scholarly journals STAT3-mediated transcription of Bcl-2, Mcl-1 and c-IAP2 prevents apoptosis in polyamine-depleted cells

2005 ◽  
Vol 392 (2) ◽  
pp. 335-344 ◽  
Author(s):  
Sujoy Bhattacharya ◽  
Ramesh M. Ray ◽  
Leonard R. Johnson
Keyword(s):  
Myeloid Cell ◽  
Dominant Negative ◽  
Cell Leukaemia ◽  
Cell Periphery ◽  
Inhibitory Peptide ◽  
Protein Levels ◽  
Tnf Α ◽  
Apoptosis Protein ◽  
Before And After ◽  
Induced Apoptosis

Activation of STAT3 (signal transducer and activator of transcription 3) plays a crucial role in cell survival and proliferation. The aim of the present study was to clarify the role of STAT3 signalling in the protection of polyamine-depleted intestinal epithelial cells against TNF-α (tumour necrosis factor-α)-induced apoptosis. Polyamine depletion by DFMO (α-difluoromethylornithine) caused phosphorylation of STAT3 at Tyr-705 and Ser-727. Phospho-Tyr-705 STAT3 was immunolocalized at the cell periphery and nucleus, whereas phospho-Ser-727 STAT3 was predominantly detected in the nucleus of polyamine-depleted cells. Sustained phosphorylation of STAT3 at tyrosine residues was observed in polyamine-depleted cells after exposure to TNF-α. Inhibition of STAT3 activation by AG490 or cell-membrane-permeant inhibitory peptide (PpYLKTK; where pY represents phospho-Tyr) increased the sensitivity of polyamine-depleted cells to apoptosis. Expression of DN-STAT3 (dominant negative-STAT3) completely eliminated the protective effect of DFMO against TNF-α-induced apoptosis. Polyamine depletion increased mRNA and protein levels for Bcl-2, Mcl-1 (myeloid cell leukaemia-1) and c-IAP2 (inhibitor of apoptosis protein-2). Significantly higher levels of Bcl-2 and c-IAP2 proteins were observed in polyamine-depleted cells before and after 9 h of TNF-α treatment. Inhibition of STAT3 by AG490 and DN-STAT3 decreased Bcl-2 promoter activity. DN-STAT3 decreased mRNA and protein levels for Bcl-2, Mcl-1 and c-IAP2 in polyamine-depleted cells. siRNA (small interfering RNA)-mediated inhibition of Bcl-2, Mcl-1 and c-IAP2 protein levels increased TNF-α-induced apoptosis. DN-STAT3 induced the activation of caspase-3 and PARP [poly(ADP-ribose) polymerase] cleavage in polyamine-depleted cells. These results suggest that activation of STAT3 in response to polyamine depletion increases the transcription and subsequent expression of anti-apoptotic Bcl-2 and IAP family proteins and thereby promotes survival of cells against TNF-α-induced apoptosis.

Discovery of N-Phenyl-4-(1H-pyrrol-3-yl)pyrimidin-2-amine Derivatives as Potent Mnk2 Inhibitors: Design, Synthesis, SAR Analysis, and Evaluation of in vitro Anti-leukaemic Activity

2019 ◽  
Vol 15 (6) ◽  
pp. 602-623 ◽  
Author(s):  
Ahmed M. Abdelaziz ◽  
Sarah Diab ◽  
Saiful Islam ◽  
Sunita K.C. Basnet ◽  
Benjamin Noll ◽  
...  
Keyword(s):  
Proliferative Activity ◽  
Myeloid Cell ◽  
Structural Diversity ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Cell Leukaemia ◽  
Aberrant Expression ◽  
Design Synthesis ◽  
Induced Apoptosis

Background:Aberrant expression of eukaryotic translation initiation factor 4E (eIF4E) is common in many types of cancer including acute myeloid leukaemia (AML). Phosphorylation of eIF4E by MAPK-interacting kinases (Mnks) is essential for the eIF4E-mediated oncogenic activity. As such, the pharmacological inhibition of Mnks can be an effective strategy for the treatment of cancer.Methods:A series of N-phenyl-4-(1H-pyrrol-3-yl)pyrimidin-2-amine derivatives was designed and synthesised. The Mnk inhibitory activity of these derivatives as well as their anti-proliferative activity against MV4-11 AML cells was determined.Results:These compounds were identified as potent Mnk2 inhibitors. Most of them demonstrated potent anti-proliferative activity against MV4-11 AML cells. The cellular mechanistic studies of the representative inhibitors revealed that they reduced the level of phosphorylated eIF4E and induced apoptosis by down-regulating the anti-apoptotic protein myeloid cell leukaemia 1 (Mcl-1) and by cleaving poly(ADP-ribose)polymerase (PARP). The lead compound 7k possessed desirable pharmacokinetic properties and oral bioavailability.Conclusion:This work proposes that exploration of the structural diversity in the context of Nphenyl- 4-(1H-pyrrol-3-yl)pyrimidin-2-amine would offer potent and selective Mnk inhibitors.

