The protein kinase C (PKC) alpha, beta and epsilon isoforms have distinct nuclear localizations in neuroblastoma x glioma hybrid cells NG 108-15. We found by immunoblotting that PKC alpha, beta II, delta and epsilon are the predominant isoforms in these cells. In contrast to other neuronal cell lines, none of ...

Lipocortin (annexin) 1 is a putative mediator of the inflammatory effects of glucocorticoids. By flow cytometric analysis (FACS) we have studied the effect of dexamethasone on the cellular localization of lipocortin 1. U-937 cells were incubated with or without 10 nM phorbol 12-myristate 13-acetate (PMA) to induce cell differentiation. Then ...

Primary B cells are induced to proliferate by cross-linking surface immunoglobulin or by its pharmacological equivalent, phorbol ester and calcium ionophore. However, nuclear responses that have been studied in activated B cells are typically inducible with phorbol esters alone. We show that a factor, indistinguishable from the nuclear factor of ...

Thapsigargin elicits histamine release on rat mast cells, and this effect is increased if cells are pretreated with thapsigargin before the addition of external calcium. Okadaic acid does not modify the response of mast cells to thapsigargin, while sodium fluoride or the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) increases several fold the ...

PURPOSE: By understanding the signal transduction pathways through which a cell responds to changes in environmental oxygen levels, we may be able to therapeutically exploit this response by manipulating these pathways. MATERIALS AND METHODS: The human adenocarcinoma cell line A549 was exposed to varying durations of hypoxia alone and then ...

In a search for a model cell system that might allow studies of the function of the Rho-related GTPase CDC42Hs in human cells, we measured the content and distribution of CDC42Hs in monocytes that were differentiating into macrophages. The total content of this protein increased 5- to 6-fold in phorbol ...

In the human leukemic HL-60 cell line, we have reported previously that monocytic/macrophage-like differentiation induced by TPA (12-O-tetradecanoylphorbol-13-acetate) was associated with a decreased sensitivity to various apoptosis-inducing stimuli (Solary, Bertrand, Pommier, Blood 1993; 81:1359-1368). In the present study, we studied further the effects of TPA alone on the induction of ...

Bufalin, an active principle of the traditional Chinese medicine chan'su, has been proved to be a potent differentiation inducer in human leukemia cells. To study the mechanism of the differentiation of human leukemia ML1 cells induced by bufalin, we measured the effect of 10 nM bufalin on cell growth, activities ...

The nuclear factor kappa B (NF-kappa B) is a eukaryotic transcription factor. In B cells and macrophages it is constitutively present in cell nuclei, whereas in many other cell types, NF-kappa B translocates from cytosol to nucleus as a result of transduction by tumor necrosis factor alpha (TNF alpha), phorbol ...

The parallel effects of simvastatin on cell cycle and PKC activity in rat C6 glioma cells were investigated. Simvastatin, 2.5 microM, for 24 h resulted in cell growth arrest in early G1 phase of the cell cycle and in a significant increase of total PKC activity (283 +/- 42 vs ...

Undifferentiated type II alveolar cells were isolated from the fetal rabbit lung on the 24th gestational day, grown in vitro for 2-3 days, and used to test the hypothesis that activation of protein kinase C by 4 beta-phorbol ester (TPA) or the diacylglycerol analogue, sn-1-oleoyl-2-acetylglycerol (OAG), stimulates disaturated phosphatidylcholine (DSPC) ...

An in vitro assay that measures the activation level of ex vivo activated (EVA) T cells currently being used in the adoptive immunotherapy of metastatic renal cell carcinoma has been developed. This assay is based on the ability of activated, but not resting. T cells to proliferate in response to ...

Connexin45 is a gap junction protein which forms channels with unique characteristics. RNA blots demonstrated that connexin45 is expressed in a number of cell lines including WB, SK Hep1, BHK, A7r5, CLEM, and BWEM cells. Connexin45 was further studied in BWEM cells using specific affinity-purified antibodies directed against a synthetic ...

A solid leukemia sarcoma has been successfully developed after subcutaneous inoculation of the cultured human promyelocytic leukemia cells (HL-60 cells) into nude mice. The solid leukemia sarcoma is a more plentiful source than the cultured cells for enzymatic study and its growing environment is closer to that of the human ...

