The effect of cyclic adenosine monophosphate on the mitogen-activated protein kinase pathway depends on both the cell type and the type of tyrosine kinase-receptor.
The mitogen-activated protein kinase (MAP kinase) is a key participant in growth factor-stimulated intracellular events such as proliferation and differentiation. We and others have previously described a cross-talk between the MAP kinase pathway and the cAMP pathway. Indeed, in several cell lines and, in particular in fibroblasts, an increase in the level of cAMP produced an inhibition of MAP kinase together with decreased cell proliferation. In contrast, in PC12 cells, cAMP induced an increase in the NGF-induced activation of MAP kinase concomitantly with augmented NGF-induced differentiation. Therefore, it has been proposed that the cellular context is important for the nature of the cAMP effects on growth factor-stimulated MAP kinase activity. Here we show that the type of tyrosine kinase receptor stimulated also participates in the nature of the cAMP effect. Thus, in NIH3T3 fibroblasts expressing NGF receptors (NIH3T3/trk cells) we found that cAMP potentiates NGF-stimulated ERK1 and MEK1 activities, whereas in NIH3T3 fibroblasts expressing insulin receptors (NIH3T3/IR cells) we saw no effect of cAMP on the activation of insulin-stimulated ERK1 and MEK1. In PC12 cells and in Rat1 fibroblasts expressing insulin receptors (PC12/IR and Rat1/IR cells) we observed, respectively, a potentiation and an inhibition of insulin-stimulated ERK1 activity. In addition, cAMP does not seem to modify the basal nor growth factor-stimulated She or IRS-1 tyrosine phosphorylation in the different cell lines studied. Finally, we observed that cAMP inhibited serum- and insulin-induced, but not NGF-induced, cell proliferation in NIH3T3 cells. However, cAMP potentiated insulin-stimulated cell differentiation in PC12/IR cells. These results led us to conclude that the cAMP effect on cell proliferation in NIH3T3 fibroblasts and PC12/IR cells appears to be correlated, in part, with the effect of cAMP on the MAP kinase pathway, but by itself this pathway cannot fully account for these observations.
Calleja
V
V
INSERM U145, Faculté de Médecine, Nice, France.
Ruiz Enríquez
P
P
Filloux
C
C
Peraldi
P
P
Baron
V
V
Van Obberghen
E
E
D016475:3T3 Cells / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D000242:Cyclic AMP / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D048369:MAP Kinase Kinase 1; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009414:Nerve Growth Factors / Q000494:pharmacology; D016716:PC12 Cells / Q000378:metabolism; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D007328:Insulin; D009414:Nerve Growth Factors; D010982:Platelet-Derived Growth Factor; D011506:Proteins; D011956:Receptors, Cell Surface; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine; D000242:Cyclic AMP; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482127:Map2k1 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases