Docosahexaenoic acid modulates phorbol ester-induced activation of extracellular signal-regulated kinases 1 and 2 in NIH/3T3 cells.
Phosphorylation of extracellular signal-regulated kinases (ERK1/ERK2) has been implicated in cell proliferation of mammalian cells. In the present study, we investigated the role of docosahexaenoic acid (DHA) in the modulation of ERK1/ERK2 phosphorylation, stimulated either with phorbol 12-myristate 13-acetate (PMA) or transforming growth factor-alpha (TGFalpha) in NIH/3T3 cells. We observed that both PMA and TGFalpha induced ERK1/ERK2 phosphorylation within 5 min of stimulation. PMA acts upstream of MEK and via activation of protein kinase C (PKC), as GF109203X, a potent PKC inhibitor, and U0126, a MEK inhibitor, abolished its actions on ERK1/ERK2 phosphorylation. TGFalpha did not act via PKC because GF109203X failed to curtail the degree of ERK1/ERK2 phosphorylation in these cells. DHA alone failed to induce the phosphorylation of these mitogen-activated protein (MAP) kinases; however, this fatty acid significantly curtailed the PMA- but not TGFalpha-induced MAP kinase enzyme activity and phosphorylation in NIH/3T3 cells. Furthermore, we observed that DHA significantly inhibited PMA-induced translocation of two PKC isoforms, PKC alpha and PKC epsilon, from cytosol to plasma membrane. Interestingly, DHA failed to inhibit the PMA-induced translocation PKC delta isoform in these cells. Furthermore, DHA decreased PMA-induced proliferation of NIH/3T3 cells. In this study, we show for the first time that DHA inhibits MAP kinase ERK1/ERK2) activation and proliferation of NIH/3T3 cells via its inhibitory action on PKC alpha and epsilon isoforms.
Denys
A
A
UPRES Lipides & Nutrition, Université de Bourgogne, Faculté des Sciences, Dijon, France.
Hichami
A
A
Maume
B
B
Khan
N A
NA
D016475:3T3 Cells / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D048728:MAP Kinase Kinase Kinase 1; D020935:MAP Kinase Signaling System; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000187:drug effects / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000187:drug effects / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D016211:Transforming Growth Factor alpha / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; D016211:Transforming Growth Factor alpha; D004281:Docosahexaenoic Acids; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; C482578:Map3k1 protein, mouse; C070515:bisindolylmaleimide I; D013755:Tetradecanoylphorbol Acetate