Hyaluronan-binding function of the CD44 molecule has not been so far detected in myeloid cells. To study pure populations of primitive myeloid cells, we investigated the hyaluronan-binding function of the CD44 molecule from three myeloid cell lines: KG1a, KG1, and HL60. Both KG1a and KG1 cells express the CD34 antigen ...

We compared the regulation of cytosolic phospholipase A2 (cPLA2) activity in undifferentiated and neutrophil-like HL60 cells. Although Ca(2+)-mobilizing P2-purinergic receptors are expressed in both cell types, arachidonic acid (AA) release stimulated by P2-purinergic agonists was 5-7-fold higher in the differentiated cells. Similarly, the stimulation of AA release by AlF4- in ...

Sphingosine-1-phosphate (Sph-1-P) has been implicated as a second messenger in control of cell motility and proliferation (e.g., Sadahira Y, et al., PNAS 89:9686, 1992; Olivera A & Spiegel S, Nature 365:557, 1993). The control mechanism for its synthesis, as catalyzed by sphingosine kinase, is crucial in signal transduction. Synthesis of ...

Previous studies have shown that activation of various PI-coupled receptors stimulates DNA synthesis in some cells, and inhibits DNA synthesis in others. In order to study this effect further, we measured carbachol-mediated [3H]thymidine incorporation in m1-transfected A9 L cells and in m1-transfected CHO cells, and found that carbachol profoundly inhibited ...

The effect of the tumor promoter phorbol 12-myristate 13-acetate (PMA) on proliferation and differentiation of normal mammary epithelial cells from 50-day-old virgin rats was investigated using a model system that allows for full morphological and functional development of the cells. In this model, mammary epithelial cells are grown within a ...

The tissue (tPA) and urokinase (uPA) types of plasminogen activator and the plasminogen activator inhibitor 1 (PAI-1) are enzymatic proteins that may play an important role in the degradation of the extracellular matrix in physiologic and neoplastic conditions. In particular, urokinase may underlie key properties of malignant cells, such as ...

We have examined the effect of protein kinase (PKC) depletion in SV40-transformed Djungarian hamster fibroblasts (DM15 cells) on the level of gap junction permeability. Cx43 electrophoretic mobility, and cell sensitivity to different uncoupling stimuli. After 24 hr exposure to 12-O-tetradecanoyl-phorbol-13-acetate (TPA), the total PKC activity in DM15 cells was reduced ...

We previously found that the enhanced activity to invade Matrigel upon stimulation with 12-O-tetradecanoylphorbol-13-acetate (TPA) was one of the major properties of a highly metastatic variant (L-10) of a human rectal adenocarcinoma cell line RCM-1. To clarify the mechanism of this enhancement, we examined the effect of TPA on 2 ...

The ability of the human neuroblastoma cell line SH-SY5Y to metabolize androgens and progesterone was studied by incubating the cells in the presence of labeled testosterone (T) or progesterone (P) to measure, respectively, the formation of dihydrotestosterone (DHT) or dihydroprogesterone (DHP) (5 alpha-reductase activity). The 3 alpha-hydroxysteroid dehydrogenase activity was ...

The human monocytic leukemia cell line THP-1 differentiates into macrophage-like cells when treated with a variety of agents, including 12-O-tetradecanoylphorbol-13-acetate (TPA). We show here that during this process, the expression of heme oxygenase, a rate-limiting enzyme in heme catabolism, is induced. Treatment with TPA increases heme oxygenase mRNA in other ...

Alterations of vascular smooth muscle cell (VSMC) proliferation have been implicated in the age-dependent susceptibility to atherosclerosis. Although it is known that protein kinase C (PKC) is involved in the mechanism of VSMC proliferation, there are no data on the possible involvement of PKC in disregulating VSMC proliferation in aged ...

The effects of interleukin 4 (IL-4) on human leukemic precursor B-cell lines were investigated. Recombinant IL-4 (rIL-4) was added to three acute lymphoblastic leukemia-derived pre B-cell lines: Reh, Km3 and Nalm-6. Our results show that rIL-4 significantly decreases continuous proliferation of Reh and Km3 cells while Nalm-6 cells have a ...

Previous findings on the induction of immortalization in SHE cells have been explained with the activation/alteration hypothesis which postulates that treatment with a carcinogen results in the induction of a so-called "activated state" which enhances the rate of a probabilistic event in the progeny of the treated cells. This event ...

Immunocytofluorescence studies were used to compare alpha-protein kinase C (PKC) localization in primary cultures of renal proximal tubule epithelial cells (RPTE) with E1A-immortalized and SV40-transformed derivatives. Both cytosolic and nuclear staining were apparent in all of the RPTE. In primary RPTE, Triton X-100-insoluble alpha-PKC was also apparent and was concentrated ...

The effects of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) on the growth characteristics of the colon cancer cell line HT-29 M6 were studied. TPA induced the scattering of proliferative HT-29 M6 cells: in the presence of the phorbol ester, HT-29 M6 colonies scattered and the cells acquired a flatter aspect with diminished ...

Recently, we have described that anti-IgM antibodies profoundly inhibited the growth of BKS-2, an immature B cell lymphoma. In this report, we demonstrated that ionomycin alone at very low concentrations (20 nM) inhibited the growth of BKS-2 cells completely. The levels of intracellular Ca2+ induced by the inhibitory concentrations of ...

The ability of 12-O-tetradecanoylphorbol-13-acetate (TPA) and D,L-buthionine-S,R-sulphoximine (BSO) to modulate cis-diamminedichloroplatinum(II) (CDDP) sensitivity was investigated in human ovarian cancer cell lines sensitive (KF) or with intrinsic resistance (KK and MH) to CDDP. The KK and MH cell lines were derived from ascites of patients with clear-cell carcinoma and serous cystadenocarcinoma ...

The osteoblast-like osteosarcoma cell line ROS 17/2.8, which expresses very low levels of estrogen receptor (ER), was stably transfected with the mouse ER in order to more easily evaluate the physiological role of estrogens in bone cell homeostasis. These transfected ROS.SMER 14 cells are highly responsive to estrogenic stimulation at ...

The selection of differentiation lineages into either erythroid or megakaryocytic series was analyzed with human erythroleukemia cell lines K562, HEL, and cytokine-dependent TF1. A tumor promoter, TPA, induced a megakaryocyte marker, glycoprotein IIb/IIIa (GP IIb/IIIa) or IIIa (GP IIIa), but suppressed erythroid differentiation. On the other hand, aphidicolin, which is ...

Exposure of early passage Syrian hamster embryo cells to high TPA concentrations (8 or 16 mum) decreased gap junctional intercellular communication (GJIC) to about 20% of the control during the first hour. Subsequently, the GJIC capacity recovered to 70-80% after 4-10 hr. Exposure to lower TPA concentrations also reduced GJIC, ...

The transformation-sensitive cell-line BPNi was more susceptible to 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inhibition of gap junctional intercellular communication (GJIC) than early passage Syrian hamster embryo (SHE) cells, while the potency of TPA to down-regulate EGF-binding was similar in the two cell types. The kinetics of TPA-induced inhibition of GJIC suggested that different ...

The effect of modulation of protein kinase C (PKC) activity by 12-O-tetradecanoylphorbol-13-acetate (TPA) on cisplatin cytotoxicity was examined in a human osteosarcoma U2-OS cell line and in a U2-OS variant (U2-OS/Pt) selected after continuous exposure to increasing concentrations of cisplatin. U2-OS/Pt cells showed a 7.5-fold resistance to the drug. A ...

A highly specific and sensitive immunoassay for soluble p55 tumor necrosis factor receptor (TNFR) has been established. The immunoassay was based on a newly developed monoclonal antibody (IV4E) recognizing a non-TNF-binding site of the p55 TNFR. The IV4E antibody immunoprecipitated a 55 kDa TNF binding protein from HL-60 cells. No ...

We previously reported that growth-associated protein-43 (GAP-43) could be involved in the maintenance of elongated neurites and that a decline in protein kinase C activity may be involved in accumulation of GAP-43. In the present study, to clarify the functional significance of GAP-43 for neurite maintenance and acetylcholine (ACh) release, ...

