Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A human non-small-cell lung carcinoma cell line, Calu-6 (from an anaplastic carcinoma), was transfected with the Ki-ras-related anti-oncogene Krev-1. Several transfectant lines were obtained that showed a reduced tumorigenicity in nude mice with respect to the parental and control transfected cell lines. This decrease was approximately 50% in tumor incidence at 4 wk after subcutaneous inoculation of the transfected cells. In addition, the volume of the Calu-6 revertant-derived tumors was three to 10 times smaller than that of the equivalent tumors produced by inoculation of the control cell line transfected with the neomycin-resistance gene. Krev-1--transfected cells that exhibited reduced tumorigenicity expressed Krev-1 mRNA and had variable numbers of copies of the Krev-1 gene. Moreover, Krev-1--transfected cells exhibited a more differentiated squamous epithelial morphology than the parental and control cell lines did. Moderately elevated levels of protein kinase C activity were detected in some revertant clones. Such activity correlated with the level of expression of Krev-1 mRNA in most cases. In summary, Krev-1 induced important morphological and biological changes in transfected Calu-6 cells that we interpreted as partial reversion of the malignant phenotype.
 ...
PMID:Partial suppression of tumorigenicity in a human lung cancer cell line transfected with Krev-1. 148 16

Cell cycle progression requires activation of different cyclin-dependent kinases (CDKs) which are positively regulated by cyclins and negatively regulated by CDK inhibitors. Growth inhibition of the Calu-1 lung carcinoma cells induced with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), a potent activator of protein kinase C, is associated with G2/M arrest and induction of expression of a novel, faster-migrating form of p21(WAF1/CIP1/SDI1) (p21) protein, an inhibitor of cyclin-dependent kinases. This faster-migrating p21 protein was also expressed in TPA-treated A549 lung carcinoma cells which also exhibited G2/M arrest but not in TPA-treated U937 leukemia cells, which only expressed a slower-migrating form of p21 protein. However, reverse transcriptase-polymerase chain reaction and Southern analysis demonstrated no evidence of novel splice in TPA-treated Calu-1 cells. On the other hand, immunoblotting analysis demonstrated that the faster-migrating p21 protein could be detected only by peptide antibody directed against the N terminus but not the C terminus, suggestive of truncation of the latter or protein modification that results in the loss of the C-terminal epitope. Correlation of G2/M arrest with expression of the faster-migrating p21 protein suggests that this novel form of p21 protein may be a mediator of G2/M arrest and growth inhibition.
 ...
PMID:Novel form of p21(WAF1/CIP1/SDI1) protein in phorbol ester-induced G2/M arrest. 893 83

Keratinocyte growth factor (KGF) has recently been shown to protect rats from hyperoxia-induced lung injury. However, the mechanism of the protective effect of KGF remains unclear. To elucidate the mechanism of action of KGF, we determined the effect of KGF on the barrier function of epithelial monolayers exposed to H(2)O(2). Calu-3 (human airway epithelial cells) were grown on Transwell membranes, and the permeability to fluorescein isothiocyanate-albumin was measured. Exposure to 0.5 mM H(2)O(2) significantly increased permeability from 1.50 +/- 0.09 to 24.8 +/- 1.5 (mean +/- SE x 10(-6) cm/s; P < 0.001). Incubation of monolayers with 50 ng/ml KGF for 24 h significantly reduced basal albumin flux (0.85 +/- 0.09; P < 0.001), and pretreatment with KGF completely abolished the H(2)O(2)-induced permeability increase (1.08 +/- 0.09). The protective effect of KGF was dose dependent and was observed at concentrations as low as 1 ng/ml. Partial amelioration of the H(2)O(2)-induced permeability increase occurred after 1 h of exposure to KGF. Treatment of cells with calphostin C, an inhibitor of protein kinase C (PKC), had no effect on the permeability of control or H(2)O(2)-treated cells. Calphostin C abolished both the KGF-mediated decrease in basal albumin flux and the protective effect of KGF against H(2)O(2)-induced increases in permeability. KGF pretreatment also prevented H(2)O(2)-induced disruption of F-actin staining patterns, suggesting stabilization of the cytoskeleton. These studies demonstrate that KGF decreases albumin flux across airway epithelial monolayers and prevents H(2)O(2)-induced increases in permeability by a PKC-dependent process that may involve stabilization of the cytoskeleton.
 ...
PMID:KGF prevents hydrogen peroxide-induced increases in airway epithelial cell permeability. 914 42

