptive immune response. However, the regulation of efferocytosis by activation of TLRs has not been well characterized. In this study, we found that activation of TLR3 or TLR9, but not of TLR2, enhances engulfment of apoptotic cells by macrophages. We found that the activation of TLR3 upregulates the expression of Triggering receptor expressed on myeloid cells (TREM)-like protein 2 (TLT2), a member of TREM receptor family, on the surface of macrophages. Blocking TLT2 on macrophage surface by either specific anti-TLT2 antibody or soluble TLT2 extracellular domain attenuated the enhanced ability of macrophages with TLR3 activation to engulf apoptotic cells. To the contrary, overexpression of TLT2 increased the phagocytosis of apoptotic cells. We found that TLT2 specifically binds to phosphatidylserine (PS), a major “eat me” signal that is exposed on the surface of apoptotic cells. Furthermore, we found that TLT2 mediates phagocytosis of apoptotic cells in vivo. Thus, our studies identified TLT2 as an engulfment receptor for apoptotic cells. Our data also suggest a novel mechanism by which TREM receptors regulate inflammation and autoimmune response. PMID:22573805

de Freitas, Andressa; Banerjee, Sami; Xie, Na; Cui, Huachun; Davis, Kasey I; Friggeri, Arnaud; Fu, Mingui; Abraham, Edward; Liu, Gang

2012-01-01

119

Mitochondrial pro-apoptotic indices do not precede the transient caspase activation associated with myogenesis.  

PubMed

Skeletal muscle differentiation requires activity of the apoptotic protease caspase-3. We attempted to identify the source of caspase activation in differentiating C2C12 skeletal myoblasts. In addition to caspase-3, caspase-2 was transiently activated during differentiation; however, no changes were observed in caspase-8 or -9 activity. Although mitochondrial Bax increased, this was matched by Bcl-2, resulting in no change to the mitochondrial Bax:Bcl-2 ratio early during differentiation. Interestingly, mitochondrial membrane potential increased on a timeline similar to caspase activation and was accompanied by an immediate, temporary reduction in cytosolic Smac and cytochrome c. Since XIAP protein expression dramatically declined during myogenesis, we investigated whether this contributes to caspase-3 activation. Despite reducing caspase-3 activity by up to 57%, differentiation was unaffected in cells overexpressing normal or E3-mutant XIAP. Furthermore, a XIAP mutant which can inhibit caspase-9 but not caspase-3 did not reduce caspase-3 activity or affect differentiation. Administering a chemical caspase-3 inhibitor demonstrated that complete enzyme inhibition was required to impair myogenesis. These results suggest that neither mitochondrial apoptotic signaling nor XIAP degradation is responsible for transient caspase-3 activation during C2C12 differentiation. PMID:25205454

Bloemberg, Darin; Quadrilatero, Joe

2014-12-01

120

The neurotoxicity of 5-S-cysteinyldopamine is mediated by the early activation of ERK1/2 followed by the subsequent activation of ASK1/JNK1/2 pro-apoptotic signalling.  

PubMed

Parkinson's disease is characterized by the progressive and selective loss of dopaminergic neurons in the substantia nigra. It has been postulated that endogenously formed CysDA (5-S-cysteinyldopamine) and its metabolites may be, in part, responsible for this selective neuronal loss, although the mechanisms by which they contribute to such neurotoxicity are not understood. Exposure of neurons in culture to CysDA caused cell injury, apparent 12-48 h post-exposure. A portion of the neuronal death induced by CysDA was preceded by a rapid uptake and intracellular oxidation of CysDA, leading to an acute and transient activation of ERK2 (extracellular-signal-regulated kinase 2) and caspase 8. The oxidation of CysDA also induced the activation of apoptosis signal-regulating kinase 1 via its de-phosphorylation at Ser967, the phosphorylation of JNK (c-Jun N-terminal kinase) and c-Jun (Ser73) as well as the activation of p38, caspase 3, caspase 8, caspase 7 and caspase 9. Concurrently, the inhibition of complex I by the dihydrobenzothiazine DHBT-1 [7-(2-aminoethyl)-3,4-dihydro-5-hydroxy-2H-1,4-benzothiazine-3-carboxylic acid], formed from the intracellular oxidation of CysDA, induces complex I inhibition and the subsequent release of cytochrome c which further potentiates pro-apoptotic mechanisms. Our data suggest a novel comprehensive mechanism for CysDA that may hold relevance for the selective neuronal loss observed in Parkinson's disease. PMID:24938188

Vauzour, David; Pinto, John T; Cooper, Arthur J L; Spencer, Jeremy P E

2014-10-01

121

EBNA3C-Mediated Regulation of Aurora Kinase B Contributes to Epstein-Barr Virus-Induced B-Cell Proliferation through Modulation of the Activities of the Retinoblastoma Protein and Apoptotic Caspases  

PubMed Central

Epstein-Barr virus (EBV) is an oncogenic gammaherpesvirus that is implicated in several human malignancies, including Burkitt's lymphoma (BL), posttransplant lymphoproliferative disease (PTLD), nasopharyngeal carcinoma (NPC), and AIDS-associated lymphomas. Epstein-Barr nuclear antigen 3C (EBNA3C), one of the essential EBV latent antigens, can induce mammalian cell cycle progression through its interaction with cell cycle regulators. Aurora kinase B (AK-B) is important for cell division, and deregulation of AK-B is associated with aneuploidy, incomplete mitotic exit, and cell death. Our present study shows that EBNA3C contributes to upregulation of AK-B transcript levels by enhancing the activity of its promoter. Further, EBNA3C also increased the stability of the AK-B protein, and the presence of EBNA3C leads to reduced ubiquitination of AK-B. Importantly, EBNA3C in association with wild-type AK-B but not with its kinase-dead mutant led to enhanced cell proliferation, and AK-B knockdown can induce nuclear blebbing and cell death. This phenomenon was rescued in the presence of EBNA3C. Knockdown of AK-B resulted in activation of caspase 3 and caspase 9, along with poly(ADP-ribose) polymerase 1 (PARP1) cleavage, which is known to be an important contributor to apoptotic signaling. Importantly, EBNA3C failed to stabilize the kinase-dead mutant of AK-B compared to wild-type AK-B, which suggests a role for the kinase domain in AK-B stabilization and downstream phosphorylation of the cell cycle regulator retinoblastoma protein (Rb). This study demonstrates the functional relevance of AK-B kinase activity in EBNA3C-regulated B-cell proliferation and apoptosis. PMID:23986604

Jha, Hem Chandra; Lu, Jie; Saha, Abhik; Cai, Qiliang; Banerjee, Shuvomoy; Prasad, Mahadesh A. J.

2013-01-01

122

Apoptotic Robotics: Programmed Death by Default  

Microsoft Academic Search

Apoptotic Computing and Apoptotic Communications are inspired by the apoptosis mechanism in biological systems. This mechanism provides security for the overall system by having a preprogrammed death and indeed a death by default at, for instance, the cellular level. It has been argued that this approach should be included in our modern ubiquitous\\/pervasive computerbased systems. This paper specifically makes that

Roy Sterritt

2011-01-01

123

A Novel Anticancer Agent, 8-Methoxypyrimido[4?,5?:4,5]thieno(2,3-b) Quinoline-4(3H)-One Induces Neuro 2a Neuroblastoma Cell Death through p53-Dependent, Caspase-Dependent and -Independent Apoptotic Pathways  

PubMed Central

Neuroblastoma is the most common cancer in infants and fourth most common cancer in children. Despite recent advances in cancer treatments, the prognosis of stage-IV neuroblastoma patients continues to be dismal which warrant new pharmacotherapy. A novel tetracyclic condensed quinoline compound, 8-methoxypyrimido [4?,5?:4,5]thieno(2,3-b) quinoline-4(3H)-one (MPTQ) is a structural analogue of an anticancer drug ellipticine and has been reported to posses anticancer property. Study on MPTQ on neuroblastoma cells is very limited and mechanisms related to its cytotoxicity on neuroblastoma cells are completely unknown. Here, we evaluated the anticancer property of MPTQ on mouse neuro 2a and human SH-SY5Y neuroblastoma cells and investigated the mechanisms underlying MPTQ-mediated neuro 2a cell death. MPTQ-mediated neuro 2a and SH-SY5Y cell deaths were found to be dose and time dependent. Moreover, MPTQ induced cell death reached approximately 99.8% and 90% in neuro 2a and SH-SY5Y cells respectively. Nuclear oligonucleosomal DNA fragmentation and Terminal dUTP Nick End Labelling assays indicated MPTQ-mediated neuro 2a cell death involved apoptosis. MPTQ-mediated apoptosis is associated with increased phosphorylation of p53 at Ser15 and Ser20 which correlates with the hyperphosphorylation of Ataxia-Telangiectasia mutated protein (ATM). Immunocytochemical analysis demonstrated the increased level of Bax protein in MPTQ treated neuro 2a cells. MPTQ-mediated apoptosis is also associated with increased activation of caspase-9, -3 and -7 but not caspase-2 and -8. Furthermore, increased level of caspase-3 and cleaved Poly (ADP Ribose) polymerase were observed in the nucleus of MPTQ treated neuro 2a cells, suggesting the involvement of caspase-dependent intrinsic but not extrinsic apoptotic pathway. Increased nuclear translocation of apoptosis inducing factor suggests additional involvement of caspase-independent apoptosis pathway in MPTQ treated neuro 2a cells. Collectively, MPTQ-induced neuro 2a cell death is mediated by ATM and p53 activation, and Bax-mediated activation of caspase-dependent and caspase-independent mitochondrial apoptosis pathways. PMID:23824039

Sahu, Upasana; Sidhar, Himakshi; Ghate, Pankaj S.; Advirao, Gopal M.; Raghavan, Sathees C.; Giri, Ranjit K.

2013-01-01

124

EPO Mediates Neurotrophic, Neuroprotective, Anti-Oxidant, and Anti-Apoptotic Effects via Downregulation of miR-451 and miR-885-5p in SH-SY5Y Neuron-Like Cells  

PubMed Central

Erythropoietin (EPO) is a neuroprotective cytokine, which has been applied in several animal models presenting neurological disorders. One of the proposed modes of action resulting in neuroprotection is post-transcriptional gene expression regulation. This directly brings to mind microRNAs (miRNAs), which are small non-coding RNAs that regulate gene expression at the post-transcriptional level. It has not yet been evaluated whether miRNAs participate in the biological effects of EPO or whether it, inversely, modulates specific miRNAs in neuronal cells. In this study, we employed miRNA and mRNA arrays to identify how EPO exerts its biological function. Notably, miR-451 and miR-885-5p are downregulated in EPO-treated SH-SY5Y neuronal-like cells. Accordingly, target prediction and transcriptome analysis of cells treated with EPO revealed an alteration of the expression of genes involved in apoptosis, cell survival, proliferation, and migration. Low expression of miRNAs in SH-SY5Y was correlated with high expression of their target genes, vascular endothelial growth factor A, matrix metallo peptidase 9 (MMP9), cyclin-dependent kinase 2 (CDK2), erythropoietin receptor, Mini chromosome maintenance complex 5 (MCM5), B-cell lymphoma 2 (BCL2), and Galanin (GAL). Cell viability, apoptosis, proliferation, and migration assays were carried out for functional analysis after transfection with miRNA mimics, which inhibited some biological actions of EPO such as neuroprotection, anti-oxidation, anti-apoptosis, and migratory effects. In this study, we report for the first time that EPO downregulates the expression of miRNAs (miR-451 and miR-885-5p) in SH-SY5Y neuronal-like cells. The correlation between the over-expression of miRNAs and the decrease in EPO-mediated biological effects suggests that miR-451 and miR-885-5p may play a key role in the mediation of biological function. PMID:25324845

Alural, Begum; Duran, Gizem Ayna; Tufekci, Kemal Ugur; Allmer, Jens; Onkal, Zeynep; Tunali, Dogan; Genc, Kursad; Genc, Sermin

2014-01-01

125

Bax targets mitochondria by distinct mechanisms before or during apoptotic cell death: a requirement for VDAC2 or Bak for efficient Bax apoptotic function.  

PubMed

In non-apoptotic cells, Bak constitutively resides in the mitochondrial outer membrane. In contrast, Bax is in a dynamic equilibrium between the cytosol and mitochondria, and is commonly predominant in the cytosol. In response to an apoptotic stimulus, Bax and Bak change conformation, leading to Bax accumulation at mitochondria and Bak/Bax oligomerization to form a pore in the mitochondrial outer membrane that is responsible for cell death. Using blue native-PAGE to investigate how Bax oligomerizes in the mitochondrial outer membrane, we observed that, like Bak, a proportion of Bax that constitutively resides at mitochondria associates with voltage-dependent anion channel (VDAC)2 prior to an apoptotic stimulus. During apoptosis, Bax dissociates from VDAC2 and homo-oligomerizes to form high molecular weight oligomers. In cells that lack VDAC2, constitutive mitochondrial localization of Bax and Bak was impaired, suggesting that VDAC2 has a role in Bax and Bak import to, or stability at, the mitochondrial outer membrane. However, following an apoptotic stimulus, Bak and Bax retained the ability to accumulate at VDAC2-deficient mitochondria and to mediate cell death. Silencing of Bak in VDAC2-deficient cells indicated that Bax required either VDAC2 or Bak in order to translocate to and oligomerize at the mitochondrial outer membrane to efficiently mediate apoptosis. In contrast, efficient Bak homo-oligomerization at the mitochondrial outer membrane and its pro-apoptotic function required neither VDAC2 nor Bax. Even a C-terminal mutant of Bax (S184L) that localizes to mitochondria did not constitutively target mitochondria deficient in VDAC2, but was recruited to mitochondria following an apoptotic stimulus dependent on Bak or upon over-expression of Bcl-xL. Together, our data suggest that Bax localizes to the mitochondrial outer membrane via alternate mechanisms, either constitutively via an interaction with VDAC2 or after activation via interaction with Bcl-2 family proteins. PMID:25146925

Ma, S B; Nguyen, T N; Tan, I; Ninnis, R; Iyer, S; Stroud, D A; Menard, M; Kluck, R M; Ryan, M T; Dewson, G

2014-12-01

126

The Anti-Apoptotic Role of Neurotensin  

PubMed Central

The neuropeptide, neurotensin, exerts numerous biological functions, including an efficient anti-apoptotic role, both in the central nervous system and in the periphery. This review summarizes studies that clearly evidenced the protective effect of neurotensin through its three known receptors. The pivotal involvement of the neurotensin receptor-3, also called sortilin, in the molecular mechanisms of the anti-apoptotic action of neurotensin has been analyzed in neuronal cell death, in cancer cell growth and in pancreatic beta cell protection. The relationships between the anti-apoptotic role of neurotensin and important physiological and pathological contexts are discussed in this review. PMID:24709648

Devader, Christelle; Beraud-Dufour, Sophie; Coppola, Thierry; Mazella, Jean

2013-01-01

127

The anti-apoptotic role of neurotensin.  

PubMed

The neuropeptide, neurotensin, exerts numerous biological functions, including an efficient anti-apoptotic role, both in the central nervous system and in the periphery. This review summarizes studies that clearly evidenced the protective effect of neurotensin through its three known receptors. The pivotal involvement of the neurotensin receptor-3, also called sortilin, in the molecular mechanisms of the anti-apoptotic action of neurotensin has been analyzed in neuronal cell death, in cancer cell growth and in pancreatic beta cell protection. The relationships between the anti-apoptotic role of neurotensin and important physiological and pathological contexts are discussed in this review. PMID:24709648

Devader, Christelle; Béraud-Dufour, Sophie; Coppola, Thierry; Mazella, Jean

2013-01-01

128

Serum-dependent processing of late apoptotic cells for enhanced efferocytosis.  

PubMed

Binding of the serum protein complement component C1q to the surface of dying cells facilitates their clearance by phagocytes in a process termed efferocytosis. Here, we investigate during which phase of apoptotic cell death progression C1q binding takes place. Purified C1q was found to bind to all dying cells and, albeit weaker, also to viable cells. The presence of serum abrogated completely the binding to viable cells. In addition, C1q binding to dying cells was limited to a specific subpopulation of late apoptotic/secondary necrotic cells. Co-culturing serum-treated apoptotic cells with human monocytes revealed a much higher phagocytosis of C1q-positive than of C1q-negative late apoptotic/secondary necrotic cells. But this phagocytosis-promoting activity could not be observed with purified C1q. Serum-treated C1q-positive late apoptotic/secondary necrotic cells exhibited a similar volume, a similar degraded protein composition, but a much lower DNA content in comparison with the remaining late apoptotic/secondary necrotic cells. This was mediated by a serum-bound nuclease activity that could be abrogated by G-actin, which is a specific inhibitor of serum DNase I. These results show that serum factors are involved in the prevention of C1q binding to viable cells and in the processing of late apoptotic/secondary necrotic cells promoting cell death progression toward apoptotic bodies. This process leads to the exposure of C1q-binding structures and facilitates efferocytosis. PMID:24874736

Liang, Y Y; Arnold, T; Michlmayr, A; Rainprecht, D; Perticevic, B; Spittler, A; Oehler, R

2014-01-01

129

Serum-dependent processing of late apoptotic cells for enhanced efferocytosis  

PubMed Central

Binding of the serum protein complement component C1q to the surface of dying cells facilitates their clearance by phagocytes in a process termed efferocytosis. Here, we investigate during which phase of apoptotic cell death progression C1q binding takes place. Purified C1q was found to bind to all dying cells and, albeit weaker, also to viable cells. The presence of serum abrogated completely the binding to viable cells. In addition, C1q binding to dying cells was limited to a specific subpopulation of late apoptotic/secondary necrotic cells. Co-culturing serum-treated apoptotic cells with human monocytes revealed a much higher phagocytosis of C1q-positive than of C1q-negative late apoptotic/secondary necrotic cells. But this phagocytosis-promoting activity could not be observed with purified C1q. Serum-treated C1q-positive late apoptotic/secondary necrotic cells exhibited a similar volume, a similar degraded protein composition, but a much lower DNA content in comparison with the remaining late apoptotic/secondary necrotic cells. This was mediated by a serum-bound nuclease activity that could be abrogated by G-actin, which is a specific inhibitor of serum DNase I. These results show that serum factors are involved in the prevention of C1q binding to viable cells and in the processing of late apoptotic/secondary necrotic cells promoting cell death progression toward apoptotic bodies. This process leads to the exposure of C1q-binding structures and facilitates efferocytosis. PMID:24874736

Liang, Y Y; Arnold, T; Michlmayr, A; Rainprecht, D; Perticevic, B; Spittler, A; Oehler, R

2014-01-01

130

Ras Homolog Enriched in Brain (Rheb) Enhances Apoptotic Signaling*  

PubMed Central

Rheb is a homolog of Ras GTPase that regulates cell growth, proliferation, and regeneration via mammalian target of rapamycin (mTOR). Because of the well established potential of activated Ras to promote survival, we sought to investigate the ability of Rheb signaling to phenocopy Ras. We found that overexpression of lipid-anchored Rheb enhanced the apoptotic effects induced by UV light, TNF?, or tunicamycin in an mTOR complex 1 (mTORC1)-dependent manner. Knocking down endogenous Rheb or applying rapamycin led to partial protection, identifying Rheb as a mediator of cell death. Ras and c-Raf kinase opposed the apoptotic effects induced by UV light or TNF? but did not prevent Rheb-mediated apoptosis. To gain structural insight into the signaling mechanisms, we determined the structure of Rheb-GDP by NMR. The complex adopts the typical canonical fold of RasGTPases and displays the characteristic GDP-dependent picosecond to nanosecond backbone dynamics of the switch I and switch II regions. NMR revealed Ras effector-like binding of activated Rheb to the c-Raf-Ras-binding domain (RBD), but the affinity was 1000-fold lower than the Ras/RBD interaction, suggesting a lack of functional interaction. shRNA-mediated knockdown of apoptosis signal-regulating kinase 1 (ASK-1) strongly reduced UV or TNF?-induced apoptosis and suppressed enhancement by Rheb overexpression. In conclusion, Rheb-mTOR activation not only promotes normal cell growth but also enhances apoptosis in response to diverse toxic stimuli via an ASK-1-mediated mechanism. Pharmacological regulation of the Rheb/mTORC1 pathway using rapamycin should take the presence of cellular stress into consideration, as this may have clinical implications. PMID:20685651

Karassek, Sascha; Berghaus, Carsten; Schwarten, Melanie; Goemans, Christoph G.; Ohse, Nadine; Kock, Gerd; Jockers, Katharina; Neumann, Sebastian; Gottfried, Sebastian; Herrmann, Christian; Heumann, Rolf; Stoll, Raphael

2010-01-01

131

Intercellular transfer of apoptotic signals via electrofusion  

SciTech Connect

We determined whether cells that are induced to undergo anoikis by matrix detachment can initiate apoptosis in healthy cells following electroporation-induced fusion. Separate populations of MDCK cells undergoing anoikis and stained with FITC-annexin or viable MDCK cells that were labeled with spectrally discrete fluorescent beads were electroporated. Cells were analyzed by flow cytometry for enumeration of viable cells with beads, apoptotic cells or fused cells. Electroporation promoted a 49-fold increase of the percentage of viable cells that had fused with apoptotic cells. Apoptotic cell-viable cell fusions were 8-fold more likely to not attach to cell culture plastic and 2.3-fold less likely to proliferate after 24 hr incubation than viable cell fusion controls. These data demonstrate that apoptotic signals can be transferred between cells by electrofusion, possibly suggesting a novel investigative approach for optimizing targeted cell deletion in cancer treatment.

Park, Jin Suk; Lee, Wilson; McCulloch, Christopher A., E-mail: christopher.mcculloch@utoronto.ca

2012-05-01

132

Toxicological and pharmacokinetic properties of QPI-1007, a chemically modified synthetic siRNA targeting caspase 2 mRNA, following intravitreal injection.  

PubMed

We report the toxicological and pharmacokinetic properties of the synthetic, small interfering RNA (siRNA), QPI-1007, following intravitreal administration. QPI-1007 is a chemically modified siRNA designed to act via the RNA interference (RNAi) pathway to temporarily inhibit expression of the caspase 2 protein and is being developed as a neuroprotectant for the treatment of nonarteritic anterior ischemic optic neuropathy and other optic neuropathies such as glaucoma that result in the death of retinal ganglion cells. The half-life of QPI-1007 in the vitreous and retina/choroid in the Dutch Belted rabbit was about 2 days, and there was no sign of accumulation after repeated administrations at either 2- or 4-week dosing intervals in the rabbit. QPI-1007 was well tolerated in Dutch Belted rabbits following single or repeated intravitreal administrations of up to 11 doses over 9 months. Test-article-related effects were limited to the eyes, with minimal to mild vitreal cellular infiltration being the major finding, which was reversible. In repeated-dose studies, a modest reduction in B-wave amplitude obtained by electroretinography was observed in animals treated with the highest dose level tested (3 mg, which is equivalent to a 12 mg/eye human dose) that was not considered to be clinically meaningful. Administration in the rat of either a single bolus intravenous (i.v.) injection of 100 mg/kg or daily bolus i.v. injections of 75 mg/kg/day for 28 days failed to elicit any macroscopic or microscopic changes, suggesting a low risk for systemic toxicity. QPI-1007 was negative in three genetic toxicity studies. Overall, the nonclinical studies support the further development of QPI-1007. PMID:25054518

Solano, Elisabeth C R; Kornbrust, Douglas J; Beaudry, Amber; Foy, Jeffrey W-D; Schneider, David J; Thompson, James D

2014-08-01

133

Anti-apoptotic effects of osteopontin through the up-regulation of Mcl-1 in gastrointestinal stromal tumors  

PubMed Central

Background Osteopontin (OPN) is a secreted phosphoprotein expressed by neoplastic cells involved in the malignant potential and aggressive phenotypes of human malignancies, including gastrointestinal stromal tumors (GISTs). Our previous study showed that OPN can promote tumor cell proliferation in GISTs. In this series, we further aim to investigate the effect of OPN on apoptosis in GISTs. Methods The expression of apoptotic and anti-apoptotic proteins in response to OPN was evaluated. In vitro effects of OPN against apoptosis in GIST were also assessed. GIST specimens were also used for analyzing protein expression of specific apoptosis-related molecules and their clinicopathologic significance. Results Up-regulation of ?-catenin and anti-apoptotic proteins Mcl-1 with concomitant suppression of apoptotic proteins in response to OPN was noted. A significant anti-apoptotic effect of OPN on imatinib-induced apoptosis was identified. Furthermore, Mcl-1 overexpression was significantly associated with OPN and ?-catenin expression in tumor tissues, as well as worse survival clinically. Conclusions Our study identifies anti-apoptotic effects of OPN that, through ?-catenin-mediated Mcl-1 up-regulation, significantly antagonized imatinib-induced apoptosis in GISTs. These results provide a potential rationale for therapeutic strategies targeting both OPN and Mcl-1 of the same anti-apoptotic signaling pathway, which may account for resistance to imatinib in GISTs. PMID:24947165

2014-01-01

134

Caspase-3 is required in the apoptotic disintegration of the nuclear matrix  

SciTech Connect

Apoptotic breakdown of cellular structures is largely mediated by caspases. One target of degradation is a proteinaceous framework of the nucleus termed the nuclear matrix. We compared the apoptotic changes of the nuclear matrix in staurosporine-treated caspase-3-deficient MCF-7 cells transfected with intact CASP-3 gene (MCF-7c3) or an empty vector (MCF-7v) as a control. Nuclear Mitotic Apparatus protein (NuMA), lamin A/C and lamin B were used as markers for internal nuclear matrix and peripheral nuclear lamina, respectively. In both cell lines, staurosporine induced rapid cytoplasmic shrinkage and partial chromatin condensation. MCF-7c3 cells formed apoptotic bodies, whereas MCF-7v cells did not. NuMA and lamins were actively cleaved in MCF-7c3 cells following caspase-3 activation, but only minimal or no cleavage was detected in MCF-7v cells. Interestingly, lamin B but not lamin A/C was relocated into cytoplasmic granules in apoptotic MCF-7v cells. Pancaspase inhibitor, z-VAD-fmk, prevented the apoptotic changes, while caspase-3 inhibitor, z-DEVD-fmk, induced lamin B granules in both cell lines. These results show that caspase-3 is involved in the cleavage of NuMA and lamins either directly or by activating other proteases. This may be essential for disintegration of the nuclear structure during apoptosis.

Kivinen, Katri [Department of Pathology, University of Turku, MediCity Research Laboratory, Tykistoekatu 6 A, 4th floor, FIN-20520 Turku (Finland); Turku Graduate School of Biomedical Sciences, Turku (Finland); Kallajoki, Markku [Department of Pathology, University of Turku, MediCity Research Laboratory, Tykistoekatu 6 A, 4th floor, FIN-20520 Turku (Finland); Taimen, Pekka [Department of Pathology, University of Turku, MediCity Research Laboratory, Tykistoekatu 6 A, 4th floor, FIN-20520 Turku (Finland)]. E-mail: pekka.taimen@utu.fi

2005-11-15

135

A stapled BIM peptide overcomes apoptotic resistance in hematologic cancers  

PubMed Central

Cancer cells subvert the natural balance between cellular life and death, achieving immortality through pathologic enforcement of survival pathways and blockade of cell death mechanisms. Pro-apoptotic BCL-2 family proteins are frequently disarmed in relapsed and refractory cancer through genetic deletion or interaction-based neutralization by overexpressed antiapoptotic proteins, resulting in resistance to chemotherapy and radiation treatments. New pharmacologic strategies are urgently needed to overcome these formidable apoptotic blockades. We harnessed the natural killing activity of BCL-2–interacting mediator of cell death (BIM), which contains one of the most potent BH3 death domains of the BCL-2 protein family, to restore BH3-dependent cell death in resistant hematologic cancers. A hydrocarbon-stapled peptide modeled after the BIM BH3 helix broadly targeted BCL-2 family proteins with high affinity, blocked inhibitory antiapoptotic interactions, directly triggered proapoptotic activity, and induced dose-responsive and BH3 sequence–specific cell death of hematologic cancer cells. The therapeutic potential of stapled BIM BH3 was highlighted by the selective activation of cell death in the aberrant lymphoid infiltrates of mice reconstituted with BIM-deficient bone marrow and in a human AML xenograft model. Thus, we found that broad and multimodal targeting of the BCL-2 family pathway can overcome pathologic barriers to cell death. PMID:22622039

LaBelle, James L.; Katz, Samuel G.; Bird, Gregory H.; Gavathiotis, Evripidis; Stewart, Michelle L.; Lawrence, Chelsea; Fisher, Jill K.; Godes, Marina; Pitter, Kenneth; Kung, Andrew L.; Walensky, Loren D.

2012-01-01

136

Skeletal muscle stem cells express anti-apoptotic ErbB receptors during activation from quiescence  

SciTech Connect

To be effective for tissue repair, satellite cells (the stem cells of adult muscle) must survive the initial activation from quiescence. Using an in vitro model of satellite cell activation, we show that erbB1, erbB2 and erbB3, members of the EGF receptor tyrosine kinase family, appear on satellite cells within 6 h of activation. We show that signalling via erbB2 provides an anti-apoptotic survival mechanism for satellite cells during the first 24 h, as they progress to a proliferative state. Inhibition of erbB2 signalling with AG825 reduced satellite cell numbers, concomitant with elevated caspase-8 activation and TUNEL labelling of apoptotic satellite cells. In serum-free conditions, satellite cell apoptosis could be largely prevented by a mixture of erbB1, erbB3 and erbB4 ligand growth factors, but not by neuregulin alone (erbB3/erbB4 ligand). Furthermore, using inhibitors specific to discrete intracellular signalling pathways, we identify MEK as a pro-apoptotic mediator, and the erbB-regulated factor STAT3 as an anti-apoptotic mediator during satellite cell activation. These results implicate erbB2 signalling in the preservation of a full compliment of satellite cells as they activate in the context of a damaged muscle.

Golding, Jon P. [Department of Biological Sciences, Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom)]. E-mail: j.p.golding@open.ac.uk; Calderbank, Emma [Muscle Cell Biology Group, Medical Research Council Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN (United Kingdom); Partridge, Terence A. [Muscle Cell Biology Group, Medical Research Council Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN (United Kingdom); Beauchamp, Jonathan R. [Muscle Cell Biology Group, Medical Research Council Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN (United Kingdom)

2007-01-15

137

Delivery of Intracellular-acting Biologics in Pro-Apoptotic Therapies  

PubMed Central

The recent elucidation of molecular regulators of apoptosis and their roles in cellular oncogenesis has motivated the development of biomacromolecular anticancer therapeutics that can activate intracellular apoptotic signaling pathways. Pharmaceutical scientists have employed a variety of classes of biologics toward this goal, including antisense oligodeoxynucleotides, small interfering RNA, proteins, antibodies, and peptides. However, stability in the in vivo environment, tumor-specific biodistribution, cell internalization, and localization to the intracellular microenvironment where the targeted molecule is localized pose significant challenges that limit the ability to directly apply intracellular-acting, pro-apoptotic biologics for therapeutic use. Thus, approaches to improve the pharmaceutical properties of therapeutic biomacromolecules are of great significance and have included chemically modifying the bioactive molecule itself or formulation with auxiliary compounds. Recently, promising advances in delivery of pro-apoptotic biomacromolecular agents have been made using tools such as peptide “stapling”, cell penetrating peptides, fusogenic peptides, liposomes, nanoparticles, smart polymers, and synergistic combinations of these components. This review will discuss the molecular mediators of cellular apoptosis, the respective mechanisms by which these mediators are dysregulated in cellular oncogenesis, the history and development of both nucleic-acid and amino-acid based drugs, and techniques to achieve intracellular delivery of these biologics. Finally, recent applications where pro-apoptotic functionality has been achieved through delivery of intracellular-acting biomacromolecular drugs will be highlighted. PMID:21348831

Li, Hongmei; Nelson, Chris E.; Evans, Brian C.; Duvall, Craig L.

2013-01-01

138

Involvement of caspase-dependent and -independent apoptotic pathways in cisplatin-induced apoptosis  

NASA Astrophysics Data System (ADS)

Cisplatin, an efficient anticancer agent, can trigger multiple apoptotic pathways in cancer cells. However, the signal transduction pathways in response to cisplatin-based chemotherapy are complicated, and the mechanism is not fully understood. In current study, we showed that, during cisplatin-induced apoptosis of human lung adenocarcinoma cells, both the caspase-dependent and -independent pathways were activated. Herein, we reported that after cisplatin treatment, the activities of caspase-9/-3 were sharply increased; pre-treatment with Z-LEHD-fmk (inhibitor of caspase-9), Z-DEVD-fmk (inhibitor of caspase-3), and Z-VAD-fmk (a pan-caspase inhibitor) increased cell viability and decreased apoptosis, suggesting that caspase-mediated apoptotic pathway was activated following cisplatin treatment. Confocal imaging of the cells transfected with AIF-GFP demonstrated that AIF release occurred about 9 h after cisplatin treatment. The event proceeded progressively over time, coinciding with a nuclear translocation and lasting for more than 2 hours. Down-regulation of AIF by siRNA also significantly increased cell viability and decreased apoptosis, these results suggested that AIF-mediated caspase-independent apoptotic pathway was involved in cispatin-induced apoptosis. In conclusion, the current study demonstrated that both caspase-dependent and -independent apoptotic pathways were involved in cisplatin-induced apoptosis in human lung adenocarcinoma cells.

Liu, Lei; Zhang, Yingjie; Wang, Xianwang

2009-02-01

139

Macrophage expression of LRP1, a receptor for apoptotic cells and unopsonized erythrocytes, can be regulated by glucocorticoids.  

PubMed

Macrophage phagocytosis of apoptotic cells, or unopsonized viable CD47(-/-) red blood cells, can be mediated by the interaction between calreticulin (CRT) on the target cell and LDL receptor-related protein-1 (LRP1/CD91/?2-macroglobulin receptor) on the macrophage. Glucocorticoids (GC) are powerful in treatment of a range of inflammatory conditions, and were shown to enhance macrophage uptake of apoptotic cells. Here we investigated if the ability of GC to promote macrophage uptake of apoptotic cells could in part be mediated by an upregulation of macrophage LRP1 expression. Using both resident peritoneal and bone marrow-derived macrophages, we found that the GC dexamethasone could dose- and time-dependently increase macrophage LRP1 expression. The GC receptor-inhibitor RU486 could dose-dependently prevent LRP1 upregulation. Dexamethasone-treated macrophages did also show enhanced phagocytosis of apoptotic thymocytes as well as unopsonized viable CD47(-/-) red blood cells, which was sensitive to inhibition by the LRP1-agonist RAP. In conclusion, these data suggest that GC-stimulated macrophage uptake of apoptotic cells may involve an upregulation of macrophage LRP1 expression and enhanced LRP1-mediated phagocytosis. PMID:22234309

Nilsson, Anna; Vesterlund, Liselotte; Oldenborg, Per-Arne

2012-01-27

140

Fas transduces dual apoptotic and trophic signals in hematopoietic progenitors.  

PubMed

Stem cells and progenitors are often required to realize their differentiation potential in hostile microenvironments. The Fas/Fas ligand (FasL) interaction is a major effector pathway of apoptosis, which negatively regulates the expansion of differentiated hematopoietic cells. The involvement of this molecular interaction in the function of hematopoietic stem and progenitor cells is not well understood. In the murine syngeneic transplant setting, both Fas and FasL are acutely upregulated in bone marrow-homed donor cells; however, the Fas(+) cells are largely insensitive to FasL-induced apoptosis. In heterogeneous populations of lineage-negative (lin(-)) bone marrow cells and progenitors isolated by counterflow centrifugal elutriation, trimerization of the Fas receptor enhanced the clonogenic activity. Inhibition of caspases 3 and 8 did not affect the trophic signals mediated by Fas, yet it efficiently blocked the apoptotic pathways. Fas-mediated tropism appears to be of physiological significance, as pre-exposure of donor cells to FasL improved the radioprotective qualities of hematopoietic progenitors, resulting in superior survival of myeloablated hosts. Under these conditions, the activity of long-term reconstituting cells was not affected, as determined in sequential secondary and tertiary transplants. Dual caspase-independent tropic and caspase-dependent apoptotic signaling place the Fas receptor at an important junction of activation and death. This regulatory mechanism of hematopoietic homeostasis activates progenitors to promote the recovery from aplasia and converts into a negative regulator in distal stages of cell differentiation. Disclosure of potential conflicts of interest is found at the end of this article. PMID:17872500

Pearl-Yafe, Michal; Stein, Jerry; Yolcu, Esma S; Farkas, Daniel L; Shirwan, Haval; Yaniv, Isaac; Askenasy, Nadir

2007-12-01

141

Apoptotic markers for primary brain tumor prognosis  

Microsoft Academic Search

Summary  Molecular studies of brain tumors have provided insights into pathogenesis, yet it is unclear how important these markers are in predicting clinical outcome and response to treatment. Quantitation of apoptosis by various techniques and the expression of several apoptotic markers have been studied in brain tumors, seeking to refine the information gained from established prognostic variables, which traditionally dictate therapeutic

A. E. Konstantinidou; P. Korkolopoulou; E. Patsouris

2005-01-01

142

Variability in apoptotic response to poliovirus infection  

Microsoft Academic Search

In several cell types, poliovirus activates the apoptotic program, implementation of which is suppressed by viral antiapoptotic functions. In such cells, productive infection leads to a necrotic cytopathic effect (CPE), while abortive reproduction, associated with inadequate viral antiapoptotic functions, results in apoptosis. Here, we describe two other types of cell response to poliovirus infection. Murine L20B cells expressing human poliovirus

Lyudmila I. Romanova; George A. Belov; Peter V. Lidsky; Elena A. Tolskaya; Marina S. Kolesnikova; Alexandra G. Evstafieva; Andrey B. Vartapetian; Denise Egger; Kurt Bienz; Vadim I. Agol

2005-01-01

143

Apoptotic germ-cell death and testicular damage in experimental diabetes: prevention by endothelin antagonism  

Microsoft Academic Search

This paper explores the role of endothelins (ETs) in diabetes-induced testicular damage by investigating, in a temporal manner,\\u000a testes from streptozotocin (STZ)-induced diabetic rats. Testicular and epididymal weights and testicular morphology were assessed.\\u000a Cell death was evaluated by light microscopy using conventional staining and morphology, and by apoptotic cell staining using\\u000a the Terminal deoxynucleotidyl transferase-mediated dUTP Nick End-Labeling (TUNEL) technique.

Lu Cai; Shali Chen; Terry Evans; Diana Xi Deng; Kallol Mukherjee; Subrata Chakrabarti

2000-01-01

144

S-nitrosylated GAPDH initiates apoptotic cell death by nuclear translocation following Siah1 binding  

Microsoft Academic Search

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) influences cytotoxicity, translocating to the nucleus during apoptosis. Here we report a signalling pathway in which nitric oxide (NO) generation that follows apoptotic stimulation elicits S-nitrosylation of GAPDH, which triggers binding to Siah1 (an E3 ubiquitin ligase), nuclear translocation and apoptosis. S-nitrosylation of GAPDH augments its binding to Siah1, whose nuclear localization signal mediates translocation of GAPDH.

Makoto R. Hara; Nishant Agrawal; Sangwon F. Kim; Matthew B. Cascio; Masahiro Fujimuro; Yuji Ozeki; Masaaki Takahashi; Jaime H. Cheah; Stephanie K. Tankou; Lynda D. Hester; Christopher D. Ferris; S. Diane Hayward; Solomon H. Snyder; Akira Sawa

2005-01-01

145

TUNEL Apoptotic Cell Detection in Tissue Sections: Critical Evaluation and Improvement  

Microsoft Academic Search

SUMMARY TUNEL, i.e., terminal deoxynucleotidyl transferase-mediated dUTP nick end- labeling, has become a widely used staining method to assist in detection of apoptotic cells in tissue sections. However, despite its apparent simplicity, this technique has led to consid- erable disappointment because of its serious limitations in sensitivity and, even more, in specificity. We reviewed the limitations and artifacts of TUNEL

Françoise Labat-Moleur; Christiane Guillermet; Philippe Lorimier; Catherine Robert; Sylvie Lantuejoul; Elisabeth Brambilla; Adrien Negoescu

1998-01-01

146

Tributyltin induces apoptotic signaling in hepatocytes through pathways involving the endoplasmic reticulum and mitochondria  

SciTech Connect

Tri-n-butyltin is a widespread environmental toxicant, which accumulates in the liver. This study investigates whether tri-n-butyltin induces pro-apoptotic signaling in rat liver hepatocytes through pathways involving the endoplasmic reticulum and mitochondria. Tri-n-butyltin activated the endoplasmic reticulum pathway of apoptosis, which was demonstrated by the activation of the protease calpain, its translocation to the plasma membrane, followed by cleavage of the calpain substrates, cytoskeletal protein vinculin, and caspase-12. Caspase-12 is localized to the cytoplasmic side of the endoplasmic reticulum and is involved in apoptosis mediated by the endoplasmic reticulum. Tri-n-butyltin also caused translocation of the pro-apoptotic proteins Bax and Bad from the cytosol to mitochondria, as well as changes in mitochondrial membrane permeability, events which can activate the mitochondrial death pathway. Tri-n-butyltin induced downstream apoptotic events in rat hepatocytes at the nuclear level, detected by chromatin condensation and by confocal microscopy using acridine orange. We investigated whether the tri-n-butyltin-induced pro-apoptotic events in hepatocytes could be linked to perturbation of intracellular calcium homeostasis, using confocal microscopy. Tri-n-butyltin caused changes in intracellular calcium distribution, which were similar to those induced by thapsigargin. Calcium was released from a subcellular compartment, which is likely to be the endoplasmic reticulum, into the cytosol. Cytosolic acidification, which is known to trigger apoptosis, also occurred and involved the Cl{sup -}/HCO{sub 3} {sup -} exchanger. Pro-apoptotic events in hepatocytes were inhibited by the calcium chelator, Bapta-AM, and by a calpain inhibitor, which suggests that changes in intracellular calcium homeostasis are involved in tri-n-butyltin-induced apoptotic signaling in rat hepatocytes.

Grondin, Melanie [Departement de Chimie, Centre de Recherche en Toxicologie de l'environnement (TOXEN), Universite du Quebec a Montreal, CP 8888, Succursale Centre-Ville, Montreal, Quebec, H3C 3P8 (Canada); Marion, Michel [Departement de Chimie, Centre de Recherche en Toxicologie de l'environnement (TOXEN), Universite du Quebec a Montreal, CP 8888, Succursale Centre-Ville, Montreal, Quebec, H3C 3P8 (Canada); Denizeau, Francine [Departement de Chimie, Centre de Recherche en Toxicologie de l'environnement (TOXEN), Universite du Quebec a Montreal, CP 8888, Succursale Centre-Ville, Montreal, Quebec, H3C 3P8 (Canada); Averill-Bates, Diana A. [Departement des Sciences Biologiques, Centre de Recherche en Toxicologie de l'environnement (TOXEN), Universite du Quebec a Montreal, Montreal, Quebec (Canada)]. E-mail: averill.diana@uqam.ca

2007-07-01

147

Pituitary mitosis and apoptotic responsiveness following adrenalectomy are independent of hypothalamic paraventricular nucleus CRH input.  

