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Query: EC:2.7.11.1 (
protein kinase
)
81,284
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Accumulated evidence from prospective studies, intervention trials and studies on animal models of cancer have suggested a strong inverse correlation between selenium intake and cancer incidence. Several putative mechanisms have been suggested to mediate the chemopreventive activities of selenium: of these, the inhibition of cellular proliferation and the induction of apoptosis are particularly attractive. The mitogen activated
protein kinase
(MAPK) pathways are known to be important regulators of cell death and our recent work has focused on the involvement of these pathways in selenium-induced apoptosis in primary cultures of oral cancers and corresponding normal mucosa derived from biopsy material. Using this system, the oral carcinoma cells were found to have enhanced sensitivity to apoptosis when treated with certain selenium compounds compared to normal oral mucosa. Induction of
Fas ligand
was associated with selenium-induced apoptosis. Signal transduction studies suggests that selenium induces several changes in the MAPK signalling pathways but functional intervention/inhibitor studies indicate that activation of the JNK pathway seems to be most important.
...
PMID:Selenium and signal transduction: roads to cell death and anti-tumour activity. 1156 49
Prospective studies and recent intervention trials suggest that the risk of some cancers, including respiratory tract cancers, may be inversely related to selenium (SE) intake, and this is supported by strong experimental evidence with chemical-induced animal cancer models. How this cancer-protective effect is mediated is unclear, but interference with the balance of growth/apoptosis during tumor outgrowth is one plausible hypothesis. In general, there is a correlation between the effectiveness of SE compounds as chemopreventive agents in vivo and their ability to inhibit cell growth and induce apoptosis in vitro. This study has investigated the signal transduction pathways affected by SE compounds in biopsies of normal human oral mucosa cells and human oral squamous carcinoma cells (SCCs), using a primary culture system. Two SE compounds were tested: selenodiglutathione (SDG), the primary metabolite of selenite and the most commonly used cancer-protective SE compound in animal models, and the synthetic SE compound, 1,4-phenylenebis(methylene)selenocyanate (p-XSC), one of the most potent chemopreventive pharmacological SE compounds. Three novel findings are reported: (a) SCCs were found to be significantly more sensitive to induction of apo ptosis by SDG than normal human oral mucosa cells, though the differences were marginal with p-XSC; (b) both SE compounds induced the expression of
Fas ligand
(Fas-L) in oral cells to a degree that correlated with the extent of apoptosis induction; and (c) both SDG and p-XSC induced the stress pathway kinases, Jun NH2-terminal kinase (JNK) and p38 kinase, at concentrations causing apoptosis; p-XSC, and to a lesser extent SDG, also activated extracellular regulated kinases 1&2 (ERKs 1&2) and
protein kinase
-B or Akt. To test their functional involvement, the effect of inhibiting each of these pathways on induction of apoptosis by SDG and p-XSC was determined in SCCs. Inhibiting the ERKs 1&2 or Akt pathways with specific chemical inhibitors (PD98059 or LY294002, respectively) did not affect the extent of apoptosis induced by SDG or p-XSC (with the exception of LY294002, which actually enhanced the level of induction of apoptosis by SDG). The JNK pathway appeared to be most important for induction of Fas-L and apoptosis because concentrations of SB202190 that inhibited activation of both the JNK and p38 kinase (but not ERKs 1&2) in SCC reduced the extent of induction of Fas-L and apoptosis by SDG and p-XSC, whereas lower concentrations that inhibited activation only of p38 kinase did not. This was confirmed by the fact that exogenous expression of a dominant negative deletion mutant of c-Jun (TAM67) reduced the induction of both apoptosis and Fas-L by SDG.
...
