Polyamine depletion inhibits irradiation-induced apoptosis in intestinal epithelia

2005 ◽  
Vol 289 (3) ◽  
pp. G599-G606 ◽  
Author(s):  
Wenlin Deng ◽  
Mary Jane Viar ◽  
Leonard R. Johnson
Keyword(s):  
Structural Damage ◽  
Caspase 3 ◽  
Intestinal Epithelial ◽  
Γ Irradiation ◽  
Intestinal Epithelia ◽  
Proapoptotic Protein ◽  
Radiation Induced ◽  
Induced Apoptosis

Our group has previously shown that polyamine depletion delays apoptosis in rat intestinal epithelial (IEC-6) cells (Ray RM, Viar MJ, Yuan Q, and Johnson LR , Am J Physiol Cell Physiol 278: C480–C489, 2000). Here, we demonstrate that polyamine depletion inhibits γ-irradiation-induced apoptosis in vitro and in vivo. Pretreatment of IEC-6 cells with 5 mM α-difluoromethylornithine (DFMO) for 4 days significantly reduced radiation-induced caspase-3 activity and DNA fragmentation. This protective effect was prevented by the addition of 10 μM exogenous putrescine. Radiation exposure to mice resulted in a high frequency of apoptosis over cells positioned fourth to seventh in crypt-villus units. Pretreatment of mice with 2% DFMO in drinking water significantly reduced apoptotic cells from ∼2.75 to 1.61 per crypt-villus unit, accompanied by significant decreases in caspase-3 levels. Further examination showed that DFMO pretreatment inhibited the radiation-induced increase in the proapoptotic protein Bax. Moreover, DFMO pretreatment significantly enhanced the intestinal crypt survival rate by 2.1-fold subsequent to radiation and ameliorated mucosal structural damage. We conclude that polyamine depletion by DFMO inhibits γ-irradiation-induced apoptosis of intestinal epithelial cells both in vitro and in vivo through inhibition of Bax and caspase-3 activity, which leads to attenuation of radiation-inflicted intestinal injury. These data indicate that DFMO may be therapeutically useful to counteract the gastrointestinal toxicity caused by chemoradiotherapy. This is the first demonstration that polyamines are required for apoptosis in vivo.

scholarly journals Activation of guanylate cyclase C signaling pathway protects intestinal epithelial cells from acute radiation-induced apoptosis

2009 ◽  
Vol 296 (4) ◽  
pp. G740-G749 ◽  
Author(s):  
M. P. Garin-Laflam ◽  
K. A. Steinbrecher ◽  
J. A. Rudolph ◽  
J. Mao ◽  
M. B. Cohen
Keyword(s):  
Guanylate Cyclase ◽  
Peptide Hormone ◽  
In Vivo Model ◽  
Proximal Jejunum ◽  
Intestinal Epithelial ◽  
Γ Irradiation ◽  
Guanylate Cyclase C ◽  
Radiation Induced ◽  
Induced Apoptosis

Uroguanylin (UGN) is a peptide hormone that binds to and activates the intestinal epithelial cell (IEC) transmembrane receptor guanylate cyclase C (GC-C), which in turn increases intracellular cGMP. Gene targeting of murine UGN or GC-C results in significantly lower levels of cGMP in IECs. On the basis of effects of cGMP in nonintestinal systems, we hypothesized that loss of GC-C activation would increase intestinal epithelial apoptosis following radiation-induced injury. We first compared apoptosis from the proximal jejunum of C57BL/6 wild-type (WT) and GC-C knockout (KO) mice 3 h after they received 5 Gy of γ-irradiation. We then investigated whether supplementation via intraperitoneal injection of 1 mM 8BrcGMP would mitigate radiation-induced apoptosis in these experimental animals. Identical experiments were performed in BALB/c UGN WT and KO mice. Apoptosis was assessed by quantitating morphological indications of cell death, terminal dUTP nick-end labeling, and cleaved caspase 3 immunohistochemistry. Both UGN KO and GC-C KO mice were more susceptible than their WT littermates in this in vivo model of apoptotic injury. Furthermore, cGMP supplementation in both GC-C and UGN KO animals ameliorated radiation-induced apoptosis. Neither WT strain demonstrated significant alteration in apoptotic susceptibility as a result of cGMP supplementation before radiation injury. These in vivo findings demonstrate increased radiosensitivity of IECs in UGN and GC-C KO mice and a role for cGMP as a primary downstream mediator of GC-C activation in the protection of these IECs from radiation-induced apoptosis.

