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Virology Feb 2019The Tyr705 STAT3 constitutive activation, besides promoting PEL cell survival, contributes to the maintenance of viral latency. We found indeed that its...
The Tyr705 STAT3 constitutive activation, besides promoting PEL cell survival, contributes to the maintenance of viral latency. We found indeed that its de-phosphorylation by AG490 induced KSHV lytic cycle. Moreover, Tyr705 STAT3 de-phosphorylation, mediated by the activation of tyrosine phosphatases, together with the increase of Ser727 STAT3 phosphorylation contributed to KSHV lytic cycle induction by TPA. We then observed that p53-p21 axis, essential for the induction of KSHV replication, was activated by the inhibition of Tyr705 and by the increase of Ser727 STAT3 phosphorylation. As a possible link between STAT3, p53-p21 and KSHV lytic cycle, we found that TPA and AG490 reduced the expression of KAP-1, promoting p53 stability, p21 transcription and KSHV lytic cycle activation in PEL cells.
Topics: Cell Line, Tumor; Cyclin-Dependent Kinase Inhibitor p21; Herpesvirus 8, Human; Humans; Phosphorylation; STAT3 Transcription Factor; Staurosporine; Tetradecanoylphorbol Acetate; Tumor Suppressor Protein p53; Virus Activation
PubMed: 30616203
DOI: 10.1016/j.virol.2018.12.015 -
Cell Structure and Function Dec 1987We have investigated the effects of various types of collagen and a tumor-promoting phorbol ester on intercellular contacts and the organization of actin in human amnion... (Comparative Study)
Comparative Study
Intercellular contacts and the organization of actin filaments in cultured epithelial FL cells are altered by growth on type I collagen and treatment with 12-O-tetradecanoylphorbol-13-acetate through the modulation of interactions between cells and the substratum.
We have investigated the effects of various types of collagen and a tumor-promoting phorbol ester on intercellular contacts and the organization of actin in human amnion epithelial FL cells and mouse fibroblast 3T3-A31 cells. Our purpose was to investigate how modulation of interactions between cells and the substratum leads to alterations in intercellular contacts and organization of actin filaments. When cells were cultured on dishes coated with a solution containing type I collagen, but not type IV, changes were induced in the morphology of FL cells and their intercellular contacts. Type I collagen also caused changes in the organization of their actin filaments, although no such effects were observed with 3T3-A31 cells. In contrast, 12-O-tetradecanoylphorbol-13-acetate (TPA) caused morphological changes, dissociation of groups of cells, and reorganization of actin filaments in cultures of FL and 3T3-A31 cells. It also disrupted the sites of adhesion of FL cells to the substratum. Both type I collagen and TPA rapidly induced spreading of FL cells in the absence of serum. However, cis-hydroxyproline, known to inhibit secretion of collagen, did not suppress the TPA-induced dissociation of groups of FL cells. These results suggest that the interactions with type I collagen of epithelial FL cells, but not of fibroblastic 3T3-A31 cells, tend to disorganize cellular morphology, intercellular contacts, and actin filaments in ways similar to, but not directly related to, the effects of TPA.
Topics: Actins; Amnion; Animals; Cell Aggregation; Cell Division; Cell Line; Collagen; Culture Media; Cytoskeleton; Epithelium; Fibroblasts; Humans; Intercellular Junctions; Tetradecanoylphorbol Acetate
PubMed: 3435916
DOI: 10.1247/csf.12.549 -
The Journal of Cell Biology Jun 1983We obtained cell preparations containing greater than 95% neutrophils from freshly drawn bovine blood. The cells were suspended in sucrose and disrupted in a Dounce...
