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)

Cell sublines were derived from Ni-induced rat rhabdomyosarcoma which differed in their degree of tumorigenicity. We compared the expression of protein kinase C isoforms alpha, beta, gamma and epsilon in three sublines developing tumors in syngeneic rats (Sy+) and in two sublines devoid of tumorigenicity in these animals (Sy-), with that of normal skeletal muscle. Northern and Western blotting experiments showed that PKC alpha was dramatically overexpressed in Sy- cells whereas it was underexpressed in Sy+ cells. Southern blot analysis provided evidence for a 3-fold increase of PKC alpha-related DNA fragments in Sy- cells. Steady-state levels of the PKC epsilon-related transcript were also markedly decreased in Sy+ cells. However, the expression of PKC beta-related RNA was increased in these cells. Our data support the concept that the differential expression of the PKC isoforms may play a critical role in determining the neoplastic phenotype.
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PMID:Tumorigenicity-associated expression of protein kinase C isoforms in rhabdomyosarcoma-derived cells. 159 8

Human rhabdomyosarcoma RD cells express the myogenic regulatory factors MyoD and myogenin but differentiate spontaneously very poorly. Prolonged treatment of RD cells with the protein kinase C (PKC) activator 12-O-tetradecanoylphorbol-13-acetate (TPA) induces growth arrest and myogenic differentiation as shown by the accumulation of alpha-actin and myosin light and heavy chains, without affecting the expression of MyoD and myogenin. In this study, we show that short-term phorbol ester treatment of the cultures is sufficient to trigger myogenic differentiation but not growth arrest. Furthermore, PKC inhibitors, such as staurosporine or calphostin C, prevent TPA-induced differentiation but not cell growth arrest. These data suggest that the two events are mediated by different pathways; a possible interpretation is that the activation of one or more PKC isoforms mediates the induction of differentiation, whereas the down-regulation of the same or different isoforms mediates the growth arrest. To address the mechanism whereby TPA affects cell growth and differentiation in RD cells, we first analyzed PKC isoenzyme distribution. We found that RD cells express the alpha, beta 1, gamma, and sigma PKC isoenzymes. Only the alpha isoform is exclusively found in the soluble fraction, but it translocates to the membrane fraction within 5 min of TPA treatment and is completely down-regulated after 6 h. The other isoenzymes are found associated to both the soluble and the particulate fractions and are down-regulated after long-term TPA treatment. By immunofluorescence analysis, we show that the PKC alpha down-regulation is specific for those cells that respond to TPA by activating the muscle phenotype. We propose that TPA-induced differentiation in RD cells is mediated by the transient activation of PKC alpha, which activates some of the intracellular events that are necessary for MyoD and myogenin transacting activity and for the induction of terminal differentiation of RD cells. By contrast, the constitutively active beta 1 and sigma are responsible for the maintenance of cell growth, and their down-regulation is responsible for long-term TPA-induced cell growth arrest.
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PMID:Rapid activation and down-regulation of protein kinase C alpha in 12-O-Tetradecanoylphorbol-13-acetate-induced differentiation of human rhabdomyosarcoma cells. 754 6

We have developed a series of immortal human-human hybrid cell lines that express phenotypic characteristics of primary oligodendrocytes, by fusing a 6-thioguanine-resistant mutant of the human rhabdomyosarcoma RD with adult human oligodendrocytes by a lectin-enhanced polyethylene glycol procedure. Hybrids were selected in an aminopterin-containing media. In contrast to the tumor parent cells, a hybrid clone M03.13 expressed surface immunoreactivity for galactosyl cerebroside and intracellular immunoreactivity for myelin basic protein (MBP), proteolipid protein (PLP), and glial fibrillary acidic protein (GFAP). Serum deprivation or chronic treatment with a protein kinase C activator 4-beta-phorbol 12-myristate 13-acetate (PMA), but not dibutyl cyclic adenosine monophosphate induced coordinate up-regulation or de novo induction of oligodendrocyte phenotypic markers with concomitant down-regulation of GFAP expression. Consistent with immunohistochemical studies, northern blot analysis demonstrated that both MBP and PLP mRNA were up-regulated in MO3.13 cells by PMA treatment. M03.13 cells provide an immortalized clonal model system suitable for study of gene expression subserving oligodendrocyte and astrocyte phenotypes.
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PMID:A human glial hybrid cell line differentially expressing genes subserving oligodendrocyte and astrocyte phenotype. 770 48