The activity of the CFTR Cl- channel is dependent on its phosphorylation status set by kinases and phosphatases. We report here that protein phosphatase 2B (PP2B) and protein kinase C (PKC) are potential regulators of the cystic fibrosis conductance regulator (CFTR). Treating CFTR-expressing 3T3 cells with either of the two specific PP2B blockers cyclosporin A (CsA, 1 microM) or deltamethrin (DM, 30 nM) caused rapid activation of CFTR in cell-attached patches. As determined by noise analysis of multi channel patches, DM- or CsA-activated CFTR displayed gating kinetics comparable to those of forskolin-activated CFTR. After activation of CFTR by blocking PP2B, CFTR still inactivated. CFTR-mediated currents were, on average, 6.1 times larger when cells were stimulated by forskolin during PP2B block compared to stimulation by forskolin alone. This suggests that, in CFTR-expressing 3T3 cells, a phosphorylation site of CFTR is regulated by cellular PKA, PP2B and another phosphatase. However, in the epithelial cell lines Calu-3 and HT-29/B6, CsA and DM had no effect on CFTR activity in both cell-attached patch-clamp and transepithelial experiments. In contrast, when exogenous PP2B was added to patches excised from 3T3 or Calu-3 cells, PKA-activated CFTR currents were quickly inactivated. This indicates that free exogenous PP2B can inactivate CFTR in patches from both cell types. We propose that in order to regulate CFTR in an intact cell, PP2B may require a selective subcellular localization to become active. When excised patches were PKC-phosphorylated, the gating kinetics of CFTR were significantly different from those of PKA-phosphorylated CFTR. Addition of PP2B also inactivated PKC-activated CFTR showing the indiscriminate dephosphorylation of different phosphorylation sites by PP2B.
 ...
PMID:Regulation of CFTR by protein phosphatase 2B and protein kinase C. 959 16

In patients undergoing radiation therapy in the thoracic region, ionizing radiation causes immediate damage to pulmonary endothelial and epithelial cells. We have recently shown that keratinocyte growth factor (KGF) protects against increases in permeability induced by hydrogen peroxide in human airway epithelial cells. Since radiation injury involves the production of oxygen free radicals, we tested the hypothesis that KGF would protect against radiation-induced increases in permeability. Two lines of human airway epithelial cells (Calu-3 and 16HBE14o-) were grown on collagen-coated polyester membranes (Transwell, Costar) and the permeability of the monolayers was determined by measuring the flux of tracers from the top chamber to the bottom chamber as a function of time. Changes in permeability were apparent 4 h after exposure. Increasing doses of radiation (2-10 Gy) stimulated significant increases in permeability compared with control monolayers (P < 0. 05, n=5-10) in Calu-3 and 16HBE14o- cells. KGF (50 ng/ml) alone reduced permeability significantly compared with controls, protected against increases in permeability with low doses of radiation and provided partial protection at higher doses. KGF also provided a significant effect in cells irradiated with 10 Gy (n=5, P < 0. 05) when given for the 4 h immediately after irradiation. The effects of KGF were sustained. After a full 24-h pretreatment with KGF, cells were incubated in medium without KGF for 8 or 12 h prior to 10 Gy irradiation. Both of these treatments significantly reduced permeability to albumin in sham-irradiated and irradiated cells (n=3, P < 0.05). To investigate the signal transduction pathways through which KGF mediates protection, permeability was measured in the presence of the protein kinase C (PKC) inhibitor, calphostin C, or the tyrosine kinase inhibitor, genistein. Inhibition of PKC blocked the decrease in basal tracer flux caused by KGF treatment in both cell types and removed the KGF-mediated protection against radiation. Incubation with genistein completely blocked the KGF-mediated decrease in the baseline tracer flux, as well as the ameliorating effect observed after irradiation. Rhodamine-phalloidin staining of the F-actin cytoskeleton showed disruption of the cytoskeleton with radiation exposure, increased density of F-actin filaments with KGF treatment, and resistance to disruption when cells were pretreated with KGF and exposed to radiation. Our results suggest that KGF regulates permeability in airway epithelium through a pathway mediated by PKC and tyrosine kinase that stabilizes the F-actin cytoskeleton.
 ...
PMID:Barrier function of airway epithelium: effects of radiation and protection by keratinocyte growth factor. 969 65