We obtained cell preparations containing greater than 95% neutrophils from freshly drawn bovine blood. The cells were suspended in sucrose and disrupted in a Dounce homogenizer, and the postnuclear supernate was fractionated by zonal differential sedimentation and by isopycnic equilibration. The subcellular fractions were characterized biochemically by testing for marker enzymes and other constituents known to occur in azurophil and specific granules of other species, and by electrophoretic analysis of extracts of the particulate material. In addition, each fraction was examined by random-sampling electron microscopy. We found that bovine neutrophils contain in addition to azurophil and specific granules a third type of granule, not known to occur in neutrophils of other species. These novel granules are larger, denser, and considerably more numerous than the two other types. Except for lactoferrin, they lack the characteristic constituents of azurophil granules (peroxidase, acid hydrolases, and neutral proteinases) and of specific granules (vitamin B12-binding protein). Instead, they contain a group of highly cationic proteins not found in the other granules, and they are the exclusive stores of powerful oxygen-independent bactericidal agents. We studied the fate of the large granules in bovine neutrophils exposed to opsonized particles, the ionophore A 23187, or phorbol myristate acetate. The appearance in the cell-free media of antibacterial activity and of the characteristic highly cationic proteins as revealed by electrophoresis was monitored and compared with the release of azurophil and specific granule markers. In addition, changes of the relative size of the large granule compartment induced by phagocytosis were assessed by morphometry. The results show that exocytosis of the large granules occurs following both phagocytosis and exposure to soluble stimuli. Like the specific granules, the large granules appear to be discharged by true secretion under conditions where the azurophil granules are fully retained.
Topics: Animals; Calcimycin; Cattle; Cytoplasmic Granules; Microscopy, Electron; Neutrophils; Oxygen; Phagocytosis; Tetradecanoylphorbol Acetate
PubMed: 6406517
DOI: 10.1083/jcb.96.6.1651 -
British Journal of Pharmacology Jul 2010Population studies have revealed that treatment with the anti-diabetic drug metformin is significantly associated with reduced cancer risk, but the underlying mode of...
Metformin blocks migration and invasion of tumour cells by inhibition of matrix metalloproteinase-9 activation through a calcium and protein kinase Calpha-dependent pathway: phorbol-12-myristate-13-acetate-induced/extracellular signal-regulated kinase/activator protein-1.
BACKGROUND AND PURPOSE
Population studies have revealed that treatment with the anti-diabetic drug metformin is significantly associated with reduced cancer risk, but the underlying mode of action has not been elucidated. The aim of our study was to determine the effect of metformin on tumour invasion and migration, and the possible mechanisms, using human fibrosarcoma HT-1080 cells.
EXPERIMENTAL APPROACH
We employed invasion, migration and gelatin zymography assays to characterize the effect of metformin on HT-1080 cells. Transient transfection assays were performed to gene promoter activities, and immunoblot analysis to study its molecular mechanisms of action.
KEY RESULTS
Metformin inhibited migration and invasion by HT-1080 cells at sub-toxic concentrations. In these cells, metformin also suppressed phorbol-12-myristate-13-acetate (PMA)-enhanced levels of matrix metalloproteinases-9 (MMP-9) protein, mRNA and transcription activity through suppression of activator protein-1 (AP-1) activation. In addition, metformin strongly repressed the PMA-induced phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and protein kinase C(PKC)alpha, whereas the phosphorylation of p38 mitogen-activated protein kinase was not affected by metformin. Metformin decreased the PMA-induced Ca(2+) influx. Furthermore, treatment with an intracellular Ca(2+) chelator (BAPTA-AM) or a selective calmodulin antagonist (W7) markedly decreased PMA-induced MMP-9 secretion and cell migration, as well as activation of ERK and JNK/AP-1.
CONCLUSIONS AND IMPLICATIONS
Metformin inhibited PMA-induced invasion and migration of human fibrosarcoma cells via Ca(2+)-dependent PKCalpha/ERK and JNK/AP-1-signalling pathways. Metformin therefore has the potential to be a potent anti-cancer drug in therapeutic strategies for fibrosarcoma metastasis.