Prevention of TNF-α-induced apoptosis in polyamine-depleted IEC-6 cells is mediated through the activation of ERK1/2

2004 ◽  
Vol 286 (3) ◽  
pp. G479-G490 ◽  
Author(s):  
Sujoy Bhattacharya ◽  
Ramesh M. Ray ◽  
Leonard R. Johnson
Keyword(s):  
Epithelial Cells ◽  
Cytochrome C ◽  
Critical Role ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Cytochrome C Release ◽  
Erk Phosphorylation ◽  
Tnf Α ◽  
Induced Apoptosis ◽  
Jnk Activation

It has been documented that polyamines play a critical role in the regulation of apoptosis in intestinal epithelial cells. We have recently reported that protection from TNF-α/cycloheximide (CHX)-induced apoptosis in epithelial cells depleted of polyamines is mediated through the inactivation of a proapoptotic mediator, JNK. In this study, we addressed the involvement of the MAPK pathway in the regulation of apoptosis after polyamine depletion of IEC-6 cells. Polyamine depletion by α-difluromethylornithine (DFMO) resulted in the sustained activation of ERK in response to TNF-α/CHX treatment. Pretreatment of polyamine-depleted IEC-6 cells with a cell membrane-permeable MEK1/2 inhibitor, U-0126, significantly inhibited TNF-α/CHX-induced ERK phosphorylation and significantly increased DNA fragmentation, JNK activity, and caspase-3 activity in response to TNF-α/CHX. Moreover, the dose dependency of U-0126-mediated inhibition of TNF-α/ CHX-induced ERK phosphorylation correlated with the reversal of the antiapoptotic effect of DFMO. IEC-6 cells expressing constitutively active MEK1 had decreased TNF-α/CHX-induced JNK phosphorylation and were significantly protected from apoptosis. Conversely, a dominant-negative MEK1 resulted in high basal activation of JNK, cytochrome c release, and spontaneous apoptosis. Polyamine depletion of the dominant-negative MEK1 cells did not prevent JNK activation or cytochrome c release and failed to confer protection from both TNF-α/CHX and camptothecin-induced apoptosis. Finally, expression of a dominant-negative mutant of JNK significantly protected IEC-6 cells from TNF-α/CHX-induced apoptosis. These data indicate that polyamine depletion results in the activation of ERK, which inhibits JNK activation and protects cells from apoptosis.

scholarly journals Myeloid cell leukaemia 1 has a vital role in retinoic acid-mediated protection of Toll-like receptor 9-stimulated B cells from spontaneous and DNA damage-induced apoptosis

Immunology ◽  
2016 ◽  
Vol 149 (1) ◽  
pp. 62-73 ◽  
Author(s):  
Kristine L. Holm ◽  
Randi L. Indrevaer ◽  
June Helen Myklebust ◽  
Arne Kolstad ◽  
Jan Øivind Moskaug ◽  
...  
Keyword(s):  
Dna Damage ◽  
Retinoic Acid ◽  
B Cells ◽  
Myeloid Cell ◽  
Vital Role ◽  
Cell Leukaemia ◽  
Toll Like Receptor ◽  
Induced Apoptosis

microRNA-29b contributes to pre-eclampsia through its effects on apoptosis, invasion and angiogenesis of trophoblast cells

2012 ◽  
Vol 124 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Pengfei Li ◽  
Wei Guo ◽  
Leilei Du ◽  
Junli Zhao ◽  
Yaping Wang ◽  
...  
Keyword(s):  
Target Genes ◽  
Inverse Correlation ◽  
Myeloid Cell ◽  
Trophoblast Cell ◽  
Trophoblast Invasion ◽  
Cell Leukaemia ◽  
Trophoblast Cells ◽  
Computer Based ◽  
Induced Apoptosis ◽  
Endothelial Growth Factor

