scholarly journals Effects of Okadaic Acid, Retinoic Acid, and Phorbol Myristate Acetate Tumor Promoter on Oncogene Expression

2014 ◽  
Vol 05 (06) ◽  
pp. 591-604 ◽  
Author(s):  
John J. Wille ◽  
Jong Y. Park
Keyword(s):  
Retinoic Acid ◽  
Okadaic Acid ◽  
Phorbol Myristate Acetate ◽  
Tumor Promoter ◽  
Myristate Acetate ◽  
Oncogene Expression

Factors which affect DNA strand breakage in human leukocytes exposed to a tumor promoter, phorbol myristate acetate

1982 ◽  
Vol 60 (11) ◽  
pp. 1359-1366 ◽  
Author(s):  
H. C. Birnboim
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Phorbol Myristate Acetate ◽  
Respiratory Burst ◽  
Superoxide Anion ◽  
Tumor Promoter ◽  
Myristate Acetate ◽  
Strand Breakage ◽  
Dna Strand ◽  
Dna Strand Breakage

We have recently reported that phorbol myristate acetate (PMA) induces extensive DNA strand break damage in human peripheral blood leukocytes. The mechanism of action involves superoxide anion and hydrogen peroxide which are generated by phagocytes during the "respiratory burst." In this report, we describe the effect of various inhibitors and scavengers on PMA-induced DNA damage. Azide and cyanide greatly increased the level of damage; sulfhydryl compounds (glutathione, cysteine, and cysteamine) and ascorbate markedly decreased the level of damage. Hydroxyl radical scavengers such as dimethyl sulfoxide (DMSO) and glycerol also decreased the level of damage but apparently did so by inhibiting the respiratory burst. Diethyldithiocarbamate (DDC) increased the level of DNA damage at low concentrations (<1 mM), but decreased DNA damage at ≥1 mM. The results are consistent with a mechanism involving superoxide anion and hydrogen peroxide, but the precise reaction (free radical or enzymatic) responsible for DNA strand breakage has not been determined. The PMA-stimulated phagocyte is an interesting model system for looking at "active oxygen" mediated DNA damage and factors which influence it.

scholarly journals Endothelial diaphragmed fenestrae: in vitro modulation by phorbol myristate acetate.

1986 ◽  
Vol 102 (5) ◽  
pp. 1965-1970 ◽  
Author(s):  
T Lombardi ◽  
R Montesano ◽  
M B Furie ◽  
S C Silverstein ◽  
L Orci
Keyword(s):  
Endothelial Cells ◽  
Cell Surface ◽  
Phorbol Myristate Acetate ◽  
Freeze Fracture ◽  
Tumor Promoter ◽  
Microvascular Endothelial Cells ◽  
Myristate Acetate ◽  
Capillary Endothelial Cells

Cultured microvascular endothelial cells isolated from fenestrated capillaries have been shown to express many properties of their in vivo differentiated phenotype, yet they contain very few diaphragmed fenestrae. We show here that treatment of capillary endothelial cells with the tumor promoter, 4 beta-phorbol 12-myristate 13-acetate, induces more than a fivefold increase in the frequency of fenestrae per micron 2 of cell surface, as determined from a quantitative evaluation on freeze-fracture replicas. In quick-frozen, deep-etched preparations, the endothelial fenestrae appeared to be bridged by a diaphragm composed of radial fibers interweaving in a central mesh, as previously observed in vivo. These results indicate that diaphragmed fenestrae are inducible structures, and provide an opportunity to study them in vitro.

scholarly journals Phorbol myristate acetate stimulates phagosome-lysosome fusion in mouse macrophages.

1981 ◽  
Vol 154 (1) ◽  
pp. 101-111 ◽  
Author(s):  
M C Kielian ◽  
Z A Cohn
Keyword(s):  
Phorbol Myristate Acetate ◽  
Background Level ◽  
Fusion Rate ◽  
Tumor Promoter ◽  
Free Medium ◽  
Protein Synthesis Inhibitors ◽  
Myristate Acetate ◽  
Mouse Macrophages ◽  
D Cells ◽  
Layer Chromatography

The effect of the tumor promoter phorbol myristate acetate (PMA) on phagosome-lysosome (P-L) fusion in mouse macrophages has been studied using a previously described (10) fluorescence assay. Treatment with 0.1--1.0 microgram PMA/ml caused a striking increase in the rate and extent of P-L fusion. Exposure of cells to phorbol, free myristate, or the monoesters of PMA did not reproduce this effect. Macrophages required from 2 to 3 h of pretreatment to express maximal P-L fusion, and this was maintained for at least 20 h when cells were returned to PMA-free medium. Catalase, superoxide dismutase, indomethacin, and hydrocortisone, agents that are known to block the effect of PMA on H2O2, O2-, prostaglandins, or plasminogen activator, did not affect the stimulation of P-L fusion by PMA. The protein-synthesis inhibitors puromycin and cycloheximide did block the PMA effect under conditions in which the high fusion rate of 4-d cells was not affected. Labeled PMA was rapidly taken up by macrophages, with a plateau of uptake at approximately 3 h. When cells were returned to PMA-free medium, cel-associated label was rapidly released, returning to background level within 1 h. The released label was found to be a metabolite of PMA by thin-layer chromatography. This product migrated between the monoester phorbol-12-myristate and free phorbol. Rapid metabolism of PMA was also observed by a macrophage cell line, J774, and, to a lesser extent, by primary rat embryo fibroblasts.

scholarly journals Regulation of plasminogen activator in 3T3 cells: effect of phorbol myristate acetate on subcellular distribution and molecular weight.

1981 ◽  
Vol 90 (3) ◽  
pp. 727-731 ◽  
Author(s):  
S Jaken ◽  
P H Black
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
Plasminogen Activator ◽  
Phorbol Myristate Acetate ◽  
Subcellular Distribution ◽  
Tumor Promoter ◽  
3T3 Cells ◽  
Myristate Acetate ◽  
Extracellular Release ◽  
Swiss 3T3

The tumor promoter, phorbol myristate acetate (PMA), stimulates plasminogen activator production and extracellular release in confluent Swiss 3T3 cells. Coordinated with the increased extracellular release is a redistribution of the activity into plasma membrane-enriched fractions and a shift in the predominant molecular weight species from 75,000 to 49,000 daltons. The evidence suggests that PMA induces the formation of the 49,000 dalton species which is preferentially located in plasma membrane-enriched fractions.

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