scholarly journals Salmonella-Induced Caspase-2 Activation in Macrophages

2000 ◽  
Vol 192 (7) ◽  
pp. 1035-1046 ◽  
Author(s):  
Veronika Jesenberger ◽  
Katarzyna J. Procyk ◽  
Junying Yuan ◽  
Siegfried Reipert ◽  
Manuela Baccarini
Keyword(s):  
Type Iii Secretion ◽  
Caspase 3 ◽  
Secretion System ◽  
Caspase 1 ◽  
Chemical Inhibition ◽  
Induction Of Apoptosis ◽  
Caspase 2 ◽  
Induced Apoptosis

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

Identification of apoptotic genes mediating TGF-β/Smad3-induced cell death in intestinal epithelial cells using a genomic approach

2007 ◽  
Vol 292 (1) ◽  
pp. G28-G38 ◽  
Author(s):  
Yanna Cao ◽  
Lu Chen ◽  
Weili Zhang ◽  
Yan Liu ◽  
Harry T. Papaconstantinou ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Target Genes ◽  
Transforming Growth Factor ◽  
Intestinal Epithelial ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Genomic Approach ◽  
Apoptotic Genes ◽  
Induced Apoptosis

Transforming growth factor (TGF)-β-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues in vivo. Previously, we have shown that TGF-β inhibits the growth of rat intestinal epithelial (RIE)-1 cells. However, RIE-1 cells are relatively resistant to TGF-β-induced apoptosis due to a low endogenous Smad3-to-Akt ratio. Overexpression of Smad3 sensitizes RIE-1 cells (RIE-1/Smad3) to TGF-β-induced apoptosis by altering the Smad3-to-Akt ratio in favor of apoptosis. In this study, we utilized a genomic approach to identify potential downstream target genes that are regulated by TGF-β/Smad3. Total RNA samples were analyzed using Affymetrix oligonucleotide microarrays. We found that TGF-β regulated 518 probe sets corresponding to its target genes. Interestingly, among the known apoptotic genes included in the microarray analyses, only caspase-3 was induced, which was confirmed by real-time RT-PCR. Furthermore, TGF-β activated caspase-3 through protein cleavage. Upstream of caspase-3, TGF-β induced mitochondrial depolarization, cytochrome c release, and cleavage of caspase-9, which suggests that the intrinsic apoptotic pathway mediates TGF-β-induced apoptosis in RIE-1/Smad3 cells.

scholarly journals DR5 Knockout Mice Are Compromised in Radiation-Induced Apoptosis

2005 ◽  
Vol 25 (5) ◽  
pp. 2000-2013 ◽  
Author(s):  
Niklas Finnberg ◽  
Joshua J. Gruber ◽  
Peiwen Fei ◽  
Dorothea Rudolph ◽  
Anka Bric ◽  
...  
Keyword(s):  
Cell Death ◽  
Null Mouse ◽  
Organ Specific ◽  
Radiation Induced ◽  
Induced Apoptosis ◽  
The Brain ◽  
Necrosis Factor

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

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

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Partha Mukhopadhyay ◽  
Mohanraj Rajesh ◽  
Sandor Bátkai ◽  
György Haskó ◽  
Csaba Szabo ◽  
...  
Keyword(s):  
Cell Death ◽  
Caspase 3 ◽  
Superoxide Generation ◽  
Cytochrome C Release ◽  
Mitochondrial Superoxide ◽  
Induced Apoptosis ◽  
Peroxynitrite Scavengers