Topics: Calcium; Cell Line, Tumor; Cell Movement; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Matrix Metalloproteinase 9; Metformin; Mitogen-Activated Protein Kinases; Neoplasm Invasiveness; Protein Kinase C; Signal Transduction; Tetradecanoylphorbol Acetate; Transcription Factor AP-1
PubMed: 20590612
DOI: 10.1111/j.1476-5381.2010.00762.x -
Molecular Medicine Reports Mar 2018The effector function of natural killer, lymphokine--activated killer cells and T lymphocytes is commonly evaluated by radioactive chromium‑release cytotoxicity...
The effector function of natural killer, lymphokine--activated killer cells and T lymphocytes is commonly evaluated by radioactive chromium‑release cytotoxicity assays. In addition to this indirect method, fluorescence assays have been described for the assessment of in vitro cell‑mediated cytotoxicity. In the present study, target cells were stained with 5‑(and‑6)‑carboxyfluorescein diacetate succinimidyl ester (CFSE), which is a stable integrated fluorescent probe that allows target and effector cells to be distinguished from one another. Staining of target THP‑1 cells with 8 µM CFSE revealed high and stable loading of fluorescence and no effect of the viability of cells. After 4 h of in vitro co‑culture between γδ T cells and CFSE‑labeled infected or uninfected THP‑1 cells, staining with propidium iodide (PI) was performed to distinguish between vital and dead cells. During sample acquisition, target cells were gated on the CFSE positivity and examined for cell death based on the uptake of PI. CFSE and PI double positive cells were recognized as the dead target cells. The percentage of cytotoxicity in the CFSE‑gated cell population was calculated by subtracting the value obtained for non‑specific PI‑positive target cells, which was measured in a control group that did not contain effector cells. The present study describes a simple and convenient assay that is based on the direct quantitative and qualitative analysis of cell damage at a single cell level utilizing a two‑color flow cytometric assay. In conclusion, the flow cytometric‑based assay described in the current study is a simple, sensitive and reliable tool to determine the cytolytic activity of γδ T lymphocytes against mycobacteria. Therefore, the present study may provide valuable information concerning the methods employed to investigate the function of γδ T cells and potentially other lymphocyte subsets.
Topics: Cell Differentiation; Cell Line; Coculture Techniques; Cytotoxicity, Immunologic; Flow Cytometry; Fluorescent Dyes; Humans; Intraepithelial Lymphocytes; Lipopolysaccharide Receptors; Microscopy, Fluorescence; Mycobacterium tuberculosis; Phagocytosis; Tetradecanoylphorbol Acetate
PubMed: 29257316
DOI: 10.3892/mmr.2017.8281 -
International Journal of Molecular... May 2022In this work, we examined the differentiation of oligodendrocytic MO3.13 cells and changes in their gene expression after treatment with phorbol 12-myristate 13-acetate,...
In this work, we examined the differentiation of oligodendrocytic MO3.13 cells and changes in their gene expression after treatment with phorbol 12-myristate 13-acetate, PMA, or with RNA polymerase I (Pol I) inhibitor, CX-5461. We found that MO3.13 cells changed their morphology when treated with both agents. Interestingly, CX-5461, but not PMA, induced noticeable changes in the integrity of the nucleoli. Then, we analyzed the p53 transcriptional activity in MO3.13 cells and found that it was increased in both cell populations, but particularly in cells treated with PMA. Interestingly, this high p53 transcriptional activity in PMA-treated cells coincided with a lower level of an unmodified (non-phosphorylated) form of this protein. Since morphological changes in MO3.13 cells after PMA and CX-5461 treatment were evident, suggesting that cells were induced to differentiate, we performed RNA-seq analysis of PMA-treated cells, to reveal the direction of alterations in gene expression. The analysis showed that the largest group of upregulated genes consisted of those involved in myogenesis and K-RAS signaling, rather than those associated with oligodendrocyte lineage progression.