PubMed

We have previously identified a series of age-dependent, temporally constrained and closely interdependent mitotic and apoptotic events in the male rat anterior pituitary that occur in response to timed single and repeated hypothalamo-pituitary-adrenal axis stimuli. One of the most dramatic of these is the short burst of apoptosis that occurs 24-48 h after exposure to dexamethasone. If bilateral adrenalectomy precedes exposure to dexamethasone by 1-2 weeks, mitotic activity is transiently increased and the subsequent apoptotic response to dexamethasone greatly enhanced. This study was designed to determine whether adrenalectomy-induced augmentation of the apoptotically sensitive pituitary cell population is mediated via glucocorticoid withdrawal at the level of the pituitary, or whether increased exposure to hypothalamo-hypophyseal trophic hormones of paraventricular origin is responsible. We used stereotaxic surgery to isolate both paraventricular nuclei without disturbing either median eminence input from the arcuate and supraoptic nuclei, or the hypothalamo-hypophyseal-portal blood flow that carries a significant proportion of the pituitary systemic supply. When bilateral adrenalectomy and paraventricular nucleus disconnection were combined, the adrenalectomy-induced increase in anterior pituitary pro-opiomelanocortin (POMC) transcript prevalence was abolished, confirming the loss of paraventricular corticotrophin-releasing hormone (CRH) input. However, the amplitude and pattern of the adrenalectomy-induced anterior pituitary mitotic response and enhancement of the apoptotic response to dexamethasone 1 week later remained completely intact. These data demonstrate that anterior pituitary trophic responses following bilateral adrenalectomy are more likely to be mediated through direct glucocorticoid withdrawal at the level of the pituitary rather than via changes in hypothalamo-hypophyseal releasing factor exposure. This finding highlights the presence of distinct control systems for pituitary hormone gene expression and pituitary mitotic and apoptotic responses. PMID:15171700

Nolan, L A; Thomas, C K; Levy, A

2004-06-01

148

Fetal bovine serum requirement for pyrrolidine dithiocarbamate-induced apoptotic cell death of MCF7 breast tumor cells  

Microsoft Academic Search

Pyrrolidine dithiocarbamate (PDTC) can form a complex with metal ions and then act as a proteasome inhibitor, which leads to tumor cell apoptosis, and could therefore be developed as an anticancer agent. In our efforts to find factors that induce PDTC-mediated apoptosis of tumor cells, the effect of serum concentration on the apoptotic activity of PDTC was investigated. PDTC could

Da Hee Oh; Jun Soo Bang; Hyun Mi Choi; Hyung-In Yang; Myung Chul Yoo; Kyoung Soo Kim

2010-01-01

149

Cytoplasmic and Nuclear Anti-Apoptotic Roles of ?B-Crystallin in Retinal Pigment Epithelial Cells  

PubMed Central

In addition to its well-characterized role in the lens, ?B-crystallin performs other functions. Methylglyoxal (MGO) can alter the function of the basement membrane of retinal pigment epithelial (RPE) cells. Thus, if MGO is not efficiently detoxified, it can induce adverse reactions in RPE cells. In this study, we examined the mechanisms underlying the anti-apoptotic activity of ?B-crystallin in the human retinal pigment epithelial cell line ARPE-19 following MGO treatment using various assays, including nuclear staining, flow cytometry, DNA electrophoresis, pulse field gel electrophoresis, western blot analysis, confocal microscopy and co-immunoprecipitation assays. To directly assess the role of phosphorylation of ?B-crystallin, we used site-directed mutagenesis to convert relevant serine residues to alanine residues. Using these techniques, we demonstrated that MGO induces apoptosis in ARPE-19 cells. Silencing ?B-crystallin sensitized ARPE-19 cells to MGO-induced apoptosis, indicating that ?B-crystallin protects ARPE-19 cells from MGO-induced apoptosis. Furthermore, we found that ?B-crystallin interacts with the caspase subtypes, caspase-2L, -2S, -3, -4, -7, -8, -9 and -12 in untreated control ARPE-19 cells and that MGO treatment caused the dissociation of these caspase subtypes from ?B-crystallin; transfection of S19A, S45A or S59A mutants caused the depletion of ?B-crystallin from the nuclei of untreated control RPE cells leading to the release of caspase subtypes. Additionally, transfection of these mutants enhanced MGO-induced apoptosis in ARPE-19 cells, indicating that phosphorylation of nuclear ?B-crystallin on serine residues 19, 45 and 59 plays a pivotal role in preventing apoptosis in ARPE-19 cells. Taken together, these results suggest that ?B-crystallin prevents caspase activation by physically interacting with caspase subtypes in the cytoplasm and nucleus, thereby protecting RPE cells from MGO-induced apoptosis. PMID:23049853

Yoo, Seung Hee; Jeong, Na Young; Ryu, Won Yeol; Ahn, Hee Bae; Park, Woo Chan; Rho, Sae Heun; Yoon, Hee Seong; Choi, Yung Hyun; Yoo, Young Hyun

2012-01-01

150

New Lives Given by Cell Death: Macrophage Differentiation Following Their Encounter with Apoptotic Leukocytes during the Resolution of Inflammation  

PubMed Central

Monocytes that migrate into tissues during inflammatory episodes and differentiate to macrophages were previously classified as classically (M1) or alternatively (M2) activated macrophages, based on their exposure to different fate-determining mediators. These macrophage subsets display distinct molecular markers and differential functions. At the same time, studies from recent years found that the encounter of apoptotic leukocytes with macrophages leads to the clearance of this cellular “debris” by the macrophages, while concomitantly reprogramming/immune-silencing the macrophages. While some of the features of M2 differentiation, such as arginase-1 (murine) and 15-lipoxygenases (human and murine) expression, were also displayed by macrophages following the engulfment of apoptotic cells, it was not clear whether apoptotic cells can be regarded as an M2-like differentiating signal. In this manuscript we review the recent information regarding the impact of apoptotic cells on macrophage phenotype changes in molecular terms. We will focus on recent evidence for the in vivo existence of distinct pro-resolving macrophages and the role of apoptotic cells, specialized lipid mediators, and glucocorticoids in their generation. Consequently, we will suggest that these pro-resolving CD11blow macrophages have metamorphed from M2-like macrophages, and modulated their protein profile to accommodate the changes in their function. PMID:22566890

Ariel, Amiram; Serhan, Charles N.

2012-01-01

151

Apoptotic microtubules delimit an active caspase free area in the cellular cortex during the execution phase of apoptosis  

PubMed Central

Apoptotic microtubule network (AMN) is organized during apoptosis, forming a cortical structure beneath plasma membrane, which has an important role in preserving cell morphology and plasma membrane permeability. The aim of this study was to examine the role of AMN in maintaining plasma membrane integrity during the execution phase of apoptosis. We demonstrated in camptothecin-induced apoptosis in H460 cells that AMN delimits an active caspase free area beneath plasma membrane that permits the preservation of cellular cortex and transmembrane proteins. AMN depolymerization in apoptotic cells by a short exposure to colchicine allowed active caspases to reach the cellular cortex and cleave many key proteins involved in plasma membrane structural support, cell adhesion and ionic homeostasis. Cleavage of cellular cortex and plasma membrane proteins, such as ?-spectrin, paxilin, focal adhesion kinase (FAK), E-cadherin and integrin subunit ?4 was associated with cell collapse and cell detachment. Otherwise, cleavage-mediated inactivation of calcium ATPase pump (PMCA-4) and Na+/Ca2+ exchanger (NCX) involved in cell calcium extrusion resulted in calcium overload. Furthermore, cleavage of Na+/K+ pump subunit ? was associated with altered sodium homeostasis. Cleavage of cell cortex and plasma membrane proteins in apoptotic cells after AMN depolymerization increased plasma permeability, ionic imbalance and bioenergetic collapse, leading apoptotic cells to secondary necrosis. The essential role of caspase-mediated cleavage in this process was demonstrated because the concomitant addition of colchicine that induces AMN depolymerization and the pan-caspase inhibitor z-VAD avoided the cleavage of cortical and plasma membrane proteins and prevented apoptotic cells to undergo secondary necrosis. Furthermore, the presence of AMN was also critical for proper phosphatidylserine externalization and apoptotic cell clearance by macrophages. These results indicate that AMN is essential to preserve an active caspase free area in the cellular cortex of apoptotic cells that allows plasma membrane integrity during the execution phase of apoptosis. PMID:23470534

Oropesa-Avila, M; Fernandez-Vega, A; de la Mata, M; Maraver, J G; Cordero, M D; Cotan, D; de Miguel, M; Calero, C P; Paz, M V; Pavon, A D; Sanchez, M A; Zaderenko, A P; Ybot-Gonzalez, P; Sanchez-Alcazar, J A

2013-01-01

152

Apoptotic microtubules delimit an active caspase free area in the cellular cortex during the execution phase of apoptosis.  

PubMed

Apoptotic microtubule network (AMN) is organized during apoptosis, forming a cortical structure beneath plasma membrane, which has an important role in preserving cell morphology and plasma membrane permeability. The aim of this study was to examine the role of AMN in maintaining plasma membrane integrity during the execution phase of apoptosis. We demonstrated in camptothecin-induced apoptosis in H460 cells that AMN delimits an active caspase free area beneath plasma membrane that permits the preservation of cellular cortex and transmembrane proteins. AMN depolymerization in apoptotic cells by a short exposure to colchicine allowed active caspases to reach the cellular cortex and cleave many key proteins involved in plasma membrane structural support, cell adhesion and ionic homeostasis. Cleavage of cellular cortex and plasma membrane proteins, such as ?-spectrin, paxilin, focal adhesion kinase (FAK), E-cadherin and integrin subunit ?4 was associated with cell collapse and cell detachment. Otherwise, cleavage-mediated inactivation of calcium ATPase pump (PMCA-4) and Na(+)/Ca(2+) exchanger (NCX) involved in cell calcium extrusion resulted in calcium overload. Furthermore, cleavage of Na(+)/K(+) pump subunit ? was associated with altered sodium homeostasis. Cleavage of cell cortex and plasma membrane proteins in apoptotic cells after AMN depolymerization increased plasma permeability, ionic imbalance and bioenergetic collapse, leading apoptotic cells to secondary necrosis. The essential role of caspase-mediated cleavage in this process was demonstrated because the concomitant addition of colchicine that induces AMN depolymerization and the pan-caspase inhibitor z-VAD avoided the cleavage of cortical and plasma membrane proteins and prevented apoptotic cells to undergo secondary necrosis. Furthermore, the presence of AMN was also critical for proper phosphatidylserine externalization and apoptotic cell clearance by macrophages. These results indicate that AMN is essential to preserve an active caspase free area in the cellular cortex of apoptotic cells that allows plasma membrane integrity during the execution phase of apoptosis. PMID:23470534

Oropesa-Ávila, M; Fernández-Vega, A; de la Mata, M; Maraver, J G; Cordero, M D; Cotán, D; de Miguel, M; Calero, C P; Paz, M V; Pavón, A D; Sánchez, M A; Zaderenko, A P; Ybot-González, P; Sánchez-Alcázar, J A

2013-01-01

153

Active deformation of apoptotic intestinal epithelial cells with adhesion-restricted polarity contributes to apoptotic clearance.  

PubMed

Dying epithelial cells are thought to be squeezed out of the epithelium by the contraction of an actomyosin ring formed in live neighboring cells, which simultaneously closes any potential gap, thereby maintaining the integrity of the epithelial layer. The shrinkage and contraction of apoptotic cells contribute little to the extrusion process. In contrast, the clearance of dying intestinal columnar epithelial cells in vivo usually leaves a transient gap via an unknown mechanism. By using freshly isolated small intestinal villus units with or without basal lamina, we found that the nucleus of apoptotic enterocytes moved apically until they budded off, leaving the cytoplasmic residue in the transient gap. Apical polarity of nucleus movement was restricted unless the basal lamina was artificially removed. F-actin mainly accumulated in apoptotic cells rather than neighboring live cells, even after the addition of resistance force against extrusion. The actin accumulation in apoptotic cells does not depend on the living state of neighboring cells. Apoptotic cells can complete the shedding process when neighboring a goblet cell, as the majority of space is occupied by mucin granules and the cytoplasm consists of intermediate filaments and microtubules, but lacks F-actin. We found that the elongation and deformation of apoptotic cells depend on the stretching force generated inside the cell, rather than the force generated by neighboring cells extending. Our findings clearly demonstrate that intestinal epithelial shedding does not depend on the formation and contraction of an actomyosin ring in live neighboring cells. Apoptotic epithelial cells may undergo an active process of cell deformation with adhesion-restricted polarity, which may contribute to maintaining barrier function during a high rate of cellular turnover. PMID:21042290

Wang, Fengchao; Wang, Fengjun; Zou, Zhongmin; Liu, Dengqun; Wang, Junping; Su, Yongping

2011-03-01

154

Apoptosis and apoptotic mimicry: the Leishmania connection  

Microsoft Academic Search

Different death-styles have been described in unicellular organisms. In most cases they evolve with phenotypic features similar\\u000a to apoptotic death of animal cells, such as phosphatidylserine (PS) exposure, oligonucleosomal DNA fragmentation, and loss\\u000a of mitochondrial transmembrane potential, hinting that similar mechanisms operate in both situations. However, the biochemical\\u000a pathways underlying death in unicellular organisms are still unclear. Host recognition of

João Luiz M. Wanderley; Marcello A. Barcinski

2010-01-01

155

Clearance of Apoptotic Cells – Mechanisms and Consequences  

Microsoft Academic Search

Cells undergo apoptosis in development, tissue homeostasis, and disease and are subsequently cleared by professional and nonprofessional\\u000a phagocytes in a multistep process. In this chapter, we first break down the clearance process into its components and then\\u000a show that there is now overwhelming evidence that phagocyte function is profoundly altered following apoptotic cell uptake\\u000a as well as mounting evidence that

Carylyn J. Marek; Lars-Peter Erwig

156

Variability in apoptotic response to poliovirus infection.  

PubMed

In several cell types, poliovirus activates the apoptotic program, implementation of which is suppressed by viral antiapoptotic functions. In such cells, productive infection leads to a necrotic cytopathic effect (CPE), while abortive reproduction, associated with inadequate viral antiapoptotic functions, results in apoptosis. Here, we describe two other types of cell response to poliovirus infection. Murine L20B cells expressing human poliovirus receptor responded to the infection by both CPE and apoptosis concurrently. Interruption of productive infection decreased rather than increased the proportion of apoptotic cells. Productive infection was accompanied by the early efflux of cytochrome c from the mitochondria in a proportion of cells and by activation of DEVD-specific caspases. Inactivation of caspase-9 resulted in a marked, but incomplete, prevention of the apoptotic response of these cells to viral infection. Thus, the poliovirus-triggered apoptotic program in L20B cells was not completely suppressed by the viral antiapoptotic functions. In contrast, human rhabdomyosarcoma RD cells did not develop appreciable apoptosis during productive or abortive infection, exhibiting inefficient efflux of cytochrome c from mitochondria and no marked activation of DEVD-specific caspases. The cells were also refractory to several nonviral apoptosis inducers. Nevertheless, typical caspase-dependent signs of apoptosis in a proportion of RD cells were observed after cessation of viral reproduction. Such "late" apoptosis was also observed in productively infected HeLa cells. In addition, a tiny proportion of all studied cells were TUNEL positive even in the presence of a caspase inhibitor. Degradation of DNA in such cells appeared to be a postmortem phenomenon. Biological relevance of variable host responses to viral infection is discussed. PMID:15629772

Romanova, Lyudmila I; Belov, George A; Lidsky, Peter V; Tolskaya, Elena A; Kolesnikova, Marina S; Evstafieva, Alexandra G; Vartapetian, Andrey B; Egger, Denise; Bienz, Kurt; Agol, Vadim I

2005-01-20

157

Antiproliferative and apoptotic effects of spanish honeys  

PubMed Central

Background: Current evidence supports that consumption of polyphenols has beneficial effects against numerous diseases mostly associated with their antioxidant activity. Honey is a good source of antioxidants since it contains a great variety of phenolic compounds. Objective: The main objective of this work was to investigate the antiproliferative and apoptotic effects of three crude commercial honeys of different floral origin (heather, rosemary and polyfloral honey) from Madrid Autonomic Community (Spain) as well as of an artificial honey in human peripheral blood promyelocytic leukemia cells (HL-60). Material and Methods: HL-60 cells were cultured in the presence of honeys at various concentrations for up to 72 hours and the percentage of cell viability was evaluated by MTT assay. Apoptotic cells were identified by chromatin condensation and flow cytometry analysis. ROS production was determined using 2´,7´-dichlorodihydrofluorescein diacetate (H2DCFDA). Results: The three types of crude commercial honey induced apoptosis in a concentration and time dependent-manner. In addition, honeys with the higher phenolic content, heather and polyfloral, were the most effective to induce apoptosis in HL-60 cells. However, honeys did not generate reactive oxygen species (ROS) and N-acetyl-L-cysteine (NAC) could not block honeys-induced apoptosis in HL-60 cells. Conclusion: These data support that honeys induced apoptosis in HL-60 cells through a ROS-independent cell death pathway. Moreover, our findings indicate that the antiproliferative and apoptotic effects of honey varied according to the floral origin and the phenolic content. PMID:23930007

Morales, Paloma; Haza, Ana Isabel

2013-01-01

158

Boolean Model of Yeast Apoptosis as a Tool to Study Yeast and Human Apoptotic Regulations  

PubMed Central

Programmed cell death (PCD) is an essential cellular mechanism that is evolutionary conserved, mediated through various pathways and acts by integrating different stimuli. Many diseases such as neurodegenerative diseases and cancers are found to be caused by, or associated with, regulations in the cell death pathways. Yeast Saccharomyces cerevisiae, is a unicellular eukaryotic organism that shares with human cells components and pathways of the PCD and is therefore used as a model organism. Boolean modeling is becoming promising approach to capture qualitative behavior and describe essential properties of such complex networks. Here we present large literature-based and to our knowledge first Boolean model that combines pathways leading to apoptosis (a type of PCD) in yeast. Analysis of the yeast model confirmed experimental findings of anti-apoptotic role of Bir1p and pro-apoptotic role of Stm1p and revealed activation of the stress protein kinase Hog proposing the maximal level of activation upon heat stress. In addition we extended the yeast model and created an in silico humanized yeast in which human pro- and anti-apoptotic regulators Bcl-2 family and Valosin-contain protein (VCP) are included in the model. We showed that accumulation of Bax in silico humanized yeast shows apoptotic markers and that VCP is essential target of Akt Signaling. The presented Boolean model provides comprehensive description of yeast apoptosis network behavior. Extended model of humanized yeast gives new insights of how complex human disease like neurodegeneration can initially be tested. PMID:23233838

Kazemzadeh, Laleh; Cvijovic, Marija; Petranovic, Dina

2012-01-01

159

Boolean model of yeast apoptosis as a tool to study yeast and human apoptotic regulations.  

PubMed

Programmed cell death (PCD) is an essential cellular mechanism that is evolutionary conserved, mediated through various pathways and acts by integrating different stimuli. Many diseases such as neurodegenerative diseases and cancers are found to be caused by, or associated with, regulations in the cell death pathways. Yeast Saccharomyces cerevisiae, is a unicellular eukaryotic organism that shares with human cells components and pathways of the PCD and is therefore used as a model organism. Boolean modeling is becoming promising approach to capture qualitative behavior and describe essential properties of such complex networks. Here we present large literature-based and to our knowledge first Boolean model that combines pathways leading to apoptosis (a type of PCD) in yeast. Analysis of the yeast model confirmed experimental findings of anti-apoptotic role of Bir1p and pro-apoptotic role of Stm1p and revealed activation of the stress protein kinase Hog proposing the maximal level of activation upon heat stress. In addition we extended the yeast model and created an in silico humanized yeast in which human pro- and anti-apoptotic regulators Bcl-2 family and Valosin-contain protein (VCP) are included in the model. We showed that accumulation of Bax in silico humanized yeast shows apoptotic markers and that VCP is essential target of Akt Signaling. The presented Boolean model provides comprehensive description of yeast apoptosis network behavior. Extended model of humanized yeast gives new insights of how complex human disease like neurodegeneration can initially be tested. PMID:23233838

Kazemzadeh, Laleh; Cvijovic, Marija; Petranovic, Dina

2012-01-01

160

Pre-Transplant IgG Reactivity to Apoptotic Cells Correlates with Late kidney Allograft Loss  

PubMed Central

Pre-existing serum antibodies have long been associated with graft loss in transplant candidates. While most studies have focused on HLA-specific antibodies, the contribution of non-HLA-reactive antibodies has been largely overlooked. We have recently characterized monoclonal antibodies secreted by B cell clones derived from kidney allograft recipients with rejection that selectively bind to apoptotic cells. Here, we assessed the presence of such antibodies in pre-transplant serum from 300 kidney transplant recipients and examined their contribution to the graft outcomes. Kaplan-Meier survival analysis revealed that patients with high pre-transplant IgG reactivity to apoptotic cells had a significantly increased rate of late graft loss. The effect was only apparent after approximately 1 year post-transplant. Moreover, the association between pre-transplant IgG reactivity to apoptotic cells and graft loss was still significant after excluding patients with high reactivity to HLA. This reactivity was almost exclusively mediated by IgG1 and IgG3 with complement fixing and activating properties. Overall, our findings support the view that IgG reactivity to apoptotic cells contribute to pre-sensitization. Taking these antibodies into consideration alongside anti-HLA antibodies during candidate evaluation would likely improve the transplant risk assessment. PMID:24935695

Gao, Baoshan; Moore, Carolina; Porcheray, Fabrice; Rong, Chunshu; Abidoglu, Cem; DeVito, Julie; Paine, Rosemary; Girouard, Timothy C.; Saidman, Susan L.; Schoenfeld, David; Levin, Bruce; Wong, Waichi; Elias, Nahel; Schuetz, Christian; Rosales, Ivy A.; Fu, Yaowen; Zorn, Emmanuel

2014-01-01

161

Ebola Virus Does Not Block Apoptotic Signaling Pathways  

PubMed Central

Since viruses rely on functional cellular machinery for efficient propagation, apoptosis is an important mechanism to fight viral infections. In this study, we sought to determine the mechanism of cell death caused by Ebola virus (EBOV) infection by assaying for multiple stages of apoptosis and hallmarks of necrosis. Our data indicate that EBOV does not induce apoptosis in infected cells but rather leads to a nonapoptotic form of cell death. Ultrastructural analysis confirmed necrotic cell death of EBOV-infected cells. To investigate if EBOV blocks the induction of apoptosis, infected cells were treated with different apoptosis-inducing agents. Surprisingly, EBOV-infected cells remained sensitive to apoptosis induced by external stimuli. Neither receptor- nor mitochondrion-mediated apoptosis signaling was inhibited in EBOV infection. Although double-stranded RNA (dsRNA)-induced activation of protein kinase R (PKR) was blocked in EBOV-infected cells, induction of apoptosis mediated by dsRNA was not suppressed. When EBOV-infected cells were treated with dsRNA-dependent caspase recruiter (dsCARE), an antiviral protein that selectively induces apoptosis in cells containing dsRNA, virus titers were strongly reduced. These data show that the inability of EBOV to block apoptotic pathways may open up new strategies toward the development of antiviral therapeutics. PMID:23468487

Olejnik, Judith; Alonso, Jesus; Schmidt, Kristina M.; Yan, Zhen; Wang, Wei; Marzi, Andrea; Ebihara, Hideki; Yang, Jinghua; Patterson, Jean L.; Ryabchikova, Elena

2013-01-01

162

Tumor necrosis factor-?-induced microvascular endothelial cell hyperpermeability: role of intrinsic apoptotic signaling.  

PubMed

Tumor necrosis factor-? (TNF-?), a pro-apoptotic cytokine, is involved in vascular hyperpermeability, tissue edema, and inflammation. We hypothesized that TNF-? induces microvascular hyperpermeability through the mitochondria-mediated intrinsic apoptotic signaling pathway. Rat lung microvascular endothelial cells grown on Transwell inserts, chamber slides, or dishes were treated with recombinant TNF-? (10 ng/ml) in the presence or absence of a caspase-3 inhibitor, Z-DEVD-FMK (100 ?M). Fluorescein isothiocyanate (FITC)-albumin (5 mg/ml) was used as a marker of monolayer permeability. Mitochondrial reactive oxygen species (ROS) was determined using dihydrorhodamine 123 and mitochondrial transmembrane potential using JC-1. The adherens junction integrity and actin cytoskeletal organization were studied using ?-catenin immunofluorescence and rhodamine phalloidin, respectively. Caspase-3 activity was measured fluorometrically. The pretreatment with Z-DEVD-FMK (100 ?M) attenuated TNF-?-induced (10 ng/ml) disruption of the adherens junctions, actin stress fiber formation, increased caspase-3 activity, and monolayer hyperpermeability (p?apoptotic signaling-mediated caspase-3 activation plays an important role in regulating TNF-?-induced endothelial cell hyperpermeability. PMID:25392259

Sawant, Devendra A; Wilson, Rickesha L; Tharakan, Binu; Stagg, Hayden W; Hunter, Felicia A; Childs, Ed W

2014-12-01

163

Current Understanding of the Mechanisms for Clearance of Apoptotic Cells--A Fine Balance  

PubMed Central

Apoptosis is an important cell death mechanism by which multicellular organisms remove unwanted cells. It culminates in a rapid, controlled removal of cell corpses by neighboring or recruited viable cells. Whilst many of the molecular mechanisms that mediate corpse clearance are components of the innate immune system, clearance of apoptotic cells is an anti-inflammatory process. Control of cell death is dependent on competing pro-apoptotic and anti-apoptotic signals. Evidence now suggests a similar balance of competing signals is central to the effective removal of cells, through so called ‘eat me’ and ‘don’t eat me’ signals. Competing signals are also important for the controlled recruitment of phagocytes to sites of cell death. Consequently recruitment of phagocytes to and from sites of cell death can underlie the resolution or inappropriate propagation of cell death and inflammation. This article highlights our understanding of mechanisms mediating clearance of dying cells and discusses those mechanisms controlling phagocyte migration and how inappropriate control may promote important pathologies.

Hawkins, Lois A; Devitt, Andrew

2013-01-01

164

E3 Ubiquitin Ligase HOIP Attenuates Apoptotic Cell Death Induced by Cisplatin  

PubMed Central

The genotoxin cisplatin is commonly used in chemotherapy to treat solid tumors, yet our understanding of the mechanism underlying the drug response is limited. In a focused siRNA screen, using an siRNA library targeting genes involved in ubiquitin and ubiquitin-like signaling, we identified the E3 ubiquitin ligase HOIP as a key regulator of cisplatin-induced genotoxicity. HOIP forms, with SHARPIN and HOIL-1L, the linear ubiquitin assembly complex (LUBAC). We show that cells deficient in the HOIP ligase complex exhibit hypersensitivity to cisplatin. This is due to a dramatic increase in caspase 8/caspase 3 mediated apoptosis that is strictly dependent on ATM-, but not ATR-mediated DNA damage checkpoint activation. Moreover, basal and cisplatin-induced activity of the stress response kinase JNK is enhanced in HOIP-depleted cells and, conversely, JNK inhibition can increase cellular resistance to cisplatin and reverse the apoptotic hyper-activation in HOIP-depleted cells. Furthermore, we show that HOIP depletion sensitizes cancer cells, derived from carcinomas of various origins, through an enhanced apoptotic cell death response. We also provide evidence that ovarian cancer cells classified as cisplatin-resistant can regain sensitivity following HOIP down-regulation. Cumulatively, our study identifies a HOIP-regulated anti-apoptotic signaling pathway, and we envisage HOIP as a potential target for the development of combinatorial chemotherapies to potentiate the efficacy of platinum-based anti-cancer drugs. PMID:24686174

Ibrahim, Adel F.M.; Garg, Amit; Inman, Gareth J.; Hay, Ronald T.; Alpi, Arno F.

2014-01-01

165

Temporal and spatial profile of apoptotic cell death in transient intracerebral mass lesion of the rat.  

PubMed

Apoptosis is involved in the pathogenesis of cerebral ischemia. Previous studies have confirmed that the brain surrounding an intracerebral hematoma develops ischemia. We investigated the number and distribution of cells exhibiting DNA fragmentation with apoptotic morphology in the transient intracerebral mass lesion to determine whether apoptosis contributed to the lesion progress after intracerebral hemorrhage (ICH). Transient intracerebral mass was created by inflation of a microballoon for 10 min (group A) or 2 h (group B) in the caudoputamen in rats, and brains were examined 1, 3, 6, 24, and 48 h after microballoon deflation. The lesion volume was calculated using parallel coronal sections with cresyl violet staining. Terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine (dUTP)-biotin nick end labeling (TUNEL) was used to detect cells undergoing DNA fragmentation. Immunohistochemistry for Fas antigen was also done to ascertain molecular mechanisms of apoptosis. Histological examination of hematoxylin and eosin-stained sections showed the typical appearance of neuronal necrosis in the caudoputaminal lesion. Lesion volume in the caudoputamen gradually increased as time advanced from 1 to 48 h. Cells stained heavily by TUNEL with apoptotic morphology were detected in the lesion, but not in the inner boundary zone of the lesion. The number of these cells significantly increased from 6 to 24 h in each experimental group (p < 0.05). The cells with positive immunoreactivity for Fas antigen was prominently observed in the lesion at 6 h. The distribution of apoptotic cells and the rapid increase in the number of apoptotic cells after 24 h propose that apoptotic cell death may contribute to lesion core formation but not to gradual development of the lesion. PMID:10098959

Nakashima, K; Yamashita, K; Uesugi, S; Ito, H

1999-02-01

166

MicroRNAs control the apoptotic threshold in primed pluripotent stem cells through regulation of BIM  

PubMed Central

Mammalian primed pluripotent stem cells have been shown to be highly susceptible to cell death stimuli due to their low apoptotic threshold, but how this threshold is regulated remains largely unknown. Here we identify microRNA (miRNA)-mediated regulation as a key mechanism controlling apoptosis in the post-implantation epiblast. Moreover, we found that three miRNA families, miR-20, miR-92, and miR-302, control the mitochondrial apoptotic machinery by fine-tuning the levels of expression of the proapoptotic protein BIM. These families therefore represent an essential buffer needed to maintain cell survival in stem cells that are primed for not only differentiation but also cell death. PMID:25184675

Pernaute, Barbara; Spruce, Thomas; Smith, Kimberley M.; Sanchez-Nieto, Juan Miguel; Manzanares, Miguel; Cobb, Bradley

2014-01-01

167

Mangiferin has an additive effect on the apoptotic properties of hesperidin in Cyclopia sp. tea extracts.  

PubMed

A variety of biological pro-health activities have been reported for mangiferin and hesperidin, two major phenolic compounds of Honeybush (Cyclopia sp.) tea extracts. Given their increasing popularity, there is a need for understanding the mechanisms underlying the biological effects of these compounds. In this study, we used real-time cytotoxicity cellular analysis of the Cyclopia sp. extracts on HeLa cells and found that the higher hesperidin content in non-fermented "green" extracts correlated with their higher cytotoxicity compared to the fermented extracts. We also found that mangiferin had a modulatory effect on the apoptotic effects of hesperidin. Quantitative PCR analysis of hesperidin-induced changes in apoptotic gene expression profile indicated that two death receptor pathway members, TRADD and TRAMP, were up regulated. The results of this study suggest that hesperidin mediates apoptosis in HeLa cells through extrinsic pathway for programmed cell death. PMID:24633329

Bartoszewski, Rafal; Hering, Anna; Marsza??, Marcin; Stefanowicz Hajduk, Justyna; Bartoszewska, Sylwia; Kapoor, Niren; Kochan, Kinga; Ochocka, Renata

2014-01-01

168

Mangiferin Has an Additive Effect on the Apoptotic Properties of Hesperidin in Cyclopia sp. Tea Extracts  

PubMed Central

A variety of biological pro-health activities have been reported for mangiferin and hesperidin, two major phenolic compounds of Honeybush (Cyclopia sp.) tea extracts. Given their increasing popularity, there is a need for understanding the mechanisms underlying the biological effects of these compounds. In this study, we used real-time cytotoxicity cellular analysis of the Cyclopia sp. extracts on HeLa cells and found that the higher hesperidin content in non-fermented "green" extracts correlated with their higher cytotoxicity compared to the fermented extracts. We also found that mangiferin had a modulatory effect on the apoptotic effects of hesperidin. Quantitative PCR analysis of hesperidin-induced changes in apoptotic gene expression profile indicated that two death receptor pathway members, TRADD and TRAMP, were up regulated. The results of this study suggest that hesperidin mediates apoptosis in HeLa cells through extrinsic pathway for programmed cell death. PMID:24633329

Bartoszewski, Rafal; Hering, Anna; Marszall, Marcin; Stefanowicz Hajduk, Justyna; Bartoszewska, Sylwia; Kapoor, Niren; Kochan, Kinga; Ochocka, Renata

2014-01-01

169

Apoptotic cell clearance: basic biology and therapeutic potential  

PubMed Central

Prompt removal of apoptotic cells by phagocytes is important for maintaining tissue homeostasis. The molecular and cellular events that underpin apoptotic cell recognition and uptake, and the subsequent biological responses are increasingly better defined. The detection and disposal of apoptotic cells generally promote an anti-inflammatory response at the tissue level, as well as immunological tolerance. Consequently, defects in apoptotic cell clearance have been linked with a variety of inflammatory diseases and autoimmunity. Conversely, under certain conditions such as killing tumour cells by specific cell death inducers, the recognition of apoptotic tumour cells can promote an immunogenic response and anti-tumour immunity. Here, we review the current understanding of the complex process of apoptotic cell clearance in physiology and pathology, and discuss how this knowledge could be harnessed for new therapeutic strategies. PMID:24481336

Poon, Ivan K. H.; Lucas, Christopher D.

2014-01-01

170

Leptin Is an Anti-Apoptotic Effector in Placental Cells Involving p53 Downregulation  

PubMed Central

Leptin, a peripheral signal synthetized by the adipocyte to regulate energy metabolism, can also be produced by placenta, where it may work as an autocrine hormone. We have previously demonstrated that leptin promotes proliferation and survival of trophoblastic cells. In the present work, we aimed to study the molecular mechanisms that mediate the survival effect of leptin in placenta. We used the human placenta choriocarcinoma BeWo and first trimester Swan-71 cell lines, as well as human placental explants. We tested the late phase of apoptosis, triggered by serum deprivation, by studying the activation of Caspase-3 and DNA fragmentation. Recombinant human leptin added to BeWo cell line and human placental explants, showed a decrease on Caspase-3 activation. These effects were dose dependent. Maximal effect was achieved at 250 ng leptin/ml. Moreover, inhibition of endogenous leptin expression with 2 µM of an antisense oligonucleotide, reversed Caspase-3 diminution. We also found that the cleavage of Poly [ADP-ribose] polymerase-1 (PARP-1) was diminished in the presence of leptin. We analyzed the presence of low DNA fragments, products from apoptotic DNA cleavage. Placental explants cultivated in the absence of serum in the culture media increased the apoptotic cleavage of DNA and this effect was prevented by the addition of 100 ng leptin/ml. Taken together these results reinforce the survival effect exerted by leptin on placental cells. To improve the understanding of leptin mechanism in regulating the process of apoptosis we determined the expression of different intermediaries in the apoptosis cascade. We found that under serum deprivation conditions, leptin increased the anti-apoptotic BCL-2 protein expression, while downregulated the pro-apoptotic BAX and BID proteins expression in Swan-71 cells and placental explants. In both models leptin augmented BCL-2/BAX ratio. Moreover we have demonstrated that p53, one of the key cell cycle-signaling proteins, is downregulated in the presence of leptin under serum deprivation. On the other hand, we determined that leptin reduced the phosphorylation of Ser-46 p53 that plays a pivotal role for apoptotic signaling by p53. Our data suggest that the observed anti-apoptotic effect of leptin in placenta is in part mediated by the p53 pathway. In conclusion, we provide evidence that demonstrates that leptin is a trophic factor for trophoblastic cells. PMID:24922063

Toro, Ayelen Rayen; Maymo, Julieta Lorena; Ibarbalz, Federico Matias; Perez, Antonio Perez; Maskin, Bernardo; Faletti, Alicia Graciela; Margalet, Victor Sanchez; Varone, Cecilia Laura

2014-01-01

171

Astrocytes protect neurons from ethanol-induced oxidative stress and apoptotic death.  

PubMed

Ethanol induces oxidative stress in cultured fetal rat cortical neurons and this is followed by apoptotic death, which can be prevented by normalization of cell content of reduced glutathione (GSH). Because astrocytes can play a central role in maintenance of neuron GSH homeostasis, the following experiments utilized cocultures of neonatal rat cortical astrocytes and fetal cortical neurons to determine if astrocytes could protect neurons from ethanol-mediated apoptotic death via this mechanism. In cortical neurons cultured in the absence of astrocytes, ethanol (2.5 and 4 mg/ml; 6-, 12-, and 24-hr exposures) decreased trypan blue exclusion and the MTT viability measures by up to 45% (P < 0.05), increased levels of reactive oxygen species (ROS) by up to 81% (P < 0.05), and decreased GSH within 1 hr of treatment by 49 and 51% for 2.5 and 4 mg/ml, respectively (P < 0.05). This was followed by onset of apoptotic cell death as determined by increased Annexin V binding and DNA fragmentation by 12 hr of ethanol exposure. Coculturing neurons with astrocytes prevented GSH depletion by 2.5 mg/ml ethanol, whereas GSH content was increased over controls in neurons exposed to 4 mg/ml ethanol (by up to 341%; P < 0.05). Ethanol generated increases in neuron ROS and apoptosis; decreases in viability were also prevented by coculture. Astrocytes were largely insensitive to ethanol, using the same measures. Only exposure to 4.0 mg/ml ethanol decreased GSH content in astrocytes, concomitant with a 204% increase in GSH efflux (P < 0.05). These studies illustrate that astrocytes can protect neurons from ethanol-mediated apoptotic death and that this may be related to maintenance of neuron GSH. PMID:15880562

Watts, Lora Talley; Rathinam, Mary Latha; Schenker, Steven; Henderson, George I

2005-06-01

172

Protective effects of melittin on transforming growth factor-{beta}1 injury to hepatocytes via anti-apoptotic mechanism  

SciTech Connect

Melittin is a cationic, hemolytic peptide that is the main toxic component in the venom of the honey bee (Apis mellifera). Melittin has multiple effects, including anti-bacterial, anti-viral and anti-inflammatory, in various cell types. However, the anti-apoptotic mechanisms of melittin have not been fully elucidated in hepatocytes. Apoptosis contributes to liver inflammation and fibrosis. Knowledge of the apoptotic mechanisms is important to develop new and effective therapies for treatment of cirrhosis, portal hypertension, liver cancer, and other liver diseases. In the present study, we investigated the anti-apoptotic effect of melittin on transforming growth factor (TGF)-{beta}1-induced apoptosis in hepatocytes. TGF-{beta}1-treated hepatocytes were exposed to low doses (0.5 and 1 {mu}g/mL) and high dose (2 {mu}g/mL) of melittin. The low doses significantly protected these cells from DNA damage in TGF-{beta}1-induced apoptosis compared to the high dose. Also, melittin suppressed TGF-{beta}1-induced apoptotic activation of the Bcl-2 family and caspase family of proteins, which resulted in the inhibition of poly-ADP-ribose polymerase (PARP) cleavage. These results demonstrate that TGF-{beta}1 induces hepatocyte apoptosis and that an optimal dose of melittin exerts anti-apoptotic effects against TGF-{beta}1-induced injury to hepatocytes via the mitochondrial pathway. These results suggest that an optimal dose of melittin can serve to protect cells against TGF-{beta}1-mediated injury. - Highlights: > We investigated the anti-apoptotic effect of melittin on TGF-{beta}1-induced hepatocyte. > TGF-{beta}1 induces hepatocyte apoptosis. > TGF-{beta}1-treated hepatocytes were exposed to low doses and high dose of melittin. > Optimal dose of melittin exerts anti-apoptotic effects to hepatocytes.

Lee, Woo-Ram; Park, Ji-Hyun; Kim, Kyung-Hyun [Department of Pathology, College of Medicine, Catholic University of Daegu, Daegu (Korea, Republic of); Park, Yoon-Yub [Department of Physiology, College of Medicine, Catholic University of Daegu, Daegu (Korea, Republic of); Han, Sang-Mi [Department of Agricultural Biology, National Institute of Agricultural Science and Technology, Suwon (Korea, Republic of); Park, Kwan-kyu, E-mail: kkpark@cu.ac.kr [Department of Pathology, College of Medicine, Catholic University of Daegu, Daegu (Korea, Republic of)

2011-10-15

173

Apoptotic process in cystic fibrosis cells.  

PubMed

Cystic fibrosis (CF) is a recessively inherited disease caused by genetic lesions in CF transmembrane conductance regulator (CFTR) gene. CF is characterized by exaggerated inflammation, progressive tissue damage, and chronic bacterial colonization, mainly in the respiratory tract. The mechanisms underlying these pathological changes are increasingly well understood. However, apoptotic dysfunction in CF disease is still debated since studies report controversial results. Nonetheless, it is clear that apoptosis participates to onset of pathology and concerns various types of cells with variable susceptibility. Apoptosis is a physiological process necessary for the preservation of homeostasis of epithelial organization and function for clearance of inflammatory cells. Increased susceptibility to apoptosis in epithelial cells and failed apoptosis in neutrophils would contribute to the self-perpetuating inflammatory cycle in CF. Also, retention of mutated CFTR in the endoplasmic reticulum participates to inflammation which may trigger apoptosis. Independently of the sensibility to apoptosis of CF cells, it has been shown that clearance of apoptotic cells, due in part to decrease in efferocytosis, is flawed and that accumulation of such cells may contribute to ongoing inflammation in CF patients. Despite great advance in understanding CF pathophysiology, there is still no cure for the disease. The most recent therapeutic strategies are directed to target CFTR protein using cell and gene therapy as well as pharmacotherapy. PMID:23793868

Soleti, Raffaella; Porro, Chiara; Martínez, Maria Carmen

2013-09-01

174

Genes of the Mitochondrial Apoptotic Pathway in Mytilus galloprovincialis  

PubMed Central

Bivalves play vital roles in marine, brackish, freshwater and terrestrial habitats. In recent years, these ecosystems have become affected through anthropogenic activities. The ecological success of marine bivalves is based on the ability to modify their physiological functions in response to environmental changes. One of the most important mechanisms involved in adaptive responses to environmental and biological stresses is apoptosis, which has been scarcely studied in mollusks, although the final consequence of this process, DNA fragmentation, has been frequently used for pollution monitoring. Environmental stressors induce apoptosis in molluscan cells via an intrinsic pathway. Many of the proteins involved in vertebrate apoptosis have been recognized in model invertebrates; however, this process might not be universally conserved. Mytilus galloprovincialis is presented here as a new model to study the linkage between molecular mechanisms that mediate apoptosis and marine bivalve ecological adaptations. Therefore, it is strictly necessary to identify the key elements involved in bivalve apoptosis. In the present study, six mitochondrial apoptotic-related genes were characterized, and their gene expression profiles following UV irradiation were evaluated. This is the first step for the development of potential biomarkers to assess the biological responses of marine organisms to stress. The results confirmed that apoptosis and, more specifically, the expression of the genes involved in this process can be used to assess the biological responses of marine organisms to stress. PMID:23626691

Figueras, Antonio; Novoa, Beatriz

2013-01-01

175

Pro-apoptotic role of integrin ?3 in glioma cells.  

