The presence of receptors for oligodeoxynucleotides (OdN) on the surface of L929 cells has previously been described. To study the possible coupling of the receptor to cellular signal transducing systems, the effect of phosphodiester OdN of different sequences on cellular phospholipase C and protein kinase C (PKC) activities in L929 ...

We previously presented a two-dimensional cell motility assay using L-10, a highly metastatic variant of the human rectal adenocarcinoma cell line RCM-1, as a motility model of tumor cells of epithelial origin. In this model, L-10 cells moved outward from the cell islands mainly as a localized coherent sheet of ...

We have examined the antioxidant properties of structurally related flavones/isoflavones in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated HL-60 cells. In the presence of 1.3% dimethyl sulfoxide in the medium for seven days, promyelocytic HL-60 cells were differentiated into neutrophil-like cells possessing phagocytic properties and the capacity to generate H2O2 on TPA stimulation. The effects ...

Autocrine factors prevent cell death in the ciliate Tetrahymena thermophila, a unicellular eukaryote, in a chemically defined medium. At certain growth conditions these factors are released at a sufficient concentration by > 500 cells ml-1 to support cell survival and proliferation. The protein kinase C activators phorbol 12-myristate 13-acetate (PMA) ...

The phorbol ester, phorbol 12-myristate 13-acetate (PMA), induces mucin secretion in the colonic tumor cell line T84 in a Ca(2+)-independent manner. To determine whether a specific protein kinase C (PKC) isoform is involved in colonic cells, we compared PMA-dependent mucin secretion by three human colonic tumor cell lines (T84, HT-29/A1, ...

We have used human mammary cells of the MCF-7 strain, which constitutively express high levels of the small heat shock protein HSP27 and we have compared the changes in the phosphorylation status of this protein together with changes in cell growth and/or morphology induced by the action of one of ...

The effect of phorbol 12-myristate-13-acetate (PMA) on the hydrolysis of phosphatidylcholine (PC) in rat hepatoma cell line CRBH7919 has been studied. It was found that PMA stimulated PC hydrolysis in CRBH7919 cells in a dose-dependent manner after treatment for 15 min. The product of PC hydrolysis was choline, not phosphocholine. ...

Protein kinase C (PKC) is an ubiquitous enzyme that mediates intracellular signal transduction in eukaryotes. Jurkat and U937 cells were exposed to microgravity during a Space Shuttle flight and stimulated with a radiolabeled phorbol ester (3H-PDBu) that specifically activates and labels several PKC isoforms. Both the total amount of 3H-PDBu ...

We investigated the effect of elevated levels of protein kinase C alpha (PKC alpha) on cell proliferation in human breast carcinoma cells (MCF-7). MCF-7 cells transfected with either the pSV2M(2)6 vector without the insert (MCF-7/Vector) or containing a full length cDNA encoding PKC alpha (MCF-7/PKC alpha) were compared. MCF-7/PKC alpha ...

Neutrophil activation by phorbol 12-myristate 13-acetate (PMA) and zymosan was assessed by luminol-dependent chemiluminescence (CL) in a novel microtiter plate format and by flow cytometry (FC) based on the oxidation of dihydrorhodamine 123. The results of this comparison demonstrated striking differences in kinetic parameters between these two techniques for neutrophil ...

The invasion/migration of two cell lines, melanoma (MEW) and glioma (BT5C), and their counterparts treated for prolonged time with TPA were studied. On Western blots both cell lines expressed alpha, beta I protein kinase C isoforms, whereas beta II and gamma were not detected. The down-regulation of alpha and beta ...

Protein kinase C (PKC) activation stimulates transport system X-AG for anionic amino acids in cultured human fibroblasts (Franchi-Gazzola, R., Visigalli, R., Bussolati, O., and Gazzola, G. C. (1994) FEBS Lett. 352, 109-112). To identify which PKC isoform is responsible for this effect, aspartate transport through system X-AG, PKC activity, and ...

Mucolipidosis type 4 (ML-4) is an autosomal recessive inborn error of metabolism, the pathogenesis of which is not known. We characterized protein kinase C (PKC) activation and cellular phosphate uptake in intact quiescent ML-4 skin fibroblasts and after stimulation with phorbol myristate acetate (PMA). [3H]Phorbol dibutyrate uptake was not altered ...