PE (pre-eclampsia), a pregnancy-specific disorder, is characterized by increased trophoblast cell death and deficient trophoblast invasion and reduced trophoblast-mediated remodelling of spiral arteries. The present study was performed to determine the function of miR-29b (microRNA-29b) in trophoblast cells and its underlying role in the pathogenesis of PE. The prediction of miR-29b target genes was performed using computer-based programs, including Targetscan, Pictar and miRBase. The function of these target genes was analysed further by gene ontology (GO). The effects of miR-29b on apoptosis, and invasion and angiogenesis of trophoblast cell lines (HTR-8/SVneo, BeWo and JAR) were examined by flow cytometry and Matrigel assay respectively. We found that miR-29b induced apoptosis and inhibited invasion and angiogenesis of trophoblast cells. Further studies confirmed that miR-29b regulated the expression of MCL1 (myeloid cell leukaemia sequence 1), MMP2 (encoding matrix metallproteinase 2), VEGFA (vascular endothelial growth factor A) and ITGB1 (integrin β1) genes by directly binding to their 3′-UTRs (untranslated regions). Moreover, we identified that there was an inverse correlation between miR-29b and its target genes in subjects with PE. Taken together, these findings support a novel role for miR-29b in invasion, apoptosis and angiogenesis of trophoblast cells, and miR-29b may become a new potential therapeutic target for PE.

THE TNF-α SYSTEM BEFORE AND AFTER HEART TRANSPLANTATION: PLASMA PROTEIN LEVELS, mRNA-EXPRESSION, SOLUBLE RECEPTORS AND SERUM BUFFER CAPACITY

1998 ◽  
Vol 65 (Supplement) ◽  
pp. 234
Author(s):  
I. C. van Riemsdijk ◽  
C. C. Baan ◽  
E. H.M. Loonen ◽  
C. J. Hesse ◽  
A. H.M.M. Balk ◽  
...  
Keyword(s):  
Heart Transplantation ◽  
Mrna Expression ◽  
Plasma Protein ◽  
Buffer Capacity ◽  
Soluble Receptors ◽  
Protein Levels ◽  
Tnf Α ◽  
Before And After

scholarly journals Human Cytomegalovirus Mir-UL70-3p Downregulates the H2O2 Induced Apoptosis in HEK293T Cells by Targeting the Modulator of Apoptosis-1 (MOAP1)

2021 ◽  
Author(s):  
Abhishek Pandeya ◽  
Anup Mishra ◽  
Raj Kumar Khalko ◽  
Sukhveer Singh ◽  
Nishant Singh ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Cellular Response ◽  
Opportunistic Infections ◽  
Ectopic Expression ◽  
Developed Countries ◽  
Productive Infection ◽  
Protein Levels ◽  
Apoptosis Protein ◽  
Cellular Apoptosis ◽  
Induced Apoptosis

Abstract Human Cytomegalovirus (HCMV), a prototypic member of the Beta-herpesvirinae subfamily, mainly responsible for congenital disabilities in newborns, cause opportunistic infections in immunocompromised individuals. Its seroprevalence varies across the globe ranging from 50–70 percent in developed countries to 90–100 percent in developing countries. Causing latent infections in the immunocompetent host suggests that it employs several strategies to escape the wrath of the host’s antiviral mechanisms. Apoptosis is an innate cellular response to viral infection, and downregulation of this mechanism by HCMV is a well-established phenomenon. HCMV utilizes its proteins, RNA and miRNA in regulating this response to establish a productive infection in the host. The role of HCMV miRNAs on cellular apoptosis is very interesting, where some miRNAs downregulate but a few upregulate this process. In the present study, we report the antiapoptotic activity of HCMV miRNA, miR-UL-70-3p, on H2O2 induced apoptosis in HEK293T cells. The ectopic expression of this HCMV miRNA in HEK293T cells downregulate the apoptosis, and continuing studies reveal that the proapoptotic gene, Modulator of Apoptosis Protein-1 (MOAP1), is a functional target for this miRNA. We verified the functionality of the binding site predicted in the 3'UTR of MOAP1 in our earlier studies through dual luciferase-based assays using both the wild and mutant 3'UTR’s of MOAP1. The MOAP1 protein levels were significantly downregulated by the miR-UL70-3p, suggesting that the MOAP1 mRNA was degraded after binding with the miR-UL70-3p. Further, the extent of MOAP1 mRNA and its protein inhibitions by HCMV miR-UL70-3p and siRNA of MOAP1 were compared and found that the siRNA of MOAP1 inhibits 69.52 percent of mRNA and 35.67 percent of MOAP1 protein; while the miR-UL70-3p inhibits 46.66 percent MOAP1 mRNA and 21.05 percent MOAP1 protein. Though the inhibitory activity of miR-UL70-3p is not equal to the siRNA of MOAP1, but it was significant enough in reversing the H2O2 induced apoptosis in HEK293T cells. These results confirm that hcmv-miR-UL70-3p downregulates H2O2 induced apoptosis in HEK293T cells by targeting the 3'UTR of MOAP1 mRNA.