PubMed

Malignant gliomas are the most destructive type of brain cancer. In order to gain a better understanding of the molecular mechanisms of glioma cell death and survival, we previously established an alkylating agent 1, 3-bis(2-chloroethyl)-1-nitrosourea (BCNU)-resistant variant of C6 rat glioma cells. Proteomic analysis indicated a significant down-regulation of integrin beta 3 (ITGB3) in the BCNU-resistant C6R cells. Re-expression of ITGB3 in C6R cells restored the BCNU sensitivity. In U87MG, U373MG, and T98G human glioma cells, there was a positive correlation between ITGB3 expression and the sensitivity to BCNU and etoposide, suggesting an important role of ITGB3 in glioma cell death. Over-expression of ITGB3 cDNA significantly increased the sensitivity of the human glioma cells to the anticancer drug-induced apoptosis. Nitric oxide showed an additive effect on the anticancer drug-induced glioma cell death by increasing ITGB3 expression. Subsequent dissection of signaling pathways indicated that extracellular signal-regulated kinase and unligated integrin-mediated cell death pathway may be involved in the pro-apoptotic role of ITGB3 in glioma cells. These results implicate ITGB3 in glioma cell death/survival and drug resistance. PMID:21332719

Kim, Jong-Heon; Zheng, Long Tai; Lee, Won-Ha; Suk, Kyoungho

2011-05-01

176

WNT signaling controls expression of pro-apoptotic BOK and BAX in intestinal cancer  

SciTech Connect

Research highlights: {yields} Intestinal adenomas initiated by aberrant activation of the WNT pathway displayed an increased sensitivity to apoptosis. {yields} Expression profiling of apoptosis-related genes in Apc{sup Min/+} mice revealed the differential expression of pro-apoptotic Bok and Bax. {yields} APC-mutant adenomatous crypts in FAP patients showed strongly increased BAX immunoreactivity. {yields} Blocking of {beta}-catenin/TCF-4-mediated signaling in colon cancer cells reduced the expression of BOK and BAX. -- Abstract: In a majority of cases, colorectal cancer is initiated by aberrant activation of the WNT signaling pathway. Mutation of the genes encoding the WNT signaling components adenomatous polyposis coli or {beta}-catenin causes constitutively active {beta}-catenin/TCF-mediated transcription, driving the transformation of intestinal crypts to cancer precursor lesions, called dysplastic aberrant crypt foci. Deregulated apoptosis is a hallmark of adenomatous colon tissue. However, the contribution of WNT signaling to this process is not fully understood. We addressed this role by analyzing the rate of epithelial apoptosis in aberrant crypts and adenomas of the Apc{sup Min/+} mouse model. In comparison with normal crypts and adenomas, aberrant crypts displayed a dramatically increased rate of apoptotic cell death. Expression profiling of apoptosis-related genes along the crypt-villus axis and in Apc mutant adenomas revealed increased expression of two pro-apoptotic Bcl-2 family members in intestinal adenomas, Bok and Bax. Analysis of the colon of familial adenomatous polyposis (FAP) patients along the crypt-to-surface axis, and of dysplastic crypts, corroborated this expression pattern. Disruption of {beta}-catenin/TCF-4-mediated signaling in the colorectal cancer cell line Ls174T significantly decreased BOK and BAX expression, confirming WNT-dependent regulation in intestinal epithelial cells. Our results suggest a feedback mechanism by which uncontrolled epithelial cell proliferation in the stem cell compartment can be counterbalanced by an increased propensity to undergo cell death.

Zeilstra, Jurrit; Joosten, Sander P.J. [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands)] [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Wensveen, Felix M. [Department of Experimental Immunology, Academic Medical Center, Amsterdam (Netherlands)] [Department of Experimental Immunology, Academic Medical Center, Amsterdam (Netherlands); Dessing, Mark C.; Schuetze, Denise M. [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands)] [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Eldering, Eric [Department of Experimental Immunology, Academic Medical Center, Amsterdam (Netherlands)] [Department of Experimental Immunology, Academic Medical Center, Amsterdam (Netherlands); Spaargaren, Marcel [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands)] [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Pals, Steven T., E-mail: s.t.pals@amc.uva.nl [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands)

2011-03-04

177

Engulfment of apoptotic cells: signals for a good meal  

Microsoft Academic Search

The clearance of apoptotic cells by phagocytes is an integral component of normal life, and defects in this process can have significant implications for self tolerance and autoimmunity. Recent studies have provided new insights into the engulfment process, including how phagocytes seek apoptotic cells, how they recognize and ingest these targets and how they maintain cellular homeostasis after the 'meal'.

Ulrike Lorenz; Kodi S. Ravichandran

2007-01-01

178

TNFR1 and TNFR2 regulate the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms  

PubMed Central

The huge majority of myeloma cell lines express TNFR2 while a substantial subset of them failed to show TNFR1 expression. Stimulation of TNFR1 in the TNFR1-expressing subset of MM cell lines had no or only a very mild effect on cellular viability. Surprisingly, however, TNF stimulation enhanced cell death induction by CD95L and attenuated the apoptotic effect of TRAIL. The contrasting regulation of TRAIL- and CD95L-induced cell death by TNF could be traced back to the concomitant NF?B-mediated upregulation of CD95 and the antiapoptotic FLIP protein. It appeared that CD95 induction, due to its strength, overcompensated a rather moderate upregulation of FLIP so that the net effect of TNF-induced NF?B activation in the context of CD95 signaling is pro-apoptotic. TRAIL-induced cell death, however, was antagonized in response to TNF because in this context only the induction of FLIP is relevant. Stimulation of TNFR2 in myeloma cells leads to TRAF2 depletion. In line with this, we observed cell death induction in TNFR1-TNFR2-costimulated JJN3 cells. Our studies revealed that the TNF-TNF receptor system adjusts the responsiveness of the extrinsic apoptotic pathway in myeloma cells by multiple mechanisms that generate a highly context-dependent net effect on myeloma cell survival. PMID:21850048

Rauert, H; Stuhmer, T; Bargou, R; Wajant, H; Siegmund, D

2011-01-01

179

CD300b regulates the phagocytosis of apoptotic cells via phosphatidylserine recognition.  

PubMed

The CD300 receptor family members are a group of molecules that modulate a variety of immune cell processes. We show that mouse CD300b (CLM7/LMIR5), expressed on myeloid cells, recognizes outer membrane-exposed phosphatidylserine (PS) and does not, as previously reported, directly recognize TIM1 or TIM4. CD300b accumulates in phagocytic cups along with F-actin at apoptotic cell contacts, thereby facilitating their engulfment. The CD300b-mediated activation signal is conveyed through CD300b association with the adaptor molecule DAP12, and requires a functional DAP12 ITAM motif. Binding of apoptotic cells promotes the activation of the PI3K-Akt kinase pathway in macrophages, while silencing of CD300b expression diminishes PI3K-Akt kinase activation and impairs efferocytosis. Collectively, our data show that CD300b recognizes PS as a ligand, and regulates the phagocytosis of apoptotic cells via the DAP12 signaling pathway. PMID:25034781

Murakami, Y; Tian, L; Voss, O H; Margulies, D H; Krzewski, K; Coligan, J E

2014-11-01

180

Apoptotic and proinflammatory effect of combustion-generated organic nanoparticles in endothelial cells.  

PubMed

Air pollution exposure in industrialized cities is associated with an increased risk of morbidity and mortality attributed to cardiovascular diseases. Combustion exhausts emitted from motor vehicles and industries represent a major source of nanoparticles in the atmosphere. Flame-generated organic carbon nanoparticles (OC NPs) provide interesting model nanoparticles that simulate fresh combustion emissions near roadways or combustion sources. These model nanoparticles can be produced by controlling flame operating conditions and used to test possible toxicological mechanisms responsible for the observed health effects. OC NPs were used to investigate their possible effect on endothelial cells (EC) growth and production of proinflammatory lipid mediators. Results indicated a dose and time-dependent reduction in cell viability following incubation of EC with OC NPs for 24 and 48h. Fluorescence-activated cell sorting revealed that EC treated with OC NPs showed a cell proliferation index significantly lower than that of control cells and an increased apoptotic cell death. The annexin assay confirmed the increased apoptotic cell death. Moreover, OC NPs also induced a time-dependent increase of proinflammatory lysophospholipid production. These results, establishing that OC NPs induce EC proinflammatory lysophosholipid production and apoptotic cell death, provide the first evidence of the detrimental effect of OC NPs on EC. PMID:23538036

Pedata, Paola; Bergamasco, Nadia; D'Anna, Andrea; Minutolo, Patrizia; Servillo, Luigi; Sannolo, Nicola; Balestrieri, Maria Luisa

2013-06-01

181

Intracellular Triggering of Fas Aggregation and Recruitment of Apoptotic Molecules into Fas-enriched Rafts in Selective Tumor Cell Apoptosis  

Microsoft Academic Search

We have discovered a new and specific cell-killing mechanism mediated by the selective uptake of the antitumor drug 1- O -octadecyl-2- O -methyl- rac -glycero-3-phosphocholine (ET-18-OCH 3 , Edelfosine) into lipid rafts of tumor cells, followed by its coaggregation with Fas death receptor (also known as APO-1 or CD95) and recruitment of apoptotic molecules into Fas-enriched rafts. Drug sensitivity was

Consuelo Gajate; Esther del Canto-Jañez; A. Ulises Acuña; Francisco Amat-Guerri; Emilio Geijo; Antonio M. Santos-Beneit; Robert J. Veldman; Faustino Mollinedo

2004-01-01

182

EKSPERIMENTINIAI TYRIMAI Application of Photoshop-based image analysis and TUNEL for the distribution and quantification of dexamethasone-induced apoptotic cells in rat thymus  

Microsoft Academic Search

Summary. The aim of the present study was to determine the target site cells in the rat thymus after exposure to the synthetic glucocorticoid, dexamethasone, at therapeutic doses. The findings of histology and histochemistry (Feulgen, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling - TUNEL) with quantification by computerized histomorphometry are described. Material and methods. A quantified investigation of apoptotic and

Piret Hussar; Ivan Tokin; Ülo Hussar; Galina Filimonova; Toivo Suuroja

183

PKC? is an anti-apoptotic kinase that predicts poor prognosis in breast and lung cancer.  

PubMed

The successful treatment of cancer in a disseminated stage using chemotherapy is limited by the occurrence of drug resistance, often mediated by anti-apoptotic mechanisms. Thus the challenge is to pinpoint the underlying key factors and to develop therapies for their direct targeting. Protein kinase C (PKC) enzymes are promising candidates, as some PKCs were shown to be involved in regulation of apoptosis. Our studies and others have shown that PKC? is an anti-apoptotic kinase, able to confer protection on tumour cells against stress and chemotherapy. We have demonstrated that PKC? shuttles between the cytoplasm and the nucleus and that upon DNA damage is tethered at the nuclear membrane. The C1b domain mediates translocation of PKC? to the nuclear envelope and, similar to the full-length protein, could also confer protection against cell death. Furthermore, its localization in cell and nuclear membranes in breast cancer biopsies of neoadjuvant-treated breast cancer patients was an indicator for poor survival and a predictor for the effectiveness of treatment. PKC? is also a novel biomarker for poor prognosis in non-small-cell lung cancer (NSCLC). Thus PKC? presents a potential target for therapy where inhibition of its activity and/or translocation to membranes could interfere with the resistance to chemotherapy. PMID:25399563

Zurgil, Udi; Ben-Ari, Assaf; Rotem-Dai, Noa; Karp, Galia; Krasnitsky, Ella; Frost, Sigal A; Livneh, Etta

2014-12-01

184

Cannabidiol induced a contrasting pro-apoptotic effect between freshly isolated and precultured human monocytes  

SciTech Connect

It has been documented that cannabidiol (CBD) induced apoptosis in a variety of transformed cells, including lymphocytic and monocytic leukemias. In contrast, a differential sensitivity between normal lymphocytes and monocytes to CBD-mediated apoptosis has been reported. The present study investigated the pro-apoptotic effect of CBD on human peripheral monocytes that were either freshly isolated or precultured for 72 h. CBD markedly enhanced apoptosis of freshly isolated monocytes in a time- and concentration-dependent manner, whereas precultured monocytes were insensitive. By comparison, both cells were sensitive to doxorubicin-induced apoptosis. CBD significantly diminished the cellular thiols and glutathione in freshly isolated monocytes. The apoptosis induced by CBD was abrogated in the presence of N-acetyl-{sub L}-cysteine, a precursor of glutathione. In addition, precultured monocytes contained a significantly greater level of glutathione and heme oxygenase-1 (HO-1) compared to the freshly isolated cells. The HO-1 competitive inhibitor zinc protoporphyrin partially but significantly restored the sensitivity of precultured monocytes to CBD-mediated apoptosis. Collectively, our results demonstrated a contrasting pro-apoptotic effect of CBD between precultured and freshly isolated monocytes, which was closely associated with the cellular level of glutathione and the antioxidative capability of the cells.

Wu, Hsin-Ying; Chang, An-Chi; Wang, Chia-Chi; Kuo, Fu-Hua; Lee, Chi-Ya [Department and Graduate Institute of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan (China); Liu, Der-Zen [Graduate Institute of Biomedical Materials and Engineering, Taipei Medical University, Taipei, Taiwan (China); Jan, Tong-Rong, E-mail: tonyjan@ntu.edu.t [Department and Graduate Institute of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan (China)

2010-08-01

185

The apoptotic pathways effect of fine particulate from cooking oil fumes in primary fetal alveolar type II epithelial cells.  

PubMed

Apoptosis occurs along three major pathways: (i) an extrinsic pathway, mediated by death receptors; (ii) an intrinsic pathway centered on mitochondria; and (iii) an ER-stress pathway. We investigated the apoptotic pathway effects of cooking oil fumes (COF) in fetal lung type II-like epithelium cells (AEC II). Exposure to COF caused up-regulation of the pro-apoptotic protein Bax and down-regulation of the anti-apoptotic protein Bcl-2. COF induced the mitochondrial permeability transition, an early event in apoptosis; cytochrome c was translocated from the mitochondria to the cytoplasm and nucleus. Caspase-9 and caspase-3 were activated, as a consequence of the mitochondrial permeability transition. The death receptor apoptotic pathway was triggered by COF, as indicated by a change in Fas expression, resulting in increased caspase-8 content. COF exposure arrested the cell cycle the at G0-G1 phase. In summary, COF can lead to apoptosis via mitochondrial and death receptor pathways in AEC II cells. PMID:24463316

Che, Zhen; Liu, Ying; Chen, Yanyan; Cao, Jiyu; Liang, Chunmei; Wang, Lei; Ding, Rui

2014-02-01

186

Mannose-binding lectin is required for the effective clearance of apoptotic cells by adipose tissue macrophages during obesity.  

PubMed

Obesity is accompanied by the presence of chronic low-grade inflammation manifested by infiltration of macrophages into adipose tissue. Mannose-binding lectin (MBL), a soluble mediator of innate immunity, promotes phagocytosis and alters macrophage function. To assess the function of MBL in the development of obesity, we studied wild-type and MBL(-/-) mice rendered obese using a high-fat diet (HFD). Whereas no gross morphological differences were observed in liver, an HFD provoked distinct changes in the adipose tissue morphology of MBL(-/-) mice. In parallel with increased adipocyte size, MBL(-/-) mice displayed an increased influx of macrophages into adipose tissue. Macrophages were polarized toward an alternatively activated phenotype known to modulate apoptotic cell clearance. MBL deficiency also significantly increased the number of apoptotic cells in adipose tissue. Consistent with these observations, recombinant MBL enhanced phagocytic capacity of the stromal vascular fraction isolated from adipose tissue and modulated uptake of apoptotic adipocytes by macrophages. Despite changes in macrophage abundance and polarity, the absence of MBL did not affect systemic insulin resistance. Finally, in humans, lower levels of circulating MBL were accompanied by enhanced macrophage influx in subcutaneous adipose tissue. We propose a novel role for MBL in the recognition and clearance of apoptotic adipocytes during obesity. PMID:25008177

Stienstra, Rinke; Dijk, Wieneke; van Beek, Lianne; Jansen, Henry; Heemskerk, Mattijs; Houtkooper, Riekelt H; Denis, Simone; van Harmelen, Vanessa; Willems van Dijk, Ko; Tack, Cees J; Kersten, Sander

2014-12-01

187

Regulation of Apoptotic Effects by Erythrocarpine E, a Cytotoxic Limonoid from Chisocheton erythrocarpus in HSC-4 Human Oral Cancer Cells  

PubMed Central

The aim of this study was to determine the cytotoxic and apoptotic effects of erythrocarpine E (CEB4), a limonoid extracted from Chisocheton erythrocarpus on human oral squamous cell carcinoma. Based on preliminary dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays, CEB4 treated HSC-4 cells demonstrated a cytotoxic effect and inhibited cell proliferation in a time and dose dependent manner with an IC50 value of 4.0±1.9 µM within 24 h of treatment. CEB4 was also found to have minimal cytotoxic effects on the normal cell line, NHBE with cell viability levels maintained above 80% upon treatment. Annexin V-fluorescein isothiocyanate (FITC), poly-ADP ribose polymerase (PARP) cleavage and DNA fragmentation assay results showed that CEB4 induces apoptosis mediated cell death. Western blotting results demonstrated that the induction of apoptosis by CEB4 appeared to be mediated through regulation of the p53 signalling pathway as there was an increase in p53 phosphorylation levels. CEB4 was also found to up-regulate the pro-apoptotic protein, Bax, while down-regulating the anti-apoptotic protein, Bcl-2, suggesting the involvement of the intrinsic mitochondrial pathway. Reduced levels of initiator procaspase-9 and executioner caspase-3 zymogen were also observed following CEB4 exposure, hence indicating the involvement of cytochrome c mediated apoptosis. These results demonstrate the cytotoxic and apoptotic ability of erythrocarpine E, and suggest its potential development as a cancer chemopreventive agent. PMID:21858194

Nagoor, Noor Hasima; Shah Jehan Muttiah, Norliza; Soon Lim, Chong; In, Lionel L. A.; Mohammad, Khalit; Awang, Khalijah

2011-01-01

188

Time course of Newcastle disease virus-induced apoptotic pathways.  

PubMed

Newcastle disease virus (NDV) causes economically significant Newcastle disease (ND) in almost all birds worldwide. Previous studies have shown that NDV induces caspase dependent apoptotic pathways in infected cells. In the present study, time course induction of apoptotic pathways in Vero cells is described. In NDV-infected cells, caspase-8 activity, percentage of cells showing TRAIL expression was higher at 24h p.i. (post-infection) compared to 48 h p.i. In contrast, caspase-9 activity, efflux of cytochrome c, loss of mitochondrial membrane potential was higher at 48 h compared to 24h p.i. The caspase-3 activity was high both times. Based on these results, it was concluded that at 24h p.i., NDV induces apoptosis through extrinsic apoptotic pathway while at 48 h p.i. predominantly through intrinsic apoptotic pathway. PMID:19501124

Ravindra, P V; Tiwari, Ashok K; Ratta, Barkha; Bais, Manish V; Chaturvedi, Uttara; Palia, Sudesh Kumar; Sharma, Bhaskar; Chauhan, R S

2009-09-01

189

Inhibitors of apoptotic proteins: new targets for anticancer therapy.  

PubMed

Inhibitors of apoptotic proteins (IAPs) can play an important role in inhibiting apoptosis by exerting their negative action on caspases (apoptotic proteins). There are eight proteins in this family: NAIP/BIRC1/NLRB, cellular IAP1 (cIAP1)/human IAP2/BIRC2, cellular IAP2 (cIAP2)/human IAP1/BIRC3, X-linked IAP (XIAP)/BIRC4, survivin/BIRC5, baculoviral IAP repeat (BIR)-containing ubiquitin-conjugating enzyme/apollon/BIRC6, livin/melanoma-IAP (ML-IAP)/BIRC7/KIAP, and testis-specific IAP (Ts-IAP)/hILP-2/BIRC8. Deregulation of these inhibitors of apoptotic proteins (IAPs) may push cell toward cancer and neurodegenerative disorders. Inhibitors of apoptotic proteins (IAPs) may provide new target for anticancer therapy. Drugs may be developed that are inhibiting these IAPs to induce apoptosis in cancerous cells. PMID:23790005

Saleem, Mohammad; Qadir, Muhammad Imran; Perveen, Nadia; Ahmad, Bashir; Saleem, Uzma; Irshad, Tehseen; Ahmad, Bashir

2013-09-01

190

Obesity impairs apoptotic cell clearance in asthma  

PubMed Central

Background Asthma in obese adults is typically more severe and less responsive to glucocorticoids than asthma in nonobese adults. Objective We sought to determine whether the clearance of apoptotic inflammatory cells (efferocytosis) by airway macrophages was associated with altered inflammation and reduced glucocorticoid sensitivity in obese asthmatic patients. Methods We investigated the relationship of efferocytosis by airway (induced sputum) macrophages and blood monocytes to markers of monocyte programming, in vitro glucocorticoid response, and systemic oxidative stress in a cohort of adults with persistent asthma. Results Efferocytosis by airway macrophages was assessed in obese (n = 14) and nonobese (n = 19) asthmatic patients. Efferocytosis by macrophages was 40% lower in obese than nonobese subjects, with a mean efferocytic index of 1.77 (SD, 1.07) versus 3.00 (SD, 1.25; P < .01). A similar reduction of efferocytic function was observed in blood monocytes of obese participants. In these monocytes there was also a relative decrease in expression of markers of alternative (M2) programming associated with efferocytosis, including peroxisome proliferator-activated receptor ? and CX3 chemokine receptor 1. Macrophage efferocytic index was significantly correlated with dexamethasone-induced mitogen-activated protein kinase phosphatase 1 expression (? = 0.46, P < .02) and baseline glucocorticoid receptor ? expression (? = 0.44, P < .02) in PBMCs. Plasma 4-hydroxynonenal levels were increased in obese asthmatic patients at 0.33 ng/mL (SD, 0.15 ng/mL) versus 0.16 ng/mL (SD, 0.08 ng/mL) in nonobese patients (P = .006) and was inversely correlated with macrophage efferocytic index (? = ?0.67, P = .02). Conclusions Asthma in obese adults is associated with impaired macrophage/monocyte efferocytosis. Impairment of this anti-inflammatory process is associated with altered monocyte/macrophage programming, reduced glucocorticoid responsiveness, and systemic oxidative stress. PMID:23154082

Fernandez-Boyanapalli, Ruby; Goleva, Elena; Kolakowski, Christena; Min, Elysia; Day, Brian; Leung, Donald Y. M.; Riches, David W. H.; Bratton, Donna L.; Sutherland, E. Rand

2014-01-01

191

Time course of Newcastle disease virus-induced apoptotic pathways  

Microsoft Academic Search

Newcastle disease virus (NDV) causes economically significant Newcastle disease (ND) in almost all birds worldwide. Previous studies have shown that NDV induces caspase dependent apoptotic pathways in infected cells. In the present study, time course induction of apoptotic pathways in Vero cells is described. In NDV-infected cells, caspase-8 activity, percentage of cells showing TRAIL expression was higher at 24h p.i.

P. V. Ravindra; Ashok K. Tiwari; Barkha Ratta; Manish V. Bais; Uttara Chaturvedi; Sudesh Kumar Palia; Bhaskar Sharma; R. S. Chauhan

2009-01-01

192

Atypical antiinflammatory activation of microglia induced by apoptotic neurons  

Microsoft Academic Search

In the central nervous system (CNS), apoptosis plays an important role during development and is a primary pathogenic mechanism\\u000a in several adult neurodegenerative diseases. A main feature of apoptotic cell death is the efficient and fast removal of dying\\u000a cells by macrophages and nonprofessional phagocytes, without eliciting inflammation in the surrounding tissue. Apoptotic cells\\u000a undergo several membrane changes, including the

Roberta De Simone; Maria Antonietta Ajmone-Cat; Luisa Minghetti

2004-01-01

193

Targeting of TRAIL Apoptotic Pathways for Glioblastoma Therapies  

Microsoft Academic Search

Recent advances in cancer biology have generated novel cancer therapeutics that can activate apoptotic pathways in human cancers.\\u000a Among the apoptotic therapeutics, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has received much attention\\u000a because it can selectively induce apoptosis in cancer cells. Preclinical studies in glioblastoma cell lines, primary cultures,\\u000a and xenografts have resulted in the development of TRAIL-based therapeutic modalities

Anita C. Bellail; Patrick Mulligan; Chunhai Hao

194

Comparison of automated haematology analysers for detection of apoptotic lymphocytes.  

PubMed

Automated haematology analysers can rapidly provide accurate blood cell counts and white blood cell differentials. In this study, we evaluated four different haematology analysers for the detection of apoptotic lymphocytes in peripheral blood: MAXM A/L Retic, H*2, Cell-Dyn 3500 and NE-8000. With the MAXM A/L Retic haematology analyser, the apoptotic lymphocyte cluster appeared below the original lymphocyte cluster on the volume/DF1, and to the right under the original lymphocyte cluster on the volume/DF2 scattergrams. With the H*2 haematology analyser, the apoptotic polymorphonuclear lymphocytes produced a higher lobularity index on the BASO channel. With the Cell-Dyn 3500 haematology analyser, the apoptotic lymphocyte cluster appeared to the right side of the original lymphocyte cluster on the 0D/10D scattergram and to the left side of the polymorphonuclear cluster on the 90D/10D scattergram. With the NE-8000 haematology analyser, the apoptotic lymphocyte cluster was not distinguishable. Thus, apoptotic lymphocytes are readily detected on scattergrams generated by selected haematology analysers. PMID:12067276

Taga, K; Sawaya, M; Yoshida, M; Kaneko, M; Okada, M; Taniho, M

2002-06-01

195

Surface code—biophysical signals for apoptotic cell clearance  

NASA Astrophysics Data System (ADS)

Apoptotic cell death and the clearance of dying cells play an important and physiological role in embryonic development and normal tissue turnover. In contrast to necrosis, apoptosis proceeds in an anti-inflammatory manner. It is orchestrated by the timed release and/or exposure of so-called ‘find-me’, ‘eat me’ and ‘tolerate me’ signals. Mononuclear phagocytes are attracted by various ‘find-me’ signals, including proteins, nucleotides, and phospholipids released by the dying cell, whereas the involvement of granulocytes is prevented via ‘stay away’ signals. The exposure of anionic phospholipids like phosphatidylserine (PS) by apoptotic cells on the outer leaflet of the plasma membrane is one of the main ‘eat me’ signals. PS is recognized by a number of innate receptors as well as by soluble bridging molecules on the surface of phagocytes. Importantly, phagocytes are able to discriminate between viable and apoptotic cells both exposing PS. Due to cytoskeleton remodeling PS has a higher lateral mobility on the surfaces of apoptotic cells thereby promoting receptor clustering on the phagocyte. PS not only plays an important role in the engulfment process, but also acts as ‘tolerate me’ signal inducing the release of anti-inflammatory cytokines by phagocytes. An efficient and fast clearance of apoptotic cells is required to prevent secondary necrosis and leakage of intracellular danger signals into the surrounding tissue. Failure or prolongation of the clearance process leads to the release of intracellular antigens into the periphery provoking inflammation and development of systemic inflammatory autoimmune disease like systemic lupus erythematosus. Here we review the current findings concerning apoptosis-inducing pathways, important players of apoptotic cell recognition and clearance as well as the role of membrane remodeling in the engulfment of apoptotic cells by phagocytes.

Biermann, Mona; Maueröder, Christian; Brauner, Jan M.; Chaurio, Ricardo; Janko, Christina; Herrmann, Martin; Muñoz, Luis E.

2013-12-01

196

Paraptosis: mediation by MAP kinases and inhibition by AIP1\\/Alix  

Microsoft Academic Search

Programmed cell death (pcd) may take the form of apoptotic or nonapoptotic pcd. Whereas cysteine aspartyl-specific proteases (caspases) mediate apoptosis, the mediators of nonapoptotic cell death programs are much less well characterized. Here, we report that paraptosis, an alternative, nonapoptotic cell death program that may be induced by the insulin-like growth factor I receptor (among other inducers), is mediated by

S Sperandio; K Poksay; I de Belle; M J Lafuente; B Liu; J Nasir; D E Bredesen

2004-01-01

197

Apoptotic Activities of Thymoquinone, an Active Ingredient of Black Seed (Nigella sativa), in Cervical Cancer Cell Lines.  

PubMed

Thymoquinone (TQ) is the main constituent of black seed (Nigella sativa, spp) essential oil which shows promising in vitro and in vivo anti-neoplastic activities in different tumor cell lines. However, to date there are only a few reports regarding the apoptotic effects of TQ on cervical cancer cells. Here, we report that TQ stimulated distinct apoptotic pathways in two human cervical cell lines, Siha and C33A. TQ markedly induced apoptosis as demonstrated by cell cycle analysis in both cell lines. Moreover, quantitative PCR revealed that TQ induced apoptosis in Siha cells through p53-dependent pathway as shown by elevated level of p53-mediated apoptosis target genes, whereas apoptosis in C33A cells was mainly associated with the activation of caspase-3. These results support previous findings on TQ as a potential therapeutic agent for human cervical cancer. PMID:25241984

Ichwan, Solachuddin J A; Al-Ani, Imad M; Bilal, Hakim G; Suriyah, Wastuti H; Taher, Muhammad; Ikeda, Masa A

2014-10-31

198

Critical role of pro-apoptotic Bcl-2 family members in andrographolide-induced apoptosis in human cancer cells.  

PubMed

Andrographolide (Andro), a diterpenoid lactone isolated from a traditional herbal medicine Andrographis paniculata, is known to possess potent anti-inflammatory activity. In this study, Andro induced apoptosis in human cancer cells via activation of caspase 8 in the extrinsic death receptor pathway and subsequently with the participation of mitochondria. Andro triggered a caspase 8-dependent Bid cleavage, followed by a series of sequential events including Bax conformational change and mitochondrial translocation, cytochrome c release from mitochondria, and activation of caspase 9 and 3. Inhibition of caspase 8 blocked Bid cleavage and Bax conformational change. Consistently, knockdown of Bid protein using small interfering RNA (siRNA) technique suppressed Andro-induced Bax conformational change and apoptosis. In conclusion, the pro-apoptotic Bcl-2 family members (Bid and Bax) are the key mediators in relaying the cell death signaling initiated by Andro from caspase 8 to mitochondria and then to downstream effector caspases, and eventually leading to apoptotic cell death. PMID:16740251

Zhou, Jing; Zhang, Siyuan; Ong, Choon-Nam; Shen, Han-Ming

2006-07-14

199

Phosphoproteomic analysis of apoptotic hematopoietic stem cells from hemoglobin E/?-thalassemia  

PubMed Central

Background Hemoglobin E/?-thalassemia is particularly common in Southeast Asia and has variable symptoms ranging from mild to severe anemia. Previous investigations demonstrated the remarkable symptoms of ?-thalassemia in terms of the acceleration of apoptotic cell death. Ineffective erythropoiesis has been studied in human hematopoietic stem cells, however the distinct apoptotic mechanism was unclear. Methods The phosphoproteome of bone marrow HSCs/CD34+ cells from HbE/?-thalassemic patients was analyzed using IMAC phosphoprotein isolation followed by LC-MS/MS detection. Decyder MS software was used to quantitate differentially expressed proteins in 3 patients and 2 normal donors. The differentially expressed proteins from HSCs/CD34+ cells were compared with HbE/?-thalassemia and normal HSCs. Results A significant change in abundance of 229 phosphoproteins was demonstrated. Importantly, the analysis of the candidate proteins revealed a high abundance of proteins that are commonly found in apoptotic cells including cytochrome C, caspase 6 and apoptosis inducing factors. Moreover, in the HSCs patients a significant increase was observed in a specific type of phosphoserine/threonine binding protein, which is known to act as an important signal mediator for the regulation of cell survival and apoptosis in HbE/?-thalassemia. Conclusions Our study used a novel method to investigate proteins that influence a particular pathway in a given disease or physiological condition. Ultimately, phosphoproteome profiling in HbE/?-thalassemic stem cells is an effective method to further investigate the cell death mechanism of ineffective erythropoiesis in ?-thalassemia. Our report provides a comprehensive phosphoproteome, an important resource for the study of ineffective erythropoiesis and developing therapies for HbE/?-thalassemia. PMID:21702968

2011-01-01

200

Apoptotic and Autophagic Effects of Sesbania grandiflora Flowers in Human Leukemic Cells  

PubMed Central

Background Identification of cytotoxic compounds that induce apoptosis has been the mainstay of anti-cancer therapeutics for several decades. In recent years, focus has shifted to inducing multiple modes of cell death coupled with reduced systemic toxicity. The plant Sesbania grandiflora is widely used in Indian traditional medicine for the treatment of a broad spectrum of diseases. This encouraged us to investigate into the anti-proliferative effect of a fraction (F2) isolated from S. grandiflora flowers in cancer cells and delineate the underlying involvement of apoptotic and autophagic pathways. Principal Findings Using MTT based cell viability assay, we evaluated the cytotoxic potential of fraction F2. It was the most effective on U937 cells (IC50?18.6 µg/ml). Inhibition of growth involved enhancement of Annexin V positivity. This was associated with elevated reactive oxygen species generation, measured by flow cytometry and reduced oxygen consumption – both effects being abrogated by anti-oxidant NAC. This caused stimulation of pro-apoptotic proteins and concomitant inhibition of anti-apoptotic protein expressions inducing mitochondrial depolarization, as measured by flow cytometry and release of cytochrome c. Interestingly, even with these molecular features of apoptosis, F2 was able to alter Atg protein levels and induce LC3 processing. This was accompanied by formation of autophagic vacuoles as revealed by fluorescence and transmission electron microscopy – confirming the occurrence of autophagy. Eventually, F2 triggered caspase cascade – executioners of programmed cell death and AIF translocation to nuclei. This culminated in cleavage of the DNA repair enzyme, poly (ADP-ribose) polymerase that caused DNA damage as proved by staining with Hoechst 33258 leading to cell death. Conclusions The findings suggest fraction F2 triggers pro-oxidant activity and mediates its cytotoxicity in leukemic cells via apoptosis and autophagy. Thus, it merits consideration and further investigation as a therapeutic option for the treatment of leukemia. PMID:23967233

Chakraborty, Biswajit; Chowdhury, Chinmay; Das, Padma

2013-01-01

201

Induction of discrete apoptotic pathways by bromo-substituted indirubin derivatives in invasive breast cancer cells  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer The effects of 6BIO and 7BIO are evaluated against five breast cancer cell lines. Black-Right-Pointing-Pointer 6BIO induces a caspase dependent apoptotic effect via the intrinsic pathway. Black-Right-Pointing-Pointer 7BIO promotes G{sub 2}/M cells cycle arrest. Black-Right-Pointing-Pointer 7BIO triggers a caspase-8 mediated apoptotic pathway. Black-Right-Pointing-Pointer 7BIO triggers and a caspase independent pathway. -- Abstract: Indirubin derivatives gained interest in recent years for their anticancer and antimetastatic properties. The objective of the present study was to evaluate and compare the anticancer properties of the two novel bromo-substituted derivatives 6-bromoindirubin-3 Prime -oxime (6BIO) and 7-bromoindirubin-3 Prime -oxime (7BIO) in five different breast cancer cell lines. Cell viability assays identified that 6BIO and 7BIO are most effective in preventing the proliferation of the MDA-MB-231-TXSA breast cancer cell line from a total of five breast cancer cell lined examined. In addition it was found that the two compounds induce apoptosis via different mechanisms. 6BIO induces caspase-dependent programmed cell death through the intrinsic (mitochondrial) caspase-9 pathway. 7BIO up-regulates p21 and promotes G{sub 2}/M cell cycle arrest which is subsequently followed by the activation of two different apoptotic pathways: (a) a pathway that involves the upregulation of DR4/DR5 and activation of caspase-8 and (b) a caspase independent pathway. In conclusion, this study provides important insights regarding the molecular pathways leading to cell cycle arrest and apoptosis by two indirubin derivatives that can find clinical applications in targeted cancer therapeutics.

Nicolaou, Katerina A. [Department of Biological Sciences, University of Cyprus, Nicosia (Cyprus)] [Department of Biological Sciences, University of Cyprus, Nicosia (Cyprus); Liapis, Vasilis; Evdokiou, Andreas [Department of Surgery, Basil Hetzel Institute, Adelaide University, Adelaide (Australia)] [Department of Surgery, Basil Hetzel Institute, Adelaide University, Adelaide (Australia); Constantinou, Constantina [St. George's University of London Medical School at the University of Nicosia, Nicosia (Cyprus)] [St. George's University of London Medical School at the University of Nicosia, Nicosia (Cyprus); Magiatis, Prokopios; Skaltsounis, Alex L. [Faculty of Pharmacy, University of Athens, Athens (Greece)] [Faculty of Pharmacy, University of Athens, Athens (Greece); Koumas, Laura; Costeas, Paul A. [Center for Study of Hematological Malignancies, Nicosia (Cyprus)] [Center for Study of Hematological Malignancies, Nicosia (Cyprus); Constantinou, Andreas I., E-mail: andreasc@ucy.ac.cy [Department of Biological Sciences, University of Cyprus, Nicosia (Cyprus)

2012-08-17

202

Rho kinase regulates fragmentation and phagocytosis of apoptotic cells  

SciTech Connect

During the execution phase of apoptosis, a cell undergoes cytoplasmic and nuclear changes that prepare it for death and phagocytosis. The end-point of the execution phase is condensation into a single apoptotic body or fragmentation into multiple apoptotic bodies. Fragmentation is thought to facilitate phagocytosis; however, mechanisms regulating fragmentation are unknown. An isoform of Rho kinase, ROCK-I, drives membrane blebbing through its activation of actin-myosin contraction; this raises the possibility that ROCK-I may regulate other execution phase events, such as cellular fragmentation. Here, we show that COS-7 cells fragment into a number of small apoptotic bodies during apoptosis; treating with ROCK inhibitors (Y-27632 or H-1152) prevents fragmentation. Latrunculin B and blebbistatin, drugs that interfere with actin-myosin contraction, also inhibit fragmentation. During apoptosis, ROCK-I is cleaved and activated by caspases, while ROCK-II is not activated, but rather translocates to a cytoskeletal fraction. siRNA knock-down of ROCK-I but not ROCK-II inhibits fragmentation of dying cells, consistent with ROCK-I being required for apoptotic fragmentation. Finally, cells dying in the presence of the ROCK inhibitor Y-27632 are not efficiently phagocytized. These data show that ROCK plays an essential role in fragmentation and phagocytosis of apoptotic cells.

Orlando, Kelly A. [Department of Pharmacology, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, PA 19104 (United States); Stone, Nicole L. [GlaxoSmithKline, 1250 S. Collegeville Rd., Collegeville, PA 19426 (United States); Pittman, Randall N. [Department of Pharmacology, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, PA 19104 (United States)]. E-mail: pittman@pharm.med.upenn.edu

2006-01-01

203

Caspase Activity Is Required for Engulfment of Apoptotic Cells  

PubMed Central

Clearance of apoptotic cells by phagocytic neighbors is crucial for normal development of multicellular organisms. However, how phagocytes discriminate between healthy and dying cells remains poorly understood. We focus on glial phagocytosis of apoptotic neurons during development of the Drosophila central nervous system. We identified phosphatidylserine (PS) as a ligand on apoptotic cells for the phagocytic receptor Six Microns Under (SIMU) and report that PS alone is not sufficient for engulfment. Our data reveal that, additionally to PS exposure, caspase activity is required for clearance of apoptotic cells by phagocytes. Here we demonstrate that SIMU recognizes and binds PS on apoptotic cells through its N-terminal EMILIN (EMI), Nimrod 1 (NIM1), and NIM2 repeats, whereas the C-terminal NIM3 and NIM4 repeats control SIMU affinity to PS. Based on the structure-function analysis of SIMU, we discovered a novel mechanism of internal inhibition responsible for differential affinities of SIMU to its ligand which might prevent elimination of living cells exposing PS on their surfaces. PMID:23754750

Shklyar, Boris; Levy-Adam, Flonia; Mishnaevski, Ketty

2013-01-01

204

Rapid reuptake of granzyme B leads to emperitosis: an apoptotic cell-in-cell death of immune killer cells inside tumor cells.  

PubMed

A cell-in-cell process refers to the invasion of one living cell into another homotypic or heterotypic cell. Different from non-apoptotic death processes of internalized cells termed entosis or cannibalism, we previously reported an apoptotic cell-in-cell death occurring during heterotypic cell-in-cell formation. In this study, we further demonstrated that the apoptotic cell-in-cell death occurred only in internalized immune killer cells expressing granzyme B (GzmB). Vacuole wrapping around the internalized cells inside the target cells was the common hallmark during the early stage of all cell-in-cell processes, which resulted in the accumulation of reactive oxygen species and subsequent mitochondrial injury of encapsulated killer or non-cytotoxic immune cells. However, internalized killer cells mediated rapid bubbling of the vacuoles with the subsequent degranulation of GzmB inside the vacuole of the target cells and underwent the reuptake of GzmB by killer cells themselves. The confinement of GzmB inside the vacuole surpassed the lysosome-mediated cell death occurring in heterotypic or homotypic entosis processes, resulting in a GzmB-triggered caspase-dependent apoptotic cell-in-cell death of internalized killer cells. On the contrary, internalized killer cells from GzmB-deficient mice underwent a typical non-apoptotic entotic cell-in-cell death similar to that of non-cytotoxic immune cells or tumor cells. Our results thus demonstrated the critical involvement of immune cells with cytotoxic property in apoptotic cell-in-cell death, which we termed as emperitosis taken from emperipolesis and apoptosis. Whereas entosis or cannibalism may serve as a feed-on mechanism to exacerbate and nourish tumor cells, emperitosis of immune killer cells inside tumor cells may serve as an in-cell danger sensation model to prevent the killing of target cells from inside, implying a unique mechanism for tumor cells to escape from immune surveillance. PMID:24113190

Wang, S; He, M-f; Chen, Y-h; Wang, M-y; Yu, X-M; Bai, J; Zhu, H-y; Wang, Y-y; Zhao, H; Mei, Q; Nie, J; Ma, J; Wang, J-f; Wen, Q; Ma, L; Wang, Y; Wang, X-n

2013-01-01

205

Macrophages Discriminate Glycosylation Patterns of Apoptotic Cell-derived Microparticles*  

PubMed Central

Inappropriate clearance of apoptotic remnants is considered to be the primary cause of systemic autoimmune diseases, like systemic lupus erythematosus. Here we demonstrate that apoptotic cells release distinct types of subcellular membranous particles (scMP) derived from the endoplasmic reticulum (ER) or the plasma membrane. Both types of scMP exhibit desialylated glycotopes resulting from surface exposure of immature ER-derived glycoproteins or from surface-borne sialidase activity, respectively. Sialidase activity is activated by caspase-dependent mechanisms during apoptosis. Cleavage of sialidase Neu1 by caspase 3 was shown to be directly involved in apoptosis-related increase of surface sialidase activity. ER-derived blebs possess immature mannosidic glycoepitopes and are prioritized by macrophages during clearance. Plasma membrane-derived blebs contain nuclear chromatin (DNA and histones) but not components of the nuclear envelope. Existence of two immunologically distinct types of apoptotic blebs may provide new insights into clearance-related diseases. PMID:22074924

Bilyy, Rostyslav O.; Shkandina, Tanya; Tomin, Andriy; Muñoz, Luis E.; Franz, Sandra; Antonyuk, Volodymyr; Kit, Yuriy Ya.; Zirngibl, Matthias; Fürnrohr, Barbara G.; Janko, Christina; Lauber, Kirsten; Schiller, Martin; Schett, Georg; Stoika, Rostyslav S.; Herrmann, Martin

2012-01-01

206

The small GTPase Cdc42 initiates an apoptotic signaling pathway in Jurkat T lymphocytes.  