Transglutaminase is a calcium-dependent enzyme that catalyzes an amine incorporation and a cross-linking of proteins. Intracellular transglutaminase is induced when human promyelocytic leukemia HL-60 cells are treated with retinoic acid and human hepatoblastoma HepG2 cells, with interleukin-6. To find whether the intracellular reaction catalyzed by transglutaminase increased when the enzyme ...

To explore the program of cell differentiation in Friend murine erythroleukemia (MEL) cells, we used three clonal variants: phorbol 12-myristate 13-acetate (PMA)-hypersensitive TS-19-101, PMA-resistant TR19-9, and hexamethylene bis-acetamide (HMBA)- and PMA-resistant DS19/R1. After treating TS19-101 cells with HMBA, topoisomerase II (topo II) enzymatic activity was dramatically reduced, and cells became ...

Butyrate is a potentially selective therapeutic agent for many adenocarcinomas. Butyrate causes reversible growth arrest as well as some death of VACO 5 colon cancer cells. Combined treatment with butyrate and the phorbol ester TPA leads instead only to cell death, while TPA causes little death on its own. Cells ...

Neuroblastoma and glioma cells differentially express isoforms of protein kinase C (PKC) and myristoylated PKC substrates (e.g. MARCKS). Correlation with metabolism of membrane phospholipids suggests that PKC-alpha and MARCKS may be required to mediate phosphatidylcholine turnover stimulated by phorbol ester (beta-TPA). To evaluate relationships to neural cell differentiation, SK-N-SH human ...

The possible regulation of the multidrug-resistant (MDR) phenotype and P-glycoprotein by protein kinase C (PKC) was investigated in the doxorubicin (Dox)-resistant MCF-7 cell line (MCF-7/Dox). In a clonogenic assay, cells exposed to 100 nM phorbol 12-myristate 13-acetate (PMA) for 1 hr were about 3-fold more resistant to Dox than were ...

We show here that the mode of cell death in IL-6-starved T1165 and T1198 plasmacytoma cell lines is apoptosis, and that it can be suppressed by phorbol ester (PMA) treatment in a protein kinase C (PKC)-mediated process that involves alpha and/or delta isozymes. PMA-induced PKC activation, but not the depletion ...

The effect of phorbol 12-myristate 13-acetate (PMA) on the expression and shedding of intercellular adhesion molecule-1 (ICAM-1) was investigated on the hematopoietic cell lines K 562 and U 937 using flow cytometry, fluorescence microscopy and ELISA technique. At low concentration of 1 nM, PMA stimulated the expression of ICAM-1 on ...

The mechanism by which an oxidant tumor promoter benzoyl peroxide (BP) influences signal transduction, was studied in promotion insensitive (P-), promotion sensitive (P+) and transformed (Tx) mouse epidermal JB6 cells. The basal levels of antioxidant enzymes CuZn-superoxide dismutase and catalase were higher in P+ and Tx JB6 cells. BP decreased ...

1. HT-29 M6 cells are a subpopulation of HT-29 cells that, contrarily to the parental cells, establish tight cell contacts and differentiate. Cell-to-cell contacts in HT-29 M6 cells are also regulated by protein kinase C; addition of the phorbol ester phorbol 12-myristate 13-acetate (PMA) decreases the homotypic contacts of these ...

Type 1 plasminogen activator inhibitor (PAI-1) and its cofactor vitronectin (Vn) are stored within the alpha-granules of platelets. The two possible sources for their biosynthetic origin are endogenous synthesis in megakaryocytes or endocytosis from plasma. Using ultrastructural and confocal laser scanning microscopic (CLSM) image analysis, we observed that treatment of ...

The renal epithelial cell line MDCK (Madin Darby canine kidney) was used as a model system to investigate the contribution of the secreted phospholipase A2 type II(sPLA2) and cyclooxygenases to prostaglandin E2 (PGE2) synthesis. Activation of protein kinase C by the phorbol ester TPA led to an enhanced PGE2 synthesis ...

The presence of prostaglandin (PG) H2 in the supernatant of human umbilical vein endothelial cells (HUVEC) stimulated by thrombin restores the capacity of aspirin-treated platelets to generate thromboxane (TX) B2. Induction of cyclooxygenase-2 (Cox-2) by interleukin (IL)-1alpha or a phorbol ester increases this formation. HUVEC treated with aspirin lost their ...