PMID:Enhanced sensitivity of human oral carcinomas to induction of apoptosis by selenium compounds: involvement of mitogen-activated protein kinase and Fas pathways. 1160 83
The engagement of antigen receptor can initiate apoptosis of T lymphocytes through the induced expression of
Fas ligand
(
FasL
). Forskolin, an activator of the cAMP/
PKA
pathway, results in antagonism of Fas-dependent, activation-induced cell death (AICD) by suppressed expression of the
FasL
. We report that forskolin-mediated induction of inducible cAMP early repressor (ICER) correlates with transcriptional attenuation of
FasL
expression in the AICD model 2B4 T cell hybridoma. ICER is inducible in human peripheral blood CD3(+) T cells, but in CD19(+) B cells, its induction is less responsive to forskolin treatment. Increased expression of ICER correlates with decreased
FasL
expression in both T and NK cells. ICER binds specifically to the proximal DNA binding site of the nuclear factor of activated T cells (NFAT) in the
FasL
promoter and in the presence of the minimal NFAT DNA-binding domain, the proximal NFAT motif allows ICER and NFAT to form an NFAT/ICER ternary complex in vitro. Moreover, in the activated 2B4 T cell hybridoma, the proximal NFAT motif participates in the down-regulation of the
FasL
promoter mediated by ICER. These findings provide further insight into the mechanism involved in cAMP-mediated transcriptional attenuation of
FasL
expression in T and NK lymphocytes.
...
PMID:Differential inducibility of the transcriptional repressor ICER and its role in modulation of Fas ligand expression in T and NK lymphocytes. 1175 61
The lung can be exposed to a variety of reactive nitrogen intermediates through the inhalation of environmental oxidants and those produced during inflammation. Reactive nitrogen species (RNS) include, nitrogen dioxide (.NO2) and peroxynitrite (ONOO-). Classically known as a major component of both indoor and outdoor air pollution, .NO2 is a toxic free radical gas. .NO2 can also be formed during inflammation by the decomposition of ONOO- or through peroxidase-catalyzed reactions. Due to their reactive nature, RNS may play an important role in disease pathology. Depending on the dose and the duration of administration, .NO, has been documented to cause pulmonary injury in both animal and human studies. Injury to the lung epithelial cells following exposure to .NO2 is characterized by airway denudation followed by compensatory proliferation. The persistent injury and repair process may contribute to airway remodeling, including the development of fibrosis. To better understand the signaling pathways involved in epithelial cell death by .NO2 or otherRNS, we routinely expose cells in culture to continuous gas-phase .NO2. Studies using the .NO2 exposure system revealed that lung epithelial cell death occurs in a density dependent manner. In wound healing experiments, .NO2 induced cell death is limited to cells localized in the leading edge of the wound. Importantly, .NO2-induced death does not appear to be dependent on oxidative stress per se. Potential cell signaling mechanisms will be discussed, which include the mitogen activated
protein kinase
, c-Jun N-terminal Kinase and the Fas/
Fas ligand
pathways. During periods of epithelial loss and regeneration that occur in diseases such as asthma or during lung development, epithelial cells in the lung may be uniquely susceptible to death. Understanding the molecular mechanisms of epithelial cell death associated with the exposure to .NO2 will be important in designing therapeutics aimed at protecting the lung from persistent injury and repair.
...
PMID:Molecular mechanisms of nitrogen dioxide induced epithelial injury in the lung. 1216 62
Regulatory RNAs are noncoding RNAs that can regulate gene expression. Our previous results showed that regulatory RNAs can induce the production of interleukin-1, interleukin-2, interleukin-8, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, and
Fas ligand
(
FasL
). These cytokines and
FasL
are involved in host defense mechanisms against tumors. B16-F10 melanoma cells are highly metastatic to the lungs and we showed that lymphocytes treated with the regulatory B16-RNA reduce significantly the number of metastatic nodules. We also found that B16-RNA activates RNA-dependent
protein kinase
(PKR) and the active B16-RNA fraction is polyadenylated with a sedimentation coefficient of 18S. Our findings suggest that the antitumor activity of B16-RNA is mediated by PKR through activation of the transcription factor NF-kappaB. Thus, B16-RNA may act as a regulatory RNA and may regulate gene expression at transcriptional level. This study provides the rationale for the use of B16-RNA as an immunomodulator in melanoma.
...