PubMed Central

Apoptosis plays an important role in regulating development and homeostasis of the immune system, yet the elements of the signaling pathways that control cell death have not been well defined. When expressed in Jurkat T cells, an activated form of the small GTPase Cdc42 induces cell death exhibiting the characteristics of apoptosis. The death response induced by Cdc42 is mediated by activation of a protein kinase cascade leading to stimulation of c-Jun amino terminal kinase (JNK). Apoptosis initiated by Cdc42 is inhibited by dominant negative components of the JNK cascade and by reagents that block activity of the ICE protease (caspase) family, suggesting that stimulation of the JNK kinase cascade can lead to caspase activation. The sequence of morphological events observed typically in apoptotic cells is modified in the presence of activated Cdc42, suggesting that this GTPase may account for some aspects of cytoskeletal regulation during the apoptotic program. These data suggest a means through which the biochemical and morphological events occurring during apoptosis may be coordinately regulated. Images PMID:9307966

Chuang, T H; Hahn, K M; Lee, J D; Danley, D E; Bokoch, G M

1997-01-01

207

Cadmium-Induced Oxidative Stress and Apoptotic Changes in the Testis of Freshwater Crab, Sinopotamon henanense  

PubMed Central

Cadmium (Cd), one of the most toxic environmental and industrial pollutants, is known to exert gonadotoxic and spermiotoxic effects. In the present study, we examined the toxic effect of Cd on the testis of freshwater crab, Sinopotamon henanense. Crabs were exposed to different Cd concentrations (from 0 to 116.00 mg·L?1) for 7 d. Oxidative stress and apoptotic changes in the testes were detected. The activities of SOD, GPx and CAT initially increased and subsequently decreased with increasing Cd concentrations, which was accompanied with the increase in malondialdehyde (MDA) and H2O2 content in a concentration-dependent manner. Typical morphological characteristic and physiological changes of apoptosis were observed using a variety of methods (HE staining, AO/EB double fluorescent staining, Transmission Electron Microscope observation and DNA fragmentation analysis), and the activities of caspase-3 and caspase-9 were increased in a concentration-dependent manner after Cd exposure. These results led to the conclusion that Cd could induced oxidative damage as well as apoptosis in the testis, and the apoptotic processes may be mediated via mitochondria-dependent apoptosis pathway by regulating the activities of caspase-3 and caspase-9. PMID:22132153

Wang, Lan; Xu, Tuan; Lei, Wen-wen; Liu, Dong-mei; Li, Ying-jun; Xuan, Rui-jing; Ma, Jing-jin

2011-01-01

208

Cell death stages in single apoptotic and necrotic cells monitored by Raman microspectroscopy  

NASA Astrophysics Data System (ADS)

Although apoptosis and necrosis have distinct features, the identification and discrimination of apoptotic and necrotic cell death in vitro is challenging. Immunocytological and biochemical assays represent the current gold standard for monitoring cell death pathways; however, these standard assays are invasive, render large numbers of cells and impede continuous monitoring experiments. In this study, both room temperature (RT)-induced apoptosis and heat-triggered necrosis were analyzed in individual Saos-2 and SW-1353 cells by utilizing Raman microspectroscopy. A targeted analysis of defined cell death modalities, including early and late apoptosis as well as necrosis, was facilitated based on the combination of Raman spectroscopy with fluorescence microscopy. Spectral shifts were identified in the two cell lines that reflect biochemical changes specific for either RT-induced apoptosis or heat-mediated necrosis. A supervised classification model specified apoptotic and necrotic cell death based on single cell Raman spectra. To conclude, Raman spectroscopy allows a non-invasive, continuous monitoring of cell death, which may help shedding new light on complex pathophysiological or drug-induced cell death processes.

Brauchle, Eva; Thude, Sibylle; Brucker, Sara Y.; Schenke-Layland, Katja

2014-04-01

209

Mitochondria-specific pro-apoptotic activity of genistein lipidic nanocarriers.  

PubMed

Genistein (Gen) soy isoflavone produces extensive pro-apoptotic anticancer effects, mediated predominantly via induction of mitochondrial damages. Rationalization of the native mitochondrial selectivity of Gen, utilizing biophysical model assumptions, led to our design of cationic lipid-based nanocarriers (NC) of Gen. Prototype nanoformulations, lipidic micelles (Mic) and nanoemulsions (NEs) incorporated Gen to serve as both therapeutic and targeting moieties, specific for mitochondria. Both Gen-NCs, showing superior physicochemical properties, produced significant cytotoxicity (5-10-fold lower EC50), compared to all drug controls, in hepatic and colon carcinomas. Owing to the mitochondria-specific accumulation of Gen-NCs, their mitochondrial depolarization effect was most evident, leading to marked activation of intrinsic apoptotic pathway markers--cytosolic cytochrme c and specific caspase-9--thus, confirming the direct mitochondrial action of Gen-NCs. This mechanistic evidence of the mitochondria specificity of our Gen-NE and Gen-Mic strongly indicates their potential as targeted delivery nanosystems to augment anticancer efficacy of many lipophilic chemotherapeutics. PMID:23992356

Pham, Jimmy; Brownlow, Bill; Elbayoumi, Tamer

2013-10-01

210

Immunoenzymatic and morphological detection of epithelial cell apoptotic stages in gastrointestinal allografts from multivisceral transplant patients.  

PubMed

Acute allograft rejection (AR) is a major contributor to morbidity and mortality among patients who undergo multivisceral transplantation. Critical to the assessment of AR is detection of apoptosis in the glandular epithelium of the gastrointestinal allograft. We utilized the TUNEL stain (TdT-mediated biotin 16-dUTP nick-end labeling) to test whether this method improved detection of apoptosis compared to standard slide evaluation. TUNEL and H&E stains were performed on paraffin-embedded tissue sections to estimate the number of apoptotic bodies per 10 high power fields, as determined by independent pathologists in blinded fashion. Both methodologies showed similar numbers and distributions of apoptotic foci present among the epithelial cells. There was a correlation between the number of apoptosis and the grade of rejection (P <.001). This is the first use of the TUNEL stain in gastrointestinal allograft biopsies to our knowledge. The similarity in pattern and sensitivity of TUNEL with standard morphology confirms that biopsy assessment with routine H&E staining allows an accurate appraisal of epithelial cell apoptosis. Therefore, current staining protocols for endoscopically derived mucosal biopsies of gastrointestinal allografts are sufficiently accurate to enumerate the critical feature of epithelial apoptosis as a determinant of the grade of acute rejection. PMID:15050151

Delacruz, V; Garcia, M; Mittal, N; Nishida, S; Levi, D; Selvaggi, G; Madariaga, J; Weppler, D; Tzakis, A; Ruiz, P

2004-03-01

211

Cell death stages in single apoptotic and necrotic cells monitored by Raman microspectroscopy  

PubMed Central

Although apoptosis and necrosis have distinct features, the identification and discrimination of apoptotic and necrotic cell death in vitro is challenging. Immunocytological and biochemical assays represent the current gold standard for monitoring cell death pathways; however, these standard assays are invasive, render large numbers of cells and impede continuous monitoring experiments. In this study, both room temperature (RT)-induced apoptosis and heat-triggered necrosis were analyzed in individual Saos-2 and SW-1353 cells by utilizing Raman microspectroscopy. A targeted analysis of defined cell death modalities, including early and late apoptosis as well as necrosis, was facilitated based on the combination of Raman spectroscopy with fluorescence microscopy. Spectral shifts were identified in the two cell lines that reflect biochemical changes specific for either RT-induced apoptosis or heat-mediated necrosis. A supervised classification model specified apoptotic and necrotic cell death based on single cell Raman spectra. To conclude, Raman spectroscopy allows a non-invasive, continuous monitoring of cell death, which may help shedding new light on complex pathophysiological or drug-induced cell death processes. PMID:24732136

Brauchle, Eva; Thude, Sibylle; Brucker, Sara Y.; Schenke-Layland, Katja

2014-01-01

212

High molecular weight kininogen binds phosphatidylserine and opsonizes urokinase plasminogen activator receptor-mediated efferocytosis.  

PubMed

Phagocytosis of apoptotic cells (efferocytosis) is essential for regulation of immune responses and tissue homeostasis and is mediated by phagocytic receptors. In this study, we found that urokinase plasminogen activator receptor (uPAR) plays an important role in internalization of apoptotic cells and also characterized the underlying mechanisms. In a flow cytometry-based phagocytic assay, uPAR-deficient macrophages displayed significant defect in internalization but not tethering of apoptotic cells. When uPAR-deficient mice were challenged with apoptotic cells, they exhibited pronounced splenomegaly resulting from accumulation of abundant apoptotic cells in spleen. Overexpression of uPAR in HEK-293 cells enhanced efferocytosis, which was inhibited by Annexin V and phosphatidylserine (PS) liposome, suggesting that uPAR-mediated efferocytosis is dependent on PS. In serum lacking high m.w. kininogen (HK), a uPAR ligand, uPAR-mediated efferocytosis was significantly attenuated, which was rescued by replenishment of HK. As detected by flow cytometry, HK selectively bound to apoptotic cells, but not viable cells. In purified systems, HK was specifically associated with PS liposome. HK binding to apoptotic cells induced its rapid cleavage to the two-chain form of HK (HKa) and bradykinin. Both the H chain and L chain of HKa were associated with PS liposome and apoptotic cells. HKa has higher binding affinity than HK to uPAR. Overexpression of Rac1/N17 cDNA inhibited uPAR-mediated efferocytosis. HK plus PS liposome stimulated a complex formation of CrkII with p130Cas and Dock-180 and Rac1 activation in uPAR-293 cells, but not in control HEK-293 cells. Thus, uPAR mediates efferocytosis through HK interaction with PS on apoptotic cells and activation of the Rac1 pathway. PMID:24688027

Yang, Aizhen; Dai, Jihong; Xie, Zhanli; Colman, Robert W; Wu, Qingyu; Birge, Raymond B; Wu, Yi

2014-05-01

213

Identification of a Novel Anti-apoptotic E3 Ubiquitin Ligase That Ubiquitinates Antagonists of Inhibitor of Apoptosis Proteins SMAC, HtrA2, and ARTS*  

PubMed Central

Identification of new anti-apoptotic genes is important for understanding the molecular mechanisms underlying apoptosis and tumorigenesis. The present study identified a novel anti-apoptotic gene named AREL1, which encodes a HECT (homologous to E6-AP carboxyl terminus) family E3 ubiquitin ligase. AREL1 interacted with and ubiquitinated IAP antagonists such as SMAC, HtrA2, and ARTS. However, AREL1 was cytosolic and did not localize to nuclei or mitochondria. The interactions between AREL1 and the IAP antagonists were specific for apoptosis-stimulated cells, in which the IAP antagonists were released into the cytosol from mitochondria. Furthermore, the ubiquitination and degradation of SMAC, HtrA2, and ARTS were significantly enhanced in AREL1-expressing cells following apoptotic stimulation, indicating that AREL1 binds to and ubiquitinates cytosolic but not mitochondria-associated forms of IAP antagonists. Furthermore, the anti-apoptotic role of AREL1-mediated degradation of SMAC, HtrA2, and ARTS was shown by simultaneous knockdown of three IAP antagonists, which caused the inhibition of caspase-3 cleavage, XIAP degradation, and induction of apoptosis. Therefore, the present study suggests that AREL1-mediated ubiquitination and degradation of cytosolic forms of three IAP antagonists plays an important role in the regulation of apoptosis. PMID:23479728

Kim, Jung-bin; Kim, So Youn; Kim, Byeong Mo; Lee, Hunjin; Kim, Insook; Yun, Jeanho; Jo, Yejin; Oh, Taeheun; Jo, Yongsam; Chae, Hee-Don; Shin, Deug Y.

2013-01-01

214

Levels of pro-apoptotic regulator Bad and anti-apoptotic regulator Bcl-xL determine the type of the apoptotic logic gate  

PubMed Central

Background Apoptosis is a tightly regulated process: cellular survive-or-die decisions cannot be accidental and must be unambiguous. Since the suicide program may be initiated in response to numerous stress stimuli, signals transmitted through a number of checkpoints have to be eventually integrated. Results In order to analyze possible mechanisms of the integration of multiple pro-apoptotic signals, we constructed a simple model of the Bcl-2 family regulatory module. The module collects upstream signals and processes them into life-or-death decisions by employing interactions between proteins from three subgroups of the Bcl-2 family: pro-apoptotic multidomain effectors, pro-survival multidomain restrainers, and pro-apoptotic single domain BH3-only proteins. Although the model is based on ordinary differential equations (ODEs), it demonstrates that the Bcl-2 family module behaves akin to a Boolean logic gate of the type dependent on levels of BH3-only proteins (represented by Bad) and restrainers (represented by Bcl-xL). A low level of pro-apoptotic Bad or a high level of pro-survival Bcl-xL implies gate AND, which allows for the initiation of apoptosis only when two stress stimuli are simultaneously present: the rise of the p53 killer level and dephosphorylation of kinase Akt. In turn, a high level of Bad or a low level of Bcl-xL implies gate OR, for which any of these stimuli suffices for apoptosis. Conclusions Our study sheds light on possible signal integration mechanisms in cells, and spans a bridge between modeling approaches based on ODEs and on Boolean logic. In the proposed scheme, logic gates switching results from the change of relative abundances of interacting proteins in response to signals and involves system bistability. Consequently, the regulatory system may process two analogous inputs into a digital survive-or-die decision. PMID:23883471

2013-01-01

215

Identification of new modulators and protein alterations in non-apoptotic programmed cell death.  

PubMed

This study describes the first proteomic analysis of paraptosis--a non-apoptotic form of programmed cell death. As with apoptosis, the first description of paraptosis was based on morphological criteria. Since there are no known markers for paraptosis, the purpose of this study was to dissect changes in the proteome profile occurring during paraptosis. Using one- and two-dimensional SDS-PAGE, Western analysis, and mass spectrometry, we show that during paraptosis, alterations occur mainly in cytoskeletal proteins, signal transduction proteins, mitochondrial proteins, and some metabolic proteins. We also report the identification of: (1) a paraptosis inhibitor, phosphatidylethanolamine binding protein (PEBP-1), and (2) a candidate mediator of paraptosis, prohibitin. Identification of specific paraptotic changes will ultimately lead to tools to detect this type of programmed cell death in in vivo systems and allow for its further characterization. PMID:20830744

Sperandio, Sabina; Poksay, Karen S; Schilling, Birgit; Crippen, Danielle; Gibson, Bradford W; Bredesen, Dale E

2010-12-15

216

[Effect of nitric oxide on expression of apoptotic genes and HSP70 in Drosophila].  

PubMed

Abstract-Data on involvement of nitric oxide in apoptosis are contradictory. The balance between anti- and proapoptotic activities of nitric oxide depends on many factors, including its concentration in a tissue and interactions with other regulators of apoptosis. This paper describes the results of a series of experiments on the effect of nitric oxide donors and inhibitors as well as dNOS1 and dNOS4 transgenes on the apoptosis on drosophila LobRSV mutant strain and wild-type strain Oregon R. It has been shown that a high nitric oxide content in cells is able to inhibit antiapoptotic effect of HSP70 and stimulate apoptosis, possibly, via the grim-mediated apoptotic pathway. Moreover, long-term action of a high nitric oxide concentration during the entire development more efficiently stimulates the proapoptotic genes as compared with short-term action of this agent. PMID:22288105

Dzhansugurova, L B

2011-01-01

217

Macrophage migration inhibitory factor interacts with HBx and inhibits its apoptotic activity  

SciTech Connect

HBx, a transcriptional transactivating protein of hepatitis B virus (HBV), is required for viral infection and has been implicated in virus-mediated liver oncogenesis. However, the precise molecular mechanism remains largely elusive. We used the yeast two-hybrid system to identify that HBx interacts with MIF directly. Macrophage migration inhibitory factor (MIF) is implicated in the regulation of inflammation, cell growth, and even tumor formation. The interaction between HBx and MIF was verified with co-immunoprecipitation, GST pull-down, and cellular colocalization. The expression of MIF was up-regulated in HBV particle producing cell 2.2.15 compared with HepG2 cell. Both HBx and MIF cause HepG2 cell G /G{sub 1} phase arrest, proliferation inhibition, and apoptosis. However, MIF can counteract the apoptotic effect of HBx. These results may provide evidence to explain the link between HBV infection and hepatocellular carcinoma.

Zhang Shimeng [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China); Lin Ruxian [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China); Zhou Zhe [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China); Wen Siyuan [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China); Lin Li [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China); Chen Suhong [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China); Shan Yajun [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China); Cong Yuwen [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China); Wang Shengqi [Beijing Institute of Radiation Medicine, No.27 Taiping Road, Beijing 100850 (China)]. E-mail: sqwang@nic.bmi.ac.cn

2006-04-07

218

p57KIP2 control of actin cytoskeleton dynamics is responsible for its mitochondrial pro-apoptotic effect  

PubMed Central

p57 (Kip2, cyclin-dependent kinase inhibitor 1C), often found downregulated in cancer, is reported to hold tumor suppressor properties. Originally described as a cyclin-dependent kinase (cdk) inhibitor, p57KIP2 has since been shown to influence other cellular processes, beyond cell cycle regulation, including cell death and cell migration. Inhibition of cell migration by p57KIP2 is attributed to the stabilization of the actin cytoskeleton through the activation of LIM domain kinase-1 (LIMK-1). Furthermore, p57KIP2 is able to enhance mitochondrial-mediated apoptosis. Here, we report that the cell death promoting effect of p57KIP2 is linked to its effect on the actin cytoskeleton. Indeed, whereas Jasplakinolide, an actin cytoskeleton-stabilizing agent, mimicked p57KIP2's pro-apoptotic effect, destabilizing the actin cytoskeleton with cytochalsin D reversed p57KIP2's pro-apoptotic function. Conversely, LIMK-1, the enzyme mediating p57KIP2's effect on the actin cytoskeleton, was required for p57KIP2's death promoting effect. Finally, p57KIP2-mediated stabilization of the actin cytoskeleton was associated with the displacement of hexokinase-1, an inhibitor of the mitochondrial voltage-dependent anion channel, from the mitochondria, providing a possible mechanism for the promotion of the mitochondrial apoptotic cell death pathway. Altogether, our findings link together two tumor suppressor properties of p57KIP2, by showing that the promotion of cell death by p57KIP2 requires its actin cytoskeleton stabilization function. PMID:22592318

Kavanagh, E; Vlachos, P; Emourgeon, V; Rodhe, J; Joseph, B

2012-01-01

219

No death without life: vital functions of apoptotic effectors  

Microsoft Academic Search

As a result of the genetic experiments performed in Caenorhabditis elegans, it has been tacitly assumed that the core proteins of the ‘apoptotic machinery’ (CED-3, -4, -9 and EGL-1) would be solely involved in cell death regulation\\/execution and would not exert any functions outside of the cell death realm. However, multiple studies indicate that the mammalian orthologs of these C.

L Galluzzi; N Joza; E Tasdemir; M C Maiuri; M Hengartner; J M Abrams; N Tavernarakis; J Penninger; F Madeo; G Kroemer

2008-01-01

220

Secondary necrosis: The natural outcome of the complete apoptotic program  

Microsoft Academic Search

The predominant definition of apoptosis considers that the elimination of the apoptosing cell is by heterolytic degradation following phagocytosis by an assisting scavenger (efferocytosis). However, an alternative and largely underestimated outcome of apoptosis is secondary necrosis, an autolytic process of cell disintegration with release of cell components that occurs when there is no intervention of scavengers and the full apoptotic

Manuel T. Silva

2010-01-01

221

Research Report Polyethylene glycol inhibits apoptotic cell death following  

E-print Network

Oxidative stress Cytochrome c Membrane repair Apoptosis 1. Introduction We have reported that polyethylene in guinea pig spinal cord repairs neuronal membrane disruptions and reduces oxidative injury. Here we report the release of cytochrome c, a pro-apoptotic cell death factor. This hypothesis is further supported by our

Shi, Riyi

222

Ethanol-Induced Apoptotic Neurodegeneration and Fetal Alcohol Syndrome  

Microsoft Academic Search

The deleterious effects of ethanol on the developing human brain are poorly understood. Here it is reported that ethanol, acting by a dual mechanism [blockade of N-methyl-D-aspartate (NMDA) glutamate receptors and excessive activation of GABAA receptors], triggers widespread apoptotic neurodegeneration in the developing rat forebrain. Vulnerability coincides with the period of synaptogenesis, which in humans extends from the sixth month

Chrysanthy Ikonomidou; Petra Bittigau; Masahiko J. Ishimaru; David F. Wozniak; Christian Koch; Kerstin Genz; Madelon T. Price; Vanya Stefovska; Friederike Hörster; Tanya Tenkova; Krikor Dikranian; John W. Olney

2000-01-01

223

Monitoring circulating apoptotic cells by in-vivo flow cytometry  

NASA Astrophysics Data System (ADS)

Chemotherapies currently constitute one main venue of cancer treatment. For a large number of adult and elderly patients, however, treatment options are poor. These patients may suffer from disease that is resistant to conventional chemotherapy or may not be candidates for curative therapies because of advanced age or poor medical conditions. To control disease in these patients, new therapies must be developed that are selectively targeted to unique characteristics of tumor cell growth and metastasis. A reliable early evaluation and prediction of response to the chemotherapy is critical to its success. Chemotherapies induce apoptosis in tumor cells and a portion of such apoptotic cancer cells may be present in the circulation. However, the fate of circulating tumor cells is difficult to assess with conventional methods that require blood sampling. We report the in situ measurement of circulating apoptotic cells in live animals using in vivo flow cytometry, a novel method that enables real-time detection and quantification of circulating cells without blood extraction. Apoptotic cells are rapidly cleared from the circulation with a half-life of ~10 minutes. Real-time monitoring of circulating apoptotic cells can be useful for detecting early changes in disease processes, as well as for monitoring response to therapeutic intervention.

Wei, Xunbin; Tan, Yuan; Chen, Yun; Zhang, Li; Li, Yan; Liu, Guangda; Wu, Bin; Wang, Chen

2008-02-01

224

Wild-type PABPN1 is anti-apoptotic and reduces toxicity of the oculopharyngeal muscular dystrophy mutation.  

PubMed

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset, progressive disease caused by the abnormal expansion of a polyalanine tract-encoding (GCG)(n) trinucleotide repeat in the poly-(A) binding protein nuclear 1 (PABPN1) gene. OPMD is generally inherited as an autosomal dominant disorder and the polyalanine expansion mutation is thought to confer a toxic gain-of-function on mutant PABPN1 which forms aggregates within skeletal myocyte nuclei. Here we describe a novel beneficial function of wild-type PABPN1. Wild-type PABPN1 over-expression can reduce mutant PABPN1 toxicity in both cell and mouse models of OPMD. In addition, wild-type PABPN1 provides some protection to cells against pro-apoptotic insults distinct from the OPMD mutation such as staurosporine treatment and Bax expression. Conversely, PABPN1 knockdown (which itself is not toxic) makes cells more susceptible to apoptotic stimuli. The protective effect of wild-type PABPN1 is mediated by its regulation of X-linked inhibitor of apoptosis (XIAP) protein translation. This normal activity of PABPN1 is partially lost for mutant PABPN1; elevated levels of XIAP are seen in mice expressing a wild-type but not a mutant PABPN1 transgene. This raises the possibility that a compromise of the anti-apoptotic function of PABPN1 might contribute to the disease mechanism of OPMD. PMID:18178579

Davies, Janet E; Sarkar, Sovan; Rubinsztein, David C

2008-04-15

225

Rutin alleviates prion peptide-induced cell death through inhibiting apoptotic pathway activation in dopaminergic neuronal cells.  

PubMed

Prion disorders are progressive neurodegenerative diseases characterized by extensive neuronal loss and accumulation of the abnormal form of the scrapie prion protein (PrP). Rutin is a flavonoid that occurs naturally in plant-derived beverages and foods and is used in traditional and folkloric medicine worldwide. In the present study, we evaluated the protective effects of rutin against PrP fragment (106-126)-induced neuronal cell death. Rutin treatment blocked PrP (106-126)-mediated increases in reactive oxygen species production and nitric oxide release and helped slowing the decrease of neurotrophic factors that results from PrP accumulation. Rutin attenuated PrP (106-126)-associated mitochondrial apoptotic events by inhibiting mitochondrial permeability transition and caspase-3 activity and blocking expression of the apoptotic signals Bax and PARP. Additionally, rutin treatment significantly decreased the expression of the death receptor Fas and its ligand Fas-L. Overall, our results demonstrated that rutin protects against the neurodegenerative effects of prion accumulation by increasing production of neurotropic factors and inhibiting apoptotic pathway activation in neuronal cells. These results suggested that rutin may have clinical benefits for prion diseases and other neurodegenerative disorders. PMID:25048806

Na, Ji-Young; Kim, Sokho; Song, Kibbeum; Kwon, Jungkee

2014-10-01

226

Apoptin T108 phosphorylation is not required for its tumor-specific nuclear localization but partially affects its apoptotic activity  

SciTech Connect

Apoptin, a chicken anemia virus-encoded protein, induces apoptosis in human tumor cells but not in normal cells. In addition, Apoptin also exhibits tumor-specific nuclear localization and tumor-specific phosphorylation on threonine 108 (T108). Here, we studied the effects of T108 phosphorylation on the tumor-specific nuclear localization and apoptotic activity of Apoptin. We first showed that a hemagglutinin (HA)-tagged Apoptin, but not the green fluorescent protein-fused Apoptin used in many previous studies, exhibited the same intracellular distribution pattern as native Apoptin. We then made and analyzed an HA-Apoptin mutant with its T108 phosphorylation site abolished. We found that Apoptin T108 phosphorylation is not required for its tumor-specific nuclear localization and abolishing the T108 phosphorylation of Apoptin does affect its apoptotic activity in tumor cells but only partially. Our results support the previous finding that Apoptin contains two distinct apoptosis domains located separately at the N- and C-terminal regions and suggest that the T108 phosphorylation may only be required for the apoptotic activity mediated through the C-terminal apoptosis domain.

Lee, Y.-H. [Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Cheng, C.-M. [Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Chang, Y.-F. [Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Wang, T.-Y. [Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Yuo, C.-Y. [Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); E-mail: m815006@kmu.edu.tw

2007-03-09

227

Secondary necrosis of apoptotic neutrophils induced by the human cathelicidin LL-37 is not proinflammatory to phagocytosing macrophages.  

PubMed

Cathelicidins are CHDP with essential roles in innate host defense but also more recently associated with the pathogenesis of certain chronic diseases. These peptides have microbicidal potential and the capacity to modulate innate immunity and inflammatory processes. PMN are key innate immune effector cells with pivotal roles in defense against infection. The appropriate regulation of PMN function, death, and clearance is critical to innate immunity, and dysregulation is implicated in disease pathogenesis. The efferocytosis of apoptotic PMN, in contrast to necrotic cells, is proposed to promote the resolution of inflammation. We demonstrate that the human cathelicidin LL-37 induced rapid secondary necrosis of apoptotic human PMN and identify an essential minimal region of LL-37 required for this activity. Using these LL-37-induced secondary necrotic PMN, we characterize the consequence for macrophage inflammatory responses. LL-37-induced secondary necrosis did not inhibit PMN ingestion by monocyte-derived macrophages and in contrast to expectation, was not proinflammatory. Furthermore, the anti-inflammatory effects of apoptotic PMN on activated macrophages were retained and even potentiated after LL-37-induced secondary necrosis. However, this process of secondary necrosis did induce the release of potentially harmful PMN granule contents. Thus, we suggest that LL-37 can be a potent inducer of PMN secondary necrosis during inflammation without promoting macrophage inflammation but may mediate host damage through PMN granule content release under chronic or dysregulated conditions. PMID:19581375

Li, Hsin-Ni; Barlow, Peter G; Bylund, Johan; Mackellar, Annie; Björstad, Ase; Conlon, James; Hiemstra, Pieter S; Haslett, Chris; Gray, Mohini; Simpson, A John; Rossi, Adriano G; Davidson, Donald J

2009-10-01

228

Secondary necrosis of apoptotic neutrophils induced by the human cathelicidin LL-37 is not proinflammatory to phagocytosing macrophages  

PubMed Central

Cathelicidins are CHDP with essential roles in innate host defense but also more recently associated with the pathogenesis of certain chronic diseases. These peptides have microbicidal potential and the capacity to modulate innate immunity and inflammatory processes. PMN are key innate immune effector cells with pivotal roles in defense against infection. The appropriate regulation of PMN function, death, and clearance is critical to innate immunity, and dysregulation is implicated in disease pathogenesis. The efferocytosis of apoptotic PMN, in contrast to necrotic cells, is proposed to promote the resolution of inflammation. We demonstrate that the human cathelicidin LL-37 induced rapid secondary necrosis of apoptotic human PMN and identify an essential minimal region of LL-37 required for this activity. Using these LL-37-induced secondary necrotic PMN, we characterize the consequence for macrophage inflammatory responses. LL-37-induced secondary necrosis did not inhibit PMN ingestion by monocyte-derived macrophages and in contrast to expectation, was not proinflammatory. Furthermore, the anti-inflammatory effects of apoptotic PMN on activated macrophages were retained and even potentiated after LL-37-induced secondary necrosis. However, this process of secondary necrosis did induce the release of potentially harmful PMN granule contents. Thus, we suggest that LL-37 can be a potent inducer of PMN secondary necrosis during inflammation without promoting macrophage inflammation but may mediate host damage through PMN granule content release under chronic or dysregulated conditions. PMID:19581375

Li, Hsin-Ni; Barlow, Peter G.; Bylund, Johan; Mackellar, Annie; Bjorstad, Ase; Conlon, James; Hiemstra, Pieter S.; Haslett, Chris; Gray, Mohini; Simpson, A. John; Rossi, Adriano G.; Davidson, Donald J.

2009-01-01

229

NDK-1, the Homolog of NM23-H1/H2 Regulates Cell Migration and Apoptotic Engulfment in C. elegans  

PubMed Central

Abnormal regulation of cell migration and altered rearrangement of cytoskeleton are characteristic of metastatic cells. The first described suppressor of metastatic processes is NM23-H1, which displays NDPK (nucleoside-diphosphate kinase) activity. To better understand the role of nm23 genes in cell migration, we investigated the function of NDK-1, the sole Caenorhabditis elegans homolog of group I NDPKs in distal tip cell (DTC) migration. Dorsal phase of DTC migration is regulated by integrin mediated signaling. We find that ndk-1 loss of function mutants show defects in this phase. Epistasis analysis using mutants of the ?-integrin ina-1 and the downstream functioning motility-promoting signaling module (referred to as CED-10 pathway) placed NDK-1 downstream of CED-10/Rac. As DTC migration and engulfment of apoptotic corpses are analogous processes, both partially regulated by the CED-10 pathway, we investigated defects of apoptosis in ndk-1 mutants. Embryos and germ cells defective for NDK-1 showed an accumulation of apoptotic cell corpses. Furthermore, NDK-1::GFP is expressed in gonadal sheath cells, specialized cells for engulfment and clearence of apoptotic corpses in germ line, which indicates a role for NDK-1 in apoptotic corpse removal. In addition to the CED-10 pathway, engulfment in the worm is also mediated by the CED-1 pathway. abl-1/Abl and abi-1/Abi, which function in parallel to both CED-10/CED-1 pathways, also regulate engulfment and DTC migration. ndk-1(-);abi-1(-) double mutant embryos display an additive phenotype (e. g. enhanced number of apoptotic corpses) which suggests that ndk-1 acts in parallel to abi-1. Corpse number in ndk-1(-);ced-10(-) double mutants, however, is similar to ced-10(-) single mutants, suggesting that ndk-1 acts downstream of ced-10 during engulfment. In addition, NDK-1 shows a genetic interaction with DYN-1/dynamin, a downstream component of the CED-1 pathway. In summary, we propose that NDK-1/NDPK might represent a converging point of CED-10 and CED-1 pathways in the process of cytoskeleton rearrangement. PMID:24658123

Fancsalszky, Luca; Monostori, Eszter; Farkas, Zsolt; Pourkarimi, Ehsan; Masoudi, Neda; Hargitai, Balazs; Bosnar, Maja Herak; Dezeljin, Martina; Zsakai, Annamaria; Vellai, Tibor; Mehta, Anil; Takacs-Vellai, Krisztina

2014-01-01

230

Prostaglandin D2 synthase: Apoptotic factor in alzheimer plasma, inducer of reactive oxygen species, inflammatory cytokines and dialysis dementia  

PubMed Central

Background: Apoptosis, reactive oxygen species (ROS) and inflammatory cytokines have all been implicated in the development of Alzheimer’s disease (AD). Objectives: The present study identifies the apoptotic factor that was responsible for the fourfold increase in apoptotic rates that we previously noted when pig proximal tubule, LLC-PK1, cells were exposed to AD plasma as compared to plasma from normal controls and multi-infarct dementia. Patients and Methods: The apoptotic factor was isolated from AD urine and identified as lipocalin-type prostaglandin D2 synthase (L-PGDS). L-PGDS was found to be the major apoptotic factor in AD plasma as determined by inhibition of apoptosis approximating control levels by the cyclo-oxygenase (COX) 2 inhibitor, NS398, and the antibody to L-PGDS. Blood levels of L-PGDS, however, were not elevated in AD. We now demonstrate a receptor-mediated uptake of L-PGDS in PC12 neuronal cells that was time, dose and temperature-dependent and was saturable by competition with cold L-PGDS and albumin. Further proof of this endocytosis was provided by an electron microscopic study of gold labeled L-PGDS and immunofluorescence with Alexa-labeled L-PGDS. Results: The recombinant L-PGDS and wild type (WT) L-PGDS increased ROS but only the WTL-PGDS increased IL6 and TNF?, suggesting that differences in glycosylation of L-PGDS in AD was responsible for this discrepancy. Conclusions: These data collectively suggest that L-PGDS might play an important role in the development of dementia in patients on dialysis and of AD. PMID:24475446

Maesaka, John K.; Sodam, Bali; Palaia, Thomas; Ragolia, Louis; Batuman, Vecihi; Miyawaki, Nobuyuki; Shastry, Shubha; Youmans, Steven; El-Sabban, Marwan

2013-01-01

231

Intravenous apoptotic spleen cell infusion induces a TGF-beta-dependent regulatory T cell expansion  

E-print Network

1 Intravenous apoptotic spleen cell infusion induces a TGF-beta-dependent regulatory T cell prevents the apoptotic spleen cell-induced beneficial effects on engraftment and graft-versus-host disease occurrence. This highlights the role of regulatory T cells in the tolerogenic effect of apoptotic spleen cell

Paris-Sud XI, Université de

232

Defects in the apoptotic machinery of cancer cells: role in drug resistance  

Microsoft Academic Search

The therapeutic goal in cancer treatment is to trigger tumor-selective cell death. Since many antineoplastic agents induce an apoptotic type of death in susceptible cells, it is likely that dysfunction of the apoptotic machinery might be an important determinant of resistance to anticancer drugs. Here we review known differences in the apoptotic machinery in cancer cells, and how this knowledge

Boris Zhivotovsky; Sten Orrenius

2003-01-01

233

Distinct localization of lipid rafts and externalized phosphatidylserine at the surface of apoptotic cells  

Microsoft Academic Search

Externalization of phosphatidylserine (PS) takes place in apoptotic cells as well as in viable cells under certain circumstances. Recent studies showed that externalized PS is localized at the lipid raft in viable activated immune cells. We found that lipid rafts and PS existed in a mutually exclusive manner in apoptotic cells. The number of PS-exposing apoptotic cells decreased when lipid

Hidenari Ishii; Tomoe Mori; Akiko Shiratsuchi; Yuji Nakai; Yukiko Shimada; Yoshiko Ohno-Iwashita; Yoshinobu Nakanishi

2005-01-01

234

Apoptotic machinery diversity in multiple myeloma molecular subtypes.  

PubMed

Multiple myeloma (MM) is a plasma-cell (PC) malignancy that is heterogeneous in its clinical presentation and prognosis. Monoclonal gammopathy of undetermined significance (MGUS) consistently preceded development of MM. The presence of primary IgH translocations and the universal overexpression of cyclin D genes led to a molecular classification of MM patients into different disease subtypes. Since Bcl-2 family proteins determine cell fate, we analyzed a publicly available Affymetrix gene expression of 44 MGUS and 414 newly diagnosed MM patients to investigate (1) the global change of Bcl-2 family members in MM versus MGUS (2) whether the four major subtypes defined as hyperdiploid, CyclinD1, MAF, and MMSET, display specific apoptotic machineries. We showed that among the main anti-apoptotic members (Bcl-2, Bcl-xL, and Mcl-1), Mcl-1 up-regulation discriminated MM from MGUS, in agreement with the prominent role of Mcl-1 in PC differentiation. Surprisingly, the expression of multi-domain pro-apoptotic Bak and Bax were increased during the progression of MGUS to MM. The combined profile of Bcl-2, Bcl-xL, and Mcl-1 was sufficient to distinguish MM molecular groups. While specific pro-apoptotic members expression was observed for each MM subtypes, CyclinD1 subgroup, was identified as a particular entity characterized by a low expression of BH3-only (Puma, Bik, and Bad) and multi-domain pro-apoptotic members (Bax and Bak). Our analysis supports the notion that MM heterogeneity is extended to the differential expression of the Bcl-2 family content in each MM subgroup. The influence of Bcl-2 family profile in the survival of the different patient groups will be further discussed to establish the potential consequences for therapeutic interventions. Finally, the use of distinct pro-survival members in the different steps of immune responses to antigen raises also the question of whether the different Bcl-2 anti-apoptotic profile could reflect a different origin of MM cells. PMID:24391642

Gomez-Bougie, Patricia; Amiot, Martine

2013-01-01

235

Mediation Analysis  

PubMed Central

Mediating variables are prominent in psychological theory and research. A mediating variable transmits the effect of an independent variable on a dependent variable. Differences between mediating variables and confounders, moderators, and covariates are outlined. Statistical methods to assess mediation and modern comprehensive approaches are described. Future directions for mediation analysis are discussed. PMID:16968208

MacKinnon, David P.; Fairchild, Amanda J.; Fritz, Matthew S.

2010-01-01

236

The Fas/Fas ligand apoptotic pathway is involved in abrin-induced apoptosis.  

PubMed

Abrin is a plant glycoprotein toxin from the seeds of Abrus precatorius, sharing similarity in structure and properties with ricin. Abrin is highly toxic, with an estimated human fatal dose of 0.1-1 µg/kg, causing death after accidental or intentional poisoning. It is a potent biological toxin warfare agent. There is no chemical antidote available against the abrin. The elucidation of molecular mechanism of abrin-induced cell death is important for development of therapy. Intrinsic pathway-mediated apoptosis has been well established in abrin-induced cell death. However, the detailed mechanism especially extrinsic receptor-mediated pathway remains uncharacterized. To assess whether some of the apoptosis known to occur after abrin exposure might be mediated by Fas/Fas ligand (Fas L) interactions, we analyzed effect of abrin on Fas pathway in Jurkat cells. Here, we report that activation of the Fas pathway is involved in abrin-induced apoptosis. Following treatment of abrin, Fas L was induced, which stimulated the Fas pathway by cross-linking Fas receptor (Fas R). Apoptosis was mediated by cleavage of the Fas R proximal caspase-8 and the downstream caspase-3, resulting in activation of the prototype caspase substrate poly-(ADP-ribose) polymerase and caspase-activated DNase. Blocking Fas L/Fas R interaction by using Fas inhibitor reduced abrin-induced apoptosis, further confirms involvement of Fas pathway. Activation of components of Fas pathway and caspases upon abrin treatment was also found in splenocytes in mice. Our findings offer new perspective for understanding the fundamental mechanism in abrin-induced apoptotic mechanism and may have implication in developing novel therapeutic strategies in the management for abrin-induced complications. PMID:23788630

Saxena, Nandita; Yadav, Preeti; Kumar, Om

2013-09-01

237

Manipulating the apoptotic pathway: potential therapeutics for cancer patients  

PubMed Central

This review summarizes the current state of scientific understanding of the apoptosis pathway, with a focus on the proteins involved in the pathway, their interactions and functions. This forms the rationale for detailing the preclinical and clinical pharmacology of drugs that modulate the pivotal proteins in this pathway, with emphasis on drugs that are furthest advanced in clinical development as anticancer agents. There is a focus on describing drugs that modulate three of the most promising targets in the apoptosis pathway, namely antibodies that bind and activate the death receptors, small molecules that inhibit the anti-apoptotic Bcl-2 family proteins, and small molecules and antisense oligonucleotides that inactivate the inhibitors of apoptosis, all of which drive the equilibrium of the apoptotic pathway towards apoptosis. These structurally different yet functionally related groups of drugs represent a promising novel approach to anticancer therapeutics whether used as monotherapy or in combination with either classical cytotoxic or other molecularly targeted anticancer agents. PMID:23782006

Bates, Darcy J P; Lewis, Lionel D

2013-01-01

238

Chemoresistance in human ovarian cancer: the role of apoptotic regulators  

PubMed Central

Ovarian cancer is among the most lethal of all malignancies in women. While chemotherapy is the preferred treatment modality, chemoresistance severely limits treatment success. Recent evidence suggests that deregulation of key pro- and anti-apoptotic pathways is a key factor in the onset and maintenance of chemoresistance. Furthermore, the discovery of novel interactions between these pathways suggests that chemoresistance may be multi-factorial. Ultimately, the decision of the cancer cell to live or die in response to a chemotherapeutic agent is a consequence of the overall apoptotic capacity of that cell. In this review, we discuss the biochemical pathways believed to promote cell survival and how they modulate chemosensitivity. We then conclude with some new research directions by which the fundamental mechanisms of chemoresistance can be elucidated. PMID:14609433

Fraser, Michael; Leung, Brendan; Jahani-Asl, Arezu; Yan, Xiaojuan; Thompson, Winston E; Tsang, Benjamin K

2003-01-01

239

Cancer Vaccine Composed of Oligonucleotides Conjugated to Apoptotic Tumor Cells  

Cancer.gov

NCI Scientists have discovered that conjugating CpG ODNs to apoptotic tumor cells to improve vaccine activity by ensuring that the ODN remains associated with the tumor antigen so that both are internalized by professional antigen presenting cells. The strategy eliminates the need to define specific tumor-associated antigens, substituting instead the entire tumor cell (which in the absence of CpG ODN is poorly immunogenic).

240

Apoptotic Death of Cancer Stem Cells for Cancer Therapy  

PubMed Central

Cancer stem cells (CSCs) play crucial roles in tumor progression, chemo- and radiotherapy resistance, and recurrence. Recent studies on CSCs have advanced understanding of molecular oncology and development of novel therapeutic strategies. This review article updates the hypothesis and paradigm of CSCs with a focus on major signaling pathways and effectors that regulate CSC apoptosis. Selective CSC apoptotic inducers are introduced and their therapeutic potentials are discussed. These include synthetic and natural compounds, antibodies and recombinant proteins, and oligonucleotides. PMID:24823879

He, Ying-Chun; Zhou, Fang-Liang; Shen, Yi; Liao, Duan-Fang; Cao, Deliang

2014-01-01

241

Preemptive donor apoptotic cell infusions induce IFN-?-producing myeloid-derived suppressor cells for cardiac allograft protection.  

PubMed

We have previously shown that preemptive infusion of apoptotic donor splenocytes treated with the chemical cross-linker ethylcarbodiimide (ECDI-SPs) induces long-term allograft survival in full MHC-mismatched models of allogeneic islet and cardiac transplantation. The role of myeloid-derived suppressor cells (MDSCs) in the graft protection provided by ECDI-SPs is unclear. In this study, we demonstrate that infusions of ECDI-SPs increase two populations of CD11b(+) cells in the spleen that phenotypically resemble monocytic-like (CD11b(+)Ly6C(high)) and granulocytic-like (CD11b(+)Gr1(high)) MDSCs. Both populations suppress T cell proliferation in vitro and traffic to the cardiac allografts in vivo to mediate their protection via inhibition of local CD8 T cell accumulation and potentially also via induction and homing of regulatory T cells. Importantly, repeated treatments with ECDI-SPs induce the CD11b(+)Gr1(high) cells to produce a high level of IFN-? and to exhibit an enhanced responsiveness to IFN-? by expressing higher levels of downstream effector molecules ido and nos2. Consequently, neutralization of IFN-? completely abolishes the suppressive capacity of this population. We conclude that donor ECDI-SPs induce the expansion of two populations of MDSCs important for allograft protection mediated in part by intrinsic IFN-?-dependent mechanisms. This form of preemptive donor apoptotic cell infusions has significant potential for the therapeutic manipulation of MDSCs for transplant tolerance induction. PMID:24808363

Bryant, Jane; Lerret, Nadine M; Wang, Jiao-Jing; Kang, Hee-Kap; Tasch, James; Zhang, Zheng; Luo, Xunrong

2014-06-15

242

PDT-apoptotic tumor cells induce macrophage immune response  

NASA Astrophysics Data System (ADS)

Photodynamic therapy (PDT) functions as a cancer therapy through two major cell death mechanisms: apoptosis and necrosis. Immunological responses induced by PDT has been mainly associated with necrosis while apoptosis associated immune responses have not fully investigated. Heat shock proteins (HSPs) play an important role in regulating immune responses. In present study, we studied whether apoptotic tumor cells could induce immune response and how the HSP70 regulates immune response. The endocytosis of tumor cells by the activated macrophages was observed at single cell level by LSM. The TNF-? release of macrophages induced by co-incubated with PDT-apoptotic tumor cells was detected by ELISA. We found that apoptotic tumor cells treated by PDT could activate the macrophages, and the immune effect decreased evidently when HSP70 was blocked. These findings not only show that apoptosis can induce immunological responses, but also show HSP70 may serves as a danger signal for immune cells and induce immune responses to regulate the efficacy of PDT.