Disruption of α-actinin-integrin interactions at focal adhesions renders osteoblasts susceptible to apoptosis

2006 ◽  
Vol 291 (5) ◽  
pp. C909-C921 ◽  
Author(s):  
Jason W. Triplett ◽  
Fredrick M. Pavalko
Keyword(s):  
Tyrosine Phosphorylation ◽  
Structural Integrity ◽  
Focal Adhesions ◽  
Bone Cell ◽  
Gfp Expression ◽  
Akt Phosphorylation ◽  
Protein Levels ◽  
Tnf Α ◽  
Survival Signaling ◽  
Induced Apoptosis

Maintenance of bone structural integrity depends in part on the rate of apoptosis of bone-forming osteoblasts. Because substrate adhesion is an important regulator of apoptosis, we have investigated the role of focal adhesions in regulating bone cell apoptosis. To test this, we expressed a truncated form of α-actinin (ROD-GFP) that competitively displaces endogenous α-actinin from focal adhesions, thus disrupting focal adhesions. Immunofluorescence and morphometric analysis of vinculin and tyrosine phosphorylation revealed that ROD-GFP expression dramatically disrupted focal adhesion organization and reduced tyrosine phosphorylation at focal adhesions. In addition, Bcl-2 protein levels were reduced in ROD-GFP-expressing cells, but caspase 3 cleavage, poly(ADP-ribose) polymerase cleavage, histone H2A.X phosphorylation, and cytotoxicity were not increased due to ROD-GFP expression alone. Increases in both ERK and Akt phosphorylation were also observed in ROD-GFP-expressing cells, although inhibition of either ERK or Akt individually or together failed to induce apoptosis. However, we did find that ROD-GFP expression sensitized, whereas α-actinin-GFP expression protected, cells from TNF-α-induced apoptosis. Further investigation revealed that activation of TNF-α-induced survival signals, specifically Akt phosphorylation and NF-κB activation, was inhibited in ROD-GFP-expressing cells. The reduced expression of antiapoptotic Bcl-2 and inhibited survival signaling rendered ROD-GFP-expressing cells more susceptible to TNF-α-induced apoptosis. Thus we conclude that α-actinin plays a role in regulating cell survival through stabilization of focal adhesions and regulation of TNF-α-induced survival signaling.

scholarly journals APP-BP1 mediates APP-induced apoptosis and DNA synthesis and is increased in Alzheimer's disease brain

2003 ◽  
Vol 163 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Yuzhi Chen ◽  
Wenyun Liu ◽  
Donna L. McPhie ◽  
Linda Hassinger ◽  
Rachael L. Neve
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Dna Synthesis ◽  
Lipid Rafts ◽  
Neuronal Apoptosis ◽  
Dominant Negative ◽  
Regulatory Subunit ◽  
Dominant Negative Mutant ◽  
Protein Levels ◽  
Induced Apoptosis

APP-BP1, first identified as an amyloid precursor protein (APP) binding protein, is the regulatory subunit of the activating enzyme for the small ubiquitin-like protein NEDD8. We have shown that APP-BP1 drives the S- to M-phase transition in dividing cells, and causes apoptosis in neurons (Chen, Y., D.L. McPhie, J. Hirschberg, and R.L. Neve. 2000. J. Biol. Chem. 275:8929–8935). We now demonstrate that APP-BP1 binds to the COOH-terminal 31 amino acids of APP (C31) and colocalizes with APP in a lipid-enriched fraction called lipid rafts. We show that coexpression of a peptide representing the domain of APP-BP1 that binds to APP, abolishes the ability of overexpressed APP or the V642I mutant of APP to cause neuronal apoptosis and DNA synthesis. A dominant negative mutant of the NEDD8 conjugating enzyme hUbc12, which participates in the ubiquitin-like pathway initiated by APP-BP1, blocks neuronal apoptosis caused by APP, APP(V642I), C31, or overexpression of APP-BP1. Neurons overexpressing APP or APP(V642I) show increased APP-BP1 protein levels in lipid rafts. A similar increase in APP-BP1 in lipid rafts is observed in the Alzheimer's disease brain hippocampus, but not in less-affected areas of Alzheimer's disease brain. This translocation of APP-BP1 to lipid rafts is accompanied by a change in the subcellular localization of the ubiquitin-like protein NEDD8, which is activated by APP-BP1.