Topics: Gene Expression Profiling; Humans; Muscle Development; RNA-Seq; Tetradecanoylphorbol Acetate; Tumor Suppressor Protein p53; Up-Regulation
PubMed: 35682649
DOI: 10.3390/ijms23115969 -
Frontiers in Immunology 2022The activation of NLRP3 inflammasome in macrophages has been proven to play a crucial role in the development of cardiovascular diseases. THP-1 monocytes can be...
BACKGROUND
The activation of NLRP3 inflammasome in macrophages has been proven to play a crucial role in the development of cardiovascular diseases. THP-1 monocytes can be differentiated to macrophages by incubation with phorbol-12-myristate 13-acetate (PMA), providing a suitable model for studies. However, PMA has been shown to have effects on the levels of IL-1β, the main mediator of NLRP3 inflammasome, while the effects on the other mediators of the inflammasome have not been reported before.
METHODS
THP-1 monocytes were incubated without (THP-1), with 5ng/ml PMA for 48h (PMA48h) or with 5ng/ml PMA for 48h plus 24h in fresh medium (PMArest). Morphological changes and the expression of macrophage surface markers (CD14, CD11b, CD36 and CD204) were evaluated by flow cytometry. Changes in intracellular levels of inflammasome components (NLRP3, ASC, pro-caspase-1, pro-IL1β) were analyzed by western blot and release of mature IL-1β in cell supernatant was analyzed by ELISA. ASC speck formation was determined by immunofluorescence.
RESULTS
After 48h incubation with PMA or subsequent rest in fresh medium, cells became adherent, and the differential expression of CD36, CD11b, CD14 and CD204 compared to THP-1 cells confirmed that PMArest resemble macrophages from a molecular point of view. Changes in the levels were detected in PMA48h group for all the NLRP3-related proteins, with increase of NLRP3 and pro-IL-1β and secretion of mature IL-1β. In PMArest, no pro-IL-1β and lower amounts of mature IL-1β were detected. No ASC speck was found in PMA treated groups, but the addition of a second stimulus to PMArest resulted in ASC speck formation, together with IL-1β production, confirming the responsiveness of the model.
CONCLUSION
Differentiation of THP-1 with 5ng/ml PMA followed by 24h resting period provides a model that morphologically and molecularly resembles macrophages. However, even at low concentrations, PMA induces production of IL-1β. The 24h rest period provides for down-regulation of pro-IL-1β in PMArest group, without affecting its ability to respond to a second stimulus through activation of inflammasome.
Topics: Inflammasomes; NLR Family, Pyrin Domain-Containing 3 Protein; Myristates; Tetradecanoylphorbol Acetate; Macrophages; Acetates
PubMed: 36618426
DOI: 10.3389/fimmu.2022.958098 -
Current Protocols in Bioinformatics Jun 2019Transcription is a chromatin mark that can be used effectively to identify the location of active enhancers and promoters, collectively known as transcriptional...
Transcription is a chromatin mark that can be used effectively to identify the location of active enhancers and promoters, collectively known as transcriptional regulatory elements (TREs). We recently introduced dREG, a tool for the identification of TREs using run-on and sequencing (RO-seq) assays, including global run-on and sequencing (GRO-seq), precision run-on and sequencing (PRO-seq), and chromatin run-on and sequencing (ChRO-seq). In this protocol, we present step-by-step instructions for running dREG on an arbitrary run-on and sequencing dataset. Users provide dREG with bigWig files (in which each read is represented by a single base) representing the location of RNA polymerase in a cell or tissue sample of interest, and dREG returns a list of genomic regions that are predicted to be active TREs. Finally, we demonstrate the use of dREG regions in discovering transcription factors controlling response to a stimulus and predicting their target genes. Together, this protocol provides detailed instructions for running dREG on arbitrary run-on and sequencing data. © 2018 by John Wiley & Sons, Inc.
