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

We have examined the effect of the macrocyclic lactone protein kinase C (PK-C) activator bryostatin 1 on the in vitro radioprotective capacity of recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) toward normal committed myeloid progenitor cells (day-14 granulocyte-macrophage colony-forming units [CFU-GM]). Preincubation of T-cell- and adherent cell-depleted bone marrow mononuclear cells with 12.5 nM bryostatin 1 and either 1.25 or 50 ng/ml rGM-CSF for 24 h resulted in an 18%-30% survival at 4-5 Gy, whereas cells exposed to rGM-CSF alone gave rise to no detectable colonies at radiation doses greater than 2.5 Gy. Coadministration of bryostatin 1 also led to a threefold increase in Do values for both rGM-CSF concentrations. A similar enhancement of radioprotective effects was observed with the tumor-promoting phorbol ester phorbol dibutyrate. Exposure of cells to both bryostatin 1 and rGM-CSF immediately following irradiation also resulted in enhanced progenitor cell survival when compared to rGM-CSF alone, but radioprotective effects were less than those observed when cells were preincubated with these factors. Cells preconditioned with bryostatin 1 and rGM-CSF prior to exposure to 2 or 4 Gy gave rise to significantly more colonies when radiation was administered as a 4-h divided dose, suggesting that bryostatin 1 may act by potentiating rGM-CSF-induced repair of sublethal radiation damage. Finally, pre-exposure of enriched progenitor cells (CD34+) to bryostatin 1 and rGM-CSF resulted in radioprotective effects that were less than those observed for partially purified populations with respect to the total population of surviving myeloid colonies. However, CD34+ cells preincubated with bryostatin 1 and rGM-CSF prior to irradiation exhibited a significant increase in both the percentage and absolute number of neutrophilic and macrophage colonies, and a reduction in eosinophilic colonies, compared to cells exposed to rGM-CSF alone. These studies suggest that bryostatin 1 (and possibly other PK-C activators) potentiates the in vitro radioprotective effects of rGM-CSF and may also regulate the lineage specificity of this response.
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PMID:Effect of bryostatin 1 on the in vitro radioprotective capacity of recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) toward committed human myeloid progenitor cells (CFU-GM). 137 43

Stimulation of hemopoietic cells with IL-3, IL-4, IL-5, granulocyte-macrophage-CSF and Steel factor-(SLF) induced tyrosine phosphorylation of a number of protein substrates. Two of these proteins, designated p42 and p44, were tyrosine phosphorylated rapidly in response to treatment with IL-3, IL-5, granulocyte-macrophage-CSF and SLF, but not IL-4. We demonstrate that these common substrates are members of the mitogen-activated protein kinase (MAP kinase) family of protein serine/threonine kinases. Ion-exchange chromatography yielded a peak of MAP kinase activity eluting at 0.3 to 0.32 M NaCl. Immunoblotting of column fractions with antiphosphotyrosine antibodies showed coelution of the peak of MAP kinase enzyme activity with the p42 and p44 tyrosine phosphorylated species, and with two proteins of 42 and 44 kDa which were immunoreactive with anti-MAP kinase antibodies. Moreover, a characteristic shift in mobility of the p42 and p44 species was observed after factor treatment. Time-course analyses and subsequent ion-exchange chromatography demonstrated SLF activation of MAP kinase activity was maximal after 2 min of factor treatment and decreased to basal levels after 30 min stimulation. By contrast, activation of MAP kinase after IL-5 treatment was not as rapid. Maximal activity was observed 15 min after stimulation and remained elevated for up to 60 min after IL-5 addition. Investigation of the role of protein kinase C in the mechanism of activation by these growth factors demonstrated that specific inhibition of protein kinase C led to a reduction, but not ablation, of the SLF and IL-3 induced stimulation of MAP kinase activity. The use of synthetic peptide substrates confirmed SLF and IL-5 activate isoforms of MAP kinases. These results demonstrate that members of the MAP kinase family are involved in common signal transduction events elicited by IL-3, IL-5, granulocyte-macrophage-CSF and Steel factor, but not those involving IL-4.
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PMID:Multiple hemopoietic growth factors stimulate activation of mitogen-activated protein kinase family members. 138 May 36