Incubation of HT-29 M6 cells with the phorbol ester phorbol 12-myristate 13-acetate (PMA) induces cell scattering, loss of cellular contacts and inactivation of E-cadherin. We have investigated the involvement of different protein kinase C (PK-C) isoforms in these processes using specific activators. Thymeleatoxin, a derivative of mezerein that activates conventional ...

The daphnane-type diterpene gnidimacrin, isolated from the root of the Chinese plant, Stellera chamaejasme L., was found to strongly inhibit cell growth of human leukemias, stomach cancers and non-small cell lung cancers in vitro at concentrations of 10(-9) to 10(-10) M. On the other hand, even at 10(-6) to 10(-5) ...

We investigated the presence of a galectin-like protein in rat mononuclear cells using a polyclonal antibody raised against a soluble lactose-binding lectin purified from adult chicken liver that immunoreacted strongly with a broad protein band of about 16 kd in Western blot assays. Immunochemical studies revealed a constitutive expression of ...

Induction of stromelysin and collagenase mRNAs in response to phorbol myristate acetate (PMA) and autocrine factors (CAF) was compared in primary cultures of lapine synovial fibroblasts and an immortalized line of these cells known as HIG-82. In both cell types, message induction was quicker for CAF than for PMA. Appearance ...

New data are provided to show that (i) rat Sertoli cells produce two types of plasminogen activators, tissue type (tPA) and urokinase type (uPA), and a plasminogen activator inhibitor type-1 (PAI-1); (ii) both tPA (but not uPA) and PAI-1 secretion in the culture are modified by FSH, forskolin, dbcAMP, GnRH, ...

We have developed a protocol that reveals two antagonistic effects of phorbol-12-myristate-12-acetate (PMA) on the G0-->G1-->S transition of mammalian cell cycle. Balb-3T3 (Clone A31) cells arrested in G0 by serum starvation can be stimulated to traverse the G1 phase and initiate DNA synthesis 12 h later by a 2-h pulse ...

Using a clonal cell line of human osteoclast precursors (FLG 29.1 cells), that after treatment with 12-O-tetradecanoyl phorbol 13-acetate (TPA) show many functional characteristics of osteoclasts, we demonstrated that catecholamines act as inducers of osteoclast maturation in vitro and as stimulators of osteoclast activity via the binding to beta 2 ...

Apart from its classical role in bone and mineral metabolism, 1,25-dihydroxyvitamin D3 (1,25-vitamin D3) has recently been shown to affect cell growth and differentiation from a variety of tissues primarily not involved in mineral metabolism and to provide immunomodulatory functions. Findings in human mesangial cells in vitro as well as ...

We tested distinct variants of a human keratinocyte line (HaCaT) for the expression of tissue-type plasminogen activator (tPA)-specific mRNA, as well as cell surface-associated and secreted tPA. Cells of early passages (passage no. 22) only expressed urokinase plasminogen activator (uPA)- but not tPA-specific mRNA. Cells after prolonged culture (passage no. ...

Studies were performed to characterise the phospholipase A2 (PLA2) responsible for the greatly increased capacity to release arachidonic acid (AA) of dimethyl sulphoxide (DMSO) differentiated U937 monocytic cells compared to undifferentiated cells (18-fold increase in response to Ca2+ ionophore A23187). Cytosolic PLA2 (cPLA2) activity could be measured in homogenates of ...

The neoplastic cell transformation induced by propylene oxide (PO) and epichlorohydrin (ECH) was studied in two in vitro assays, mouse embryo fibroblasts (C3H/10T1/2) and Syrian hamster embryo (SHE) cells. In C3H/10T1/2 cells treated with PO (2.5-10 mM), the transformation frequencies were enhanced about 2-4 times in the presence of 12-O-tetradecanoylphorbol-13-acetate ...

We previously found that 12-O-tetradecanoylphorbol-13-acetate (TPA)-enhanced invasion of Matrigel was associated with augmentation of cell motility but not with metalloproteinase activity in a highly metastatic variant (L-10) of human rectal adenocarcinoma cell line RCM-1. In a two-dimensional cell motility assay, TPA induced active L-10 cell locomotion with characteristic morphology; the ...