Topics: Base Sequence; Genome; Internet; Ionomycin; Nucleotide Motifs; Regulatory Elements, Transcriptional; Sequence Analysis, RNA; Software; Tetradecanoylphorbol Acetate; Transcription Factors
PubMed: 30589513
DOI: 10.1002/cpbi.70 -
The Journal of Biological Chemistry Feb 2007Kallikrein type serine proteases, KLK8/neuropsin, KLK6, and KLK7, have been implicated in the proliferation and differentiation of epidermal keratinocytes and in the...
Kallikrein type serine proteases, KLK8/neuropsin, KLK6, and KLK7, have been implicated in the proliferation and differentiation of epidermal keratinocytes and in the pathogenesis of psoriasis. However, their mechanistic roles in these processes remain largely unknown. We applied 12-O-tetradecanoylphorbol-13-acetate on the wild type (WT) and the Klk8 gene-disrupted (Klk8(-/-)) mouse skin, inducing keratinocyte proliferation similar to the human psoriatic lesion. Klk8 mRNA as well as Klk6 and Klk7 mRNA were up-regulated after 12-O-tetradecanoylphorbol-13-acetate application in the WT mice. In contrast, Klk8(-/-) mice showed minimum increases of Klk6 and Klk7 transcripts, the proteins, and enzymatic activities. Relative to the WT, the Klk8(-/-) skin showed less proliferation and an increase in the number of cell layers in the stratum corneum. However, overexpression of Klk8 by adenovirus vector in knock-out keratinocytes did not result in an increase in Klk6 or Klk7 mRNA. The inefficient cleavage of adhesion molecules DSG1 and CDSN in Klk8(-/-) skin contributes to a delay in corneocyte shedding, resulting in the hyperkeratosis phenotype. We propose that in psoriatic lesion, KLK8 modulates hyperproliferation and prevents excessive hyperkeratosis by shedding the corneocytes.
Topics: Animals; Cell Differentiation; Cell Proliferation; Dermis; Desmoglein 1; Disease Models, Animal; Humans; Kallikreins; Keratinocytes; Mice; Mice, Knockout; Psoriasis; Tetradecanoylphorbol Acetate
PubMed: 17182622
DOI: 10.1074/jbc.M607998200 -
Clinical and Experimental Immunology Jan 1993Suramin is a polysulphonated compound which can selectively bind to, and inhibit the activity of, a wide range of growth factors. There has been renewed interest...
Suramin is a polysulphonated compound which can selectively bind to, and inhibit the activity of, a wide range of growth factors. There has been renewed interest recently in suramin as an anti-cancer agent and therefore we have studied its effects on lymphocyte subset populations and recombinant human IL-2 (rhIL-2) activation on lymphocytes in vitro. In the presence of rhIL-2 (1000 U/ml), suramin (200 micrograms/ml) caused a decrease in percentage of cells expressing the predominantly T cell antigen CD3; no change in percentage of cells expressing the T suppressor/cytotoxic subset antigen, CD8; a small rise in those expressing the natural killer cell antigen, CD56; and a large significant fall in those expressing the T helper subset antigen CD4 (48.51% versus 27.97%; P < 0.001). CD4 modulation by suramin was also found on the CD4+ cell lines CEM and MOLT-4. The effect of suramin on rhIL-2-induced activation antigen expression remains equivocal, since a small rise in CD25 expression and small falls in CD71 and HLA-Dr expression were recorded. The modulatory effect of suramin on CD4 expression was not reversible over a 96-h culture period in its continued presence. However, on removal of suramin by extensive washing, recovery of CD4 expression was detected within 24 h. Suramin-induced modulation, but not PMA-induced modulation, could be partially inhibited by preincubation with tyrphostin (12 microM), a tyrosine kinase inhibitor.
Topics: CD4 Antigens; Humans; Interleukin-2; Recombinant Proteins; Suramin; Tetradecanoylphorbol Acetate
PubMed: 8419075
DOI: 10.1111/j.1365-2249.1993.tb03369.x