PMID:Antitumor activity induced by regulatory RNA: possible role of RNA-dependent protein kinase and nuclear factor-kappaB. 1268 31
Opioid effects on tumor growth have been a controversial topic of discussion. In the present study, morphine inhibited tumor cell proliferation at concentrations of >or=10 micro M. This was primarily caused by inhibition of cell cycle progression from G(1) to S phase. At higher concentrations (>or=500 micro M for 24 h), morphine also caused cell death. In nude mice, morphine significantly reduced the growth of MCF-7 and MDA-MB231 tumors but had no effect on HT-29 tumor growth. In these experiments, morphine plasma concentrations were similar to those found in cancer patients receiving chronic morphine treatment for pain relief (0.9-3.4 micro M). In MCF-7 and MDA-MB231 cells, morphine caused a naloxone (Nx)- and pertussis toxin-sensitive, concentration-dependent increase of GTPase activity, indicating that morphine signals could be transduced by opioid receptors via a G protein. However, the antiproliferative effects of morphine were not antagonized by Nx, pertussis toxin, forskolin, and 8-bromo-cAMP, suggesting that the typical opioid receptor-coupled signaling cascade involving the G(i), adenylyl cyclase, and
protein kinase A
was not involved. Instead, morphine caused an NH(2)-terminal phosphorylation of p53 at Ser(9) and/or Ser(15) and a stabilization of p53 in MCF-7 cells that express wild-type p53. p53 phosphorylation was not antagonized by Nx and resulted in an increase of p53-dependent proteins including p21, Bax, and the death receptor Fas. Blockade of Fas by Fas-fusion protein or inhibition of caspase 8 resulted in a partial inhibition of morphine-induced apoptosis. In addition,
Fas ligand
only induced apoptosis when administered together with morphine. However, the sensitivity of the tumor cells toward
Fas ligand
remained low. HT-29 cells, which express dominant negative p53 and show no increase of GTPase activity when treated with morphine, were less sensitive in vitro and were not affected in vivo. Our results suggest that morphine, alone or in combination with Nx, may reduce the growth of certain tumors, apparently in part through activation of p53.
...
PMID:G protein-independent G1 cell cycle block and apoptosis with morphine in adenocarcinoma cells: involvement of p53 phosphorylation. 1270 72
Recently, it has been shown that
Fas ligand
(
FasL
) interacts with the extracellular matrix (ECM) protein fibronectin (FN), and that the bound
FasL
retains its cytotoxic efficacy. Herein, we examined the ramifications of
FasL
-ECM protein interactions throughout a specific time period, in the absence or presence of additional activating molecules, assuming that these complexed interactions occur during inflammation. We found that exposure of purified human T cells to FN-associated recombinant
FasL
for as brief as 5-10 min at 0.1-100 ng/ml induced their adhesion in beta(1) integrin- and FasR-dependent manners while activating the intracellular
protein kinase
, Pyk-2. The FN-associated
FasL
stops the CXCL12 (stromal cell-derived factor 1alpha)-induced chemotaxis of T cells by inhibiting the chemokine-induced extracellular signal-regulated kinase signaling and cytoskeletal rearrangement. This short term exposure of T cells to the FN-bound
FasL
(1 ng/ml), which was followed by T cell activation via the CD3 complex, resulted in 1) increased secretion of IFN-gamma (measured after 24 h), and 2) enhanced T cell apoptosis (measured after 72 h). Thus, in the context of inflamed ECM and depending on the time after
FasL
activation, its concentration, and the nature of other contextual mediators,
FasL
initially retains effector T cells at sites of inflammation and, later, induces T cell apoptosis and return to homeostasis.
...
PMID:Fibronectin-associated Fas ligand rapidly induces opposing and time-dependent effects on the activation and apoptosis of T cells. 1463 98
cAMP has previously been shown to promote cell survival in a variety of cell types, but the downstream signaling pathway(s) of this antiapoptotic effect is unclear. Thus the role of cAMP signaling through
PKA
and cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs) in cAMP's antiapoptotic action was investigated in the present study. cAMP's protective effect against bile acid-,
Fas ligand
-, and TNF-alpha-induced apoptosis in rat hepatocytes was largely unaffected by the selective
PKA
inhibitor, Rp-8-(4-chlorophenylthio)-cAMP (Rp-cAMP). In contrast, a novel cAMP analog, 8-(4-chlorophenylthio)-2'-O-methyl (CPT-2-Me)-cAMP, which activated cAMP-GEFs in hepatocytes without activating
PKA
, protected hepatocytes against apoptosis induced by bile acids,
Fas ligand
, and TNF-alpha. The role of cAMP-GEF and
PKA
on activation of Akt, a kinase implicated in cAMP survival signaling, was investigated. Inhibition of
PKA
with RP-cAMP had no effect on cAMP-mediated Akt phosphorylation, whereas CPT-2-Me-cAMP, which did not activate
PKA
, induced phosphatidylinositol 3-kinase (PI3-kinase)-dependent activation of Akt. Pretreatment of hepatocytes with the PI3-kinase inhibitor, Ly-294002, prevented CPT-2-Me-cAMP's protective effect against bile acid and
Fas ligand
, but not TNF-alpha-mediated apoptosis. Glucagon, CPT-cAMP, and CPT-2-Me-cAMP all activated Rap 1, a downstream effector of cAMP-GEF. These results suggest that a
PKA
-independent cAMP/cAMP-GEF/Rap pathway exists in hepatocytes and that activation of cAMP-GEFs promotes Akt phosphorylation and hepatocyte survival. Thus a cAMP/cAMP-GEF/Rap/PI3-kinase/Akt signaling pathway may confer protection against bile acid- and Fas-induced apoptosis in hepatocytes.