Zhou, Fei-fan; Xing, Da; Chen, Wei R.

2008-02-01

243

STAT1, STAT3 and p38MAPK are involved in the apoptotic effect induced by a chimeric cyclic interferon-{alpha}2b peptide  

SciTech Connect

In the search of mimetic peptides of the interferon-{alpha}2b molecule (IFN-{alpha}2b), we have previously designed and synthesized a chimeric cyclic peptide of the IFN-{alpha}2b that inhibits WISH cell proliferation by inducing an apoptotic response. Here, we first studied the ability of this peptide to activate intracellular signaling pathways and then evaluated the participation of some signals in the induction of apoptosis. Stimulation of WISH cells with the cyclic peptide showed tyrosine phosphorylation of Jak1 and Tyk2 kinases, tyrosine and serine phosphorylation of STAT1 and STAT3 transcription factors and activation of p38 MAPK pathway, although phosphorylation levels or kinetics were in some conditions different to those obtained under IFN-{alpha}2b stimulus. JNK and p44/42 pathways were not activated by the peptide in WISH cells. We also showed that STAT1 and STAT3 downregulation by RNA interference decreased the antiproliferative activity and the amount of apoptotic cells induced by the peptide. Pharmacological inhibition of p38 MAPK also reduced the peptide growth inhibitory activity and the apoptotic effect. Thus, we demonstrated that the cyclic peptide regulates WISH cell proliferation through the activation of Jak/STAT signaling pathway. In addition, our results indicate that p38 MAPK may also be involved in cell growth regulation. This study suggests that STAT1, STAT3 and p38 MAPK would be mediating the antitumor and apoptotic response triggered by the cyclic peptide in WISH cells.

Blank, Viviana C.; Pena, Clara [Institute of Biochemistry and Biophysics (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956-C1113AAD Buenos Aires (Argentina)] [Institute of Biochemistry and Biophysics (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956-C1113AAD Buenos Aires (Argentina); Roguin, Leonor P., E-mail: rvroguin@qb.ffyb.uba.ar [Institute of Biochemistry and Biophysics (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956-C1113AAD Buenos Aires (Argentina)

2010-02-15

244

RGDechi-hCit: ?v?3 Selective Pro-Apoptotic Peptide as Potential Carrier for Drug Delivery into Melanoma Metastatic Cells  

PubMed Central

?v?3 integrin is an important tumor marker widely expressed on the surface of cancer cells. Recently, we reported some biological features of RGDechi-hCit, an ?v?3 selective peptide antagonist. In the present work, we mainly investigated the pro-apoptotic activity of the molecule and its ability to penetrate the membrane of WM266 cells, human malignant melanoma cells expressing high levels of ?v?3 integrin. For the first time we demonstrated the pro-apoptotic effect and the ability of RGDechi-hCit to enter into cell overexpressing ?v?3 integrin mainly by clathrin- and caveolin-mediated endocytosis. Furthermore, we deepened and confirmed the selectivity, anti-adhesion, and anti-proliferative features of the peptide. Altogether these experiments give insight into the biological behavior of RGDechi-hCit and have important implications for the employment of the peptide as a new selective carrier to deliver drugs into the cell and as a therapeutic and diagnostic tool for metastatic melanoma. Moreover, since the peptide shows a pro-apoptotic effect, a great perspective could be the development of a new class of selective systems containing RGDechi-hCit and pro-apoptotic molecules or other therapeutic agents to attain a synergic action. PMID:25248000

Del Gatto, Annarita; Di Gaetano, Sonia; Guarnieri, Daniela; Saviano, Michele; Zaccaro, Laura

2014-01-01

245

Glutathione depletion regulates both extrinsic and intrinsic apoptotic signaling cascades independent from multidrug resistance protein 1  

PubMed Central

Glutathione (GSH) depletion is an important hallmark of apoptosis. We previously demonstrated that GSH depletion, by its efflux, regulates apoptosis by modulation of executioner caspase activity. However, both the molecular identity of the GSH transporter(s) involved and the signaling cascades regulating GSH loss remain obscure. We sought to determine the role of multidrug resistance protein 1 (MRP1) in GSH depletion and its regulatory role on extrinsic and intrinsic pathways of apoptosis. In human lymphoma cells, GSH depletion was stimulated rather than inhibited by pharmacological blockage of MRP1 with MK571. GSH loss was dependent on initiator caspases 8 and 9 activity. Genetic knock-down (>60%) of MRP1 by stable transfection with short-hairpin small interfering RNA significantly reduced MRP1 protein levels, which correlated directly with the loss of MRP1-mediated anion transport. However, GSH depletion and apoptosis induced by both extrinsic and intrinsic pathways were not affected by MRP1 knock-down. Interestingly, stimulation of GSH loss by MK571 also enhanced the initiator phase of apoptosis by stimulating initiator caspase 8 and 9 activity and pro-apoptotic BID cleavage. Our results clearly show that caspase-dependent GSH loss and apoptosis are not mediated by MRP1 proteins and that GSH depletion stimulates the initiation phase of apoptosis in lymphoid cells. PMID:24146141

Franco, Rodrigo; Bortner, Carl; Schmitz, Ingo; Cidlowski, John A.

2014-01-01

246

Dyrk1A Positively Stimulates ASK1-JNK Signaling Pathway during Apoptotic Cell Death  

PubMed Central

Dual-specificity tyrosine (Y)-phosphorylation-regulated protein kinase 1A (Dyrk1A) is the mammalian homologue of Drosophila melanogaster minibrain and its human gene is mapped to the Down syndrome critical region of chromosome 21. Dyrk1A phosphorylates several transcription factors, including NFAT and CREB and a number of cytosolic proteins such as APP, tau, and ?-synuclein. Although Dyrk1A is involved in the control of cell growth and postembryonic neurogenesis, its potential role during cell death and signaling pathway is not clearly understood. In the present study, we show that Dyrk1A is activated under the condition of apoptotic cell death. In addition, Dyrk1A is coupled to JNK1 activation, and directly interacts with apoptosis signal-regulating kinase 1 (ASK1). Moreover, Dyrk1A positively regulates ASK1-mediated JNK1-signaling, and appears to directly phosphorylate ASK1. These data indicate that Dyrk1A regulates cell death through facilitating ASK1-mediated signaling events. PMID:22110360

Choi, Hyoung Kyoung

2011-01-01

247

The Extrathyronine Actions of Iodine as Antioxidant, Apoptotic, and Differentiation Factor in Various Tissues  

PubMed Central

Background Seaweed is an important dietary component and a rich source of iodine in several chemical forms in Asian communities. Their high consumption of this element (25 times higher than in Western countries) has been associated with the low incidence of benign and cancerous breast and prostate disease in Japanese people. Summary We review evidence showing that, in addition to being a component of the thyroid hormone, iodine can be an antioxidant as well as an antiproliferative and differentiation agent that helps to maintain the integrity of several organs with the ability to take up iodine. In animal and human studies, molecular iodine (I2) supplementation exerts a suppressive effect on the development and size of both benign and cancerous neoplasias. Investigations by several groups have demonstrated that these effects can be mediated by a variety of mechanisms and pathways, including direct actions, in which the oxidized iodine dissipates the mitochondrial membrane potential, thereby triggering mitochondrion-mediated apoptosis, and indirect effects through iodolipid formation and the activation of peroxisome proliferator–activated receptors type gamma, which, in turn, trigger apoptotic or differentiation pathways. Conclusions We propose that the International Council for the Control of Iodine Deficient Disorders recommend that iodine intake be increased to at least 3?mg/day of I2 in specific pathologies to obtain the potential extrathyroidal benefits described in the present review. PMID:23607319

Anguiano, Brenda; Delgado, Guadalupe

2013-01-01

248

Deep Sequencing Identification of Novel Glucocorticoid-Responsive miRNAs in Apoptotic Primary Lymphocytes  

PubMed Central

Apoptosis of lymphocytes governs the response of the immune system to environmental stress and toxic insult. Signaling through the ubiquitously expressed glucocorticoid receptor, stress-induced glucocorticoid hormones induce apoptosis via mechanisms requiring altered gene expression. Several reports have detailed the changes in gene expression mediating glucocorticoid-induced apoptosis of lymphocytes. However, few studies have examined the role of non-coding miRNAs in this essential physiological process. Previously, using hybridization-based gene expression analysis and deep sequencing of small RNAs, we described the prevalent post-transcriptional repression of annotated miRNAs during glucocorticoid-induced apoptosis of lymphocytes. Here, we describe the development of a customized bioinformatics pipeline that facilitates the deep sequencing-mediated discovery of novel glucocorticoid-responsive miRNAs in apoptotic primary lymphocytes. This analysis identifies the potential presence of over 200 novel glucocorticoid-responsive miRNAs. We have validated the expression of two novel glucocorticoid-responsive miRNAs using small RNA-specific qPCR. Furthermore, through the use of Ingenuity Pathways Analysis (IPA) we determined that the putative targets of these novel validated miRNAs are predicted to regulate cell death processes. These findings identify two and predict the presence of additional novel glucocorticoid-responsive miRNAs in the rat transcriptome, suggesting a potential role for both annotated and novel miRNAs in glucocorticoid-induced apoptosis of lymphocytes. PMID:24250753

Mav, Deepak; Scoltock, Alyson B.; Cidlowski, John A.

2013-01-01

249

The study of the Oxytropis kansuensis-induced apoptotic pathway in the cerebrum of SD rats  

PubMed Central

Background Locoweeds cause significant livestock poisoning and economic loss all over the world. Animals can develop locoism, a chronic neurological disease, after grazing on locoweeds. Oxytropis kansuensis is a variety of locoweed that contains swainsonine as its main toxic ingredient. The purpose of this study was to investigate the apoptotic pathway induced in the cerebrum by swainsonine. Results Twenty-four Sprague-Dawley rats were randomly divided into four groups (experimental groups I, II, III and a control group) and 6 SD rats of each group were feed in 3 cages separately. Rats were penned as groups and fed with feeds containing 15% (SW content 0.03‰), 30% (SW content 0.06‰), or 45% (SW content 0.09‰) O. kansuensis for experimental groups I, II, and III, respectively, or complete feed in the case of the control group. One hundred and nineteen days after poisoning, and all rats showed neurological disorders at different degrees, which were considered to be successful established a chronic poisoning model of O. kansuensis. rats were sacrificed and the expression of Fas, FasL, Bcl-2, Bax as well as cleaved caspase-3, -8 and -9 proteins in brain tissues were detected by Western blot. The results showed that SW treatment up-regulated Fas and Fas ligand (FasL) (P?mediated, caspase-dependent apoptotic pathways in the brain tissue of SD rats. PMID:24148892

2013-01-01

250

Lamin A/C cleavage by caspase-6 activation is crucial for apoptotic induction by photodynamic therapy with hexaminolevulinate in human B-cell lymphoma cells.  

PubMed

Photodynamic therapy (PDT) with a light-activated drug is an approved modality for cancer treatment. Hexaminolevulinate (HAL), a hexylester of 5-aminolevulinic acid as the photosensitising protoporphyrin IX (PpIX) precursor, is clinically used for both PDT and photodetection. Our previous studies have shown that HAL-PDT can effectively induce apoptosis in several human blood malignant cell lines. However, the mechanisms involved in the apoptotic induction are still not fully elucidated. In this study we have focused on the role of cellular lamin A/C in the apoptotic induction. HAL-PDT-mediated apoptosis was confirmed by various techniques including fluorescence microscopy and electron microscopy in both human B-cell lymphoma Ramos and Daudi cell lines. The lamin A/C, together with caspases-6 and -3, was cleaved during the apoptosis. Western blots, immunocytochemistry, fluorescence microscopy and electron microscopy demonstrated that the specific caspase-6 inhibitor abrogated the HAL-PDT-mediated cleavages of both caspase-6 and lamin A/C and subsequent apoptosis in these two cell lines, suggesting that the cleavage of lamin A/C by the caspase-6 activation is crucial for such apoptotic induction. PMID:23916608

Shahzidi, Susan; Brech, Andreas; Sioud, Mouldy; Li, Xiaoran; Suo, Zhenhe; Nesland, Jahn M; Peng, Qian

2013-10-01

251

Resveratrol protects astrocytes against traumatic brain injury through inhibiting apoptotic and autophagic cell death.  

PubMed

Traumatic brain injury (TBI) is often caused by accidents that damage the brain. TBI can induce glutamate excitotoxicity and lead to neuronal and glial cell death. In this study, we investigated the mechanism of cell death during the secondary damage caused by TBI in vivo and in vitro, as well as the protective effect of resveratrol (RV). Here we report that glycogen synthase kinase-3? (GSK-3?) activation and microtubule-associated protein light chain 3 processing were induced in rat brains exposed to TBI. In the in vitro TBI model, apoptotic and autophagic cell death were induced through glutamate-mediated GSK-3? activation in normal CTX TNA2 astrocytes. The GSK-3? inhibitor SB216763 or transfection of GSK-3? small-interfering RNA increases cell survival. By contrast, overexpression of GSK-3? enhanced glutamate excitotoxicity. Administration of RV reduced cell death in CTX TNA2 astrocytes by suppressing reactive oxygen species (ROS)-mediated GSK-3? activation, the mechanism by which RV also exerted protective effects in vivo. Mitochondrial damages, including the opening of mitochondrial permeability transition pore (MPTP) and mitochondrial depolarization, were induced by glutamate through the ROS/GSK-3? pathway. Moreover, cyclosporine A, an MPTP inhibitor, suppressed mitochondrial damage and the percentages of cells undergoing autophagy and apoptosis and thereby increased cell survival. Taken together, our results demonstrated that cell death occurring after TBI is induced through the ROS/GSK-3?/mitochondria signaling pathway and that administration of RV can increase cell survival by suppressing GSK-3?-mediated autophagy and apoptosis. Therefore, the results indicated that resveratrol may serve as a potential therapeutic agent in the treatment of TBI. PMID:24675465

Lin, C-J; Chen, T-H; Yang, L-Y; Shih, C-M

2014-01-01

252

Second-hand smoke-induced cardiac fibrosis is related to the Fas death receptor apoptotic pathway without mitochondria-dependent pathway involvement in rats.  

PubMed

Exposure to environmental tobacco smoke has been epidemiologically linked to heart disease among nonsmokers. However, the molecular mechanism behind the pathogenesis of cardiac disease is unknown. In this study, we found that Wistar rats, exposed to tobacco cigarette smoke at doses of 5, 10, or 15 cigarettes for 30 min twice a day for 1 month, had a dose-dependently reduced heart weight to body weight ratio and enhanced interstitial fibrosis as identified by histopathologic analysis. The mRNA and activity of matrix metalloprotease-2 (MMP-2), representing the progress of cardiac remodeling, were also elevated in the heart. In addition, we used reverse-transcriptase polymerase chain reaction and Western blotting to demonstrate significantly increased levels of the apoptotic effecter caspase-3 in treated animal hearts. Dose-dependently elevated mRNA and protein levels of Fas, and promoted apoptotic initiator caspase-8 (active form), a molecule of a death-receptor-dependent pathway, coupled with unaltered or decreased levels of cytosolic cytochrome c and the apoptotic initiator caspase-9 (active form), molecules of mitochondria-dependent pathways, may be indicative of cardiac apoptosis, which is Fas death-receptor apoptotic-signaling dependent, but not mitochondria pathway dependent in rats exposed to second-hand smoke (SHS). With regard to the regulation of survival pathway, using dot blotting, we found cardiac insulin-like growth factor-1 (IGF-1) and IGF-1 receptor mRNA levels to be significantly increased, indicating that compensative effects of IGF-1 survival signaling could occur. In conclusion, we found that the effects of SHS on cardiomyocyte are mediated by the Fas death-receptor-dependent apoptotic pathway and might be related to the epidemiologic incidence of cardiac disease of SHS-exposed nonsmokers. PMID:16203245

Kuo, Wei-Wen; Wu, Chieh-Hsi; Lee, Shin-Da; Lin, James A; Chu, Chia-Yih; Hwang, Jin-Ming; Ueng, Kwo-Chang; Chang, Mu-Hsin; Yeh, Yu-Lan; Wang, Chau-Jong; Liu, Jer-Yuh; Huang, Chih-Yang

2005-10-01

253

The Bax/Bcl-2 apoptotic pathway is not responsible for the increase in apoptosis in the RU486-treated rat uterus during early pregnancy.  

PubMed

An increase in apoptotic activity has been observed in both the rabbit and the rat endometria following treatment with RU486. The aim of this study was to assess whether Bax and Bcl-2 signaling, in response to RU486, could be crucial role players mediating apoptosis in the rat uterus during early pregnancy. RU486 is a partial progesterone (P4) and estrogen receptor antagonist, functioning to actively silence P4 receptor gene-associated transcription. Although an increase in apoptosis as a result of RU486 administration has been previously reported in rabbits, the specific apoptotic factors and pathways involved in driving this process have not yet been established. Immunofluorescent techniques were used to determine protein expression levels of both Bax and Bcl-2 in RU486-treated endometria at days 4.5, 5.5 and 6.5 of pregnancy. The Bax/Bcl-2 index was used to determine the overall pro- or anti-apoptotic setting at each day of pregnancy, following RU486 administration. Changes in the Bax and Bcl-2 gene expression levels as a consequence of RU486 administration were evaluated using RT-qPCR. Both the protein and gene expression analyses suggest that RU486 induces a change toward an overall anti-apoptotic signal within the Bax/Bcl-2 pathway. These results suggest that the observed increase in apoptosis following RU486 administration is not driven by a shift in the Bax/Bcl-2 ratio toward cell death, when the P4 and estrogen receptors are partially inactivated by RU486, but is possibly regulated by another apoptotic pathway. PMID:24287037

Theron, Kathrine E; Penny, Clement B; Hosie, Margot J

2013-12-01

254

Double-Effector Nanoparticles: A Synergistic Approach to Apoptotic Hyperthermia**  

PubMed Central

Temperature control is an important method of self-defense in biological systems. For example, one response mounted by humans in an effort to fight injury, including viral and bacterial infections, involves an increase in body temperature, thus producing the well-recognized symptoms of fever.[1] Today, the idea of using artificial temperature control for disease removal is being realized with the aid of various techniques, such as ultrasound, near-infrared light, and magnetic field by increasing localized temperature in a targeted region.[2] Magnetic nanoparticles have attracted considerable attention for hyperthermia applications owing to their ability to generate heat effectively when exposed to an alternating magnetic field without a penetration depth limit.[3] Hyperthermia, the artificially induced heat treatment of a disease, uses temperatures ranging between 42 °C and 47°C. Generally, a temperature below 45 °C induces apoptotic cell death.[4] As compared to necrosis, apoptosis is a more benign form of “programmed” cell death.[5] Nonliving cells produced as the result of apoptotic process are cleaned by phagocytosis without affecting neighboring normal cells. In contrast, necrosis, typically generated by harsh and high-temperature hyperthermia, is considered relatively harmful because it can be correlated with inflammatory disease and metastasis.[6] However, achieving effective apoptotic hyperthermia is often difficult, as cells typically acquire resistance to induced thermal stress.[7] Repeated exposures to high temperatures with high concentration of magnetic nanoparticles are usually necessary to achieve a useful level of therapeutic efficacy even though the conditions could favor necrotic cell death rather than apoptosis. Because cancer cells are susceptible to heat at about 43 °C, while most normal tissues remain undamaged,[8] hyperthermia using this temperature defines a recognized but unmet goal. PMID:23139178

Yoo, Dongwon; Jeong, Heeyeong; Preihs, Christian; Choi, Jin-sil; Shin, Tae-Hyun

2013-01-01

255

Activation of p53-regulated pro-apoptotic signaling pathways in PrP-mediated myopathy  

Microsoft Academic Search

BACKGROUND: We have reported that doxycycline-induced over-expression of wild type prion protein (PrP) in skeletal muscles of Tg(HQK) mice is sufficient to cause a primary myopathy with no signs of peripheral neuropathy. The preferential accumulation of the truncated PrP C1 fragment was closely correlated with these myopathic changes. In this study we use gene expression profiling to explore the temporal

Jingjing Liang; Debra Parchaliuk; Sarah Medina; Garrett Sorensen; Laura Landry; Shenghai Huang; Meiling Wang; Qingzhong Kong; Stephanie A Booth

2009-01-01

256

Lysosomal-Mediated Degradation of Apoptotic Thymocytes within Thymic Nurse Cells  

Microsoft Academic Search

A thymic epithelial cell line (tsTNC-1) that maintains the ability to selectively bind and internalize immature ??TCRloCD4+CD8+ thymocytes in vitro was used in long-term coincubation experiments to determine the ultimate fate of thymocytes that remained within intracytoplasmic vacuoles of thymic nurse cells (TNCs). In an earlier report, a subset of the population released from the TNC interaction was shown to

Michael Samms; Deborah Philp; Finbar Emanus; Obi Osuji; Mark Pezzano; Jerry C. Guyden

1999-01-01

257

Acetaminophen-mediated cardioprotection via inhibition of the mitochondrial permeability transition pore-induced apoptotic pathway.  

E-print Network

??Historically, acetaminophen has been employed as a safe and effective analgesic and antipyretic agent. However, our laboratory has recently reported that acetaminophen also confers functional… (more)

Hadzimichalis, Norell Melissa

2008-01-01

258

Protopine, a novel microtubule-stabilizing agent, causes mitotic arrest and apoptotic cell death in human hormone-refractory prostate cancer cell lines.  

PubMed

In this study, we investigated the anticancer effect of protopine on human hormone-refractory prostate cancer (HRPC) cells. Protopine exhibited an anti-proliferative effect by induction of tubulin polymerization and mitotic arrest, which ultimately led to apoptotic cell death. The data suggest that protopine increased the activity of cyclin-dependent kinase 1 (Cdk1)/cyclin B1 complex and that contributed to cell apoptosis by modulating mitochondria-mediated signaling pathways, such as Bcl-2 phosphorylation and Mcl-1 down-regulation. In conclusion, the data suggest that protopine is a novel microtubule stabilizer with anticancer activity in HRPC cells through apoptotic pathway by modulating Cdk1 activity and Bcl-2 family of proteins. PMID:22033245

Chen, Chun-Han; Liao, Cho-Hwa; Chang, Ya-Ling; Guh, Jih-Hwa; Pan, Shiow-Lin; Teng, Che-Ming

2012-02-01

259

Regulation of Fas receptor/Fas-asssociated protein with death domain apoptotic complex and associated signalling systems by cannabinoid receptors in the mouse brain  

PubMed Central

Background and purpose: Natural and synthetic cannabinoids (CBs) induce deleterious or beneficial actions on neuronal survival. The Fas-associated protein with death domain (FADD) promotes apoptosis, and its phosphorylated form (p-FADD) mediates non-apoptotic actions. The regulation of Fas/FADD, mitochondrial apoptotic proteins and other pathways by CB receptors was investigated in the mouse brain. Experimental approach: Wild-type, CB1 and CB2 receptor knock-out (KO) mice were used to assess differences in receptor genotypes. CD1 mice were used to evaluate the effects of CB drugs on canonical apoptotic pathways and associated signalling systems. Target proteins were quantified by Western blot analysis. Key results: In brain regions of CB1 receptor KO mice, Fas/FADD was reduced, but p-Ser191 FADD and the p-FADD/FADD ratio were increased. In CB2 receptor KO mice, Fas/FADD was increased, but the p-FADD/FADD ratio was not modified. In mutant mice, cleavage of poly(ADP-ribose)-polymerase (PARP) did not indicate alterations in brain cell death. In CD1 mice, acute WIN55212-2 (CB1 receptor agonist), but not JWH133 (CB2 receptor agonist), inversely modulated brain FADD and p-FADD. Chronic WIN55212-2 induced FADD down-regulation and p-FADD up-regulation. Acute and chronic WIN55212-2 did not alter mitochondrial proteins or PARP cleavage. Acute, but not chronic, WIN55212-2 stimulated activation of anti-apoptotic (ERK, Akt) and pro-apoptotic (JNK, p38 kinase) pathways. Conclusions and implications: CB1 receptors appear to exert a modest tonic activation of Fas/FADD complexes in brain. However, chronic CB1 receptor stimulation decreased pro-apoptotic FADD and increased non-apoptotic p-FADD. The multifunctional protein FADD could participate in the mechanisms of neuroprotection induced by CBs. This article is part of a themed issue on Cannabinoids. To view the editorial for this themed issue visit http://dx.doi.org/10.1111/j.1476-5381.2010.00831.x PMID:20590568

Alvaro-Bartolome, M; Esteban, S; Garcia-Gutierrez, MS; Manzanares, J; Valverde, O; Garcia-Sevilla, JA

2010-01-01

260

Apoptosis induced by desmethyl-lasiodiplodin is associated with upregulation of apoptotic genes and downregulation of monocyte chemotactic protein-3.  

PubMed

There is growing interest in the discovery of bioactive metabolites from endophytes as an alternative source of therapeutics. Identification of their therapeutic targets is essential in understanding the underlying mechanisms and enhancing the resultant therapeutic effects. As such, bioactive compounds produced by endophytic fungi from plants at the National Park, Pahang, Malaysia, were investigated. Five known compounds were identified using LC-UV-MS-NMR and they include trichodermol, 7-epi-brefeldin A, (3R,4S)-4-hydroxymellein, desmethyl-lasiodiplodin and cytochalasin D. The present study went on to investigate the potential anticancer effects of these compounds and the corresponding molecular mechanisms of the lead compound against human breast adenocarcinoma, MCF-7. For the preliminary screening, the cytotoxicity and apoptotic effects of these compounds against MCF-7 were examined. The compounds were also tested against noncarcinogenic hepatocytes (WRL68). The differential cytotoxicity was then determined using the MTT assay. Desmethyl-lasiodiplodin was found to suppress the growth of MCF-7, yielding an inhibitory concentration (IC50) that was seven-fold lower than that of the normal cells. The cytotoxic effect of desmethyl-lasiodiplodin was accompanied by apoptosis. Subsequent analysis demonstrated increased expression levels of caspase 3, c-myc and p53. Further, desmethyl-lasiodiplodin resulted in inhibition of monocyte chemotactic protein (MCP)-3, a cytokine involved in cell survival and metastasis. Hence, this study proposed that desmethyl-lasiodiplodin inhibited growth and survival of MCF-7 through the induction of apoptosis. This anticancer effect is mediated, in part, by upregulation of apoptotic genes and downregulation of MCP-3. As desmethyl-lasiodiplodin elicited minimal impact against normal hepatocytes, our findings also imply its potential use as a specific apoptotic agent in breast cancer treatment. PMID:23764760

Hazalin, Nurul Aqmar M N; Lim, Siong Meng; Cole, Anthony L J; Majeed, Abu Bakar A; Ramasamy, Kalavathy

2013-09-01

261

Molecular analysis of functional redundancy among anti-apoptotic Bcl-2 proteins and its role in cancer cell survival.  

PubMed

Bcl-2 family proteins act as essential regulators and mediators of intrinsic apoptosis. Several lines of evidence suggest that the anti-apoptotic members of the family, including Bcl-2, Bcl-xL and Mcl-1, exhibit functional redundancy. However, the current evidence is largely indirect, and based mainly on pharmacological data using small-molecule inhibitors. In order to study compensation and redundancy of anti-apoptotic Bcl-2 proteins at the molecular level, we used a combined knockdown/overexpression strategy to essentially replace the function of one member with another. The results show that HeLa cells are strictly dependent on Mcl-1 for survival and correspondingly refractory to the Bcl-2/Bcl-xL inhibitor ABT-263, and remain resistant to ABT-263 in the context of Bcl-xL overexpression because endogenous Mcl-1 continues to provide the primary guardian role. However, if Mcl-1 is knocked down in the context of Bcl-xL overexpression, the cells become Bcl-xL-dependent and sensitive to ABT-263. We also show that Bcl-xL compensates for loss of Mcl-1 by sequestration of two key pro-apoptotic Bcl-2 family members, Bak and Bim, normally bound to Mcl-1, and that Bim is essential for cell death induced by Mcl-1 knockdown. To our knowledge, this is the first example where cell death induced by loss of Mcl-1 was rescued by the silencing of a single BH3-only Bcl-2 family member. In colon carcinoma cell lines, Bcl-xL and Mcl-1 also play compensatory roles, and Mcl-1 knockdown sensitizes cells to ABT-263. The results, obtained employing a novel strategy of combining knockdown and overexpression, provide unique molecular insight into the mechanisms of compensation by pro-survival Bcl-2 family proteins. PMID:24556425

Eichhorn, Joshua M; Alford, Sarah E; Sakurikar, Nandini; Chambers, Timothy C

2014-04-01

262

Autoimmune Disease and Impaired Uptake of Apoptotic Cells in MFG-E8Deficient Mice  

Microsoft Academic Search

Apoptotic cells expose phosphatidylserine and are swiftly engulfed by macrophages. Milk fat globule epidermal growth factor (EGF) factor 8 (MFG-E8) is a protein that binds to apoptotic cells by recognizing phosphatidylserine and that enhances the engulfment of apoptotic cells by macrophages. We report that tingible body macrophages in the germinal centers of the spleen and lymph nodes strongly express MFG-E8.

Rikinari Hanayama; Masato Tanaka; Kay Miyasaka; Katsuyuki Aozasa; Masato Koike; Yasuo Uchiyama; Shigekazu Nagata

2004-01-01

263

Short term apoptotic activity of intravitreal bevacizumab on rabbit retina  

PubMed Central

AIM To evaluate the safety and the short term apoptotic activity of intravitreal bevacizumab in rabbit eyes by histopathological analysis. METHODS Twenty-eight eyes of 14 rabbits were divided into three groups: 8 rabbits in group 1 and 3 rabbits in each of group 2 and group 3. Intravitreal bevacizumab (1.25mg/0.05mL) was applied to the right eyes of each subject in group 1 and group 2 (11 eyes) and the same volume of saline was applied to the left eyes of each subject in group 1 and group 3 (11 eyes). The left eyes in group 2 and the right eyes in group 3 were left untreated and used as control. Enucleated eyes were used for histopathologic analyses. RESULTS After immunohistochemical staining with caspase-3 and p53, there was no histological evidence of toxicity to the retina and the optic nerve in any of the sections that were analyzed in all three groups. In addition, vascular endothelial cells located at the retina and the optic nerve tissues in all groups showed a similar staining pattern with caspase-3 and p53. CONCLUSION Our study showed that intravitreal bevacizumab with the dose of 1.25mg/0.05mL caused no histological signs of toxicity or apoptotic activity on the rabbit retina. PMID:24392325

Turkcu, Fatih Mehmet; Alp, Mehmet Numan; Turkcu, Gul; Kulacoglu, Sezer; Kural, Gulcan

2013-01-01

264

Specific lipid mediator signatures of human phagocytes: microparticles stimulate macrophage efferocytosis and pro-resolving mediators.  

PubMed

Phagocytes orchestrate acute inflammation and host defense. Here we carried out lipid mediator (LM) metabololipidomics profiling distinct phagocytes: neutrophils (PMN), apoptotic PMN, and macrophages. Efferocytosis increased specialized pro-resolving mediator (SPM) biosynthesis, including Resolvin D1 (RvD1), RvD2, and RvE2, which were further elevated by PMN microparticles. Apoptotic PMN gave elevated prostaglandin E(2), lipoxin B(4) and RvE2, whereas zymosan-stimulated PMN showed predominantly leukotriene B(4) and 20-OH-leukotriene B(4), as well as lipoxin marker 5,15-diHETE. Using deuterium-labeled precursors (d(8)-arachidonic acid, d(5)-eicosapentaenoic acid, and d(5)-docosahexaenoic acid), we found that apoptotic PMN and microparticles contributed to SPM biosynthesis during efferocytosis. M2 macrophages produced SPM including maresin-1 (299 ± 8 vs 45 ± 6 pg/2.5 × 10(5) cells; P < .01) and lower amounts of leukotriene B(4) and prostaglandin than M1. Apoptotic PMN uptake by both macrophage subtypes led to modulation of their LM profiles. Leukotriene B(4) was down-regulated in M2 (668 ± 81 vs 351 ± 39 pg/2.5 × 10(5) cells; P < .01), whereas SPM including lipoxin A(4) (977 ± 173 vs 675 ± 167 pg/2.5 × 10(5) cells; P < .05) were increased. Conversely, uptake of apoptotic PMN by M2 macrophages reduced (? 25%) overall LM. Together, these results establish LM signature profiles of human phagocytes and related subpopulations. Moreover, they provide evidence for microparticle regulation of specific endogenous LM during defined stages of the acute inflammatory process and their dynamic changes in human primary phagocytes. PMID:22904297

Dalli, Jesmond; Serhan, Charles N

2012-10-11

265

Specific lipid mediator signatures of human phagocytes: microparticles stimulate macrophage efferocytosis and pro-resolving mediators  

PubMed Central

Phagocytes orchestrate acute inflammation and host defense. Here we carried out lipid mediator (LM) metabololipidomics profiling distinct phagocytes: neutrophils (PMN), apoptotic PMN, and macrophages. Efferocytosis increased specialized pro-resolving mediator (SPM) biosynthesis, including Resolvin D1 (RvD1), RvD2, and RvE2, which were further elevated by PMN microparticles. Apoptotic PMN gave elevated prostaglandin E2, lipoxin B4 and RvE2, whereas zymosan-stimulated PMN showed predominantly leukotriene B4 and 20-OH-leukotriene B4, as well as lipoxin marker 5,15-diHETE. Using deuterium-labeled precursors (d8-arachidonic acid, d5-eicosapentaenoic acid, and d5-docosahexaenoic acid), we found that apoptotic PMN and microparticles contributed to SPM biosynthesis during efferocytosis. M2 macrophages produced SPM including maresin-1 (299 ± 8 vs 45 ± 6 pg/2.5 × 105 cells; P < .01) and lower amounts of leukotriene B4 and prostaglandin than M1. Apoptotic PMN uptake by both macrophage subtypes led to modulation of their LM profiles. Leukotriene B4 was down-regulated in M2 (668 ± 81 vs 351 ± 39 pg/2.5 × 105 cells; P < .01), whereas SPM including lipoxin A4 (977 ± 173 vs 675 ± 167 pg/2.5 × 105 cells; P < .05) were increased. Conversely, uptake of apoptotic PMN by M2 macrophages reduced (? 25%) overall LM. Together, these results establish LM signature profiles of human phagocytes and related subpopulations. Moreover, they provide evidence for microparticle regulation of specific endogenous LM during defined stages of the acute inflammatory process and their dynamic changes in human primary phagocytes. PMID:22904297

Dalli, Jesmond

2012-01-01

266

The Differential Effects of Cyclophosphamide, Epirubicin and 5Fluorouracil on Apoptotic Marker (CPP32), Pro-Apoptotic Protein (p21 WAF ?1 ) and Anti-Apoptotic Protein (bcl-2) in Breast Cancer Cells  

Microsoft Academic Search

Cyclophosphamide (CYC), epirubicin (EPI) and 5-fluorouracil (5FU) are commonly used cytotoxic drugs for the treatment of breast cancer. The efficacy of these drugs in the induction of caspases (CPP-32), pro-apoptotic (p21WAF-1) and anti-apoptotic (bcl-2) proteins is tested in vitro on breast cancer cells lines MDA-MB-231 and MCF-7. The cell proliferation rate and the levels of CPP-32, p21WAF-1 and bcl-2 are

Louis W. C. Chow; Wings T. Y. Loo

2003-01-01

267

Vitronectin inhibits efferocytosis through interactions with apoptotic cells as well as with macrophages.  

PubMed

Effective removal of apoptotic cells, particularly apoptotic neutrophils, is essential for the successful resolution of acute inflammatory conditions. In these experiments, we found that whereas interaction between vitronectin and integrins diminished the ability of macrophages to ingest apoptotic cells, interaction between vitronectin with urokinase-type plasminogen activator receptor (uPAR) on the surface of apoptotic cells also had equally important inhibitory effects on efferocytosis. Preincubation of vitronectin with plasminogen activator inhibitor-1 eliminated its ability to inhibit phagocytosis of apoptotic cells. Similarly, incubation of apoptotic cells with soluble uPAR or Abs to uPAR significantly diminished efferocytosis. In the setting of LPS-induced ALI, enhanced efferocytosis and decreased numbers of neutrophils were found in bronchoalveolar lavage obtained from vitronectin-deficient (vtn(-/-)) mice compared with wild type (vtn(+/+)) mice. Furthermore, there was increased clearance of apoptotic vtn(-/-) as compared with vtn(+/+) neutrophils after introduction into the lungs of vtn(-/-) mice. Incubation of apoptotic vtn(-/-) neutrophils with purified vitronectin before intratracheal instillation decreased efferocytosis in vivo. These findings demonstrate that the inhibitory effects of vitronectin on efferocytosis involve interactions with both the engulfing phagocyte and the apoptotic target cell. PMID:23345331

Bae, Hong-Beom; Tadie, Jean-Marc; Jiang, Shaoning; Park, Dae Won; Bell, Celeste P; Thompson, Lawrence C; Peterson, Cynthia B; Thannickal, Victor J; Abraham, Edward; Zmijewski, Jaroslaw W

2013-03-01

268

Vitronectin inhibits efferocytosis through interactions with apoptotic cells as well as with macrophages  

PubMed Central

Effective removal of apoptotic cells, particularly apoptotic neutrophils, is essential for the successful resolution of acute inflammatory conditions. In the present experiments, we found that whereas interaction between vitronectin and integrins diminished the ability of macrophages to ingest apoptotic cells, interaction between vitronectin with urokinase type Plasminogen Activator receptor (uPAR) on the surface of apoptotic cells also had equally important inhibitory effects on efferocytosis. Pre-incubation of vitronectin with Plasminogen Activator inhibitor-1 (PAI-1) eliminated its ability to inhibit phagocytosis of apoptotic cells. Similar, incubation of apoptotic cells with soluble uPAR or antibodies to uPAR significantly diminished efferocytosis. In the setting of LPS-induced ALI, enhanced efferocytosis and decreased numbers of neutrophils was found in bronchoalveolar lavage obtained from vitronectin deficient (vtn?/?) mice compared to wild type (vtn+/+) mice. Furthermore, there was increased clearance of apoptotic vtn?/? as compared to vtn+/+ neutrophils after introduction into the lungs of vtn?/? mice. Incubation of apoptotic vtn?/? neutrophils with purified vitronectin prior to intratracheal instillation decreased efferocytosis in vivo. These findings demonstrate that the inhibitory effects of vitronectin on efferocytosis involve interactions with both the engulfing phagocyte as well as the apoptotic target cell. PMID:23345331

Bae, Hong-Beom; Tadie, Jean-Marc; Jiang, Shaoning; Park, Dae Won; Bell, Celeste P; Thompson, Lawrence C.; Peterson, Cynthia B.; Thannickal, Victor J.; Abraham, Edward; Zmijewski, Jaroslaw W.

2013-01-01

269

Tolerance Strategies Employing Antigen-Coupled Apoptotic Cells and Carboxylated PLG Nanoparticles for the Treatment of Type 1 Diabetes  

PubMed Central

The development of therapies that specifically target autoreactive immune cells for the prevention and treatment of type 1 diabetes (T1D) without inducing generalized immunosuppression that often compromises the host's ability to clear non-self antigen is highly desired. This review discusses the mechanisms and potential therapeutic applications of antigen-specific T cell tolerance techniques using syngeneic apoptotic cellular carriers and synthetic nanoparticles that are covalently cross-linked to diabetogenic peptides or proteins through ethylene carbodiimide (ECDI) to prevent and treat T1D. Experimental models have demonstrated that intravenous injection of autoantigen decorated splenocytes and biodegradable nanoparticles through ECDI fixation effectively induce and maintain antigen-specific T cell abortive activation and anergy by T cell intrinsic and extrinsic mechanisms. The putative mechanisms include, but are not limited to, the uptake and processing of antigen-coupled nanoparticles or apoptotic cellular carriers for tolerogenic presentation by host splenic antigen-presenting cells, the induction of regulatory T cells, and the secretion of immune-suppressive cytokines, such as IL-10 and TGF-?. The safety profile and efficacy of this approach in preclinical animal models of T1D, including non-obese diabetic (NOD), BDC2.5 transgenic, and humanized mice, have been extensively investigated, and will be the focus of this review. Translation of this approach to clinical trials of T1D and other T cell-mediated autoimmune diseases will also be reviewed in this chapter. PMID:23804269

Prasad, Suchitra; Xu, Dan; Miller, Stephen D.

2012-01-01

270

PIAS3 activates the intrinsic apoptotic pathway in non-small cell lung cancer cells independent of p53 status  

PubMed Central

Protein inhibitor of activated STAT3 (PIAS3) is an endogenous inhibitor of STAT3 that negatively regulates STAT3 transcriptional activity and cell growth and demonstrates limited expression in the majority of human squamous cell carcinomas of the lung. In the present study we sought to determine if PIAS3 inhibits cell growth in non-small cell lung cancer (NSCLC) cell lines by inducing apoptosis. Our results demonstrate that over-expression of PIAS3 promotes mitochondrial depolarization, leading to cytochrome c release, caspase 9 and 3 activation and PARP cleavage. This intrinsic pathway activation was associated with decreased Bcl-xL expression and increased Noxa expression and was independent of p53 status. Furthermore, PIAS3 inhibition of STAT3 activity was also p53 independent. Microarray experiments were performed to discover STAT3-independent mediators of PIAS3-induced apoptosis by comparing the apoptotic gene expression signature induced by PIAS3 over-expression with that induced by STAT3 siRNA. The results showed that a subset of apoptotic genes was uniquely expressed only after PIAS3 expression. Thus, PIAS3 may represent a promising lung cancer therapeutic target because of its p53-independent efficacy as well as its potential to synergize with Bcl-2 targeted inhibitors. PMID:23959540

Dabir, Snehal; Kluge, Amy; McColl, Karen; Liu, Yu; Lam, Minh; Halmos, Balazs; Wildey, Gary; Dowlati, Afshin

2014-01-01

271

Polarized release of RANTES by cytotoxic T cells paints tumor targets and enhances apoptotic cell removal.  

PubMed

The release of regulated on activation normal T-cell expressed and secreted (RANTES) from CD8+ lymphocytes has been shown to be dependent on T-cell receptor triggering by major histocompatability complex class I/peptide complex engagement. We characterized the secretion of RANTES by human leukocyte antigen-A2-restricted tyrosinase-specific cytotoxic T lymphocyte (CTL) in the context of human melanoma cell killing. CTL contact with tumor cell targets elicited a vectorial release of the chemokine RANTES resulting in the selective deposition of RANTES on target cells but not on nontarget bystander cells or the CTL. RANTES on the surface of apoptotic cells enhanced their phagocytosis by murine macrophages. This effect appeared unique to RANTES as the related chemokines macrophage inflammatory protein (MIP) -1alpha, MIP-1beta, and monocyte chemoattractant protein-1 did not significantly affect uptake and were mediated through chemokine receptor CCR1. Oligomerization of RANTES, at least at the level of a tetramer, was required for the enhanced phagocytosis. These results suggest that the role of RANTES in inflammatory disorders might not be restricted to inducing leukocyte infiltration but could also extend to potent macrophage modulation, directly regulating inflammation. PMID:18198213

Li, Zhen; Xia, Feng; Zhang, Yuanqiang

2008-06-01

272

The anti-apoptotic effect of fucoxanthin on carbon tetrachloride-induced hepatotoxicity.  