The proliferative cystic squamous cell lesion inducible by inhalation of particulate matter in the rat lung is characterized by the formation of keratin-filled cystic cavities of various sizes bordered by multiple layers of keratinizing squamous epithelial cells. The current investigation is primarily concerned with two points. One is whether the ...

Recently developed HT-29-derived cell lines, which display variable differentiated phenotypes provide an invaluable opportunity to analyze the mechanism by which cell differentiation is regulated in the intestine. We have studied the effects of the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in the differentiation phenotype of mucus-secreting (HT-29 M6) and absorptive (HT-29 M3) ...

The growth-modulating effects of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] were studied on three mouse embryo fibroblast cell lines. Concentrations ranging from 0.1 to 100 nM inhibited dose-dependently proliferation in the non-tumorigenic C3H/10T1/2 Cl 8 (10T1/2) and the chemically transformed C3H/10T1/2 Cl 16 (Cl 16) cells. The hormone had a biphasic effect on ...

This study was undertaken to assess the role of protein kinase C (PKC) in activin action in the rat pituitary. Pretreatment with 500 nM phorbol 12-myristate 13-acetate (PMA) for 22-24 h reduced subsequent FSH and LH release (percentage of total cellular FSH and LH released) in response to 100 nM ...

The present study was performed to examine whether parathyroid hormone (PTH) and parathyroid hormone-related peptide (PTHrP) would stimulate osteoclast-like cell formation via soluble factor(s) released from osteoblasts and, if so, to characterize the involvement of PTH/PTHrP-responsive dual signal transduction systems [cAMP-dependent protein kinase (PKA) and calcium/protein kinase C(PKC)]. Osteoblasts-conditioned medium ...

The steady-state population of stratified squamous epithelium is maintained by balanced cell proliferation and apoptosis. Protein kinase C (PKC) is intimately involved in the regulation of cell proliferation and cell survival. In order to gain insight into the mechanisms regulating apoptosis, the immunocytochemical localization of six PKC isozymes (PKC-alpha, -beta, ...

The phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), induced increased expression of the retinoblastoma (RB) tumor suppressor gene product in the course of megakaryocytic differentiation of the K562 human leukemia cell line, a differentiatively multipotent hematopoietic precursor cell. The induced increase in RB protein per cell occurred early, by 8 h of treatment, ...

Previously, we have demonstrated that protein kinase C-activating phorbol esters selectively induce IgA synthesis by mouse B cells whether stimulated or not by lipopolysaccharide (LPS). In this study, we investigated in detail whether this maturation into IgA-secreting cells is preceded by cell proliferation. T-depleted spleen B cell suspensions were fractionated ...

In murine erythroleukemia (MEL) cells the length of the latent period before the onset of hexamethylenebisacetamide induced terminal erythroid differentiation is inversely correlated to the intracellular level of delta-PKC. This is supported by the following experimental evidence. V3.17[44] MEL cell line, characterized by a very high rate of differentiation, contains ...

To study the role of 1 alpha,25-dihydroxyvitamin D3 (calcitriol) in tumor promotion, we used JB6 C141.5a cells, a mouse epidermal cell model of tumor promotion. The phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) irreversibly induces anchorage-independent growth and tumorigenicity in these cells. Since we previously showed that calcitriol does not transform these cells ...

Immunocytochemistry revealed an association between growth inhibition and a translocation of retinoblastoma protein (pRB) to the nucleoli of U-2 osteosarcoma cells inhibited in their growth by the negative growth factor NCPI (natural cell proliferation inhibitor). Similar phenomenon was demonstrated by Western blot analysis and immunocytochemistry in U937 leukemic cells inhibited ...

BACKGROUND: Malignant rhabdoid tumor (MRT), originally described as a rare renal sarcoma in childhood, has been known to express phenotypic diversity. In this study, unique characteristics of the MRT cells were investigated by using established cell lines. METHODS: Immunocytochemical, ultrastructural, cytogenetic, and molecular (by polymerase chain reaction, PCR) analyses were ...