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

Indole-3-Carbinol Inhibits Nasopharyngeal Carcinoma

2010 ◽  
Vol 29 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Wei Zhu ◽  
Wenxue Li ◽  
Guangyu Yang ◽  
Quanxin Zhang ◽  
Ming Li ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Nasopharyngeal Carcinoma ◽  
Glutathione Peroxidase ◽  
Tumor Growth ◽  
Caspase 3 ◽  
Caspase 9 ◽  
Human Nasopharyngeal Carcinoma ◽  
Induced Apoptosis

This study explored the effects of indole-3-carbinol on the proliferation of human nasopharyngeal carcinoma, both in vitro and in vivo, and the underlying mechanisms in inducing apoptosis of CNE1 cells. Proliferation, apoptosis, malondialdehyde, superoxide dismutase, glutathione peroxidase, expressions of caspase-9, and caspase-3 in human nasopharyngeal carcinoma cells CNE1 were examined. Indole-3-carbinol suppressed proliferation, induced apoptosis, decreased malondialdehyde level, increased the activity of superoxide dismutase and glutathione peroxidase, and up-regulated the expression of active fragments of caspase-9 and caspase-3 both in vitro and in vivo. It was concluded that indole-3-carbinol could inhibit proliferation and induce apoptosis of CNE1 cells and inhibit tumor growth in mice. Increased activity of superoxide dismutase and glutathione peroxidase and activated expression of caspase-9 and caspase-3 were also observed in indole-3-carbinol–treated tumors or tumor cells, suggesting that stress- and apoptosis-related molecules are involved in the indole-3-carbinol–induced apoptosis and inhibition of tumor growth.

scholarly journals Hexarelin Modulation of MAPK and PI3K/Akt Pathways in Neuro-2A Cells Inhibits Hydrogen Peroxide—Induced Apoptotic Toxicity

2021 ◽  
Vol 14 (5) ◽  
pp. 444
Author(s):  
Ramona Meanti ◽  
Laura Rizzi ◽  
Elena Bresciani ◽  
Laura Molteni ◽  
Vittorio Locatelli ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Viability ◽  
Caspase 3 ◽  
Mrna Levels ◽  
Protective Effects ◽  
Neuroprotective Effects ◽  
Caspase 7 ◽  
Induced Apoptosis

Hexarelin, a synthetic hexapeptide, exerts cyto-protective effects at the mitochondrial level in cardiac and skeletal muscles, both in vitro and in vivo, may also have important neuroprotective bioactivities. This study examined the inhibitory effects of hexarelin on hydrogen peroxide (H2O2)-induced apoptosis in Neuro-2A cells. Neuro-2A cells were treated for 24 h with various concentrations of H2O2 or with the combination of H2O2 and hexarelin following which cell viability and nitrite (NO2−) release were measured. Cell morphology was also documented throughout and changes arising were quantified using Image J skeleton and fractal analysis procedures. Apoptotic responses were evaluated by Real-Time PCR (caspase-3, caspase-7, Bax, and Bcl-2 mRNA levels) and Western Blot (cleaved caspase-3, cleaved caspase-7, MAPK, and Akt). Our results indicate that hexarelin effectively antagonized H2O2-induced damage to Neuro-2A cells thereby (i) improving cell viability, (ii) reducing NO2− release and (iii) restoring normal morphologies. Hexarelin treatment also reduced mRNA levels of caspase-3 and its activation, and modulated mRNA levels of the BCL-2 family. Moreover, hexarelin inhibited MAPKs phosphorylation and increased p-Akt protein expression. In conclusion, our results demonstrate neuroprotective and anti-apoptotic effects of hexarelin, suggesting that new analogues could be developed for their neuroprotective effects.