PubMed

This study evaluated the anti-apoptotic activity of fucoxanthin in carbon tetrachloride (CCl(4))-induced hepatotoxicity. An in vitro study using the 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay clearly demonstrated an attenuation of CCl(4)-induced hepatotoxicity with fucoxanthin. This effect was dose-dependent; 25 µM was more effective than 10 µM of fucoxanthin for attenuating the hepatotoxicity induced by 5 mM of CCl(4). Acute CCl(4)-hepatotoxicity in rats, with numerous cells positive for the terminal deoxynucleotidyl - transferase (TdT) -mediated deoxyuridine triphosphate-digoxigenin (dUTP) nick-end labeling (TUNEL) stain were seen in the pericentral area of the hepatic lobule. Oral pretreatment of CCl(4)- injected rats with fucoxanthin significantly reduced hepatocyte apoptosis. Fucoxanthin was immunohistochemically shown to increase heme oxygenase-1 expression in the cultured liver cells of Hc cells and TRL1215 cells. By oral pretreatment of CCl(4)-injected rats with fucoxanthin, the hepatic heme oxygenase-1 protein levels were significantly increased compared to those not pretreated with fucoxanthin. Heme oxygenase-1 mRNA expression after CCl(4 )injection was higher in the CCl(4)+fucoxanthin group than in the CCl(4 )group, although the difference was not significant. The findings suggest that fucoxanthin attenuates hepatocyte apoptosis through heme oxygenase-1 induction in CCl(4)-induced acute liver injury. PMID:23358145

Kaneko, Mieko; Nagamine, Takeaki; Nakazato, Kyoumi; Mori, Masatomo

2013-02-01

273

Apoptotic effects of ?-mangostin from the fruit hull of Garcinia mangostana on human malignant glioma cells.  

PubMed

Gliomas are a common type of primary brain tumor with glioblastoma multiforme accounting for the majority of human brain tumors. In this paper, high grade human malignant glioblastomas (MGs) including U87 MG and GBM 8401 were used to evaluate the antitumor effects of ?-mangostin, a xanthone derivative isolated and purified from the hull of the tropical fruit Garcinia mangostana. The ?-mangostin showed potent antiproliferative activity toward MGs in dose- and time-dependent manners. In addition, flow cytometric analysis of cell morphology in the apoptotic cells revealed an increase in hypodiploid cells in ?-mangostin treated U87 MG and GBM 8401 cells, while significant enhancement of intracellular peroxide production was detected in the same ?-mangostin treated cells by DCHDA assay and DiOC(6)(3) stain. g-Mangostin induced apoptosis, which in turn mediates cytotoxicity in human MG cells was prevented by the addition of catalase. Naturally derived medicines and herbal therapies are drawing increasing attention in regard to the treatment of many health issues, and this includes the testing of new phytochemicals or nutrients for brain tumor patients. This has led to ?-mangostin being identified as a potential leading compound for the development of an anti-brain tumor agent. PMID:21139533

Chang, Hui-Fang; Huang, Wen-Tsung; Chen, Hui-Ju; Yang, Ling-Ling

2010-01-01

274

Serotonin activates cell survival and apoptotic death responses in cultured epithelial thyroid cells.  

PubMed

Anatomic and physiological interactions between central serotonergic system and thyroid gland are well established. However, the effects of locally available serotonin on the thyroid functions are poorly known. Here, we first demonstrate the expression of serotonin transporter SERT and 5-HT2A receptor subtype in rat thyroid epithelial cell line FRT both at mRNA and protein levels. In order to investigate the molecular mechanisms of serotonin action, FRT cells were exposed to increasing concentrations of the amine. Low concentrations of serotonin (up to 5 ?M) enhanced FRT cell growth, and ERK1/2 and SMAD2/3 phosphorylation. Cell exposure to the selective 5-HT2A receptor agonist DOI recapitulated the effects of 5-HT on ERK1/2 phosphorylation. By contrast, administration of M100907, a specific 5-HT2A receptor inhibitor, prevented 5-HT induced ERK1/2 activation. On the other hand, high doses of serotonin (50 ?M up to 1 mM) activated a caspase-3 mediated apoptosis of cells. Overall, our findings demonstrate that low levels of serotonin, interacting with 5-HT2A receptor, are able to activate proliferative signals in the thyroid epithelial cells, while high levels of serotonin cause pro-apoptotic responses, thus suggesting an active role of the amine in the thyroid functions and disorders. PMID:24997405

Cerulo, Giuliana; Tafuri, Simona; De Pasquale, Valeria; Rea, Silviana; Romano, Simona; Costagliola, Anna; Della Morte, Rossella; Avallone, Luigi; Pavone, Luigi Michele

2014-10-01

275

HIPK2 sustains apoptotic response by phosphorylating Che-1/AATF and promoting its degradation  

PubMed Central

Che-1/AATF is an RNA polymerase II-binding protein that is involved in the regulation of gene transcription, which undergoes stabilization and accumulation in response to DNA damage. We have previously demonstrated that following apoptotic induction, Che-1 protein levels are downregulated through its interaction with the E3 ligase HDM2, which leads to Che-1 degradation by ubiquitylation. This interaction is mediated by Pin1, which determines a phosphorylation-dependent conformational change. Here we demonstrate that HIPK2, a proapoptotic kinase, is involved in Che-1 degradation. HIPK2 interacts with Che-1 and, upon genotoxic stress, phosphorylates it at specific residues. This event strongly increases HDM2/Che-1 interaction and degradation of Che-1 protein via ubiquitin-dependent proteasomal system. In agreement with these findings, we found that HIPK2 depletion strongly decreases Che-1 ubiquitylation and degradation. Notably, Che-1 overexpression strongly counteracts HIPK2-induced apoptosis. Our results establish Che-1 as a new HIPK2 target and confirm its important role in the cellular response to DNA damage. PMID:25210797

De Nicola, F; Catena, V; Rinaldo, C; Bruno, T; Iezzi, S; Sorino, C; Desantis, A; Camerini, S; Crescenzi, M; Floridi, A; Passananti, C; Soddu, S; Fanciulli, M

2014-01-01

276

Jedi-1 and MEGF10 signal engulfment of apoptotic neurons through the tyrosine kinase Syk.  

PubMed

During the development of the peripheral nervous system there is extensive apoptosis, and these neuronal corpses need to be cleared to prevent an inflammatory response. Recently, Jedi-1 and MEGF10, both expressed in glial precursor cells, were identified in mouse as having an essential role in this phagocytosis (Wu et al., 2009); however, the mechanisms by which they promote engulfment remained unknown. Both Jedi-1 and MEGF10 are homologous to the Drosophila melanogaster receptor Draper, which mediates engulfment through activation of the tyrosine kinase Shark. Here, we identify Syk, the mammalian homolog of Shark, as a signal transducer for both Jedi-1 and MEGF10. Syk interacted with each receptor independently through the immunoreceptor tyrosine-based activation motifs (ITAMs) in their intracellular domains. The interaction was enhanced by phosphorylation of the tyrosines in the ITAMs by Src family kinases (SFKs). Jedi association with Syk and activation of the kinase was also induced by exposure to dead cells. Expression of either Jedi-1 or MEGF10 in HeLa cells facilitated engulfment of carboxylated microspheres to a similar extent, and there was no additive effect when they were coexpressed. Mutation of the ITAM tyrosines of Jedi-1 and MEGF10 prevented engulfment. The SFK inhibitor PP2 or a selective Syk inhibitor (BAY 61-3606) also blocked engulfment. Similarly, in cocultures of glial precursors and dying sensory neurons from embryonic mice, addition of PP2 or knock down of endogenous Syk decreased the phagocytosis of apoptotic neurons. These results indicate that both Jedi-1 and MEGF10 can mediate phagocytosis independently through the recruitment of Syk. PMID:22993420

Scheib, Jami L; Sullivan, Chelsea S; Carter, Bruce D

2012-09-19

277

ARMS depletion facilitates UV irradiation induced apoptotic cell death in melanoma.  

PubMed

Tumor cells often aberrantly reexpress molecules that mediate proper embryonic development for advantageous growth or survival. Here, we report that ankyrin repeat-rich membrane spanning (ARMS), a transmembrane protein abundant in the developing and adult neural tissues, is overexpressed in melanoma, a tumor ontogenetically originating from neural crest. Immunohistochemical study of 79 melanocytic lesions showed significantly increased expression of ARMS in primary malignant melanomas (92.9%) and metastatic melanoma (60.0%) in comparison with benign nevocellular nevi (26.7%). To investigate the role of ARMS in melanoma formation, murine B16F0 melanoma cells with stable knockdown of ARMS were established by RNA interference. Down-regulation of ARMS resulted in significant inhibition of anchorage-independent growth in soft agar and restrictive growth of melanoma in severe combined immunodeficient mice. Importantly, depletion of ARMS facilitated UVB-induced apoptosis in melanoma cells through inactivation of mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK. Addition of MEK inhibitor PD98059 further sensitized ARMS-depleted melanoma cells to UVB-induced apoptosis, whereas constitutively active MEK rescued ARMS-depleted cells from apoptosis. We further showed that BRAF, a downstream signaling molecule of ARMS in ERK pathway, is not mutated as a constitutively active form in acral lentiginous melanoma; in contrast, BRAF(T1799A) mutation, which leads to constitutive activation of ERK signaling, was detected in 57.1% of superficial spreading melanoma. Our study suggests that overexpression of ARMS per se serves as one mechanism to promote melanoma formation by preventing stress-induced apoptotic death mediated by the MEK/ERK signaling pathway, especially in acral lentiginous melanoma, most of which does not harbor BRAF mutation. PMID:18089783

Liao, Yi-Hua; Hsu, Su-Ming; Huang, Pei-Hsin

2007-12-15

278

ANTICANCER MEDICINAL PLANT, Epipremnum pinnatum (L.) Engl. CHLOROFORM EXTRACTS ELICITED BOTH APOPTOTIC AND NON-APOPTOTIC CELL DEATHS IN T- 47D MAMMARY CARCINOMA CELLS  

Microsoft Academic Search

Epipremnum pinnatum (L.) Engl. chloroform extract produced significant growth inhibition against T-47D breast carcinoma cells and analysis of cell death mechanisms indicated that the extract elicited both apoptotic and non-apoptotic programmed cell deaths. T-47D cells exposed to the extract produced a significant up-regulation of c-myc and caspase-3 mRNA expression levels as compared to untreated cells. The up-regulation of caspase-3 mRNA

Tan Mei Lan; Shaida Fariza Sulaiman; Nazalan Najimudin

279

ProNGF: a neurotrophic or an apoptotic molecule?  

PubMed

Nerve growth factor (NGF) acts on various classes of central and peripheral neurons to promote cell survival, stimulate neurite outgrowth and modulate differentiation. NGF is synthesized as a precursor, proNGF, which undergoes processing to generate mature NGF. It has been assumed, based on studies in the mouse submandibular gland, that NGF in vivo is largely mature NGF, and that mature NGF accounts for the molecule's biological activity. However, recently we have shown that proNGF is abundant in central nervous system tissues whereas mature NGF is undetectable, suggesting that proNGF may have a function distinct from its role as a precursor. A recent report that proNGF has apoptotic activity contrasts with other data demonstrating that proNGF has neurotrophic activity. This chapter will review the structure and processing of NGF and what is known about the biological activity of proNGF. Possible reasons for the discrepancies in recent reports are discussed. PMID:14699959

Fahnestock, Margaret; Yu, Guanhua; Coughlin, Michael D

2004-01-01

280

Detection of apoptotic cells using propidium iodide staining.  

PubMed

Flow cytometry assays are often used to detect apoptotic cells in in vitro cultures. Depending on the experimental model, these assays can also be useful in evaluating apoptosis in vivo. In this protocol, we describe a propidium iodide (PI) flow cytometry assay to evaluate B-cell lymphomas that have undergone apoptosis in vivo. B-cell lymphoma cells are injected into recipient mice and, on tumor formation, the mice are treated with the apoptosis inducer vorinostat (a histone deacetylase inhibitor). Tumor samples collected from the lymph nodes and/or the spleen are used to prepare a single-cell suspension that is exposed to a hypotonic solution containing the fluorochrome PI. The DNA content of the cells, now labeled with PI, is analyzed by flow cytometry. Nuclear DNA content is lost during apoptosis, resulting in a hypodiploid (or sub-G1) DNA profile during flow cytometry. In contrast, healthy cells display a sharp diploid DNA profile. PMID:25368311

Newbold, Andrea; Martin, Ben P; Cullinane, Carleen; Bots, Michael

2014-01-01

281

Gastroprotective effect of nymphayol isolated from Nymphaea stellata (Willd.) flowers: Contribution of antioxidant, anti-inflammatory and anti-apoptotic activities.  

PubMed

Gastric ulcer is an illness that affects a great number of people worldwide. The goal of the present research was to assess the anti-ulcerogenic activity of nymphayol (NYM), isolated from Nymphaea stellata, against an ethanol-induced ulcer model in rats. Administration of ethanol elevates the levels of the ulcer index (UI) along with causing tremendous increases in lipid peroxidation and myeloperoxidase (MPO) and significant decreases in gastric mucus, catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx), and prostaglandin E2 (PGE2). However, the NYM- (45mg/kg) pretreated animals showed considerable increases in antioxidants, gastric mucus, and PGE2 level and significant decreases in UI, lipid peroxidation, and MPO level. Pro-inflammatory cytokines such as interleukin-6 (IL-6), interleukin-1? (IL-1?), tumor necrosis factor-? (TNF-?), and interferon-? (IFN-?) were increased and the level of interleukin-10 (IL-10), an anti-inflammatory cytokine, was decreased in ethanol-induced ulcerated animals, and these inequalities were amended by NYM pretreatment. Pro-apoptotic markers including caspase-8, caspase-9, and caspase-3 were decreased and Bcl-2, an anti-apoptotic marker, was increased through NYM pretreatment, as compared with the ethanol-induced ulcer group. Pretreatment with indomethacin, SC560, rofecoxib, and N?-Nitro-l-arginine methyl ester (l-NAME) considerably prevented the ulcer protective activity of NYM (45mg/kg), indicating the involvement of cyclooxygenase (COX) and nitric oxide synthase (NOS) in NYM-mediated gastroprotection against ethanol-induced ulcer. These outcomes suggest that the gastroprotective effect of NYM might be mediated by adjustment of inflammatory mediators and apoptotic markers and increasing antioxidants. PMID:25289771

Antonisamy, Paulrayer; Subash-Babu, Pandurangan; Alshatwi, Ali A; Aravinthan, Adithan; Ignacimuthu, Savarimuthu; Choi, Ki Choon; Kim, Jong-Hoon

2014-12-01

282

Apoptotic and anti-metastatic effects of the whole skin of Venenum bufonis in A549 human lung cancer cells  

PubMed Central

In the present study, the effects of the whole skin of Venenum bufonis on apoptotic and anti-invasive activity in A549 human lung cancer cells were investigated. Treatment with extract of the whole skin of V. bufonis (SVB) resulted in a significant decrease in cell growth of A549 cells, depending on dosage, which was associated with apoptosis induction, as proved by chromatin condensation and accumulation of apoptotic fraction. SVB treatment induced expression of death receptor-related proteins, such as death receptor 4, which further triggered activation of caspase-8 and cleavage of Bid. In addition, the increase in apoptosis by SVB treatment was correlated with dysfunction of mitochondria, activation of caspase-9 and -3, downregulation of IAP family proteins, such as XIAP, cIAP-1 and cIAP-2, and concomitant degradation of activated caspase-3-specific target proteins, such as poly (ADP-ribose) polymerase and ?-catenin proteins. However, z-DEVD-fmk, a caspase-3-specific inhibitor, blocked SVB-induced apoptosis and increased the survival rate of SVB-treated cells, indicating that activation of caspase-3 plays a key role in SVB-induced apoptosis. In addition, within concentrations that were not cytotoxic to A549 cells, SVB induced marked inhibition of cell motility and invasiveness. Activities of matrix metalloproteinase (MMP)-2 and MMP-9 in AGS cells were dose-dependently inhibited by treatment with SVB, and this was also correlated with a decrease in expression of their mRNA and proteins, and upregulation of tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2 mRNA expression. Further studies are needed; however, the results indicated that SVB induces apoptosis of A549 cells through a signaling cascade of death receptor-mediated extrinsic as well as mitochondria-mediated intrinsic caspase pathways. Our data also demonstrated that MMPs are critical targets of SVB-induced anti-invasiveness in A549 cells. PMID:22200726

PARK, JEONG-SEOK; SHIN, DONG YEOK; LEE, YEON-WEOL; CHO, CHONG-KWAN; KIM, GI YOUNG; KIM, WUN-JAE; YOO, HWA-SEUNG; CHOI, YUNG HYUN

2012-01-01

283

Apoptotic and anti-metastatic effects of the whole skin of Venenum bufonis in A549 human lung cancer cells.  

PubMed

In the present study, the effects of the whole skin of Venenum bufonis on apoptotic and anti-invasive activity in A549 human lung cancer cells were investigated. Treatment with extract of the whole skin of V. bufonis (SVB) resulted in a significant decrease in cell growth of A549 cells, depending on dosage, which was associated with apoptosis induction, as proved by chromatin condensation and accumulation of apoptotic fraction. SVB treatment induced expression of death receptor-related proteins, such as death receptor 4, which further triggered activation of caspase-8 and cleavage of Bid. In addition, the increase in apoptosis by SVB treatment was correlated with dysfunction of mitochondria, activation of caspase-9 and -3, downregulation of IAP family proteins, such as XIAP, cIAP-1 and cIAP-2, and concomitant degradation of activated caspase-3-specific target proteins, such as poly (ADP-ribose) polymerase and ?-catenin proteins. However, z-DEVD-fmk, a caspase-3-specific inhibitor, blocked SVB-induced apoptosis and increased the survival rate of SVB-treated cells, indicating that activation of caspase-3 plays a key role in SVB-induced apoptosis. In addition, within concentrations that were not cytotoxic to A549 cells, SVB induced marked inhibition of cell motility and invasiveness. Activities of matrix metalloproteinase (MMP)-2 and MMP-9 in AGS cells were dose-dependently inhibited by treatment with SVB, and this was also correlated with a decrease in expression of their mRNA and proteins, and upregulation of tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2 mRNA expression. Further studies are needed; however, the results indicated that SVB induces apoptosis of A549 cells through a signaling cascade of death receptor-mediated extrinsic as well as mitochondria-mediated intrinsic caspase pathways. Our data also demonstrated that MMPs are critical targets of SVB-induced anti-invasiveness in A549 cells. PMID:22200726

Park, Jeong-Seok; Shin, Dong Yeok; Lee, Yeon-Weol; Cho, Chong-Kwan; Kim, Gi Young; Kim, Wun-Jae; Yoo, Hwa-Seung; Choi, Yung Hyun

2012-04-01

284

Tributyltin induces apoptotic signaling in hepatocytes through pathways involving the endoplasmic reticulum and mitochondria  

E-print Network

Tributyltin induces apoptotic signaling in hepatocytes through pathways involving the endoplasmic-n-butyltin induces pro-apoptotic signaling in rat liver hepatocytes through pathways involving the endoplasmic hepatocytes at the nuclear level, detected by chromatin condensation and by confocal microscopy using acridine

Sarhan, Fathey

285

Cell Death Differ . Author manuscript Intravenous apoptotic spleen cell infusion induces a TGF-beta-dependent  

E-print Network

Cell Death Differ . Author manuscript Page /1 14 Intravenous apoptotic spleen cell infusion induces infusion prevents theIn vivo apoptotic spleen cell-induced beneficial effects on engraftment and graft spleen cell infusion. This novel association between apoptosis and regulatory T cell expansion may also

Paris-Sud XI, Université de

286

Leptin Enhances Availability of Apoptotic Cell-Derived Self-Antigen in Systemic Lupus Erythematosus  

PubMed Central

In systemic lupus erythematosus (SLE), the availability of self-antigen promotes and fuels self-reactive immune responses. Apoptotic cells represent a major source of self-antigens, and an impairment of the removal of apoptotic material containing self-antigen can contribute to the development of autoimmunity. To address whether the adipocytokine leptin - which favors autoimmune responses through little understood mechanisms - could modulate the handling of apoptotic cells in SLE, we evaluated the ability of leptin to modulate the capacity of macrophages to phagocytose apoptotic bodies in (NZB×NZW)F1 lupus mice. It was found that leptin promoted phagocytosis of apoptotic cells by macrophages by modulating cAMP levels in macrophages. This finding associated with an increased availability of antigen that favored the development of T cell responses to apoptotic-derived antigen. As leptin promotes macrophage phagocytosis of apoptotic bodies in SLE and subsequent availability of apoptotic-derived antigen to T cells, an inhibition of this process via leptin blockade might have a therapeutic potential in SLE. PMID:25401752

Matarese, Giuseppe; La Cava, Antonio

2014-01-01

287

Autoantigens as substrates for apoptotic proteases: implications for the pathogenesis of systemic autoimmune disease  

Microsoft Academic Search

Systemic autoimmune diseases are a genetically complex, heterogeneous group of diseases in which the immune system targets a diverse, but highly specific group of intracellular autoantigens. The clustering and marked concentration of these molecules in the surface blebs of apoptotic cells, and their modification by apoptosis-specific proteolytic cleavage and\\/or phosphorylation at these sites, has focused attention on a unique apoptotic

Antony Rosen; Livia Casciola-Rosen

1999-01-01

288

Cholesterol-derived novel anti-apoptotic agents on the structural basis of ginsenoside Rk1  

E-print Network

Cholesterol-derived novel anti-apoptotic agents on the structural basis of ginsenoside Rk1 Sujin Cholesterol Ginsenoside Rk1 a b s t r a c t Design and synthesis of cholesterol-derived anti-apoptotic agents were described. The synthesized cho- lesterol analogs designed on the structural basis of ginsenoside

Suh, Young-Ger

289

Spatiotemporal evolution of apoptotic neurodegeneration following traumatic injury to the developing rat brain  

Microsoft Academic Search

Closed head injury to the developing rat brain causes an acute excitotoxic lesion and axonal disruption at the impact site followed by a delayed pattern of apoptotic damage at various distant sites. Using an electromagnetic impact device to deliver a precisely controlled degree of mechanical deformation to the P7 infant rat skull, we studied the distribution of distant apoptotic lesions

Philip V. Bayly; Krikor T. Dikranian; Erin E. Black; Chainllie Young; Yue-Qin Qin; Joann Labruyere; John W. Olney

2006-01-01

290

Cooperative binding of Annexin A5 to phosphatidylserine on apoptotic cell membranes  

NASA Astrophysics Data System (ADS)

Healthy cells exhibit an asymmetric plasma membrane with phosphatidylserine (PS) located on the cytoplasmic leaflet of the plasma membrane bilayer. Annexin A5-FITC, a PS binding protein, is commonly used to evaluate apoptosis in flow cytometry. PS exposed by apoptotic cells serves as a major ‘eat-me’ signal for phagocytes. Although exposition of PS has been observed after alternative stimuli, no clearance of viable, PS exposing cells has been detected. Thus, besides PS exposure, membranes of viable and apoptotic cells might exhibit specific characteristics. Here, we show that Annexin A5 binds in a cooperative manner to different types of dead cells. Shrunken apoptotic cells thereby showed the highest Hill coefficient values. Contrarily, parafomaldehyde fixation of apoptotic cells completely abrogates the cooperativity effect seen with dead and dying cells. We tend to speculate that the cooperative binding of Annexin A5 to the membranes of apoptotic cells reflects higher fluidity of the exposed membranes facilitating PS clustering.

Janko, Christina; Jeremic, Ivica; Biermann, Mona; Chaurio, Ricardo; Schorn, Christine; Muñoz, Luis E.; Herrmann, Martin

2013-12-01

291

Unphosphorylated STAT1 promotes sarcoma development through repressing expression of Fas and Bad and conferring apoptotic resistance  

PubMed Central

STAT1 exists in phosphorylated (pSTAT1) and unphosphorylated (uSTAT1) forms each regulated by IFN-?. Although STAT1 is a key mediator of the IFN-? signaling pathway, an essential component of the host cancer immunosurveillance system, STAT1 is also overexpressed in certain human cancers where the functions of pSTAT1 and uSTAT1 are ill-defined. Using a murine model of soft tissue sarcoma (STS), we demonstrate that disruption of the IFN effector molecule IRF8 decreases pSTAT1 and increases uSTAT1 in STS cells, thereby increasing their metastatic potential. We determined that the IRF8 gene promoter was hypermethylated frequently in human STS. An analysis of 123 human STS specimens revealed that high uSTAT1 levels in tumor cells was correlated with a reduction in disease-specific survival, whereas high pSTAT1 levels in tumor cells was correlated with an increase in disease-specific survival. In addition, uSTAT1 levels were negatively correlated with pSTAT1 levels in these STS specimens. Mechanistic investigations revealed that IRF8 suppressed STAT1 transcription by binding the STAT1 promoter. RNAi-mediated silencing of STAT1 in STS cells was sufficient to increase expression of the apoptotic mediators Fas and Bad and to elevate the sensitivity of STS cells to Fas-mediated apoptosis. Together, our findings show how the phosphorylation status of pSTAT1 determines its function as a tumor suppressor, with uSTAT1 acting as a tumor promoter that acts by elevating resistance to Fas-mediated apoptosis to promote immune escape. PMID:22805310

Zimmerman, Mary A.; Rahman, Nur-Taz; Yang, Dafeng; Lahat, Guy; Lazar, Alexander J.; Pollock, Raphael; Lev, Dina; Liu, Kebin

2012-01-01

292

Multisite phosphorylation of c-Jun at threonine 91/93/95 triggers the onset of c-Jun pro-apoptotic activity in cerebellar granule neurons.  

PubMed

Cerebellar granule cell (CGC) apoptosis by trophic/potassium (TK) deprivation is a model of election to study the interplay of pro-apoptotic and pro-survival signaling pathways in neuronal cell death. In this model, the c-Jun N-terminal kinase (JNK) induces pro-apoptotic genes through the c-Jun/activator protein 1 (AP-1) transcription factor. On the other side, a survival pathway initiated by lithium leads to repression of pro-apoptotic c-Jun/AP-1 target genes without interfering with JNK activity. Yet, the mechanism by which lithium inhibits c-Jun activity remains to be elucidated. Here, we used this model system to study the regulation and function of site-specific c-Jun phosphorylation at the S63 and T91/T93 JNK sites in neuronal cell death. We found that TK-deprivation led to c-Jun multiphosphorylation at all three JNK sites. However, immunofluorescence analysis of c-Jun phosphorylation at single cell level revealed that the S63 site was phosphorylated in all c-Jun-expressing cells, whereas the response of T91/T93 phosphorylation was more sensitive, mirroring the switch-like apoptotic response of CGCs. Conversely, lithium prevented T91T93 phosphorylation and cell death without affecting the S63 site, suggesting that T91T93 phosphorylation triggers c-Jun pro-apoptotic activity. Accordingly, a c-Jun mutant lacking the T95 priming site for T91/93 phosphorylation protected CGCs from apoptosis, whereas it was able to induce neurite outgrowth in PC12 cells. Vice versa, a c-Jun mutant bearing aspartate substitution of T95 overwhelmed lithium-mediate protection of CGCs from TK-deprivation, validating that inhibition of T91/T93/T95 phosphorylation underlies the effect of lithium on cell death. Mass spectrometry analysis confirmed multiphosphorylation of c-Jun at T91/T93/T95 in cells. Moreover, JNK phosphorylated recombinant c-Jun at T91/T93 in a T95-dependent manner. On the basis of our results, we propose that T91/T93/T95 multiphosphorylation of c-Jun functions as a sensitivity amplifier of the JNK cascade, setting the threshold for c-Jun pro-apoptotic activity in neuronal cells. PMID:24113186

Reddy, C E; Albanito, L; De Marco, P; Aiello, D; Maggiolini, M; Napoli, A; Musti, A M

2013-01-01

293

Apoptosis and expression of Bax, Bcl-x, and Bcl-2 apoptotic regulatory proteins in colorectal carcinomas, and association with p53 genotype/phenotype.  

PubMed Central

AIMS: Spontaneous apoptosis and expression of the apoptotic regulatory proteins Bax, Bcl-x, and Bcl-2 were investigated in 50 colorectal carcinomas. The p53 genotypes/phenotypes and BAX genotypes were also determined, and possible associations of these with apoptosis and/or with expression of the different apoptotic regulatory proteins were studied. METHODS: Terminal deoxynucleotidyl transferase (TdT) mediated dUTP labelling of DNA fragments was used to detect apoptotic tumour cells in sections and peroxidase immunohistochemistry was used to assess protein expression. p53 genotype/phenotype was determined using constant denaturant gel electrophoresis/immunoblotting and bax genotype was determined using polymerase chain reaction based methods. RESULTS: The distribution of tumour apoptotic indices was bimodal with a natural cut off at 1.0% (range, 0.0-5.4%); the median fraction of apoptotic tumour cells was 0.8%. Tumour apoptosis was not associated significantly with tumour DNA ploidy status. Normal mucosal tissue had less than 0.1% apoptotic cells. Staining intensities for Bax, Bcl-x, and Bcl-2 were strong; that is, equivalent to or greater than positive normal mucosal cells, in 11 of 50, 20 of 49, and 20 of 48 carcinomas. Frameshift mutations in the bax gene were detected in three of 42 tumours analysed, all of which were DNA diploid, and Bax protein expression in these tumours was absent or very low. Bax, Bcl-x, and Bcl-2 protein expression were not correlated with tumour apoptosis or tumour DNA ploidy status. p53 was expressed in 34 of 50 tumours and p53 gene mutations were detected in 22 of 29 p53 positive tumours analysed. Apoptosis was significantly lower in a greater number of p53 positive tumours than p53 negative tumours. In addition, Bcl-2 protein expression was significantly higher in a greater number of p53 positive tumours compared with p53 negative tumours. Bax and Bcl-x protein expression were not significantly associated with p53 phenotype/genotype. CONCLUSIONS: The results indicate that acquisition of a p53 phenotype is associated with lower spontaneous apoptosis and higher expression of Bcl-2. The results also suggest that p53 is not a major determinant for Bax expression in colorectal carcinomas in vivo. PMID:10193519

De Angelis, P M; Stokke, T; Thorstensen, L; Lothe, R A; Clausen, O P

1998-01-01

294

Host cell killing by the West Nile Virus NS2B-NS3 proteolytic complex: NS3 alone is sufficient to recruit caspase-8-based apoptotic pathway  

SciTech Connect

The West Nile Virus (WNV) non-structural proteins 2B and 3 (NS2B-NS3) constitute the proteolytic complex that mediates the cleavage and processing of the viral polyprotein. NS3 recruits NS2B and NS5 proteins to direct protease and replication activities. In an effort to investigate the biology of the viral protease, we cloned cDNA encoding the NS2B-NS3 proteolytic complex from brain tissue of a WNV-infected dead crow, collected from the Lower Merion area (Merion strain). Expression of the NS2B-NS3 gene cassette induced apoptosis within 48 h of transfection. Electron microscopic analysis of NS2B-NS3-transfected cells revealed ultra-structural changes that are typical of apoptotic cells including membrane blebbing, nuclear disintegration and cytoplasmic vacuolations. The role of NS3 or NS2B in contributing to host cell apoptosis was examined. NS3 alone triggers the apoptotic pathways involving caspases-8 and -3. Experimental results from the use of caspase-specific inhibitors and caspase-8 siRNA demonstrated that the activation of caspase-8 was essential to initiate apoptotic signaling in NS3-expressing cells. Downstream of caspase-3 activation, we observed nuclear membrane ruptures and cleavage of the DNA-repair enzyme, PARP in NS3-expressing cells. Nuclear herniations due to NS3 expression were absent in the cells treated with a caspase-3 inhibitor. Expression of protease and helicase domains themselves was sufficient to trigger apoptosis generating insight into the apoptotic pathways triggered by NS3 from WNV.

Ramanathan, Mathura P. [Department of Pathology and Laboratory Medicine, 422 Curie Blvd., 505 Stellar-Chance Laboratories, University of Pennsylvania School of Medicine, Philadelphia, PA 19104 (United States); Chambers, Jerome A. [Department of Pathology and Laboratory Medicine, 422 Curie Blvd., 505 Stellar-Chance Laboratories, University of Pennsylvania School of Medicine, Philadelphia, PA 19104 (United States); Pankhong, Panyupa [Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University, Bangkok 10700 (Thailand); Chattergoon, Michael [Department of Pathology and Laboratory Medicine, 422 Curie Blvd., 505 Stellar-Chance Laboratories, University of Pennsylvania School of Medicine, Philadelphia, PA 19104 (United States); Attatippaholkun, Watcharee [Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University, Bangkok 10700 (Thailand); Dang, Kesen [Department of Pathology and Laboratory Medicine, 422 Curie Blvd., 505 Stellar-Chance Laboratories, University of Pennsylvania School of Medicine, Philadelphia, PA 19104 (United States); Shah, Neelima [Department of Pathology and Laboratory Medicine, 422 Curie Blvd., 505 Stellar-Chance Laboratories, University of Pennsylvania School of Medicine, Philadelphia, PA 19104 (United States); Weiner, David B. [Department of Pathology and Laboratory Medicine, 422 Curie Blvd., 505 Stellar-Chance Laboratories, University of Pennsylvania School of Medicine, Philadelphia, PA 19104 (United States)]. E-mail: dbweiner@mail.med.upenn.edu

2006-02-05

295

O Death Where Is Thy Sting? Immunologic Tolerance To Apoptotic Self  

PubMed Central

In higher organisms, innate scavenging cells maintain physiologic homeostasis by removal of the billions of apoptotic cells generated on a daily basis. Apoptotic cell removal requires efficient recognition and uptake by professional and non-professional phagocytic cells, which are governed by an array of soluble and apoptotic cell-integral signals resulting in immunologically silent clearance. While apoptosis is associated with profound suppression of adaptive and innate inflammatory immunity, we have only begun to scratch the surface in understanding how immunologic tolerance to apoptotic self manifest at either the molecular or cellular level. In the last 10 years data has emerged implicating professional phagocytes, most notably stromal macrophages and CD8?+CD103+ dendritic cells, as critical in initiation of the regulatory cascade that will ultimately lead to long-term whole animal immune tolerance. Importantly, recent work by our lab and others has shown that alterations in apoptotic cell perception by the innate immune system either by removal of critical phagocytic sentinels in secondary lymphoid organs or blockage of immunosuppressive pathways leads to pronounced inflammation with a breakdown of tolerance towards self. This challenges the paradigm that apoptotic cells are inherently immunosuppressive suggesting that apoptotic cell tolerance is a “context dependent” event. PMID:23377225

Ravishankar, Buvana; McGaha, Tracy L.

2013-01-01

296

Marginal zone CD169+ macrophages coordinate apoptotic cell-driven cellular recruitment and tolerance  

PubMed Central

Tolerance to apoptotic cells is essential to prevent inflammatory pathology. Though innate responses are critical for immune suppression, our understanding of early innate immunity driven by apoptosis is lacking. Herein we report apoptotic cells induce expression of the chemokine CCL22 in splenic metallophillic macrophages, which is critical for tolerance. Systemic challenge with apoptotic cells induced rapid production of CCL22 in CD169+ (metallophillic) macrophages, resulting in accumulation and activation of FoxP3+ Tregs and CD11c+ dendritic cells, an effect that could be inhibited by antagonizing CCL22-driven chemotaxis. This mechanism was essential for suppression after apoptotic cell challenge, because neutralizing CCL22 or its receptor, reducing Treg numbers, or blocking effector mechanisms abrogated splenic TGF-? and IL-10 induction; this promoted a shift to proinflammatory cytokines associated with a failure to suppress T cells. Similarly, CCR4 inhibition blocked long-term, apoptotic cell-induced tolerance to allografts. Finally, CCR4 inhibition resulted in a systemic breakdown of tolerance to self after apoptotic cell injection with rapid increases in anti-dsDNA IgG and immune complex deposition. Thus, the data demonstrate CCL22-dependent chemotaxis is a key early innate response required for apoptotic cell-induced suppression, implicating a previously unknown mechanism of macrophage-dependent coordination of early events leading to stable tolerance. PMID:24591636

Ravishankar, Buvana; Shinde, Rahul; Liu, Haiyun; Chaudhary, Kapil; Bradley, Jillian; Lemos, Henrique P.; Chandler, Phillip; Tanaka, Masato; Munn, David H.; Mellor, Andrew L.; McGaha, Tracy L.

2014-01-01

297

Tumor-derived endothelial cells evade apoptotic activity of the interferon-inducible IFI16 gene.  

PubMed

The human interferon (IFN)-inducible IFI16 protein is a member of the 200-amino acid repeat family encoded by the HIN-200 genes. Forced IFI16 expression in normal human endothelial cells (ECs) inhibits cell growth and tube morphogenesis of ECs through the triggering of apoptosis by caspase-2 and caspase-3 via nuclear factor-?B (NF-?B) complex activation. Accumulating evidence suggests that tumor-derived ECs (TECs) possess a distinct and unique phenotype compared with normal ECs, and they may be able to acquire resistance to antiangiogenic agents such as IFNs. However, few functional studies are available on cultured TEC. In the present study, we have demonstrated that TEC obtained from tumors of various histological origin, namely kidney (Eck25), breast (B-TEC), and head and neck (HN4), continued to proliferate and generate microtubules on Matrigel following IFI16 overexpression. In contrast to normal ECs, they were resistant to apoptosis triggered by caspase-2 and caspase-3 activation via the NF-?B complex. At the molecular level, when overexpressed in TEC, IFI16 appeared unable to regulate NF-?B activity and lead to caspase activation. Altogether, these results indicate that TECs display abnormal responses, in terms of survival and angiogenic properties, to an antiproliferative and antiangiogenic IFN-inducible gene such as IFI16. PMID:21488755

Gugliesi, Francesca; Dell'oste, Valentina; De Andrea, Marco; Baggetta, Rossella; Mondini, Michele; Zannetti, Claudia; Bussolati, Benedetta; Camussi, Gianni; Gariglio, Marisa; Landolfo, Santo

2011-08-01

298

Lysosomal photodamage induces cell death via mitochondrial apoptotic pathway  

NASA Astrophysics Data System (ADS)

Lysosomal photosensitizers have been used in photodynamic therapy (PDT). Combination of such photosensitizers and light causes lysosomal photodamage, inducing cell death. The lysosomal disruption can lead to apoptosis but its signaling pathways remain to be elucidated. In this study, we selected N-aspartyl chlorin e6 (NPe6), an effective photosensitizer which preferentially accumulates in lysosomes, to study the mechanism of apoptosis caused by lysosomal photodamage. Apoptosis in living human lung adenocarcinoma cells treated by NPe6-PDT was studied using real-time single-cell analysis. In this study, the fluorescence probes Cyto c-GFP and DsRed-Mit were used to detect the spatial and temporal changes of cytochrome c in real-time in sub-cell level; the Rhodamine 123 dyes were used to monitor the changes of mitochondrial membrane potential. The results showed that, after PDT treatment,the mitochondrial membrane potential decreased, and cytochrome c released from mitochondria; The caspase-3 was activated obviously. These results suggested that lysosomal photodamage activates mitochondrial apoptotic pathway to induce cell death.

Liu, Lei; Wang, Xian-wang; Li, Hui

2009-11-01

299

Non-apoptotic functions of caspase-7 during osteogenesis.  

PubMed

Caspase-3 and -7 are generally known for their central role in the execution of apoptosis. However, their function is not limited to apoptosis and under specific conditions activation has been linked to proliferation or differentiation of specialised cell types. In the present study, we followed the localisation of the activated form of caspase-7 during intramembranous (alveolar and mandibular bones) and endochondral (long bones of limbs) ossification in mice. In both bone types, the activated form of caspase-7 was detected from the beginning of ossification during embryonic development and persisted postnatally. The bone status was investigated by microCT in both wild-type and caspase-7-deficient adult mice. Intramembranous bone in mutant mice displayed a statistically significant decrease in volume while the mineral density was not altered. Conversely, endochondral bone showed constant volume but a significant decrease in mineral density in caspase-7 knock-out mice. Cleaved caspase-7 was present in a number of cells that did not show signs of apoptosis. PCR array analysis of the mandibular bone of caspase-7-deficient versus wild-type mice pointed to a significant decrease in mRNA levels for Msx1 and Smad1 in early bone formation. These observations might explain the decrease in the alveolar bone volume of adult knock-out mice. In conclusion, this study is the first to report a non-apoptotic function of caspase-7 in osteogenesis and also demonstrates further specificities in endochondral versus intramembranous ossification. PMID:25118926

Svandova, E; Lesot, H; Vanden Berghe, T; Tucker, A S; Sharpe, P T; Vandenabeele, P; Matalova, E

2014-01-01

300

Inhibition of Rac GTPase triggers a c-Jun- and Bim-dependent mitochondrial apoptotic cascade in cerebellar granule neurons.  

PubMed

Rho GTPases are key transducers of integrin/extracellular matrix and growth factor signaling. Although integrin-mediated adhesion and trophic support suppress neuronal apoptosis, the role of Rho GTPases in neuronal survival is unclear. Here, we have identified Rac as a critical pro-survival GTPase in cerebellar granule neurons (CGNs) and elucidated a death pathway triggered by its inactivation. GTP-loading of Rac1 was maintained in CGNs by integrin-mediated (RGD-dependent) cell attachment and trophic support. Clostridium difficile toxin B (ToxB), a specific Rho family inhibitor, induced a selective caspase-mediated degradation of Rac1 without affecting RhoA or Cdc42 protein levels. Both ToxB and dominant-negative N17Rac1 elicited CGN apoptosis, characterized by cytochrome c release and activation of caspase-9 and -3, whereas dominant-negative N19RhoA or N17Cdc42 did not cause significant cell death. ToxB stimulated mitochondrial translocation and conformational activation of Bax, c-Jun activation, and induction of the BH3-only protein Bim. Similarly, c-Jun activation and Bim induction were observed with N17Rac1. A c-jun N-terminal protein kinase (JNK)/p38 inhibitor, SB203580, and a JNK-specific inhibitor, SP600125, significantly decreased ToxB-induced Bim expression and blunted each subsequent step of the apoptotic cascade. These results indicate that Rac acts downstream of integrins and growth factors to promote neuronal survival by repressing c-Jun/Bim-mediated mitochondrial apoptosis. PMID:16092944

Le, Shoshona S; Loucks, F Alexandra; Udo, Hiroshi; Richardson-Burns, Sarah; Phelps, Reid A; Bouchard, Ron J; Barth, Holger; Aktories, Klaus; Tyler, Kenneth L; Kandel, Eric R; Heidenreich, Kim A; Linseman, Daniel A

2005-08-01

301

The Apoptotic Initiator Caspase-8: Its Functional Ubiquity and Genetic Diversity during Animal Evolution.  

PubMed

The caspases, a family of cysteine proteases, play multiple roles in apoptosis, inflammation, and cellular differentiation. Caspase-8 (Casp8), which was first identified in humans, functions as an initiator caspase in the apoptotic signaling mediated by cell-surface death receptors. To understand the evolution of function in the Casp8 protein family, casp8 orthologs were identified from a comprehensive range of vertebrates and invertebrates, including sponges and cnidarians, and characterized at both the gene and protein levels. Some introns have been conserved from cnidarians to mammals, but both losses and gains have also occurred; a new intron arose during teleost evolution, whereas in the ascidian Ciona intestinalis, the casp8 gene is intronless and is organized in an operon with a neighboring gene. Casp8 activities are near ubiquitous throughout the animal kingdom. Exogenous expression of a representative range of nonmammalian Casp8 proteins in cultured mammalian cells induced cell death, implying that these proteins possess proapoptotic activity. The cnidarian Casp8 proteins differ considerably from their bilaterian counterparts in terms of amino acid residues in the catalytic pocket, but display the same substrate specificity as human CASP8, highlighting the complexity of spatial structural interactions involved in enzymatic activity. Finally, it was confirmed that the interaction with an adaptor molecule, Fas-associated death domain protein, is also evolutionarily ancient. Thus, despite structural diversity and cooption to a variety of new functions, the ancient origins and near ubiquitous distribution of this activity across the animal kingdom emphasize the importance and utility of Casp8 as a central component of the metazoan molecular toolkit. PMID:25205508

Sakamaki, Kazuhiro; Shimizu, Kouhei; Iwata, Hiroaki; Imai, Kenichiro; Satou, Yutaka; Funayama, Noriko; Nozaki, Masami; Yajima, Mamiko; Nishimura, Osamu; Higuchi, Mayura; Chiba, Kumiko; Yoshimoto, Michi; Kimura, Haruna; Gracey, Andrew Y; Shimizu, Takashi; Tomii, Kentaro; Gotoh, Osamu; Akasaka, Koji; Sawasaki, Tatsuya; Miller, David J

2014-12-01

302

The apoptotic response to strenuous exercise of the gastrocnemius and solues muscle fibers in rats.  