Delivery of IgA to the mucosal surface occurs via transcytosis of polymeric IgA (pIgA) across the epithelium, a process mediated by the pIgR. Several factors increase pIgR expression in human epithelial cells, including IL-4 and IFN-gamma. Using an RNase protection assay, we found that IL-4 and IFN-gamma increase steady state levels of pIgR mRNA in both human intestinal (HT29) and airway (Calu-3) epithelial cells. Time course studies in HT29 clone 19A cells showed that with each cytokine alone and with both together: 1) there was a significant lag before mRNA levels increased; 2) maximal levels were not reached until 48-72 h after the addition of cytokines; 3) mRNA levels remained elevated in the continued presence of cytokines; and 4) addition of actinomycin D or removal of cytokines led to decreases in mRNA levels with a half-life of approximately 20-28 h. Cytokine-dependent increases in steady state levels of pIgR mRNA were inhibited by cycloheximide and by protein tyrosine kinase inhibitors but not by inhibitors of protein kinase C or cAMP-dependent protein kinase A. Both IFN-gamma and IL-4 increased expression of the inducible transcription factor IFN regulatory factor-1 (IRF-1), but levels of IRF-1 only weakly correlated with levels of pIgR mRNA, suggesting that additional transcription factors are required. These studies provide additional insights into the mechanisms by which cytokines regulate expression of the pIgR, a central player in mucosal immunity.
 ...
PMID:IL-4 and IFN-gamma increase steady state levels of polymeric Ig receptor mRNA in human airway and intestinal epithelial cells. 1022 81

The intracellular pathway of polymeric immunoglobulin receptor (pIgR) is governed by multiple signals that lead to constitutive transcytosis. In addition, in transfected polarized MDCK cells, polymeric immunoglobulin A (pIgA) binding stimulates rabbit pIgR-transcytosis, owing to phospholipase-C gamma 1 activation and increase of intracellular calcium. Transcytosis of rat pIgR across hepatocytes is similarly accelerated by pIgA injection. In contrast we show here that human Madrin-Darby Canine Kidney (pIgR)-transcytosis, in human Calu-3 and human pIgR-transfected MDCK cells, is not promoted by pIgA, as monitored by a continuous apical release of its secreted ectodomain. However, the incubation of cells expressing human or rabbit pIgR with pIgA induces a comparable IP3 production, and pIgR-transcytosis of either species is accelerated by the protein kinase C (PKC)-activator phorbol myristate acetate. Without pIgA, mimicking phospholipase-C activation by combining low concentrations of phorbol myristate acetate with ionomycin, or high concentrations of ionomycin alone, stimulates the rabbit, but not the human, pIgR transcytosis. These data suggest that the species difference in pIgA-induced pIgR-transcytosis does not stem from the defective production of second messengers, but from a different sensitivity of pIgR to intracellular calcium. Our results outline the danger of extrapolating to humans the abundant data obtained from mucosal vaccination of laboratory animals.
 ...
PMID:Polymeric IgA binding to the human pIgR elicits intracellular signalling, but fails to stimulate pIgR-transcytosis. 1116 7