Induced focal adhesion kinase expression suppresses apoptosis by activating NF-κB signaling in intestinal epithelial cells

2006 ◽  
Vol 290 (5) ◽  
pp. C1310-C1320 ◽  
Author(s):  
Huifang M. Zhang ◽  
Kaspar M. Keledjian ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Lan Liu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Intestinal Epithelial Cells ◽  
Ectopic Expression ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Intestinal Epithelial ◽  
Tnf Α ◽  
Induced Apoptosis

Focal adhesion kinase (FAK) integrates various extracellular and intracellular signals and is implicated in a variety of biological functions, but its exact role and downstream targeting signals in the regulation of apoptosis in intestinal epithelial cells (IECs) remains unclear. The current study tested the hypothesis that FAK has an antiapoptotic role in the IEC-6 cell line by altering NF-κB signaling. Induced FAK expression by stable transfection with the wild-type (WT)-FAK gene increased FAK phosphorylation, which was associated with an increase in NF-κB activity. These stable WT-FAK-transfected IECs also exhibited increased resistance to apoptosis when they were exposed to TNF-α plus cycloheximide (TNF-α/CHX). Specific inhibition of NF-κB by the recombinant adenoviral vector containing the IκBα superrepressor prevented increased resistance to apoptosis in WT-FAK-transfected cells. In contrast, inactivation of FAK by ectopic expression of dominant-negative mutant of FAK (DNM-FAK) inhibited NF-κB activity and increased the sensitivity to TNF-α/CHX-induced apoptosis. Furthermore, induced expression of endogenous FAK by depletion of cellular polyamines increased NF-κB activity and resulted in increased resistance to TNF-α/CHX-induced apoptosis, both of which were prevented by overexpression of DNM-FAK. These results indicate that increased expression of FAK suppresses TNF-α/CHX-induced apoptosis, at least partially, through the activation of NF-κB signaling in IECs.

scholarly journals Cleavage of Cdc6 by caspase-3 promotes ATM/ATR kinase–mediated apoptosis of HeLa cells

2006 ◽  
Vol 174 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Hyungshin Yim ◽  
In Sun Hwang ◽  
Joon-Seok Choi ◽  
Kwang-Hoon Chun ◽  
Ying Hua Jin ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Replication Initiation ◽  
Dominant Negative ◽  
Ataxia Telangiectasia Mutated ◽  
Activation Kinetics ◽  
Kinase Activation ◽  
Tnf Α ◽  
Induced Apoptosis ◽  
Atr Kinase ◽  
Interfering Rna

We show that caspase-3 cleaves Cdc6 at D290/S and D442/G sites, producing p32-tCdc6 (truncated Cdc6) and p49-tCdc6, respectively, during etoposide- or tumor necrosis factor (TNF)-α–induced apoptosis. The expression of these tCdc6 proteins, p32- and p49-tCdc6, promotes etoposide-induced apoptosis. The expression of tCdc6 perturbs the loading of Mcm2 but not Orc2 onto chromatin and activates ataxia telangiectasia mutated (ATM) and ATM and Rad-3 related (ATR) kinase activities with kinetics similar to that of the phosphorylation of Chk1/2. The activation kinetics are consistent with elevated cellular levels of p53 and mitochondrial levels of Bax. The tCdc6-induced effects are all suppressed to control levels by expressing a Cdc6 mutant that cannot be cleaved by caspase-3 (Cdc6-UM). Cdc6-UM expression attenuates the TNF-α–induced activation of ATM and caspase-3 activities. When ATM or ATR is down-expressed by using the small interfering RNA technique, the TNF-α– or tCdc6-induced activation of caspase-3 activities is suppressed in the cells. These results suggest that tCdc6 proteins act as dominant-negative inhibitors of replication initiation and that they disrupt chromatin structure and/or induce DNA damage, leading to the activation of ATM/ATR kinase activation and p53–Bax-mediated apoptosis.

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