...
PMID:Activation of cAMP-guanine exchange factor confers PKA-independent protection from hepatocyte apoptosis. 1504 79
Herpes simplex virus 1 encodes at least four genes whose functions include blocking apoptosis induced by exogenous agents (e.g., sorbitol,
Fas ligand
, and BAD protein) or replication-incompetent mutants (e.g., the d120 mutant lacking both copies of the alpha 4 gene). U(S)3, one of these four genes, encodes a serine-threonine kinase that has been demonstrated to block apoptosis induced by proapoptotic cellular proteins or by the d120 mutant. The amino acid context of serine-threonine phosphorylated by U(S)3 is similar to that of the
cAMP-dependent protein kinase
PKA
. We report that (i) the pattern of proteins phosphorylated by U(S)3 in transduced cells or in cells infected with WT virus overlaps that of phosphoproteins targeted by
PKA
, (ii) activation of
PKA
blocks apoptosis induced by d120 mutant or by BAD protein independently of U(S)3, (iii) U(S)3
protein kinase
phosphorylates peptides containing the serine or threonine targeted by
PKA
including that present in the regulatory type II alpha subunit of
PKA
, and (iv) in WT virus-infected cells the regulatory type II alpha subunit is phosphorylated in a U(S)3-dependent manner. We conclude that a major determinant of the antiapoptotic activity of the U(S)3
protein kinase
is the phosphorylation of
PKA
substrates by either or both enzymes.
...
PMID:Herpes simplex virus protein kinase US3 activates and functionally overlaps protein kinase A to block apoptosis. 1519 52
We have been investigating an apoptosis induction in human fetal membrane cells by influenza virus (IV) infection and the contribution of apoptosis induction to the viral infection-defense response between a fetus and the maternal body. For studying any role of uterine cells in the anti-viral response, we investigated the molecular mechanism of the apoptotic induction in human uterine cervical fibroblast cell line (HCF) by IV infection. IV type A and B infection induced DNA fragmentation in HCF. In IV-infected HCF, gene mRNA expression levels of interleukine (IL)-1beta, IL-6, tumor necrosis factor (TNF) alpha,
Fas ligand
, interferon regulatory factor (IRF)-1, interferon (IFN) alpha and IFN beta increased as compared with those in mock treatment cells, and the induction of mRNAs for double stranded RNA dependent
protein kinase
(PKR), indolamine 2,3-deoxygenase (IDO) and 2'-5' oligoadenylate synthetase (2-5 OAS) were indicated, which had a role for a host defense response induced by IFN-beta. The amount of IFN-beta protein increased by IV-infection, and DNA fragmentation was inhibited with anti-IFN-beta antibody and PKR inhibitor (2-aminopurine). Furthermore, a synthetic double stranded RNA, poly I : C, could induce almost the same phenomena as that induced by virus infection. We conclude that IV-infection induces the apoptosis in HCF cells through the IFN-beta expression regulated by double stranded RNA and IRF-1 induction, and suggest that the IFN-beta induction may be the predominant contribution to the IV infection induced HCF apoptosis.
...
PMID:Predominant contribution of IFN-beta expression to apoptosis induction in human uterine cervical fibroblast cells by influenza-virus infection. 1551 17
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