Cl- transport proteins expressed in a Calu-3 airway epithelial cell line were differentiated by function and regulation by protein kinase C (PKC) isotypes. mRNA expression of Cl- transporters was semiquantitated by RT-PCR after transfection with a sense or antisense oligonucleotide to the PKC isotypes that modulate the activity of the cystic fibrosis transmembrane conductance regulator [CFTR (PKC-epsilon)] or of the Na/K/2Cl (NKCC1) cotransporter (PKC-delta). Expression of NKCC1 and CFTR mRNAs and proteins was independent of antisense oligonucleotide treatment. Transport function was measured in cell monolayers grown on a plastic surface or on filter inserts. With both culture methods, the antisense oligonucleotide to PKC-epsilon decreased the amount of PKC-epsilon and reduced cAMP-dependent activation of CFTR but not alpha(1)-adrenergic activation of NKCC1. The antisense oligonucleotide to PKC-delta did not affect CFTR function but did block alpha(1)-adrenergic activation of NKCC1 and reduce PKC-delta mass. These results provide the first evidence for mRNA and protein expression of NKCC1 in Calu-3 cells and establish the differential regulation of CFTR and NKCC1 function by specific PKC isotypes at a site distal to mRNA expression and translation in airway epithelial cells.
 ...
PMID:Differential regulation of Cl- transport proteins by PKC in Calu-3 cells. 1123 15

In this study, we tested the hypothesis that intracellular Cl(-) (Cl) regulates the activity of protein kinase C (PKC)-delta and thus the activation of Na-K-Cl cotransport (NKCC1) in a Calu-3 cell line. The alpha(1)-adrenergic agonist methoxamine (MOX) and hypertonic sucrose increased Cl and increased or decreased intracellular volume, respectively, without changing Cl concentration ([Cl(-)](i)). Titration of [Cl(-)](i) from 20-140 mM in nystatin-permeabilized cell monolayers did not affect the baseline activity of PKC-delta, PKC-zeta, or rottlerin-sensitive NKCC1. At 200 mM Cl(-), rottlerin-sensitive NKCC1 was activated, and PKC isotypes were localized predominantly to a particulate fraction. MOX induced a biphasic increase in NKCC1 activity and PKC-delta in activity and particulate localization of PKC-delta and -zeta. Activity of NKCC1 and PKC-delta decreased with increasing Cl from 20 to 80 mM Cl then increased at 140-200 mM Cl apparently as an additive effect to high [Cl(-)](i) levels. Rottlerin inhibited the effects of MOX, which indicates that PKC-delta was required for activation of NKCC1. The results indicate that, in airway epithelial cells, a Cl electrochemical gradient alone is not sufficient to stimulate NKCC1 activity; rather, elevated activity of PKC-delta is necessary. Further, high Cl levels induce a subcellular redistribution of PKC-delta, which results in increased enzyme activity.
 ...
PMID:Modulation of Na-K-2Cl cotransport by intracellular Cl(-) and protein kinase C-delta in Calu-3 cells. 1194 82

The goal of this study was to determine whether the extracellular regulated kinases (ERK1/2) are involved in leukocyte transmigration across airway epithelium and the associated changes in epithelial permeability. In vitro, we used formyl-methionyl-leucyl-phenylalanine (fMLP) to induce migration of HL-60 cells (a human leukocyte cell line) across sheets of polarized Calu-3 airway epithelial cells and also to induce migration of human neutrophils across primary cultures of cow tracheal epithelial cells. In both systems, leukocyte migration decreased transepithelial electrical resistance (R(te)), increased epithelial permeability to albumin (P(alb)), and increased ERK1/2 phosphorylation in epithelial cells. Leukocyte migration and the associated changes in R(te), P(alb), and ERK1/2 phosphorylation were inhibited by calphostin C, a blocker of protein kinase C (PKC), and by PD98059 (a blocker of ERK1/2). Leukocyte transmigration in rat tracheas in vivo was induced with fMLP, and was associated with increased P(alb) and phosphorylation of epithelial ERK1/2. Again, migration and the associated changes were inhibited by luminal PD98059 or calphostin C though neither agent affected rat leukocyte migration in Boyden chambers in vitro. We conclude that PKC and ERK1/2 pathways are activated in airway epithelial cells during migration of leukocytes and are important regulators of airway epithelial permeability.
 ...
PMID:Activation of extracellular regulated kinases is required for the increase in airway epithelial permeability during leukocyte transmigration. 1284 51


1 2 3 Next >>