The activity of protein kinase C (PK-C) has been implicated in the regulation of the growth and differentiation of both normal and neoplastic hematopoietic cells. We have examined the effects of the PK-C-activating agents phorbol 12,13-dibutyrate (PDBu), mezerein, and bryostatin 1 on the proliferation and lineage commitment of CD34+ human myeloid progenitor cells stimulated by recombinant interleukin-3 (rIL-3) and/or recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF). Although each of the PK-C activators administered alone induced no colony formation, coadministration of these agents with plateau concentrations of each cytokine (eg, 50 ng/mL) increased the number of day 14 granulocyte-macrophage colony-forming units by 100% to 150%. The number of pure and mixed neutrophil and macrophage colonies was substantially enhanced in the presence of PK-C activators, whereas the percentage and, in most cases, the absolute number of eosinophilic colonies was significantly reduced. The inhibition of eosinophilic colony formation was not overcome by the addition of rIL-5. Although addition of bryostatin 1 24 hours before rIL-3 abrogated the increase in total colony formation observed with simultaneous administration of factors, the inhibition of eosinophilic colonies and the increase in neutrophil/macrophage colonies persisted under these conditions. The addition of bryostatin 1 for up to 144 hours after rIL-3 continued to potentiate total colony formation, whereas the inhibition of eosinophilic commitment was lost after 120 hours. Together, these results suggest that pharmacologic interventions at the level of PK-C may regulate both the proliferation as well as the lineage commitment of human hematopoietic progenitors exposed to rGM-CSF and rIL-3.
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PMID:Bryostatin 1 modulates the proliferation and lineage commitment of human myeloid progenitor cells exposed to recombinant interleukin-3 and recombinant granulocyte-macrophage colony-stimulating factor. 142 72

We have examined the effect of a combined 24 h exposure to cytosine arabinoside (ara-C) and the protein kinase C activator bryostatin 1, either alone or in conjunction with recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF), on the clonogenic growth of 14 primary samples from acute myelogenous leukemia (AML) patients, as well as normal human committed and early hematopoietic progenitors. Incubation of blasts with 1 microM ara-C and 12.5 nM bryostatin 1(+/- 1.25 ng/ml rGM-CSF) resulted in a heterogeneous pattern of inhibitory effects toward primary leukemic colonies, ranging from 32-98%, and subadditive to synergistic drug interactions. However, exposure of blasts to ara-C and bryostatin 1, either with or without rGM-CSF, eliminated leukemic cell self-renewal in 80-93% of samples, and very substantially reduced growth in the remainder. Exposure of normal human bone marrow mononuclear cells to identical concentrations of ara-C and byostatin 1 permitted the survival of 23% of committed myeloid progenitors (granulocyte-macrophage colony-forming units), and greater than 50% when rGM-CSF was included. Finally, exposure of bone marrow populations highly enriched for progenitor cells (CD34+, DR-, CD71-) to ara-C and bryostatin 1 +/- rGM-CSF for 24 h led to minimal reductions (e.g. 10-15%) in the survival of early hematopoietic progenitors (high proliferative potential colony-forming cells). Together, these findings indicate that combined exposure in vitro to ara-C and bryostatin 1, both with and without rGM-CSF, effectively inhibits the growth of leukemic cells with self-renewal capacity, while sparing a significant fraction of normal committed and primitive hematopoietic progenitors.
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PMID:Effect of a combined exposure to cytosine arabinoside, bryostatin 1, and recombinant granulocyte-macrophage colony-stimulating factor on the clonogenic growth in vitro of normal and leukemic human hematopoietic progenitor cells. 159 8

The immunomodulator AS101 has recently been found to have radioprotective properties when injected prior to sublethal and lethal doses of irradiation. In addition, this compound was found to protect mice from hemopoietic damage caused by sublethal doses of cyclophosphamide (CYP) and to increase the rate of survival of mice treated with lethal doses of CYP. AS101 was previously shown to exert a synergistic effect with the PKC-inducer bryostatin in cytokine secretion in vitro. The present studies were designed to evaluate the effects of in vivo combined treatment with AS101 and bryostatin on bone marrow and spleen cellularity and on the number of committed progenitors in the bone marrow at various points of time after their treatment with a sublethal dose of CYP or irradiation. In addition, the combined effect was tested on the survival of mice irradiated with a lethal dose of irradiation. Our data show the presence of synergism which greatly enhances the number of bone marrow and spleen cells 48 hr and 9 days after CYP treatment or irradiation. The combined effect was also demonstrated when bone marrow colony-forming units granulocyte-macrophage (CFU-GM) progenitor cells were evaluated. Moreover, AS101 and bryostatin synergized in their protective effects against lethal damages of irradiation. These results strongly suggest that bryostatin, which lacks tumor-promoting activity, is a particularly good candidate in combination with AS101 for treatment in vivo in counteracting chemotherapy- or radiation-induced hematopoietic suppression or in generally improving the restoration of immune response under conditions involving immune or hemopoietic damage.
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PMID:In vivo synergistic effect of the immunomodulator AS101 and the PKC inducer bryostatin. 162 62