PubMed

The purposes of this study were to investigate the effects of strenuous exercise on apoptosis of the gastrocnemius and soleus muscle fibers and clarify the role of oxidative metabolism in the strenuous exercise-induced apoptosis. The experiment was designed with 49 (n = 49) male, 24-week-old, L. Wistar albino rats. Strenuous exercise model was applied to 42 (n = 42) rats and seven (n = 7) rats served as rested controls. All rats were randomly assigned to one of the following groups (n = 7): rested control (C), immediately after exercise (0 h) and 3, 6, 12, 24, and 48 h after exercise. Apoptotic nuclei were shown by single stranded DNA (ssDNA) determination. Oxidative damage in mitochondrial fractions of the muscle tissues was evaluated by malondialdehyde (MDA) levels and reduced/oxidized glutathione (GSH/GSSG) ratios. Caspase-9, -8 and -3 activities and the level of cytochrome c (Cyt c) were measured in the cytosolic fractions of muscle tissues to follow mitochondrial-dependent (intrinsic) or ligand-mediated death receptor (extrinsic) pathways of apoptosis. Plasma interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) levels were also determined. Based on our results, apoptosis is significantly triggered in muscle fibers by strenuous exercise (P < 0.05). Apoptosis in the soleus muscle tissues mostly depends on the intrinsic pathway and may be triggered by increased oxidative stress. In contrast, extrinsic pathway of apoptosis was predominant in the gastrocnemius muscle and increases of TNF-alpha and IL-6 may play a significant role. PMID:18030491

Koçtürk, S; Kayatekin, B M; Resmi, H; Açikgöz, O; Kaynak, C; Ozer, E

2008-03-01

303

Apoptotic activity of caged xanthones from Garcinia hanburyi in cholangiocarcinoma cell lines  

PubMed Central

AIM: To investigate the growth inhibitory mechanism of four caged xanthones from Garcinia hanburyi in cholangiocarcinoma (CCA) KKU-100 and KKU-M156 cells. METHODS: Four caged xanthones, selected on the basis of their anticancer potency and chemical structure diversities (i.e. isomorellin, isomorellinol, forbesione and gambogic acid) were used in this study. Growth inhibition of these caged xanthones was determined using the sulforhodamine B assay. Induction of apoptosis was assessed by observing cell morphology, ethidium bromide and acridine orange staining and DNA fragmentation assay. Levels of apoptotic-related gene and protein expressions were determined by a real-time reverse transcriptase polymerase chain reaction and Western blotting analysis, respectively. RESULTS: The compounds were found to inhibit growth of both cell lines in a dose-dependent manner and also showed selective cytotoxicity against the cancer cells when compared with normal peripheral blood mononuclear cells. Growth suppression by these compounds was due to apoptosis, as evidenced by the cell morphological changes, chromatin condensation, nuclear fragmentation, and DNA ladder formation. At the molecular level, these compounds induced down-regulation of Bcl-2 and survivin proteins with up-regulation of Bax and apoptosis-inducing factor proteins, leading to the activation of caspase-9 and -3 and DNA fragmentation. The functional group variations did not appear to affect the anticancer activity with regard to the two CCA cell lines; however, at a mechanistic level, isomorellinol exhibited the highest potency in increasing the Bax/Bcl-2 protein expression ratio (120 and 41.4 for KKU-100 and KKU-M156, respectively) and in decreasing survivin protein expression (0.01 fold as compared to control cells in both cell lines). Other activities at the molecular level indicate that functional groups on the prenyl side chain may be important. CONCLUSION: Our findings for the first time demonstrate that four caged xanthones induce apoptosis in CCA cells which is mediated through a mitochondria-dependent signaling pathway. PMID:20458760

Hahnvajanawong, Chariya; Boonyanugomol, Wongwarut; Nasomyon, Tapanawan; Loilome, Watcharin; Namwat, Nisana; Anantachoke, Natthinee; Tassaneeyakul, Wichittra; Sripa, Banchob; Namwat, Wises; Reutrakul, Vichai

2010-01-01

304

Asymmetric neuroblast divisions producing apoptotic cells require the cytohesin GRP-1 in Caenorhabditis elegans.  

PubMed

Cytohesins are Arf guanine nucleotide exchange factors (GEFs) that regulate membrane trafficking and actin cytoskeletal dynamics. We report here that GRP-1, the sole Caenorhabditis elegans cytohesin, controls the asymmetric divisions of certain neuroblasts that divide to produce a larger neuronal precursor or neuron and a smaller cell fated to die. In the Q neuroblast lineage, loss of GRP-1 led to the production of daughter cells that are more similar in size and to the transformation of the normally apoptotic daughter into its sister, resulting in the production of extra neurons. Genetic interactions suggest that GRP-1 functions with the previously described Arf GAP CNT-2 and two other Arf GEFs, EFA-6 and BRIS-1, to regulate the activity of Arf GTPases. In agreement with this model, we show that GRP-1's GEF activity, mediated by its SEC7 domain, is necessary for the posterior Q cell (Q.p) neuroblast division and that both GRP-1 and CNT-2 function in the Q.posterior Q daughter cell (Q.p) to promote its asymmetry. Although functional GFP-tagged GRP-1 proteins localized to the nucleus, the extra cell defects were rescued by targeting the Arf GEF activity of GRP-1 to the plasma membrane, suggesting that GRP-1 acts at the plasma membrane. The detection of endogenous GRP-1 protein at cytokinesis remnants, or midbodies, is consistent with GRP-1 functioning at the plasma membrane and perhaps at the cytokinetic furrow to promote the asymmetry of the divisions that require its function. PMID:25053664

Teuliere, Jerome; Cordes, Shaun; Singhvi, Aakanksha; Talavera, Karla; Garriga, Gian

2014-09-01

305

Involvement of ER stress and activation of apoptotic pathways in fisetin induced cytotoxicity in human melanoma.  

PubMed

The prognosis of malignant melanoma remains poor in spite of recent advances in therapeutic strategies for the deadly disease. Fisetin, a dietary flavonoid is currently being investigated for its growth inhibitory properties in various cancer models. We previously showed that fisetin inhibited melanoma growth in vitro and in vivo. Here, we evaluated the molecular basis of fisetin induced cytotoxicity in metastatic human melanoma cells. Fisetin treatment induced endoplasmic reticulum (ER) stress in highly aggressive A375 and 451Lu human melanoma cells, as revealed by up-regulation of ER stress markers including IRE1?, XBP1s, ATF4 and GRP78. Time course analysis indicated that the ER stress was associated with activation of the extrinsic and intrinsic apoptotic pathways. Fisetin treated 2-D melanoma cultures displayed autophagic response concomitant with induction of apoptosis. Prolonged treatment (16days) with fisetin in a 3-D reconstituted melanoma model resulted in inhibition of melanoma progression with significant apoptosis, as evidenced by increased staining of cleaved Caspase-3 in the treated constructs. However, no difference in the expression of autophagic marker LC-3 was noted between treated and control groups. Fisetin treatment to 2-D melanoma cultures resulted in phosphorylation and activation of the multifunctional AMP-activated protein kinase (AMPK) involved in the regulation of diverse cellular processes, including autophagy and apoptosis. Silencing of AMPK failed to prevent cell death indicating that fisetin induced cytotoxicity is mediated through both AMPK-dependent and -independent mechanisms. Taken together, our studies confirm apoptosis as the primary mechanism through which fisetin inhibits melanoma cell growth and that activation of both extrinsic and intrinsic pathways contributes to fisetin induced cytotoxicity. PMID:25016296

Syed, Deeba N; Lall, Rahul K; Chamcheu, Jean Christopher; Haidar, Omar; Mukhtar, Hasan

2014-12-01

306

Role of endoplasmic reticulum stress induction by the plant toxin, persin, in overcoming resistance to the apoptotic effects of tamoxifen in human breast cancer cells  

PubMed Central

Background: Persin is a plant toxin that displays synergistic cytotoxicity with tamoxifen in human breast cancer cell lines. Here, we examined the ability of persin to circumvent tamoxifen resistance and delineated the intracellular signalling pathways involved. Methods: The induction of apoptosis in tamoxifen-resistant and -sensitive breast cancer cells was measured by flow cytometry following treatment with persin±tamoxifen. Markers of endoplasmic reticulum stress (ERS) were analysed following treatment, and their causal role in mediating persin-induced apoptosis was determined using chemical inhibitors and RNA interference. Results: Cells that were resistant to an apoptotic concentration of tamoxifen maintained an apoptotic response to persin. Persin-induced apoptosis was associated with an increase in markers of ERS, that is, CHOP expression and XBP-1 splicing and was decreased by CHOP siRNA. The CASP-4 inhibitor Z-YVAD-FMK markedly inhibited persin-induced apoptosis in both tamoxifen-sensitive and -resistant cells. Conclusion: The cytotoxic effects of persin are CASP-4 dependent and mediated by CHOP-dependent and -independent ERS signalling cascades. Increased ERS signalling contributes to persin-induced reversal of tamoxifen resistance. PMID:24178758

McCloy, R A; Shelley, E J; Roberts, C G; Boslem, E; Biden, T J; Nicholson, R I; Gee, J M; Sutherland, R L; Musgrove, E A; Burgess, A; Butt, A J

2013-01-01

307

Anti-apoptotic Role of Caspase-cleaved GAB1 Adaptor Protein in Hepatocyte Growth Factor/Scatter Factor-MET Receptor Protein Signaling*  

PubMed Central

The GRB2-associated binder 1 (GAB1) docking/scaffold protein is a key mediator of the MET-tyrosine kinase receptor activated by hepatocyte growth factor/scatter factor (HGF/SF). Activated MET promotes recruitment and tyrosine phosphorylation of GAB1, which in turn recruits multiple proteins and mediates MET signaling leading to cell survival, motility, and morphogenesis. We previously reported that, without its ligand, MET is a functional caspase target during apoptosis, allowing the generation of a p40-MET fragment that amplifies apoptosis. In this study we established that GAB1 is also a functional caspase target by evidencing a caspase-cleaved p35-GAB1 fragment that contains the MET binding domain. GAB1 is cleaved by caspases before MET, and the resulting p35-GAB1 fragment is phosphorylated by MET upon HGF/SF binding and can interact with a subset of GAB1 partners, PI3K, and GRB2 but not with SHP2. This p35-GAB1 fragment favors cell survival by maintaining HGF/SF-induced MET activation of AKT and by hindering p40-MET pro-apoptotic function. These data demonstrate an anti-apoptotic role of caspase-cleaved GAB1 in HGF/SF-MET signaling. PMID:22915589

Le Goff, Arnaud; Ji, Zongling; Leclercq, Berenice; Bourette, Roland P.; Mougel, Alexandra; Guerardel, Cateline; de Launoit, Yvan; Vicogne, Jerome; Goormachtigh, Gautier; Fafeur, Veronique

2012-01-01

308

Plasminogen activation: a mediator of vascular smooth muscle cell apoptosis in atherosclerotic plaques  

E-print Network

specimens, apoptotic vascular smooth muscle cells (VSMC) were observed in areas with loss of pericellularPlasminogen activation: a mediator of vascular smooth muscle cell apoptosis in atherosclerotic and recent in vitro data suggest that plasminogen activation may trigger vascular smooth muscle cell (VSMC

Paris-Sud XI, Université de

309

?-Phenylethyl isothiocyanate mediated apoptosis; contribution of Bax and the mitochondrial death pathway  

Microsoft Academic Search

The initiating events that lead to the induction of apoptosis mediated by the chemopreventative agent ?-phenyethyl isothiocyanate (PEITC) have yet to be elucidated. In the present investigation, we examined the effects of PEITC on mitochondrial function and apoptotic signaling in hepatoma HepG2 cells and isolated rat hepatocyte mitochondria. PEITC induced a conformational change in Bax leading to its translocation to

Peter Rose; Jeffery S. Armstrong; Yee Liu Chua; Choon Nam Ong; Matthew Whiteman

2005-01-01

310

Mitochondrial hexokinases, novel mediators of the antiapoptotic effects of growth factors and Akt  

Microsoft Academic Search

Cell survival has been closely linked to both trophic growth factor signaling and cellular metabolism. Such couplings have obvious physiologic and pathophysiologic implications, but their underlying molecular bases remain incompletely defined. As a common mediator of both the metabolic and anti-apoptotic effects of growth factors, the serine\\/threonine kinase Akt – also known as protein kinase B or PKB – is

R B Robey; N Hay

2006-01-01

311

Acrolein activates cell survival and apoptotic death responses involving the endoplasmic reticulum in A549 lung cells.  

PubMed

Acrolein, a highly reactive ?,?-unsaturated aldehyde, is a product of endogenous lipid peroxidation. It is a ubiquitous environmental pollutant that is generated mainly by smoke, overheated cooking oil and vehicle exhaust. Acrolein damages cellular proteins, which could lead to accumulation of aberrantly-folded proteins in the endoplasmic reticulum (ER). This study determines the mechanisms involved in acrolein-induced apoptosis mediated by the ER and possible links with the ER stress response in human A549 lung cells. The exposure of cells to acrolein (15-50?M) for shorter times of 15 to 30min activated several ER stress markers. These included the ER chaperone protein BiP and the three ER sensors: (i) the survival/rescue molecules protein kinase RNA (PKR)-like ER kinase (PERK) and eukaryotic initiation factor 2 alpha (eIF2?) were phosphorylated; (ii) cleavage of activating transcription factor 6 (ATF6) occurred, and (iii) inositol-requiring protein-1 alpha (IRE1?) was phosphorylated. Acrolein (25-50?M) caused apoptotic cell death mediated by the ER after 2h, which was characterised by the induction of CHOP and activation of ER proteases calpain and caspase-4. Calpain and caspase-7 were the initiating factors for caspase-4 activation in acrolein-induced apoptosis. These results increase our knowledge about cellular responses to acrolein in lung cells, which have implications for human health. PMID:24373849

Tanel, André; Pallepati, Pragathi; Bettaieb, Ahmed; Morin, Patrick; Averill-Bates, Diana A

2014-05-01

312

Phototherapy-treated apoptotic tumor cells induce pro-inflammatory cytokines production in macrophage  

NASA Astrophysics Data System (ADS)

Our previous studies have demonstrated that as a mitochondria-targeting cancer phototherapy, high fluence low-power laser irradiation (HF-LPLI) induces mitochondrial superoxide anion burst, resulting in oxidative damage to tumor cells. In this study, we further explored the immunological effects of HF-LPLI-induced apoptotic tumor cells. When macrophages were co-incubated with apoptotic cells induced by HF-LPLI, we observed the increased levels of TNF-? secretion and NO production in macrophages. Further experiments showed that NF-?B was activated in macrophages after co-incubation with HF-LPLI-induced apoptotic cells, and inhibition of NF-?B activity by pyrrolidinedithiocarbamic acid (PDTC) reduced the elevated levels of TNF-? secretion and NO production. These data indicate that HF-LPLI-induced apoptotic tumor cells induce the secretion of pro-inflammatory cytokines in macrophages, which may be helpful for better understanding the biological effects of cancer phototherapy.

Lu, Cuixia; Wei, Yanchun; Xing, Da

2014-09-01

313

Quantitative analysis of apoptotic decisions in single cells and cell populations  

E-print Network

Apoptosis is a form of programmed cell death that is essential for the elimination of damaged or unneeded cells in multicellular organisms. Inactivation of apoptotic cell death is a necessary step in the development of ...

Albeck, John G

2007-01-01

314

Abl Kinase Inhibits the Engulfment of Apoptotic [corrected] Cells in Caenorhabditis elegans  

E-print Network

The engulfment of apoptotic cells is required for normal metazoan development and tissue remodeling. In Caenorhabditis elegans, two parallel and partially redundant conserved pathways act in cell-corpse engulfment. One ...

Hurwitz, Michael Eliezer

315

Melanocortin MC? receptor agonists counteract late inflammatory and apoptotic responses and improve neuronal functionality after cerebral ischemia.  

PubMed

Indirect evidence indicates that, in cerebral ischemia, melanocortins have neuroprotective effects likely mediated by MC? receptors. To gain direct insight into the role of melanocortin MC? receptors in ischemic stroke, we investigated the effects of a highly selective MC? receptor agonist. Gerbils were subjected to transient global cerebral ischemia by occluding both common carotid arteries for 10 min. In saline-treated stroke animals, an impairment in learning and memory occurred that, at day 11 after stroke, was associated with hippocampus up-regulation of tumor necrosis factor-? (TNF-?), BAX, activated extracellular signal-regulated kinases (ERK1/2), c-jun N-terminal kinases (JNK1/2) and caspase-3, down-regulation of Bcl-2, and neuronal loss. Treatment for 11days with the selective melanocortin MC? receptor agonist RO27-3225, as well as with the well known non-selective [Nle?,D-Phe?]?-melanocyte-stimulating hormone (NDP-?-MSH) as a reference non-selective melanocortin, counteracted the inflammatory and apoptotic responses, as indicated by the changes in TNF-?, BAX, ERK1/2, JNK1/2, caspase-3 and Bcl-2 protein expression. Furthermore, melanocortin treatment reduced neuronal loss and dose-dependently improved learning and memory. These positive effects were associated with overexpression of Zif268, an immediate early gene involved in injury repair, synaptic plasticity and memory formation. Pharmacological blockade of MC? receptors with the selective MC? receptor antagonist HS024 prevented all effects of RO27-3225 and NDP-?-MSH. These data give direct evidence that stimulation of MC? receptors affords neuroprotection and promotes functional recovery from stroke, by counteracting prolonged and/or recurrent inflammatory and apoptotic responses, and likely by triggering brain repair pathways. PMID:21946115

Spaccapelo, Luca; Bitto, Alessandra; Galantucci, Maria; Ottani, Alessandra; Irrera, Natasha; Minutoli, Letteria; Altavilla, Domenica; Novellino, Ettore; Grieco, Paolo; Zaffe, Davide; Squadrito, Francesco; Giuliani, Daniela; Guarini, Salvatore

2011-11-30

316

Antitumour effect of polyoxomolybdates: induction of apoptotic cell death and autophagy in in vitro and in vivo models  

PubMed Central

Polyoxomolybdates (PMs) as discrete molybdenum-oxide cluster anions have been investigated in the course of study of their medical applications. Here, we show the significant antitumour potency of the polyoxomolybdate [Me3NH]6[H2MoV12O28(OH)12(MoVIO3)4]·2H2O (PM-17), which is a photo-reduced compound of [NH3Pri]6[Mo7O24]·3H2O. The effect of PM-17 on the growth of cancer cell lines and xenografts was assessed by a cell viability test and analysis of tumour expansion rate. Morphological analysis was carried out by Hoechst staining, flow-cytometric analysis of Annexin V staining, terminal deoxynucleotidyl transferase-mediated ‘nick-end' labelling staining, and electron-microscopic analysis. Activation of autophagy was detected by western blotting and fluorescence-microscopic analysis of the localisation of GFP-LC3 in transfected tumour cells. PM-17 inhibited the growth of human pancreatic cancer (AsPC-1) xenografts in a nude mice model, and induced morphological alterations in tumour cells. Correspondingly, PM-17 repressed the proliferation of AsPC-1 cells and human gastric cancer cells (MKN45) depending on the dose in vitro. We observed apoptotic patterns as the formation of apoptotic small bodies and translocation of phosphatidylserine by Hoechst staining and flow-cytometric analysis following Annexin V staining, and in parallel, autophagic conformation by the formulation of autophagosomes and localisation of GFP-LC3 by electron- and fluorescence-microscopic analysis. PMID:18087283

Ogata, A; Yanagie, H; Ishikawa, E; Morishita, Y; Mitsui, S; Yamashita, A; Hasumi, K; Takamoto, S; Yamase, T; Eriguchi, M

2007-01-01

317

Catalase inhibition in diabetic rats potentiates DNA damage and apoptotic cell death setting the stage for cardiomyopathy.  

PubMed

Diabetes is a risk factor for cardiovascular disease that has a multifactorial etiology, with oxidative stress as an important component. Our previous observation of a significant diabetes-related increase in rat cardiac catalase (CAT) activity suggested that CAT could play a major role in delaying the development of diabetic cardiomyopathy. Thus, in the present work, we examined the effects of the daily administration of the CAT inhibitor, 3-amino-1,2,4-triazole (1 mg/g), on the hearts of streptozotocin (STZ)-induced diabetic rats. Administration of CAT inhibitor was started from the 15th day after the last STZ treatment (40 mg/kg/5 days), and maintained until the end of the 4th or 6th weeks of diabetes. Compared to untreated diabetic rats, at the end of the observation period, CAT inhibition lowered the induced level of cardiac CAT activity to the basal level and decreased CAT protein expression, mediated through a decline in the nuclear factor erythroid-derived 2-like 2 /nuclear factor-kappa B p65 (Nrf2/NF-?B p65) subunit ratio. The perturbed antioxidant defenses resulting from CAT inhibition promoted increased H2O2 production (P?apoptotic events, observed as a decrease (P?apoptotic fragment and cytoplasmic levels of cytochrome C. These findings confirm an important function of CAT in the suppression of events leading to diabetes-promoted cardiac dysfunction and cardiomyopathy. PMID:25298180

Ivanovi?-Mati?, Svetlana; Bogojevi?, Desanka; Martinovi?, Vesna; Petrovi?, Anja; Jovanovi?-Stojanov, Sofija; Poznanovi?, Goran; Grigorov, Ilijana

2014-12-01

318

ABT-263 enhances sensitivity to metformin and 2-deoxyglucose in pediatric glioma by promoting apoptotic cell death.  

PubMed

Pediatric high grade glioma is refractory to conventional multimodal treatment, highlighting a need to develop novel efficacious therapies. We investigated tumor metabolism as a potential therapeutic target in a panel of diverse pediatric glioma cell lines (SF188, KNS42, UW479 and RES186) using metformin and 2-deoxyglucose. As a single agent, metformin had little effect on cell viability overall. SF188 cells were highly sensitive to 2-deoxyglucose however, combination of metformin with 2-deoxyglucose significantly reduced cell proliferation compared to either drug alone in all cell lines tested. In addition, the combination of the two agents was associated with a rapid decrease in cellular ATP and subsequent AMPK activation. However, increased cell death was only observed in select cell lines after prolonged exposure to the drug combination and was caspase independent. Anti-apoptotic BCL-2 family proteins have been indicated as mediators of resistance against metabolic stress. Therefore we sought to determine whether pharmacological inhibition of BCL-2/BCL-xL with ABT-263 could potentiate apoptosis in response to these agents. We found that ABT-263 increased sensitivity to 2-deoxyglucose and promoted rapid and extensive cell death in response to the combination of 2-deoxyglucose and metformin. Furthermore, cell death was inhibited by the pan-caspase inhibitor, z-VAD-FMK suggesting that ABT-263 potentiated caspase-dependent cell death in response to 2-deoxyglucose or its combination with metformin. Overall, these data provide support for the concept that targeting metabolic and anti-apoptotic pathways may be an effective therapeutic strategy in pediatric glioma. PMID:23691145

Levesley, Jane; Steele, Lynette; Taylor, Claire; Sinha, Priyank; Lawler, Sean E

2013-01-01

319

ABT-263 Enhances Sensitivity to Metformin and 2-Deoxyglucose in Pediatric Glioma by Promoting Apoptotic Cell Death  

PubMed Central

Pediatric high grade glioma is refractory to conventional multimodal treatment, highlighting a need to develop novel efficacious therapies. We investigated tumor metabolism as a potential therapeutic target in a panel of diverse pediatric glioma cell lines (SF188, KNS42, UW479 and RES186) using metformin and 2-deoxyglucose. As a single agent, metformin had little effect on cell viability overall. SF188 cells were highly sensitive to 2-deoxyglucose however, combination of metformin with 2-deoxyglucose significantly reduced cell proliferation compared to either drug alone in all cell lines tested. In addition, the combination of the two agents was associated with a rapid decrease in cellular ATP and subsequent AMPK activation. However, increased cell death was only observed in select cell lines after prolonged exposure to the drug combination and was caspase independent. Anti-apoptotic BCL-2 family proteins have been indicated as mediators of resistance against metabolic stress. Therefore we sought to determine whether pharmacological inhibition of BCL-2/BCL-xL with ABT-263 could potentiate apoptosis in response to these agents. We found that ABT-263 increased sensitivity to 2-deoxyglucose and promoted rapid and extensive cell death in response to the combination of 2-deoxyglucose and metformin. Furthermore, cell death was inhibited by the pan-caspase inhibitor, z-VAD-FMK suggesting that ABT-263 potentiated caspase-dependent cell death in response to 2-deoxyglucose or its combination with metformin. Overall, these data provide support for the concept that targeting metabolic and anti-apoptotic pathways may be an effective therapeutic strategy in pediatric glioma. PMID:23691145

Levesley, Jane; Steele, Lynette; Taylor, Claire; Sinha, Priyank; Lawler, Sean E.

2013-01-01

320

Engulfment of apoptotic cells by macrophages: a role of microRNA-21 in the resolution of wound inflammation.  

PubMed

At an injury site, efficient clearance of apoptotic cells by wound macrophages or efferocytosis is a prerequisite for the timely resolution of inflammation. Emerging evidence indicates that microRNA-21 (miR-21) may regulate the inflammatory response. In this work, we sought to elucidate the significance of miR-21 in the regulation of efferocytosis-mediated suppression of innate immune response, a key process implicated in resolving inflammation following injury. An increased expression of inducible miR-21 was noted in postefferocytotic peripheral blood monocyte-derived macrophages. Such induction of miR-21 was associated with silencing of its target genes PTEN and PDCD4. Successful efferocytosis of apoptotic cells by monocyte-derived macrophages resulted in the suppression of LPS-induced NF-?B activation and TNF-? expression. Interestingly, bolstering of miR-21 levels alone, using miR mimic, resulted in significant suppression of LPS-induced TNF-? expression and NF-?B activation. We report that efferocytosis-induced miR-21, by silencing PTEN and GSK3?, tempers the LPS-induced inflammatory response. Macrophage efferocytosis is known to trigger the release of anti-inflammatory cytokine IL-10. This study demonstrates that following successful efferocytosis, miR-21 induction in macrophages silences PDCD4, favoring c-Jun-AP-1 activity, which in turn results in elevated production of anti-inflammatory IL-10. In summary, this work provides direct evidence implicating miRNA in the process of turning on an anti-inflammatory phenotype in the postefferocytotic macrophage. Elevated macrophage miR-21 promotes efferocytosis and silences target genes PTEN and PDCD4, which in turn accounts for a net anti-inflammatory phenotype. Findings of this study highlight the significance of miRs in the resolution of wound inflammation. PMID:24391209

Das, Amitava; Ganesh, Kasturi; Khanna, Savita; Sen, Chandan K; Roy, Sashwati

2014-02-01

321

Induction of Non-Apoptotic Cell Death by Activated Ras Requires Inverse Regulation of Rac1 and Arf6  

PubMed Central

Methuosis is a unique form of non-apoptotic cell death triggered by alterations in the trafficking of clathrin-independent endosomes, ultimately leading to extreme vacuolization and rupture of the cell. Methuosis can be induced in glioblastoma cells by expression of constitutively active Ras. This study identifies the small GTPases, Rac1 and Arf6, and the Arf6 GTPase-activating-protein, GIT1, as key downstream components of the signaling pathway underlying Ras-induced methuosis. The extent to which graded expression of active H-Ras(G12V) triggers cytoplasmic vacuolization correlates with the amount of endogenous Rac1 in the active GTP state. Blocking Rac1 activation with the specific Rac inhibitor, EHT 1864, or co-expression of dominant-negative Rac1(T17N), prevents the accumulation of vacuoles induced by H-Ras(G12V). Coincident with Rac1 activation, H-Ras(G12V) causes a decrease in the amount of active Arf6, a GTPase that functions in recycling of clathrin-independent endosomes. The effect of H-Ras(G12V) on Arf6 is blocked by EHT 1864, indicating that the decrease in Arf6-GTP is directly linked to activation of Rac1. Constitutively active Rac1(G12V) interacts with GIT1 in immunoprecipitation assays. Ablation of GIT1 by shRNA prevents the decrease in active Arf6, inhibits vacuolization, and prevents loss of cell viability in cells expressing Rac1(G12V). Together the results suggest that perturbations of endosome morphology associated with Ras-induced methuosis are due to downstream activation of Rac1, combined with reciprocal inactivation of Arf6. The latter appears to be mediated through Rac1 stimulation of GIT1. Further insights into this pathway could suggest opportunities for induction of methuosis in cancers that are resistant to apoptotic cell death. PMID:20713492

Bhanot, Haymanti; Young, Ashley M.; Overmeyer, Jean H.; Maltese, William A.

2010-01-01

322

Syntaxin-binding domain of Kv2.1 is essential for the expression of apoptotic K+ currents.  

PubMed

Intracellular signalling cascades triggered by oxidative injury can lead to upregulation of Kv2.1 K(+) channels at the plasma membrane of dying neurons. Membrane incorporation of new channels is necessary for enhanced K(+) efflux and a consequent reduction of intracellular K(+) that facilitates apoptosis. We showed previously that the observed increase in K(+) currents is a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated process, and that the SNARE protein syntaxin binds directly to Kv2.1 channels. In the present study, we tested whether disrupting the interaction of Kv2.1 and syntaxin promoted the survival of cortical neurons following injury. Syntaxin is known to bind to Kv2.1 in a domain comprising amino acids 411-522 of the channel's cytoplasmic C terminus (C1a). Here we show that this domain is required for the apoptotic K(+) current enhancement. Moreover, expression of an isolated, Kv2.1-derived C1a peptide is sufficient to suppress the injury-induced increase in currents by interfering with Kv2.1/syntaxin binding. By subdividing the C1a peptide, we were able to localize the syntaxin binding site on Kv2.1 to the most plasma membrane-distal residues of C1a. Importantly, expression of this peptide segment in neurons prevented the apoptotic K(+) current enhancement and cell death following an oxidative insult, without greatly impairing baseline K(+) currents or normal electrical profiles of neurons. These results establish that binding of syntaxin to Kv2.1 is crucial for the manifestation of oxidant-induced apoptosis, and thereby reveal a potential new direction for therapeutic intervention in the treatment of neurodegenerative disorders. PMID:24928958

McCord, Meghan C; Kullmann, Paul H; He, Kai; Hartnett, Karen A; Horn, John P; Lotan, Ilana; Aizenman, Elias

2014-08-15

323

Apoptotic and behavioral sequelae of mild brain trauma in mice.  

PubMed

Mild traumatic brain injury (mTBI) is a not uncommon event in adolescents and young adults. Although it does not result in clear morphological brain defects, it is associated with long-term cognitive, emotional, and behavioral problems. Herein, we characterized the biochemical and behavioral changes associated with experimental mTBI in mice that may act as either targets or surrogate markers for interventional therapy. Specifically, mTBI was induced by 30-g and 50-g weight drop, and at 8 and 72 hr thereafter markers of cellular apoptosis-caspase-3, Bax, apoptosis-inducing factor (AIF), and cytochrome-c (Cyt-c)-were quantified by Western blot analysis in hippocampus ipsilateral to the impact. Levels of amyloid-beta precursor protein (APP) were also measured, and specific behavioral tests-passive avoidance, open field, and forced swimming (Porsolt) paradigms-were undertaken to assess learning, emotionality, and emotional memory. In the absence of hemorrhage or infarcts, as assessed by triphenyltetrazolium chloride staining, procaspase-3 and Bax levels were markedly altered following mTBI at both times. No cleaved caspase-3 was detected, and levels of AIF and Cyt-c, but not APP, were significantly changed at 72 hr. Mice subjected to mTBI were indistinguishable from controls by neurological examination at 1 and 24 hr, and by passive avoidance/open field at 72 hr, but could be differentiated in the forced swimming paradigm. In general, this model mimics the diffuse effects of mTBI on brain function associated with the human condition and highlights specific apoptotic proteins and a behavioral paradigm as potential markers for prospective interventional strategies. PMID:17243171

Tweedie, David; Milman, Anat; Holloway, Harold W; Li, Yazhou; Harvey, Brandon K; Shen, Hui; Pistell, Paul J; Lahiri, Debomoy K; Hoffer, Barry J; Wang, Yun; Pick, Chaim G; Greig, Nigel H

2007-03-01

324

Death receptor-associated pro-apoptotic signaling in aged skeletal muscle  

Microsoft Academic Search

Tumor necrosis factor-alpha (TNF-?) is elevated in the serum as a result of aging and it promotes pro-apoptotic signaling\\u000a upon binding to the type I TNF receptor. It is not known if activation of this apoptotic pathway contributes to the well-documented\\u000a age-associated decline in muscle mass (i.e. sarcopenia). We tested the hypothesis that skeletal muscles from aged rodents\\u000a would exhibit

Emidio E. Pistilli; Janna R. Jackson; Stephen E. Alway

2006-01-01

325

Hydrogen peroxide produced inside mitochondria takes part in cell-to-cell transmission of apoptotic signal  

Microsoft Academic Search

In monolayer of HeLa cells treated with tumor necrosis factor (TNF), apoptotic cells formed clusters indicating possible transmission\\u000a of apoptotic signal via the culture media. To investigate this phenomenon, a simple method of enabling two cell cultures to\\u000a interact has been employed. Two coverslips were placed side by side in a Petri dish, one coverslip covered with apoptogen-treated\\u000a cells (the

O. Yu. Pletjushkina; E. K. Fetisova; K. G. Lyamzaev; O. Yu. Ivanova; L. V. Domnina; M. Yu. Vyssokikh; A. V. Pustovidko; A. V. Alexeevski; D. A. Alexeevski; J. M. Vasiliev; M. P. Murphy; B. V. Chernyak; V. P. Skulachev

2006-01-01

326

Lack of Effective Anti-Apoptotic Activities Restricts Growth of Parachlamydiaceae in Insect Cells  

PubMed Central

The fundamental role of programmed cell death in host defense is highlighted by the multitude of anti-apoptotic strategies evolved by various microbes, including the well-known obligate intracellular bacterial pathogens Chlamydia trachomatis and Chlamydia (Chlamydophila) pneumoniae. As inhibition of apoptosis is assumed to be essential for a successful infection of humans by these chlamydiae, we analyzed the anti-apoptotic capacity of close relatives that occur as symbionts of amoebae and might represent emerging pathogens. While Simkania negevensis was able to efficiently replicate within insect cells, which served as model for metazoan-derived host cells, the Parachlamydiaceae (Parachlamydia acanthamoebae and Protochlamydia amoebophila) displayed limited intracellular growth, yet these bacteria induced typical features of apoptotic cell death, including formation of apoptotic bodies, nuclear condensation, internucleosomal DNA fragmentation, and effector caspase activity. Induction of apoptosis was dependent on bacterial activity, but not bacterial de novo protein synthesis, and was detectable already at very early stages of infection. Experimental inhibition of host cell death greatly enhanced parachlamydial replication, suggesting that lack of potent anti-apoptotic activities in Parachlamydiaceae may represent an important factor compromising their ability to successfully infect non-protozoan hosts. These findings highlight the importance of the evolution of anti-apoptotic traits for the success of chlamydiae as pathogens of humans and animals. PMID:22253735

Sixt, Barbara S.; Hiess, Birgit; Konig, Lena; Horn, Matthias

2012-01-01

327

The Bcl-2 repertoire of mesothelioma spheroids underlies acquired apoptotic multicellular resistance  

PubMed Central

Three-dimensional (3D) cultures are a valuable platform to study acquired multicellular apoptotic resistance of cancer. We used spheroids of cell lines and actual tumor to study resistance to the proteasome inhibitor bortezomib in mesothelioma, a highly chemoresistant tumor. Spheroids from mesothelioma cell lines acquired resistance to bortezomib by failing to upregulate Noxa, a pro-apoptotic sensitizer BH3-only protein that acts by displacing Bim, a pro-apoptotic Bax/Bak-activator protein. Surprisingly, despite their resistance, spheroids also upregulated Bim and thereby acquired sensitivity to ABT-737, an inhibitor of anti-apoptotic Bcl-2 molecules. Analysis using BH3 profiling confirmed that spheroids acquired a dependence on anti-apoptotic Bcl-2 proteins and were ‘primed for death'. We then studied spheroids grown from actual mesothelioma. ABT-737 was active in spheroids grown from those tumors (5/7, ?70%) with elevated levels of Bim. Using immunocytochemistry of tissue microarrays of 48 mesotheliomas, we found that most (33, 69%) expressed elevated Bim. In conclusion, mesothelioma cells in 3D alter the expression of Bcl-2 molecules, thereby acquiring both apoptotic resistance and sensitivity to Bcl-2 blockade. Mesothelioma tumors ex vivo also show sensitivity to Bcl-2 blockade that may depend on Bim, which is frequently elevated in mesothelioma. Therefore, mesothelioma, a highly resistant tumor, may have an intrinsic sensitivity to Bcl-2 blockade that can be exploited therapeutically. PMID:21697949

Barbone, D; Ryan, J A; Kolhatkar, N; Chacko, A D; Jablons, D M; Sugarbaker, D J; Bueno, R; Letai, A G; Coussens, L M; Fennell, D A; Broaddus, V C

2011-01-01

328

Development of selective inhibitors for anti-apoptotic Bcl-2 proteins from BHI-1  

PubMed Central

A series of inhibitors for anti-apoptotic Bcl-2 proteins based on BHI-1 were synthesized and their binding interactions with Bcl-2, Bcl-XL, and Bcl-w were evaluated. It was found that modification of BHI-1 resulted in varied binding profiles among Bcl-2, Bcl-XL, and Bcl-w and a set of inhibitors with varied selectivity to Bcl-2, Bcl-XL, and Bcl-w protein have been identified. Molecular modeling of the interaction of the BHI-1 based analogs with the anti-apoptotic Bcl-2 proteins suggested that the binding site for the BHI-1 based inhibitor was the least conserved section among Bcl-2, Bcl-XL, and Bcl-w: targeting the non-conserved section may account for the observed selectivity of the BHI-1 based inhibitors among the anti-apoptotic Bcl-2 proteins. The validity of the model was supported by a strong correlation between the model-calculated binding energy and the experimental binding affinity. In summary, our studies suggest that most of the reported inhibitors for anti-apoptotic Bcl-2 proteins are nonselective and BHI-1 is a promising template to distinguish among Bcl-2, Bcl-XL, and Bcl-w by targeting the nonconserved domain among the anti-apoptotic Bcl-2 proteins. Molecular-modeling aided rational development of BHI-1 based selective inhibitor for anti-apoptotic Bcl-2 proteins is underway. PMID:17227711

Xing, Chengguo; Wang, Liangyou; Tang, XiaoHu; Sham, Yuk Y

2007-01-01

329

Long-term apoptotic cell death process with increased expression and activation of caspase-3 and -6 in adult rat germ cells exposed in utero to flutamide.  

PubMed

Although it is established that in utero exposure to antiandrogenic compounds such as flutamide induces hypospermatogenesis in adult male rat offspring, the cellular and molecular mechanisms remain to be investigated. By using adult rats exposed in utero to flutamide (0.4, 2, 10 mg/kg.d) as a model, we show that the hypospermatogenesis could be related to a chronic apoptotic cell death process associated with a long-term increase in caspase-3 and -6 expression and activation in germ cells. The number of apoptotic (terminal deoxynucleotidyl transferase-mediated deoxyuridine positive) adult germ cells was dependent on the dose of flutamide. The apoptotic germ cell death process could be related to an increased expression and activation of effector caspases-3 and -6. Procaspases-3 and -6 were immunodetected in germ cells from both untreated or flutamide-treated rats, whereas cleaved active caspase-3 was detected exclusively in germ cells from adult rat exposed in utero to flutamide. Exposure to the antiandrogen increased in a dose-dependent manner as caspase-3 and -6 mRNA (in RT-PCR approaches) as well as procaspase-3 and -6 protein (in Western blotting analyses) levels in the adult rat testis. Flutamide also activates procaspases. Indeed, whereas cleaved active caspase-3 and -6 proteins were absent in control animals, they were detected in adult rat testes exposed in utero to flutamide. Our results show that whereas the apoptotic germ cell death process associated with the increased caspase expression and activation in adult rat germ cells was chronic and nonreversible when exposure to flutamide occurred in utero, it was transient when such an exposure occurred during adulthood. Indeed, although an increase in caspase-3 and -6 mRNA and procaspase-3 and -6 protein levels was observed in germ cells after 3 d of exposure to flutamide, 1-2 wk after the cessation of the antiandrogen exposure, the caspase mRNA and procaspase protein levels were back to control. Active cleaved caspase-3 and -6 protein appeared following the exposure to the antiandrogen, whereas they disappeared at cessation of exposure to flutamide. In summary, the present findings indicate that in utero exposure to the antiandrogen induced in the adult rat testes a chronic apoptotic germ cell death associated with a long-term increase in the expression and activation in germ cells of caspases-3 and -6, two key components in the death machinery. PMID:12538628

Omezzine, Asma; Chater, Sonia; Mauduit, Claire; Florin, Anne; Tabone, Eric; Chuzel, Franck; Bars, Remi; Benahmed, Mohamed

2003-02-01

330

Regulation of the extrinsic and intrinsic apoptotic pathways in the prefrontal cortex of short- and long-term human opiate abusers.  

PubMed

Opiate addiction is a chronic medical disorder characterized by drug tolerance and dependence, behavioral sensitization, vulnerability to compulsive relapse, and high mortality. In laboratory animals, the potential effect of opiate drugs to induce cell death by apoptosis is a controversial topic. This postmortem human brain study examined the status of the extrinsic and intrinsic apoptotic pathways in the prefrontal cortex of a large group of well-characterized heroin or methadone abusers. In these subjects (n=36), the immunocontent of apoptosis-1 protein (Fas) death receptor did not differ from that in age-, gender-, and postmortem delay-matched controls. In contrast, Fas-associated protein with death domain (FADD), the mediator of the death signal, was significantly decreased in the same brain samples (all addicts: 30%, n=36; short-term abuse (ST): 31%, n=15; long-term abuse (LT): 29%, n=21). The initiator caspase-8 was not altered, but FLIP(L) (Fas-associated protein with death domain-like interleukin-1beta-converting enzyme-inhibitory protein), a dominant inhibitor of caspase-8, was increased in LT addicts (19%). In the intrinsic pathway, the pro-apoptotic mitochondrial proteins Bax (Bcl-2-associated X protein) and AIF (apoptosis-inducing factor) remained unchanged, but cytochrome c was decreased (all addicts: 25%; ST: 31%; LT: 20%) and anti-apoptotic B-cell leukemia 2 (Bcl-2) increased in LT addicts (24%). The content of executioner caspase-3 and the pattern of cleavage of the nuclear enzyme poly-(ADP-ribose)-polymerase-1 (PARP-1) were similar in opiate addicts and control subjects. Taken together, the data revealed that the extrinsic and intrinsic canonical apoptotic pathways are not abnormally activated in the prefrontal cortex of opiate abusers. Instead, the chronic modulation of some of their components (downregulation of FADD and cytochrome c; upregulation of FLIP(L) and Bcl-2) suggests the induction of non-apoptotic actions by opiate drugs related to phenomena of synaptic plasticity in the brain. These neurochemical adaptations could play a major role in the development of opiate tolerance, sensitization and relapse in human addicts. PMID:18834930

García-Fuster, M J; Ramos-Miguel, A; Rivero, G; La Harpe, R; Meana, J J; García-Sevilla, J A

2008-11-11

331

Silymarin modulates doxorubicin-induced oxidative stress, Bcl-xL and p53 expression while preventing apoptotic and necrotic cell death in the liver.  

