Transcriptional activation of cyclooxygenase-2 by tumor suppressor p53 requires nuclear factor-kappaB

ABSTRACT The tumor suppressor p53 plays a key role in inducing G1 arrest and apoptosis following DNA damage. The double-stranded-RNA-activated protein PKR is a serine/threonine interferon (IFN)-inducible kinase which plays an important role in regulation of gene expression at both transcriptional and translational levels. Since a cross talk between IFN-inducible proteins and p53 had already been established, we investigated whether and how p53 function was modulated by PKR. We analyzed p53 function in several cell lines derived from PKR+/+ and PKR−/− mouse embryonic fibroblasts (MEFs) after transfection with the temperature-sensitive (ts) mutant of mouse p53 [p53(Val135)]. Here we report that transactivation of transcription by p53 and G0/G1 arrest were impaired in PKR−/− cells upon conditions that ts p53 acquired a wild-type conformation. Phosphorylation of mouse p53 on Ser18 was defective in PKR−/− cells, consistent with an impaired transcriptional induction of the p53-inducible genes encoding p21WAF/Cip1 and Mdm2. In addition, Ser18 phosphorylation and transcriptional activation by mouse p53 were diminished in PKR−/− cells after DNA damage induced by the anticancer drug adriamycin or γ radiation but not by UV radiation. Furthermore, the specific phosphatidylinositol-3 (PI-3) kinase inhibitor LY294002 inhibited the induction of phosphorylation of Ser18 of p53 by adriamycin to a higher degree in PKR+/+ cells than in PKR−/− cells. These novel findings suggest that PKR enhances p53 transcriptional function and implicate PKR in cell signaling elicited by a specific type of DNA damage that leads to p53 phosphorylation, possibly through a PI-3 kinase pathway.

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Requirement of nuclear factor kappaB for the constitutive expression of nitric oxide synthase-2 and cyclooxygenase-2 in rat trophoblasts

Journal of Cell Science ◽

10.1242/jcs.112.18.3147 ◽

1999 ◽

Vol 112 (18) ◽

pp. 3147-3155

Author(s):

N.A. Callejas ◽

M. Casado ◽

L. Bosca ◽

P. Martin-Sanz

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Cyclooxygenase 2 ◽

Nuclear Factor Kappab ◽

Mrna Levels ◽

Nuclear Factor ◽

Cox 2 ◽

Nf Kappab ◽

Nitric Oxide Synthase 2 ◽

Oxide Synthase

Recently isolated trophoblasts express nitric oxide synthase 2 (NOS-2) and cyclooxygenase 2 (COX-2), decreasing the levels of the corresponding mRNAs when the cells were maintained in culture. The sustained expression of COX-2 and NOS-2 in trophoblasts was dependent on the activation of nuclear factor kappaB (NF-kappaB) since proteasome inhibitors and antioxidants that abrogated NF-kappaB activity suppressed the induction of both genes. The time-dependent fall of the mRNA levels of NOS-2 and COX-2 paralleled the inhibition of NF-kappaB, determined by electrophoretic mobility shift assays, and the increase of the IkappaBalpha and IkappaBbeta inhibitory proteins. Isolated trophoblasts synthesized reactive oxygen intermediates (ROI), a process impaired after culturing the cells, and that might be involved in the NF-kappaB activation process. Moreover, treatment of recently isolated cells with ROI scavengers suppressed the expression of COX-2 and NOS-2. Challenge of trophoblasts with interleukin-1beta up-regulated the expression of both proteins, an effect that was potentiated by lipopolysaccharide. These results indicate that the physiological expression of NOS-2 and COX-2 in trophoblasts involves a sustained activation of NF-kappaB which inhibition abrogates the inducibility of both genes.

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Preventive effect of methanol extract from Agrocybe cylindracea (MEAC) mushroom on the cooking oil fumes-induced expressions of cyclooxygenase-2 via suppression of nuclear factor-kappaB (NF-kB) in CL-3 cells

Journal of Food and Drug Analysis ◽

10.38212/2224-6614.2194 ◽

2020 ◽

Vol 19 (3) ◽

Author(s):

L.-H. Wang ◽

H. Lee ◽

T.-A. Chiang ◽

M.-J. Chen ◽

S.-Y. Lin

Keyword(s):

Methanol Extract ◽

Cyclooxygenase 2 ◽

Nuclear Factor Kappab ◽

Nuclear Factor ◽

Preventive Effect ◽

Agrocybe Cylindracea ◽

Cooking Oil ◽

Cooking Oil Fumes

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Negative regulation of nuclear factor-kappaB activation and function by glucocorticoids

Journal of Molecular Endocrinology ◽

10.1677/jme.0.0280069 ◽

2002 ◽

Vol 28 (2) ◽

pp. 69-78 ◽

Cited By ~ 157

Author(s):

WY Almawi ◽

OK Melemedjian

Keyword(s):

Transcription Factors ◽

Transcriptional Activation ◽

Promoter Region ◽

Nuclear Translocation ◽

Nuclear Factor Kappab ◽

Nuclear Factor ◽

Creb Binding Protein ◽

Transcriptional Initiation ◽

Nf Kappab ◽

And Function

Glucocorticoids (GCs) exert their anti-inflammatory and antiproliferative effects principally by inhibiting the expression of cytokines and adhesion molecules. Mechanistically, GCs diffuse through the cell membrane, and bind to their inactive cytosolic receptors (GRs), which then undergo conformational modifications that allow for their nuclear translocation. In the nucleus, activated GRs modulate transcriptional events by directly associating with DNA elements, compatible with the GCs response elements (GRE) motif, and located in variable copy numbers and at variable distances from the TATA box, in the promoter region of GC-responsive genes. In addition, activated GRs also acted by antagonizing the activity of transcription factors, in particular nuclear factor-kappaB (NF-kappaB), by direct and indirect mechanisms. GCs induced gene transcription and protein synthesis of the NF-kappaB inhibitor, IkappaB. Activated GR also antagonized NF-kappaB activity through protein-protein interaction involving direct complexing with, and inhibition of, NF-kappaB binding to DNA (Simple Model), or association with NF-kappaB bound to the kappaB DNA site (Composite Model). In addition, and according to the Transmodulation Model, GRE-bound GR may interact with and inhibit the activity of kappaB-bound NF-kappaB via a mechanism involving cross-talk between the two transcription factors. Lastly, GR may compete with NF-kappaB for nuclear coactivators, including CREB binding protein and p300, thereby reducing and inhibiting transcriptional activation by NF-kappaB. It should be noted that, in exerting its effect, activated GR did not affect the correct assembly of the pre-initiation (DAB) complex, but acted rather more proximally in inhibiting the correct assembly of transcription factors in the promoter region, and thus transcriptional initiation.

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