Purified hematopoietic growth factors such as colony-stimulating factor-1 (CSF-1) or macrophage CSF, granulocyte-macrophage CSF, and interleukin-3 or multi-CSF, stimulate the urokinase-type plasminogen activator (u-PA) activity of murine bone marrow-derived macrophages (BMM) and resident peritoneal macrophages. Granulocyte-CSF was inactive. The increases in BMM u-PA activity were inhibited by the glucocorticoid dexamethasone, and by agents that raise intracellular cyclic adenosine monophosphate levels, including prostaglandin E2 and cholera toxin. These changes in u-PA activity were paralleled by corresponding changes in u-PA mRNA levels. Evidence was obtained for protein kinase C and phospholipase C-mediated stimulation of BMM u-PA activity and mRNA levels; however, no evidence was found for an involvement of Na+/H+ exchange or Na+, K(+)-ATPase activity, Ca2+ fluxes, or pertussis toxin-sensitive G proteins. Several findings point to a dissociation between macrophage u-PA expression and DNA synthesis.
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PMID:Activation and proliferation signals in murine macrophages. Biochemical signals controlling the regulation of macrophage urokinase-type plasminogen activator activity by colony-stimulating factors and other agents. 184 64

The effect of pharmacologic manipulation of protein kinase C (PK-C) activity on the response of committed human myeloid progenitor cells (CFU-GM) to recombinant human granulocyte-macrophage colony stimulating factor (rGM-CSF) was assessed. Coadministration of the PK-C activating agents, phorbol dibutyrate (PDBu) or bryostatin 1, with rGM-CSF resulted in a dose-dependent and, under some conditions, highly synergistic increase in the number of CFU-GM. With optimal combinations, colony formation far exceeded that which could be obtained with high concentrations of rGM-CSF alone. High concentrations of PDBu (e.g. greater than or equal to 50 nM), but not bryostatin 1, completely inhibited the CFU-GM response. These inhibitory effects could be reversed by bryostatin 1, but not by high concentrations of rGM-CSF. Bryostatin 1 also potentiated colony formation in response to rGM-CSF, and blocked the inhibitory effects of high concentrations of PDBu in bone marrow cells highly enriched for progenitors bearing the MY-10 antigen. The increase in CFU-GM induced by PDBu or bryostatin 1 was associated with little change in the morphologic type of colony observed. Continuous exposure of cells to the calcium ionophore, ionomycin (500 nM), reduced the number of granulocyte-macrophage colonies, but produced little change in the concentration-response of rGM-CSF and PK-C activating agents. Finally, the PK-C inhibitors H-7 and tamoxifen, when administered at concentrations exhibiting minimal inhibitory effects in the presence of rGM-CSF alone, led to no change or small increases in the numbers of colonies formed in response to rGM-CSF and bryostatin-1, and a substantial increase in the number of colonies formed in the presence of rGM-CSF and PDBu. These results suggest that PK-C activation may play a complex role in regulating the response of normal myeloid progenitors to growth factors such as rGM-CSF. They also raise the possibility that under some circumstances the phorbol ester PDBu may trigger events that inhibit the growth of myeloid progenitors, and that this process may be blocked by bryostatin 1.
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PMID:Effect of pharmacologic manipulation of protein kinase C by phorbol dibutyrate and bryostatin 1 on the clonogenic response of human granulocyte-macrophage progenitors to recombinant GM-CSF. 199 97