Previous studies have shown that human rhabdomyosarcoma cells are induced to differentiate by TPA, in the absence of appreciable alterations of the muscle regulatory genes and their products (1). The question was addressed whether the tumor suppressor p53 could be a target of TPA action in these cells. Genomic analysis by a Polymerase Chain Reaction/Single-Strand Conformation Polymorphism (PCR/SSCP) and direct sequencing indicate the presence of a mutation in exon VII at codon 248 (C to T transition) and a loss of heterozygosity of p53 gene in human rhabdomyosarcoma cell line (RD). It is here shown that transcription of p53 mRNA strongly decreases in RD cells induced to growth arrest and differentiate by TPA treatment. In these cells immunoprecipitation and immunoblot analysis show that both synthesis and total cellular concentration of the protein are also reduced by TPA. Nevertheless nuclear p53 accumulation is at much higher extent, whereas 32P-orthophosphate labelling, followed by immunoprecipitation, demonstrates a decrease of phosphorylation of both cytoplasmic and nuclear p53. These results indicate that TPA causes a number of alterations of mutant p53, likely mediated through a protein kinase C dependent mechanism, which might impair the transforming ability of mutant p53 in growth-arrested and differentiating RD cells.
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PMID:TPA-induced differentiation of human rhabdomyosarcoma cells involves dephosphorylation and nuclear accumulation of mutant P53. 803 10

In the present study, we used a cloned derivative, KYM-1D4, of the human rhabdomyosarcoma cell line, KYM-1, known to express high numbers of the two tumor necrosis factor (TNF) receptors, TR60 and TR80, and to be highly sensitive to TNF alpha-mediated cytotoxicity/antiproliferation, to investigate the role of TR60 and TR80 in protein phosphorylation. Using permeabilized KYM-1D4 cells, it was found that TNF alpha strongly induced phosphorylation of proteins of molecular weight 80, 65, 58, 42, and 30 kD. Addition of a monoclonal antibody (MoAb) against TR60 was shown to induce cytotoxicity/antiproliferation in KYM-1D4 cells and the same pattern of protein phosphorylation as TNF alpha, whereas addition of an MoAb against TR80 was both noncytotoxic and ineffective in inducing protein phosphorylation. In contrast, in a highly TNF alpha-resistant KYM-1-derived cell line, 37B8R, no protein phosphorylation was induced with either TNF alpha or the agonistic anti-TR60 MoAb. However, when 37B8R was allowed to revert to partial TNF sensitivity by culture in the absence of TNF alpha, the resultant cell line, 37B8S, was found to regain inducibility of protein phosphorylation by TNF alpha. These results indicate that expression of functional TR60 in KYM-1-related cell lines is principally involved in TNF-mediated cytotoxicity/antiproliferation and is necessary for the induction of protein phosphorylation. Nevertheless, the latter, although apparently strongly associated with cytotoxicity, was probably involved in protective mechanisms because protein kinase C inhibitors that inhibited TNF alpha and anti-TR60-induced phosphorylation increased the cytotoxic/antiproliferative response to these mediators.
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PMID:Tumor necrosis factor (TNF)-induced protein phosphorylation in a human rhabdomyosarcoma cell line is mediated by 60-kD TNF receptors (TR60). 816 87

We have previously demonstrated that the protein kinase C (PKC) activity of human glioma cell lines was significantly elevated (by 3 orders of magnitude) when compared to non-malignant adult human glia, and that the proliferation rate of several established human glioma cell lines correlated with the measured protein kinase C activity. The purpose of this study was to determine whether 1) elevated PKC activity was also a characteristic of fast growing cell lines of non-glial origin, 2) the proliferation rate of non-glioma cell lines correlated with their PKC activity and 3) the proliferation of non-glioma cell lines could be inhibited by staurosporine, a relatively selective PKC inhibitor, which significantly attenuates the growth of glioma cells. Eight established human non-glioma cell lines (bladder, colorectal, rhabdomyosarcoma-oligodendrocyte hybrid, melanoma, cervix, and fibroblast) were compared to the highly proliferative A172 glioma cell line. PKC activity was significantly higher in the glioma cell lines even though 3 of 8 of the non-glioma lines had higher proliferation rates than A172. In non-glioma cell lines, no correlation was found between the PKC activity and proliferation rates. Staurosporine was more effective in decreasing the proliferation of three glioma cell lines compared to the non-glioma cell lines. We conclude that PKC activity is differentially increased in glioma cell lines and that their proliferation rate is more sensitive to inhibition by staurosporine. Targetting the PKC system may prove to be of therapeutic benefit to patients with malignant gliomas.
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PMID:Staurosporine differentially inhibits glioma versus non-glioma cell lines. 828 91