Certain protein kinase C (PKC) isotypes are localized to the nucleus during cellular proliferation in murine erythroid cells, as well as in human promyelocytic leukemia and erythroleukemia cells. Because the structure of these PKC isotypes contains a conserved cysteine-rich region that contains the zinc finger DNA binding motif, we tested ...

Phospholipase C (PLC) is a key enzyme in the T cell antigen receptor (TCR)-mediated signal transduction pathway in human T cells. Agonist-induced PLC activation leads to a cascade of intracellular events that ultimately regulate gene transcription and T cell activation. We studied the effects of U-73122, a putative inhibitor of ...

Previous studies in human myeloid leukemia cells (HL-60, U-937, THP-1) suggested an involvement of the c-myc gene in the control of mutually exclusive pathways, such as retrodifferentiation and cell death. Treatment of U-937 cells with 12-O-tetradecanoyl phorbol-13-acetate (TPA) which is associated with the induction of a monocytic differentiation program and ...

Protein kinase C (PKC) modulates growth, differentiation and apoptosis in a cell-specific fashion. Overexpression of PKC-alpha in MCF-7 breast cancer cells (MCF-7-PKC-alpha cell) leads to expression of a more transformed phenotype. The response of MCF-7 and MCF-7-PKC-alpha cells to phorbol esters (TPA) was examined. TPA-treated MCF-7 cells demonstrated a modest ...

The conditioning effect of RK-28, one of the nitroimidazole nucleoside analogues, in a combined treatment with irradiation against aerobic V-79 cells in an exponentially-growing phase was investigated. The growth rate of the V-79 cells in 5% DMEM was not different from that in the medium containing 0.2 mM RK-28. The ...

Alpha 1-proteinase inhibitor (alpha 1-Pi) is the main physiological inhibitor of neutrophil elastase, a serine protease that has been implicated in tissue degradation at inflammatory sites. We report here on an immunocytochemical study of various eukaryotic cells in order to show their content of alpha 1-Pi. The proteinase inhibitor is ...

Monoblasts transformed by v-Myb can be induced to differentiate into macrophages by treatment with phorbol ester (TPA). This differentiation occurs during both the G1 and the G2 phases of the cell cycle and is accompanied by cell cycle arrest. The introduction of a protein consisting of the three repeats (3R) ...

1,2-Diacyl-sn-glycerol (DAG) is a product of cell activation that has emerged as an important intracellular messenger whose primary function appears to be the activation of protein kinase C. They originate by the activation of phospholipases, which hydrolyze different phospholipids depending on the external stimulus and the nature of the cells, ...

We have examined the regulation of the AP-1 DNA transcription complex during T cell activation in response to interleukin 1 (IL-1) and phorbol ester (TPA) treatment of the IL-1 responsive murine thymoma T cell line, EL4 6.1 C 10. IL-1 synergistically enhances the stimulatory effect of TPA on AP-1-mediated gene ...

Combined treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) and dibutyryl cyclic AMP (diBu-cAMP) induced significantly longer neurites than treatment with each alone in NG108-15 cells. We performed differential screening to identify genes expressed only by treatment with TPA plus diBu-cAMP but not by that with diBu-cAMP for 72 h alone in NG108-15 ...

Although the ceramide components of both glycosphingolipids (GSLs) and sphingomyelin (SM) in HL-60 cells were identical, the molecular species of the ceramides preferentially used in biosynthesis were quite different in GSLs and SM. When HL-60 cells were stimulated to differentiate into macrophage-like cells by phorbol ester after their sphingolipids had ...

We compared the influence of exogenous N-ras oncogene and treatment with PKC agonist 12-O-tetradecanoylphorbol-13-acetate (TPA) on P-glycoprotein (Pgp) function in various human, rat and dog cell lines. Two approaches were used: (a) flow cytometry analysis of Rhodamine 123 (Rh123) exclusion; and (b) sensitivity to cytotoxic action of colchicine. We have ...

Phosphatidylserine (PS) synthesis was studied in glioma C6 cells with [14C]serine and in the presence or absence of the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA). It was found that incubation of the cells with 10 nM or 100 nM TPA for 1 h inhibited PS formation by 30% and 60%, respectively. ...