PubMed

The emergence of silymarin (SMN) as a natural remedy for liver diseases, coupled with its entry into NIH clinical trial, signifies its hepatoprotective potential. SMN is noted for its ability to interfere with apoptotic signaling while acting as an antioxidant. This in vivo study was designed to explore the hepatotoxic potential of Doxorubicin (Dox), the well-known cardiotoxin, and in particular whether pre-exposures to SMN can prevent hepatotoxicity by reducing Dox-induced free radical mediated oxidative stress, by modulating expression of apoptotic signaling proteins like Bcl-xL, and by minimizing liver cell death occurring by apoptosis or necrosis. Groups of male ICR mice included Control, Dox alone, SMN alone, and Dox with SMN pre/co-treatment. Control and Dox groups received saline i.p. for 14 days. SMN was administered p.o. for 14 days at 16 mg/kg/day. An approximate LD(50) dose of Dox, 60 mg/kg, was administered i.p. on day 12 to animals receiving saline or SMN. Animals were euthanized 48 h later. Dox alone induced frank liver injury (>50-fold increase in serum ALT) and oxidative stress (>20-fold increase in malondialdehyde [MDA]), as well as direct damage to DNA (>15-fold increase in DNA fragmentation). Coincident genomic damage and oxidative stress influenced genomic stability, reflected in increased PARP activity and p53 expression. Decreases in Bcl-xL protein coupled with enhanced accumulation of cytochrome c in the cytosol accompanied elevated indexes of apoptotic and necrotic cell death. Significantly, SMN exposure reduced Dox hepatotoxicity and associated apoptotic and necrotic cell death. The effects of SMN on Dox were broad, including the ability to modulate changes in both Bcl-xL and p53 expression. In animals treated with SMN, tissue Bcl-xL expression exceeded control values after Dox treatment. Taken together, these results demonstrated that SMN (i) reduced, delayed onset, or prevented toxic effects of Dox which are typically associated with hydroxyl radical production, (ii) performed as an antioxidant limiting oxidative stress, (iii) protected the integrity of the genome, and (iv) antagonized apoptotic and necrotic cell death while increasing antiapoptotic Bcl-xL protein levels and minimizing the leakage of proapoptotic cytochrome c from liver mitochondria. These observations demonstrate the protective actions of SMN in liver, and raise the possibility that such protection may extend to other organs during Dox treatment including the heart. PMID:20144634

Patel, Nirav; Joseph, Cecil; Corcoran, George B; Ray, Sidhartha D

2010-06-01

332

MiR-630 inhibits proliferation by targeting CDC7 kinase, but maintains the apoptotic balance by targeting multiple modulators in human lung cancer A549 cells  

PubMed Central

MicroRNAome analyses have shown microRNA-630 (miR-630) to be involved in the regulation of apoptosis. However, its apoptotic role is still debated and its participation in DNA replication is unknown. Here, we demonstrate that miR-630 inhibits cell proliferation by targeting cell-cycle kinase 7 (CDC7) kinase, but maintains the apoptotic balance by targeting multiple activators of apoptosis under genotoxic stress. We identified a novel regulatory mechanism of CDC7 gene expression, in which miR-630 downregulated CDC7 expression by recognizing and binding to four binding sites in CDC7 3'-UTR. We found that miR-630 was highly expressed in A549 and NIH3T3 cells where CDC7 was downregulated, but lower in H1299, MCF7, MDA-MB-231, HeLa and 2BS cells where CDC7 was upregulated. Furthermore, the induction of miR-630 occurred commonly in a variety of human cancer and immortalized cells in response to genotoxic agents. Importantly, downregulation of CDC7 by miR-630 was associated with cisplatin (CIS)-induced inhibitory proliferation in A549 cells. Mechanistically, miR-630 exerted its inhibitory proliferation by blocking CDC7-mediated initiation of DNA synthesis and by inducing G1 arrest, but maintains apoptotic balance under CIS exposure. On the one hand, miR-630 promoted apoptosis by downregulation of CDC7; on the other hand, it reduced apoptosis by downregulating several apoptotic modulators such as PARP3, DDIT4, EP300 and EP300 downstream effector p53, thereby maintaining the apoptotic balance. Our data indicate that miR-630 has a bimodal role in the regulation of apoptosis in response to DNA damage. Our data also support the notion that a certain mRNA can be targeted by several miRNAs, and in particular an miRNA may target a set of mRNAs. These data afford a comprehensive view of microRNA-dependent control of gene expression in the regulation of apoptosis under genotoxic stress. PMID:25255219

Cao, J-X; Lu, Y; Qi, J-J; An, G-S; Mao, Z-B; Jia, H-T; Li, S-Y; Ni, J-H

2014-01-01

333

Extracellular matrix proteins modulate antimigratory and apoptotic effects of Doxorubicin.  

PubMed

Anticancer drug resistance is a multifactorial process that includes acquired and de novo drug resistances. Acquired resistance develops during treatment, while de novo resistance is the primary way for tumor cells to escape chemotherapy. Tumor microenvironment has been recently shown to be one of the important factors contributing to de novo resistance and called environment-mediated drug resistance (EMDR). Two forms of EMDR have been described: soluble factor-mediated drug resistance (SFM-DR) and cell adhesion-mediated drug resistance (CAM-DR). Anthracyclines, among the most potent chemotherapeutic agents, are widely used in clinics against hematopoietic and solid tumors. Their main mechanism of action relies on the inhibition of topoisomerase I and/or II and the induction of apoptosis. Beyond this well-known antitumor activity, it has been recently demonstrated that anthracyclines may display potent anti-invasive effects when used at subtoxic concentrations. In this paper, we will describe two particular modes of EMDR by which microenvironment may influence tumor-cell response to one of these anthracyclines, doxorubicin. The first one considers the influence of type I collagen on the antimigratory effect of doxorubicin (CAM-DR). The second considers the protection of tumor cells by thrombospondin-I against doxorubicin-induced apoptosis (SFM-DR). PMID:22811904

Said, Georges; Guilbert, Marie; Morjani, Hamid; Garnotel, Roselyne; Jeannesson, Pierre; El Btaouri, Hassan

2012-01-01

334

Extracellular Matrix Proteins Modulate Antimigratory and Apoptotic Effects of Doxorubicin  

PubMed Central

Anticancer drug resistance is a multifactorial process that includes acquired and de novo drug resistances. Acquired resistance develops during treatment, while de novo resistance is the primary way for tumor cells to escape chemotherapy. Tumor microenvironment has been recently shown to be one of the important factors contributing to de novo resistance and called environment-mediated drug resistance (EMDR). Two forms of EMDR have been described: soluble factor-mediated drug resistance (SFM-DR) and cell adhesion-mediated drug resistance (CAM-DR). Anthracyclines, among the most potent chemotherapeutic agents, are widely used in clinics against hematopoietic and solid tumors. Their main mechanism of action relies on the inhibition of topoisomerase I and/or II and the induction of apoptosis. Beyond this well-known antitumor activity, it has been recently demonstrated that anthracyclines may display potent anti-invasive effects when used at subtoxic concentrations. In this paper, we will describe two particular modes of EMDR by which microenvironment may influence tumor-cell response to one of these anthracyclines, doxorubicin. The first one considers the influence of type I collagen on the antimigratory effect of doxorubicin (CAM-DR). The second considers the protection of tumor cells by thrombospondin-I against doxorubicin-induced apoptosis (SFM-DR). PMID:22811904

Said, Georges; Guilbert, Marie; Morjani, Hamid; Garnotel, Roselyne; Jeannesson, Pierre; El Btaouri, Hassan

2012-01-01

335

Interactions of pro-apoptotic BH3 proteins with anti-apoptotic Bcl-2 family proteins measured in live MCF-7 cells using FLIM FRET  

PubMed Central

Increased interactions between pro-apoptotic BH3-only proteins and anti-apoptotic Bcl-2 family proteins at mitochondria result in tumor initiation, progression and resistance to traditional chemotherapy. Drugs that mimic the BH3 region are expected to release BH3-only proteins from anti-apoptotic proteins, inducing apoptosis in some cancer cells and sensitizing others to chemotherapy. Recently, we applied fluorescence lifetime imaging microscopy and fluorescence resonance energy transfer to measure protein:protein interactions for the Bcl-2 family of proteins in live MCF-7 cells using fluorescent fusion proteins. While the BH3-proteins bound to Bcl-XL and Bcl-2, the BH3 mimetic ABT-737 inhibited binding of only Bad and tBid, but not Bim. We have extended our studies by investigating ABT-263, a clinical drug based on ABT-737. We show that the inhibitory effects and pattern of the two drugs are comparable for both Bcl-XL and Bcl-2. Furthermore, we show that mutation of a conserved residue in the BH3 region in Bad and tBid disrupted their interactions with Bcl-XL and Bcl-2, while the corresponding BimEL mutant showed no decrease in binding to these anti-apoptotic proteins. Therefore, in MCF-7 cells, Bim has unique binding properties compared with other BH3-only proteins that resist displacement from Bcl-XL and Bcl-2 by BH3 mimetics. PMID:22895112

Liu, Qian; Leber, Brian; Andrews, David W.

2012-01-01

336

Caspase-dependant activation of chymotrypsin-like proteases mediates nuclear events during Jurkat T cell apoptosis  

SciTech Connect

Apoptosis involves a cascade of biochemical and morphological changes resulting in the systematic disintegration of the cell. Caspases are central mediators of this process. Supporting and primary roles for serine proteases as pro-apoptotic mediators have also been highlighted. Evidence for such roles comes largely from the use of pharmacological inhibitors; as a consequence information regarding their apoptotic function and biochemical properties has been limited. Here, we circumvented limitations associated with traditional serine protease inhibitors through use of a fluorescently labelled inhibitor of serine proteases (FLISP) that allowed for analysis of the specificity, regulation and positioning of apoptotic serine proteases within a classical apoptotic cascade. We demonstrate that staurosporine triggers a caspase-dependant induction of chymotrypsin-like activity in the nucleus of apoptotic Jurkat T cells. We show that serine protease activity is required for the generation of late stage nuclear events including condensation, fragmentation and DNA degradation. Furthermore, we reveal caspase-dependant activation of two chymotrypsin-like protein species that we hypothesize mediate cell death-associated nuclear events.

O'Connell, A.R. [National Centre for Biomedical Engineering Science, National University of Ireland, Galway (Ireland); Lee, B.W. [Immunochemistry Technologies LLC., 9401 James Avenue South Suite 155, Bloomington, MN 55431 (United States); Stenson-Cox, C. [National Centre for Biomedical Engineering Science, National University of Ireland, Galway (Ireland)]. E-mail: catherine.stenson@nuigalway.ie

2006-06-30

337

Effect of apoptotic cell recognition on macrophage polarization and mycobacterial persistence.  

PubMed

Intracellular Mycobacterium leprae infection modifies host macrophage programming, creating a protective niche for bacterial survival. The milieu regulating cellular apoptosis in the tissue plays an important role in defining susceptible and/or resistant phenotypes. A higher density of apoptotic cells has been demonstrated in paucibacillary leprosy lesions than in multibacillary ones. However, the effect of apoptotic cell removal on M. leprae-stimulated cells has yet to be fully elucidated. In this study, we investigated whether apoptotic cell removal (efferocytosis) induces different phenotypes in proinflammatory (M?1) and anti-inflammatory (M?2) macrophages in the presence of M. leprae. We stimulated M?1 and M?2 cells with M. leprae in the presence or absence of apoptotic cells and subsequently evaluated the M. leprae uptake, cell phenotype, and cytokine pattern in the supernatants. In the presence of M. leprae and apoptotic cells, M?1 macrophages changed their phenotype to resemble the M?2 phenotype, displaying increased CD163 and SRA-I expression as well as higher phagocytic capacity. Efferocytosis increased M. leprae survival in M?1 cells, accompanied by reduced interleukin-15 (IL-15) and IL-6 levels and increased transforming growth factor beta (TGF-?) and IL-10 secretion. M?1 cells primed with M. leprae in the presence of apoptotic cells induced the secretion of Th2 cytokines IL-4 and IL-13 in autologous T cells compared with cultures stimulated with M. leprae or apoptotic cells alone. Efferocytosis did not alter the M?2 cell phenotype or cytokine secretion profile, except for TGF-?. Based on these data, we suggest that, in paucibacillary leprosy patients, efferocytosis contributes to mycobacterial persistence by increasing the M?2 population and sustaining the infection. PMID:25024361

de Oliveira Fulco, Tatiana; Andrade, Priscila Ribeiro; de Mattos Barbosa, Mayara Garcia; Pinto, Thiago Gomes Toledo; Ferreira, Paula Fernandez; Ferreira, Helen; da Costa Nery, José Augusto; Real, Suzana Côrte; Borges, Valéria Matos; Moraes, Milton Ozório; Sarno, Euzenir Nunes; Sampaio, Elizabeth Pereira; Pinheiro, Roberta Olmo

2014-09-01

338

Sigma-2 receptor agonists activate a novel apoptotic pathway and potentiate antineoplastic drugs in breast tumor cell lines.  

PubMed

We have reported previously that sigma-2 receptors are expressed in high densities in a variety of tumor cell types (B. J. Vilner et al., Cancer Res., 55: 408-413, 1995) and that various sigma ligands have cytotoxic effects (B. J. Vilner et al., J. Neurosci., 15: 117-134, 1995). Other investigators have demonstrated increased expression of sigma-2 receptors in rapidly proliferating tumors (R. H. Mach et al., Cancer Res., 57: 156-161, 1997) and the ability of some sigma ligands to inhibit proliferation (P. J. Brent and G. T. Pang, Eur. J. Pharmacol., 278: 151-160, 1995). We demonstrate here the ability of sigma-2 receptor agonists to induce cell death by a mechanism consistent with apoptosis. In breast tumor cell lines that are sensitive (MCF-7) and resistant (MCF-7/Adr-, T47D, and SKBr3) to antineoplastic agents, incubation with the sigma-2 subtype-selective agonists CB-64D and CB-184 produced dose-dependent cytotoxicity (measured by lactate dehydrogenase release into medium). The EC(50) for this response was similar across cell lines, irrespective of p53 genotype and drug-resistance phenotype. CB-64D and the subtype nonselective sigma-2 agonists haloperidol and reduced haloperidol induced terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining in MCF-7 and T47D cells, indicating that cell death occurs via apoptosis. Apoptosis was also indicated by increases in Annexin V binding caused by CB-64D. In MCF-7 cells, cytotoxicity and Annexin V binding induced by the antineoplastics doxorubicin and actinomycin D was partially or completely abrogated by certain specific and general inhibitors of caspases. In contrast, caspase inhibitors had no effect on sigma-2 receptor-mediated (CB-64D and CB-184) cytotoxicity or Annexin V binding. Marked potentiation of cytotoxicity was observed when a subtoxic dose of CB-184 was combined with doxorubicin or actinomycin D, both in drug-sensitive (MCF-7) and drug-resistant (MCF-7/Adr-) cell lines. Haloperidol potentiated doxorubicin only in drug-resistant cells. These findings suggest the involvement of a novel p53- and caspase-independent apoptotic pathway used by sigma-2 receptors, which is distinct from mechanisms used by some DNA-damaging, antineoplastic agents and other apoptotic stimuli. These observations further suggest that sigma-2 receptors may be targets that can be therapeutically exploited in the treatment of both drug-sensitive and drug-resistant metastatic tumors. PMID:11782394

Crawford, Keith W; Bowen, Wayne D

2002-01-01

339

Is there a common upstream link for autophagic and apoptotic cell death in human high-grade gliomas?  

PubMed Central

The prognosis of patients with human high-grade gliomas (HGGs) remains dismal despite major advances in their management, due mainly to the high resistance of these infiltrative tumor cells to programmed cell death (PCD). Most therapeutic strategies for HGGs are aimed to maximize PCD type I, apoptosis or type II, autophagy. These are predominantly distinctive processes, but many studies suggest a cross-talk between the two. A better understanding of the link between PCD types I and II might allow development of more effective therapies for HGGs. In this study, we examined whether there is a common upstream signaling event responsible for both apoptotic and autophagic PCD using 3 chemotherapeutic agents in human HGG cells. Our study shows that each agent caused a significant decrease in cell viability in each of the HGG cell lines tested. The increase rate of apoptosis and autophagy varied among cell lines and chemotherapeutic agents used. Increased expression of cytidine-cytidine-adenosine-adenosine-thymidine (C)/enhancer binding protein (EBP) homologous transcription factor C/EBP homologous protein (CHOP)/growth arrest and DNA damage–inducible gene 153 (GADD153) was documented after use of either pro-autophagic or pro-apoptotic agents. The involvement of CHOP/GADD153 in both type I and type II PCD was confirmed by overexpression and gene-silencing studies. Gene silencing by small-interfering RNA–mediated CHOP/GADD153 resulted in increased cell viability, decreased upregulation of microtubule-associated protein light-chain 3? type II (LC3II) and cleaved caspase-3, and inhibition of apoptosis and autophagy. Exogenous expression of CHOP/GADD153 triggered apoptosis and autophagy in the absence of other stimuli. The clinical significance of these findings was supported by the evidence that celecoxib, a nonsteroidal anti-inflammatory drug known to induce GADD153-mediated apoptosis, strongly increases both type I and type II PCD in HGG cells when combined with another inducer of GADD153. These data suggest that CHOP/GADD153 should be investigated as a novel targetable signaling step to improve therapies for HGGs. PMID:21727211

Emdad, Luni; Qadeer, Zulekha A.; Bederson, Lucia B.; Kothari, Harini P.; Uzzaman, Mahmud; Germano, Isabelle M.

2011-01-01

340

The N-terminus and alpha-5, alpha-6 helices of the pro-apoptotic protein Bax, modulate functional interactions with the anti-apoptotic protein Bcl-xL  

Microsoft Academic Search

BACKGROUND: Bcl-2 family proteins are key regulators of mitochondrial integrity and comprise both pro- and anti-apoptotic proteins. Bax a pro-apoptotic member localizes as monomers in the cytosol of healthy cells and accumulates as oligomers in mitochondria of apoptotic cells. The Bcl-2 homology-3 (BH3) domain regulates interactions within the family, but regions other than BH3 are also critical for Bax function.

Neha Parikh; Caroline Koshy; Vaigundan Dhayabaran; Lakshmi R Perumalsamy; R Sowdhamini; Apurva Sarin

2007-01-01

341

Phosphorylation Drives an Apoptotic Protein to Activate Antiapoptotic Genes  

PubMed Central

During infection, viral proteins target cellular pathways that regulate cellular innate immune responses and cell death. We demonstrate that influenza A virus matrix 1 protein (M1), an established proapoptotic protein, activates nuclear factor-?B member RelB-mediated survival genes (cIAP1, cIAP2, and cFLIP), a function that is linked with its nuclear translocation during early infection. Death domain-associated protein 6 (Daxx) is a transcription co-repressor of the RelB-responsive gene promoters. During influenza virus infection M1 binds to and stabilizes Daxx protein by preventing its ubiquitination and proteasomal degradation. Binding of M1 with Daxx through its Daxx binding motif prevents binding of RelB and Daxx, resulting in up-regulation of survival genes. This interaction also prevents promoter recruitment of DNA methyltransferases (Dnmt1 and Dnmt3a) and lowers CpG methylation of the survival gene promoters, leading to the activation of these genes. Thus, M1 prevents repressional function of Daxx during infection, thereby exerting a survival role. In addition to its nuclear localization signal, translocation of M1 to the nucleus depends on cellular kinase-mediated phosphorylation as the protein kinase C inhibitor calphostin C effectively down-regulates virus replication. The study reconciles the ambiguity of dual antagonistic function of viral protein and potentiates a possible target to limit virus infection. PMID:23548901

Halder, Umesh Chandra; Bhowmick, Rahul; Roy Mukherjee, Tapasi; Nayak, Mukti Kant; Chawla-Sarkar, Mamta

2013-01-01

342

Evidence for a novel anti-apoptotic pathway in human keratinocytes involving the aryl hydrocarbon receptor, E2F1, and checkpoint kinase 1  

PubMed Central

Exposure of keratinocytes (KC) to ultraviolet (UV) radiation results in the initiation of apoptosis, a protective mechanism that eliminates cells harboring irreparable DNA damage. Hence, a manipulation of UV-induced apoptosis may significantly influence photocarcinogenesis. We have discovered that the aryl hydrocarbon receptor (AHR), a key regulator of drug metabolism and an UVB-sensitive transcription factor, serves an anti-apoptotic function in UVB-irradiated human KC. Chemical and shRNA-mediated inhibition of AHR signaling sensitized KC to UVB-induced apoptosis by decreasing the expression of E2F1 and its target gene checkpoint kinase 1 (CHK1). The decreased expression of these cell-cycle regulators was due to an enhanced expression of p27KIP1 and an associated decrease in phosphorylation of both cyclin-dependent kinase 2 and its substrate molecule retinoblastoma protein. The subsequent inhibition of E2F1 autoregulation and downstream CHK1 expression resulted in an enhanced susceptibility of damaged cells to undergo apoptosis. Accordingly, ectopic overexpression of either E2F1 or CHK1 in AHR-knockdown KC attenuated the observed sensitization to UVB-induced apoptosis. Using an AHR-knockout SKH-1 hairless mouse model, we next demonstrated the physiological relevance of the anti-apoptotic function of AHR. In contrast to their AHR-proficient littermates, the constitutive expression of E2F1 and CHK1 was significantly reduced in the skin of AHR-knockout mice. Accordingly, a single exposure of the animals to UVB resulted in an enhanced cleavage of caspase-3 in the skin of AHR-knockout mice. These results identify for the first time the AHR-E2F1-CHK1 axis as a novel anti-apoptotic pathway in KC, which may represent a suitable target for chemoprevention of non-melanoma skin cancer. PMID:23912710

Frauenstein, K; Sydlik, U; Tigges, J; Majora, M; Wiek, C; Hanenberg, H; Abel, J; Esser, C; Fritsche, E; Krutmann, J; Haarmann-Stemmann, T

2013-01-01

343

Acetylcholinesterase (AChE) is an important link in the apoptotic pathway induced by hyperglycemia in Y79 retinoblastoma cell line  

PubMed Central

Acetylcholinesterase (AChE) expression was found to be induced in the mammalian CNS, including the retina, by different types of stress leading to cellular apoptosis. Here, we tested possible involvement of AChE in hyperglycemia-induced apoptosis in a retinal cell line. Y79 retinoblastoma cells were incubated in starvation media (1% FBS and 1 mg/ml glucose) for 16–24 h, and then exposed to hyperglycemic environment by raising extracellular glucose concentrations to a final level of 3.5 mg/ml or 6 mg/ml. Similar levels of mannitol were used as control for hyperosmolarity. Cells were harvested at different time intervals for analysis of apoptosis and AChE protein expression. Apoptosis was detected by the cleavage of Poly ADP-ribose polymerase (PARP) using western blot, and by Terminal deoxynucleotidyl-transferase-mediated dUTP nick-end-labeling (TUNEL) assay. AChE protein expression and activity was detected by western blot and by the Karnovsky and Roots method, respectively. MissionTM shRNA for AChE was used to inhibit AChE protein expression. Treating Y79 cells with 3.5 mg/ml of glucose, but not with 3.5 mg/ml mannitol, induced apoptosis which was confirmed by TUNEL assay and by cleavage of PARP. A part of the signaling pathway accompanying the apoptotic process involved up-regulation of the AChE-R variant and an N-extended AChE variant as verified at the mRNA and protein level. Inhibition of AChE protein expression by shRNA protected Y79 cell from entering the apoptotic pathway. Our data suggest that expression of an N-extended AChE variant, most probably an R isoform, is involved in the apoptotic pathway caused by hyperglycemia in Y79 cells. PMID:22685426

Masha'our, R. Shehadeh; Heinrich, R.; Garzozi, H. J.; Perlman, I.

2012-01-01

344

Nanosecond pulsed electric fields induce poly(ADP-ribose) formation and non-apoptotic cell death in HeLa S3 cells  

SciTech Connect

Highlights: •Nanosecond pulsed electric field (nsPEF) is a new and unique means for life sciences. •Apoptosis was induced by nsPEF exposure in Jurkat cells. •No signs of apoptosis were detected in HeLa S3 cells exposed to nsPEFs. •Formation of poly(ADP-ribose) was induced in nsPEF-exposed HeLa S3 cells. •Two distinct modes of cell death were activated by nsPEF in a cell-dependent manner. -- Abstract: Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs.

Morotomi-Yano, Keiko; Akiyama, Hidenori [Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan)] [Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan); Yano, Ken-ichi, E-mail: yanoken@kumamoto-u.ac.jp [Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-8555 (Japan)] [Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-8555 (Japan)

2013-08-30

345

Cigarette smoke impairs phagocytosis of apoptotic neutrophils by alveolar macrophages via inhibition of the histone deacetylase/Rac/CD9 pathways.  

PubMed

Efferocytosis, which is the homeostatic phagocytosis of apoptotic cells, prevents the release of toxic intracellular contents and subsequent tissue damage. Impairment of efferocytosis was reported in alveolar macrophages (AMs) of patients with chronic obstructive pulmonary disease (COPD), a common disease caused by smoking. In COPD, histone deacetylase (HDAC) activity is reduced in AMs. We investigated whether the reduction of HDAC activity is associated with the impairment of efferocytosis. Murine AMs were collected by bronchoalveolar lavage and their ability to efferocytose apoptotic human polymorphonuclear leukocytes was assessed. Pre-treatment of AMs with cigarette smoke extract (CSE) or trichostatin A (TSA), an HDAC inhibitor, suppressed efferocytosis and CSE reduced HDAC activity. TSA inhibited the activity of Rac, a key mediator of efferocytosis. These TSA-induced impairments were restored by treatment of AMs with aminophylline, a potent activator of HDAC. To further elucidate the underlying mechanism, we explored a role of CD9 in TSA-induced impairment of efferocytosis. CD9 is a transmembrane protein of the tetraspanin family that facilitates the uptake of several pathogens and other material. TSA profoundly down-regulated the expression of CD9 on AMs. The expression of CD9 was partly down-regulated by the Rac inhibitor. Pretreatment with an anti-CD9 mAb or CD9 small interfering RNA inhibited efferocytosis, which was attributable to the reduced binding of AMs to apoptotic cells. These results suggest that smoking impairs efferocytosis via inhibition of HDAC/Rac/CD9 pathways. Aminophylline/theophylline is effective in restoring the impairment of efferocytosis and might have benefit for the treatment of patients with COPD. PMID:23988617

Noda, Naotaka; Matsumoto, Koichiro; Fukuyama, Satoru; Asai, Yukari; Kitajima, Hiroko; Seki, Nanae; Matsunaga, Yuko; Kan-O, Keiko; Moriwaki, Atsushi; Morimoto, Konosuke; Inoue, Hiromasa; Nakanishi, Yoichi

2013-11-01

346

Sinulariolide induced hepatocellular carcinoma apoptosis through activation of mitochondrial-related apoptotic and PERK/eIF2?/ATF4/CHOP pathway.  

PubMed

Sinulariolide, an active compound isolated from the cultured soft coral Sinularia flexibilis, has potent anti-microbial and anti-tumorigenesis effects towards melanoma and bladder cancer cells. In this study, we investigated the effects of sinulariolide on hepatocellular carcinoma (HCC) cell growth and protein expression. Sinulariolide suppressed the proliferation and colony formation of HCC HA22T cells in a dose-dependent manner and induced both early and late apoptosis according to flow cytometry, Annexin V/PI stain and TUNEL/DAPI stain analyses. A mechanistic analysis demonstrated that sinulariolide-induced apoptosis was activated through a mitochondria-related pathway, showing up-regulation of Bax, Bad and AIF, and down- regulation of Bcl-2, Bcl-xL, MCl-1 and p-Bad. Sinulariolide treatment led to loss of the mitochondrial membrane potential, release of mitochondrial cytochrome c to the cytosol, and activation of both caspase-9 and caspase-3. Sinulariolide-induced apoptosis was significantly blocked by the caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK. The increased expression of cleaved PARP also suggested that caspase-independent apoptotic pathway was involved. In the western blotting; the elevation of ER chaperones GRP78; GRP94; and CALR; as well as up-regulations of PERK/eIF2?/ATF4/CHOP; and diminished cell death with pre-treatment of eIF2? phosphatase inhibitor; salubrinal; implicated the involvement of ER stress-mediated PERK/eIF2?/ATF4/CHOP apoptotic pathway following sinulariolide treatment in hepatoma cells. The current study suggested sinulariolide-induced hepatoma cell cytotoxicity involved multiple apoptotic signal pathways. This may implicate that sinulariolide is a potential compound for the treatment of hepatocellular carcinoma. PMID:23973991

Chen, Yi-Jen; Su, Jui-Hsin; Tsao, Chia-Yu; Hung, Chun-Tzu; Chao, Hsiang-Hao; Lin, Jen-Jie; Liao, Ming-Hui; Yang, Zih-Yan; Huang, Han Hisang; Tsai, Feng-Jen; Weng, Shun-Hsiang; Wu, Yu-Jen

2013-01-01

347

EGFRvIII-Induced Estrogen-Independence, Tamoxifen-Resistance Phenotype Correlates with PgR expression and Modulation of Apoptotic Molecules in Breast Cancer  

PubMed Central

The tumor specific, ligand-independent, constitutively active Epidermal Growth Factor Receptor (EGFR) variant, EGFRvIII, remains understudied in breast cancer. Here, we report that expression of EGFRvIII in the ErbB-2-overexpressing, estrogen-dependent MDA-MB-361 breast cancer cell line resulted in significant estrogen-independent tumor growth in ovariectomized, athymic nude mice in comparison to MDA-MB-361/wt cells. MDA-MB-361/vIII breast cancer cells maintained estrogen-induced tumor growth, but were tamoxifen-resistant in the presence of estrogen, while MDA-MB-361/wt cells had a significant reduction in tumor growth in the presence of estrogen and tamoxifen. Tamoxifen alone did not have a significant effect on EGFRvIII-mediated estrogen-independent tumor growth. Constitutive signaling from the EGFRvIII receptor resulted in increased activation of both the Akt and MAPK pathways. Compared to estrogen-dependent, tamoxifen-sensitive MCF-7/vIII breast cancer cells, which had unchanged levels of ER?, but an increase in progesterone receptor (PgR) in comparison to MCF-7/wt cells, MDA-MB-361/vIII cells had a reduction in ER? expression as well as a more pronounced reduction in progesterone receptor (PgR) compared to MDA-MB-361/wt cells. EGFRvIII expression was also significantly associated with an absence of PgR protein in invasive human breast cancer specimens. Alterations of pro-apoptotic proteins and anti-apoptotic proteins were observed in EGFRvIII transfectants. In conclusion, constitutive signaling through EGFRvIII and its down-stream effector proteins crosstalks with the ER? pathway, resulting in loss of PgR expression and alterations in the apoptotic pathway which may result in the estrogen-independent, tamoxifen-resistant phenotype conferred to EGFRvIII-expressing breast cancer cells. PMID:19588487

Zhang, Yang; Su, Hua; Rahimi, Massod; Tochihara, Ryan; Tang, Careen

2009-01-01

348

Antiproliferative and apoptotic effects of telmisartan in human colon cancer cells  

PubMed Central

Telmisartan is an angiotensin I (AT1) receptor blocker used in the treatment of essential hypertension, with partial peroxisome proliferator-activated receptor ? (PPAR?) agonism. In prior studies, PPAR? activation led to apoptosis and cell cycle inhibition in various cancer cells. The aim of the present study was to investigate the potential antiproliferative and apoptotic effects of telmisartan by partially activating PPAR?. HT-29, SW-480 and SW-620 cells were incubated with telmisartan (0.2–5 ?M) or the full agonist, pioglitazone (0.2–5.0 ?M). The antiproliferative and apoptotic effects of telmisartan in the human colon cancer cells were significant at therapeutic serum concentrations, and telmisartan exhibited a potency at least equivalent to the full PPAR? agonist, pioglitazone. The antiproliferative and apoptotic effects of pioglitazone in the human colon cancer cells were not completely deregulated by PPAR? blockade with GW9662. In the telmisartan-treated cells, PPAR? blockade resulted in an increased antiproliferative and apoptotic effect. These effects are not entirely explained by PPAR? activation, however, possible hypotheses that require further experimental investigation are as follows: i) Ligand-independent PPAR? activation through the activation-function 1 domain; ii) a PPAR?-independent mechanism; or iii) independent antiproliferative and apoptotic effects through GW9662. PMID:25360175

LEE, LUCAS D.; MAFURA, BENJAMIN; LAUSCHER, JOHANNES C.; SEELIGER, HENDRIK; KREIS, MARTIN E.; GRONE, JORN

2014-01-01

349

Allogeneic apoptotic thymocyte-stimulated dendritic cells expand functional regulatory T cells  

PubMed Central

Dendritic cells (DCs) play an important role in the clearance of apoptotic cells. The removal of apoptotic cells leads to peripheral tolerance, although their role is still not clear. We show that the uptake of apoptotic thymocytes by DCs converts these cells into tolerogenic DCs resistant to maturation by lipopolysaccharide, modulating the production of interleukin-12 and up-regulating the expression of transforming growth factor-?1 latency associated peptide. We also observed that DCs pulsed with apoptotic cells in the allogeneic context were more efficient in the expansion of regulatory T cells (Tregs), and that this expansion requires contact between DCs and the T cell. The Tregs sorted from in vitro culture suppressed the proliferation of splenocytes in vitro in a specific and non-specific manner. In the in vivo model, the transfer of CD4+ CD25? cells to Nude mice induced autoimmunity, with cell infiltrate found in the stomach, colon, liver and kidneys. The co-transfer of CD4+ CD25? and CD4+ CD25+ prevented the presence of cell infiltrates in several organs and increased the total cell count in lymph nodes. Our data indicate that apoptotic cells have an important role in peripheral tolerance via induction of tolerogenic DCs and CD4+ CD25+ Foxp3+ cells that present regulatory functions. PMID:21355864

da Costa, Thais Boccia; Sardinha, Luiz R; Larocca, Rafael; Peron, Jean P S; Rizzo, Luiz V

2011-01-01

350

Number of apoptotic cells as a prognostic marker in invasive breast cancer  

PubMed Central

Apoptosis plays an important role in tumorigenesis. Tumour growth is determined by the rate of cell proliferation and cell death. We counted the number of apoptotic cells in haematoxylin and eosin (H&E)-stained tumour sections in series of 172 grade I and II invasive breast cancers with long-term follow-up. The number of apoptotic cells in ten high-power fields were converted to the number of apoptotic cells per mm2to obtain the apoptotic index (AI). The AI showed a positive correlation to the mitotic activity index (MAI) (P = 0.0001), histological grade (P< 0.0001) and worse tumour differentiation. Patients with high AI showed shorter overall survival than patients with low AI in the total group as well as in the lymph node-positive group. Tumour size, MAI, lymph node status and AI were independent prognostic indicators in multivariate analysis. The AI was shown to be of additional prognostic value to the MAI in the total patients group as well as in the lymph node-positive group. The correlation between the AI and the MAI points to linked mechanisms of apoptosis and proliferation. Since apoptotic cells can be counted with good reproducibility in H&E-stained tumour sections, the AI may be used as an additional prognostic indicator in invasive breast cancer. © 2000 Cancer Research Campaign PMID:10646890

Jong, J S de; Diest, P J van; Baak, J P A

2000-01-01

351

Selection of Apoptotic Cell Specific Human Antibodies from Adult Bone Marrow  

PubMed Central

Autoreactive antibodies that recognize neo-determinants on apoptotic cells in mice have been proposed to have protective, homeostatic and immunoregulatory properties, although our knowledge about the equivalent antibodies in humans has been much more limited. In the current study, human monoclonal antibodies with binding specificity for apoptotic cells were isolated from the bone marrow of healthy adults using phage display technology. These antibodies were shown to recognize phosphorylcholine (PC)-associated neo-determinants. Interestingly, three of the four identified apoptotic cell-specific antibody clones were encoded by VH3 region rearrangements with germline or nearly germline configuration without evidence of somatic hypermutation. Importantly, the different identified antibody clones had diverse heavy chain CDR3 and deduced binding surfaces as suggested by structure modeling. This may suggest a potentially great heterogeneity in human antibodies recognizing PC-related epitopes on apoptotic cells. To re-construct the postulated structural format of the parental anti-PC antibody, the dominant clone was also expressed as a recombinant human polymeric IgM, which revealed a substantially increased binding reactivity, with dose-dependent and antigen-inhibitable binding of apoptotic cells. Our findings may have implication for improved prognostic testing and therapeutic interventions in human inflammatory disease. PMID:24760047

Gronwall, Caroline; Charles, Edgar D.; Dustin, Lynn B.; Rader, Christoph; Silverman, Gregg J.

2014-01-01

352

Transition from Caspase-dependent to Caspase-independent Mechanisms at the Onset of Apoptotic Execution  

PubMed Central

We have compared cytoplasmic extracts from chicken DU249 cells at various stages along the apoptotic pathway. Extracts from morphologically normal “committed stage” cells induce apoptotic morphology and DNA cleavage in substrate nuclei but require ongoing caspase activity to do so. In contrast, extracts from frankly apoptotic cells induce apoptotic events in added nuclei in a caspase-independent manner. Biochemical fractionation of these extracts reveals that a column fraction enriched in endogenous active caspases is unable to induce DNA fragmentation or chromatin condensation in substrate nuclei, whereas a caspase-depleted fraction induces both changes. Further characterization of the “execution phase” extracts revealed the presence of an ICAD/DFF45 (inhibitor of caspase-activated DNase/DNA fragmentation factor)- inhibitable nuclease resembling CAD, plus another activity that was required for the apoptotic chromatin condensation. Despite the presence of active caspases, committed stage extracts lacked these downstream activities, suggesting that the caspases and downstream factors are segregated from one another in vivo during the latent phase. These observations not only indicate that caspases act in an executive fashion, serving to activate downstream factors that disassemble the nucleus rather than disassembling it themselves, but they also suggest that activation of the downstream factors (rather than the caspases) is the critical event that occurs at the transition from the latent to active phase of apoptosis. PMID:9763434

Samejima, Kumiko; Toné, Shigenobu; Kottke, Timothy J.; Enari, Masato; Sakahira, Hideki; Cooke, Carol A.; Durrieu, Françoise; Martins, Luis M.; Nagata, Shigekazu; Kaufmann, Scott H.; Earnshaw, William C.

1998-01-01

353

NOD macrophages produce high levels of inflammatory cytokines upon encounter of apoptotic or necrotic cells.  

PubMed

During the development of type 1 diabetes, pancreatic beta-cells are subject to an immune attack, leading to their apoptotic or necrotic cell death. Apoptotic beta-cells are also present during periods of tissue remodeling, such as in early life. Macrophages should clear apoptotic cells silently without production of pro-inflammatory cytokines. The aim of the present study was to investigate the cytokine pattern of NOD macrophages exposed to apoptotic or necrotic cells in vitro. In contrast to the limited response of macrophages from C57BL/6 or NOR mice, NOD macrophages reacted aberrantly to both necrotic and apoptotic cells, with secretion of inappropriately high amounts of IL1beta and TNFalpha. Further exploration of the macrophage behavior showed an excessive response of NOD macrophages when exposed to LPS (high iNOS and IL12p40 levels), accompanied by hyper-activation of NF-kappaB(p65). In contrast, NOD macrophages failed to up-regulate IL1beta and IL12p40 in response to IFNgamma. This failure correlated with low protein levels and a low phosphorylation state of STAT1alpha. We conclude that NOD macrophages have severely aberrant cytokine expression patterns that could contribute to the initiation or continuation of an immune attack towards the pancreatic beta-cells and thus onset and progression of type 1 diabetes. PMID:15236748

Stoffels, K; Overbergh, L; Giulietti, A; Kasran, A; Bouillon, R; Gysemans, C; Mathieu, C

2004-08-01

354

The TIM and TAM Families of Phosphatidylserine Receptors Mediate Dengue Virus Entry  

PubMed Central

SUMMARY Dengue viruses (DVs) are responsible for the most medically relevant arboviral diseases. However, the molecular interactions mediating DV entry are poorly understood. We determined that TIM and TAM proteins, two receptor families that mediate the phosphatidylserine (PtdSer)-dependent phagocytic removal of apoptotic cells, serve as DV entry factors. Cells poorly susceptible to DV are robustly infected after ectopic expression of TIM or TAM receptors. Conversely, DV infection of susceptible cells is inhibited by anti-TIM or anti-TAM antibodies or knockdown of TIM and TAM expression. TIM receptors facilitate DV entry by directly interacting with virion-associated PtdSer. TAM-mediated infection relies on indirect DV recognition, in which the TAM ligand Gas6 acts as a bridging molecule by binding to PtdSer within the virion. This dual mode of virus recognition by TIM and TAM receptors reveals how DVs usurp the apoptotic cell clearance pathway for infectious entry. PMID:23084921

Meertens, Laurent; Carnec, Xavier; Lecoin, Manuel Perera; Ramdasi, Rasika; Guivel-Benhassine, Florence; Lew, Erin; Lemke, Greg; Schwartz, Olivier; Amara, Ali

2013-01-01

355

Visualization of proteolytic activity associated with the apoptotic response in cancer cells  

NASA Astrophysics Data System (ADS)

Caspases execute programmed cell death, where low levels of caspase activity are linked to cancer. Chemotherapies utilize induction of apoptosis as a key mechanism for cancer treatment, where caspase-3 is a major player involved in dismantling these aberrant cells. The ability to sensitively measure the initial caspase-3 cleavage events during apoptosis is important for understanding the initiation of this complex cellular process, however, current ensemble methods are not sensitive enough to measure single cleavage events in cells. By utilizing the optical properties of plasmon coupling, peptide-linked gold nanoparticles were developed to enable single molecule imaging of caspase-3 activity in two different cancer systems. Au crown nanoparticles were assembled in a multimeric fashion to overcome the high and heterogeneous background scattering of live cells. In a colon cancer (SW620) cell line challenged with tumor necrosis factor-alpha (TNF-alpha), single molecule trajectories show early stage caspase-3 activation within minutes, which was not detectable by ensemble assays until 23 hours. Variability in caspase-3 activation among the population of cells was identified and likely a result of each cell's specific resistance to death receptor-induced apoptosis. Following these studies, improvements by way of sensitivity and selectivity were tailored into an improved nanosensor construct. Au nanoshell dimers were prepared as a comparably bright construct with 1) reduced heterogeneity compared to the synthesis of the crown nanoparticles and 2) a peptide sequence highly selective for caspase-3. Chronic myeloid leukemia (CML) K562 cells were assessed for their early apoptotic response upon treatment with dasatinib, a clinically approved tyrosine kinase inhibitor that specifically targets BCR-ABL. It has been demonstrated that inhibition of BCR-ABL by dasatinib commits K562 cells to apoptosis. Single molecule experiments with Au nanoshell dimers show caspase-3 activation as early as 8 hours than previously reported. This suggests an early commitment to apoptosis that precedes the competing fate of growth factor mediated survival in CML patient-derived BCR-ABL cells. These nanosensors are sensitive and selective in observing caspase-3 activation compared to ensemble methods; and allow the possibility to detect caspase-3 activity for use as a drug screening or diagnostic tool for personalized care in the treatment of cancer.

Tice, Brian George

356

Perturbation of sphingolipid metabolism induces endoplasmic reticulum stress-mediated mitochondrial apoptosis in budding yeast.  

PubMed

Sphingolipids are a class of membrane lipids conserved from yeast to mammals which determine whether a cell dies or survives. Perturbations in sphingolipid metabolism cause apoptotic cell death. Recent studies indicate that reduced sphingolipid levels trigger the cell death, but little is known about the mechanisms. In the budding yeast Saccharomyces cerevisiae, we show that reduction in complex sphingolipid levels causes loss of viability, most likely due to the induction of mitochondria-dependent apoptotic cell death pathway, accompanied by changes in mitochondrial and endoplasmic reticulum morphology and endoplasmic reticulum stress. Elevated cytosolic free calcium is required for the loss of viability. These results indicate that complex sphingolipids are essential for maintaining endoplasmic reticulum homeostasis and suggest that perturbation in complex sphingolipid levels activates an endoplasmic reticulum stress-mediated and calcium-dependent pathway to propagate apoptotic signals to the mitochondria. PMID:23062268

Kajiwara, Kentaro; Muneoka, Tetsuya; Watanabe, Yu; Karashima, Takefumi; Kitagaki, Hiroshi; Funato, Kouichi

2012-12-01

357