scholarly journals 12-Epi-Napelline Inhibits Leukemia Cell Proliferation via the PI3K/AKT Signaling Pathway In Vitro and In Vivo

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jia Han ◽  
Wei Hou ◽  
Bi-qing Cai ◽  
Fan Zhang ◽  
Jian-cai Tang
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Caspase 3 ◽  
Animal Experiments ◽  
Leukemia Cell ◽  
Tumor Model ◽  
Inhibitory Effect ◽  
Induced Apoptosis

This study aimed to investigate the inhibitory effect of 12-epi-napelline on leukemia cells and its possible mechanisms. The inhibitory effects of 12-epi-napelline on K-562 and HL-60 cells were evaluated using the CCK-8 assay, cell cycle arrest and apoptosis were detected by flow cytometry, and the expression of related proteins was measured by western blot. A K-562 tumor model was established to evaluate the antitumor effect of 12-epi-napelline in vivo. A reduction in leukemia cell viability was observed after treatment with 12-epi-napelline. It was determined that the cell cycle was arrested in the G0/G1 phase, and the cell apoptosis rate was increased. Moreover, caspase-3 and Bcl-2 were downregulated, whereas cleaved caspase-3 and caspase-9 were upregulated. Further study revealed that 12-epi-napelline could suppress the expression of PI3K, AKT, p-AKT, and mTOR. Insulin-like growth factor 1 (IGF-1) attenuated 12-epi-napelline-induced apoptosis and ameliorated the repression of PI3K, AKT, p-AKT, and mTOR by 12-epi-napelline. Animal experiments clearly showed that 12-epi-napelline inhibited tumor growth. In conclusion, 12-epi-napelline restrained leukemia cell proliferation by suppressing the PI3K/AKT/mTOR pathway in vitro and in vivo.

Atiprimod inhibits the growth of mantle cell lymphoma in vitro and in vivo and induces apoptosis via activating the mitochondrial pathways

Blood ◽  
2007 ◽  
Vol 109 (12) ◽  
pp. 5455-5462 ◽  
Author(s):  
Michael Wang ◽  
Liang Zhang ◽  
Xiaohong Han ◽  
Jing Yang ◽  
Jianfei Qian ◽  
...  
Keyword(s):  
Mantle Cell Lymphoma ◽  
Cell Apoptosis ◽  
Caspase 3 ◽  
Cell Lymphoma ◽  
Caspase 9 ◽  
Mantle Cell ◽  
Induced Apoptosis ◽  
Apoptosis Inducing Factor

Abstract Atiprimod is a novel cationic amphiphilic compound and has been shown to exert antimyeloma effects both in vitro and in mouse experiments. This study was undertaken to evaluate the therapeutic efficacy of atiprimod on mantle cell lymphoma (MCL) and elucidate the mechanism by which it induces cell apoptosis. Atiprimod inhibited the growth and induced apoptosis of MCL cell lines and freshly isolated primary tumor cells in vitro. More importantly, atiprimod significantly inhibited tumor growth in vivo and prolonged the survival of tumor-bearing mice. However, atiprimod also exhibited lower cytotoxicity toward normal lymphocytes. Atiprimod activated c-Jun N-terminal protein kinases (JNK) and up-regulated the level of Bax, Bad, and phosphorylated Bcl-2, resulting in release of apoptosis-inducing factor (AIF) and cytochrome c from mitochondria and activation and cleavage of caspase-9, caspase-3, and PARP. However, AIF, but not activation of caspases or PARP, was responsible for apoptosis in MCL cells because an AIF inhibitor, but not pan-caspase or paspase-9 inhibitors, completely abrogated atiprimod-induced apoptosis. Taken together, our results demonstrate that atiprimod displays a strong anti-MCL activity. Cell apoptosis was induced mainly via activation of the AIF pathway. These results support the use of atiprimod as a potential agent in MCL chemotherapy.

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