Interleukin 1-beta (IL1-beta) is a pleiotropic cytokine that stimulates a number of signal transduction pathways in cells, leading to different cellular responses. In this study we investigated the signal transduction pathways activated by IL1-beta in two different human cell lines: RD/TE671, a rhabdomyosarcoma, and EJ, a bladder-derived carcinoma. We showed that this cytokine induced the activation of protein kinase C-zeta (PKC-zeta) and the accumulation of a putative physiological PKC-zeta activator, phosphatidic acid [Limatola, Schaap, Moolenaar and van Blitterswijk (1994) Biochem. J. 304, 1001-1008]. Exogenously supplied phospholipase D, which generated cellular phosphatidic acid, was able to mimic the cytokine effect, supporting the hypothesis that this lipid second messenger might contribute to cytokine-induced PKC-zeta activation. In addition, we show that IL1-beta stimulation of BOSC23 cells, transiently overexpressing PKC-zeta, induced an increase in PKC-zeta autophosphorylation. These results give the first direct evidence that IL1-beta can activate this atypical PKC isoform and suggest that this enzyme might be involved in mediating some of the biological effects induced by IL1-beta.
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PMID:Interleukin 1-beta-induced protein kinase C-zeta activation is mimicked by exogenous phospholipase D. 902 Aug 86

Committed skeletal muscle myoblasts undergo terminal differentiation when shifted from a high-mitogen medium to a low-mitogen medium. However, expression of the myogenic regulatory factor MyoD seems to be similar in proliferating and differentiating cells, suggesting that its function is attenuated in proliferating myoblasts. To further understand the potential mechanisms that may attenuate MyoD function, we have examined the effect of posttranslational modification. By analogy with myogenin, we have examined the role of phosphorylation in regulating the function of MyoD. MyoD contains two putative protein kinase C (PKC) phosphorylation sites (Thr115 and Ser200). The former site is analogous to Thr85 within the highly conserved basic domain of myogenin that has been demonstrated to negatively regulate the myogenic differentiation functions of myogenin. To test whether hyperphosphorylation of the same PKC site in MyoD would attenuate its function, we generated a mutant MyoD with a single amino acid substitution (Thr115-Ala) that disrupts the PKC phosphorylation site (Thr115) within the conserved basic domain. Wild-type and mutant MyoD were introduced into cells using an E1, E3-deleted adenoviral vector. In mouse C3H10T1/2 fibroblasts, both wild-type and mutant MyoD induced terminal myogenic differentiation when growth factors were withdrawn from the cell culture. Consistent with these results, nuclear extracts from infected cells, but not those from uninfected cells, demonstrated complex formation with an oligonucleotide containing an E-box consensus sequence. Growth arrest was associated with the up-regulation of p21cip1, cell fusion to multinucleated myotubes, and the expression of a muscle differentiation marker (myosin heavy chain). On the other hand, when infected cells were maintained under high mitogenic conditions (in the presence of 10% fetal bovine serum), the expression of wild-type or mutant MyoD slowed cell growth and induced p21cip1. Only mutant MyoD caused cell fusion, myosin heavy chain expression, and altered mobility of the E-box oligonucleotide in gel shift assays. Furthermore, after infection, MyoD was phosphorylated, and phosphothreonine was detected in wild-type MyoD immunoprecipitated only from C3H10T1/2 cells grown under high mitogenic conditions. These results suggest that Thr115 may play an important role in the regulation of MyoD function under conditions of high mitogenesis. MyoD was also phosphorylated in malignant rhabdomyosarcoma (RMS) cells in which MyoD function was attenuated. Phosphothreonine was also detected in MyoD immunoprecipitates. Rh30 alveolar RMS cells were infected with an adenovirus expressing either wild-type or mutant MyoD. In contrast to the results in fibroblasts, when overexpressed in malignant Rh30 RMS cells, mutant MyoD arrested cell growth without inducing p21cip1 and caused cell fusion. However, no muscle differentiation markers were detected, indicating that an overexpression of mutant MyoD lacking Thr115 caused Rh30 cells to become quiescent and recapitulate at least some aspects of myogenesis (cell fusion).
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PMID:Mutation of Thr115 in MyoD positively regulates function in murine fibroblasts and human rhabdomyosarcoma cells. 975 Nov 14