The process of signal transduction by interleukin 1 (IL-1) or tumor necrosis factor alpha (TNF alpha) for the production of hematopoietic growth factors by cultured fibroblasts was studied using inhibitors for protein kinase C, cyclic nucleotide-dependent protein kinases, calmodulin-dependent protein kinases, and the Na(+)-H+ antiport system. The protein kinase C inhibitor H-7 was shown to inhibit both IL-1 beta- and TNF alpha-induced granulocyte-macrophage colony-stimulating activity (GM-CSA) production and release from cultured fibroblasts in a dose-dependent manner, with 40 microM H-7 demonstrating maximum suppression of the GM-CSA response. In addition, 100-200 nM staurosporine, a more potent inhibitor of protein kinase C, also completely suppressed GM-CSA from IL-1 beta- and TNF alpha-induced fibroblasts. In contrast, a potent inhibitor of cyclic nucleotide-dependent protein kinases, HA1004, showed no effect when used at 10-40 microM. In addition, an inhibitor of calmodulin-induced protein kinases, W-7, also showed no effect when used at 10-30 microM. Prior incubation with H-7 did not inhibit the ability of fibroblasts to subsequently respond to IL-1 beta or TNF alpha, nor did H-7 directly inhibit the granulocyte-macrophage colony-forming assay. Both dibutyryl cyclic adenosine monophosphate (10-30 microM) and forskolin (1-100 nM), activators of adenylate cyclase, in the presence or absence of the phosphodiesterase inhibitor isobutylmethylxanthine, failed to stimulate a GM-CSA response from cultured fibroblasts, indicating a lack of effect of cyclic nucleotide-dependent protein kinases. Furthermore, the addition of H-7 30 min after induction with IL-1 beta or TNF alpha showed little effect on the synthesis of GM-CSA by cultured fibroblasts, indicating that the signal transduction process probably occurred within the first 30 min of ligand-receptor interaction. Finally, amelioride, an inhibitor of the Na(+)-H+ antiport, was shown to inhibit IL-1 beta-induced GM-CSA in a dose-dependent manner.
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PMID:The role of protein kinase C in interleukin 1 and tumor necrosis factor alpha induction of fibroblasts to produce and release granulocyte-macrophage colony-stimulating activity. 216 34

Eicosanoid release during multilineage hematopoiesis was assessed using freshly isolated mouse bone marrow cells cultured in the presence of interleukin-3 (IL-3) (10% WEHI-3 culture-conditioned medium). Cells that could release prostaglandin E2 (PGE2) when stimulated with calcium ionophore A23187, but not with phorbol ester (PMA), appeared within 4 days. The cells harvested on day 10 released 42 ng of PGE2/10(6) cells/mL after A23187 stimulation. Leukotriene B4 (LTB4) (4 ng/mL) was also detected after A23187 stimulation, but there was no detectable LTC4 (less than 0.5 ng/mL). Nonadherent bone marrow cells were isolated from 28-day cultures and cloned. All clones were strongly IL-3-dependent. Although other growth factors such as granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), and CSF-1 failed to promote survival or support proliferation of the cells, three clones (11-1-A6, 3-2-D5, and 11-1-A1) showed significant increases in 3H-thymidine incorporation, respectively, after PMA treatment for 24 hours. Surviving cells displayed dominantly myeloid type morphology and phenotypic characteristics. The data suggest that IL-3 is important in the formation of PGE2-producing cells. In contrast to many macrophages (MO), neither the IL-3-dependent cell lines nor the IL-3-cultured bone marrow cells released significant amounts of PGE2 when stimulated with PMA or IL-3, although PMA and IL-3 both induced translocation of protein kinase C (PKC) to the membrane fraction. The lack of production of PGE2 and other eicosanoids by the PMA- and IL-3-stimulated cell lines was confirmed by measuring the release of 3H-arachidonic acid. The data suggest that in IL-3-dependent bone marrow cell lines the activation of eicosanoid metabolism requires elevated cellular Ca2+; PKC activation alone does not appear to be a sufficient stimulus.
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PMID:Calcium ionophore but not phorbol ester promotes eicosanoids release by proliferating interleukin-3-dependent bone marrow cells. 216 25

The subclone M-07e, derived from the interleukin-3 (IL-3)-responsive human myeloid cell line M-07, is strictly dependent on either IL-3 or granulocyte-macrophage-colony-stimulating factor (GM-CSF) for its growth and survival. This cell line may be regarded as a candidate model to investigate the poorly understood events triggered by growth factors binding to human hemopoietic cells. Both IL-3 and GM-CSF induce in M-07e cells an increase of ornithine decarboxylase (ODC) activity, which reaches its maximum at 24-30 h and fully depends on de novo protein synthesis. The growth factors do not elicit translocation of protein kinase C to the membrane; thus a role of the kinase in ODC induction is ruled out. An amiloride-inhibitable Na+/H+ exchanger is present in the membrane of M-07e cells; its apparent Km for extracellular Na+ is 47.77 mM; and its activity is greatly enhanced when the cytoplasm is acidified. Growth-factor-evoked ODC activation and DNA synthesis are blocked in a dose- and time-dependent manner when M-07e cells are incubated with ethylisopropylamiloride, a specific inhibitor of Na+/H+ exchanger. The exchanger does not appear to be directly activated by IL-3 or GM-CSF, but its operation is strictly required for the biological effects of these growth factors on M-07e cell line.
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PMID:Evidence for a role of the Na+/H+ exchanger in the colony-stimulating-factor-induced ornithine decarboxylase activity and proliferation of the human cell line M-07e. 217 Apr 28


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