The long-term genetic consequences of chronic exposure to low-dose irradiation constitutes a major concern to the general public and research community, especially as chronic radiation has recently been proven to be much more mutagenic and carcinogenic than previously thought. Here we report the results of the first ever comparison of the effects of acute and chronic whole body low-dose radiation exposure on global gene expression. We found a substantial difference between males and females in the expression of genes involved in signaling, growth control, transcription and other pathways upon acute and chronic radiation exposure. Specifically, we found sex differences in the expression of genes coding for G protein-coupled receptors and nuclear receptors. We also found different induction of PKCdelta, PKCbeta and PKCmu, members of PKC signaling pathway as well as in TGF and WNT signaling in males and females. Very pronounced difference, that was confirmed on the level of protein, was observed in the expression of WNT5A that plays an important role in carcinogenesis and muscle regeneration. WNT5A expression was significantly elevated only in chronically exposed females. We also provide the first evidence of the effect of ionizing radiation on the estrogen receptor in females. Repetitive irradiation of muscle tissue has been linked to development of rhabdomyosarcoma (RMS), which, enigmatically, occurs more frequently in males. Our data may be used to study possible mechanisms of RMS development upon chronic radiation exposure. They may provide some clues about the molecular background of the sex differences of RMS occurrence and may in the future lead to the discovery of new biomarkers for RMS predisposition in the irradiated tissue. Overall, differences in male and female responses to acute and chronic low-dose radiation obtained by this study were more drastic than we could have predicted. If confirmed in other experimental systems, these findings could potentially lead to fundamental changes in radiation safety regulations.
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PMID:Dissimilar genome response to acute and chronic low-dose radiation in male and female mice. 1513 41

The ADAM (a disintegrin and metalloprotease) family consists of multidomain cell-surface proteins that have a major impact on cell behavior. These transmembrane-anchored proteins are synthesized as proforms that have (from the N terminus): a prodomain; a metalloprotease-, disintegrin-like-, cysteine-rich, epidermal growth factor-like, and transmembrane domain; and a cytoplasmic tail. The 90-kDa mature form of human ADAM12 is generated in the trans-Golgi through cleavage of the prodomain by a furin-peptidase and is stored intracellularly until translocation to the cell surface as a constitutively active protein. However, little is known about the regulation of ADAM12 cell-surface translocation. Here, we used human RD rhabdomyosarcoma cells, which express ADAM12 at the cell surface, in a temporal pattern. We report that protein kinase C (PKC) epsilon induces ADAM12 translocation to the cell surface and that catalytic activity of PKCepsilon is required for this translocation. The following results support this conclusion: 1) treatment of cells with 0.1 microM phorbol 12-myristate 13-acetate (PMA) enhanced ADAM12 cell-surface immunostaining, 2) ADAM12 and PKCepsilon could be co-immunoprecipitated from membrane-enriched fractions of PMA-treated cells, 3) RD cells transfected with EGFP-tagged, myristoylated PKCepsilon expressed more ADAM12 at the cell surface than did non-transfected cells, and 4) RD cells transfected with a kinase-inactive PKCepsilon mutant did not exhibit ADAM12 cell-surface translocation upon PMA treatment. Finally, we demonstrate that the C1 and C2 domains of PKCepsilon both contain a binding site for ADAM12. These studies show that PKCepsilon plays a critical role in the regulation of ADAM12 cell-surface expression.
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PMID:Regulation of ADAM12 cell-surface expression by protein kinase C epsilon. 1536 51


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