Activation of mitogen-activated protein kinases is required for alpha1-adrenergic agonist-induced cell scattering in transfected HepG2 cells.
Activation of alpha1B-adrenergic receptors ((alpha1B)AR) by phenylephrine (PE) induces scattering of HepG2 cells stably transfected with the (alpha1B)AR (TFG2 cells). Scattering was also observed after stimulation of TFG2 cells with phorbol myristate acetate (PMA) but not with hepatocyte growth factor/scatter factor, epidermal growth factor, or insulin. PMA but not phenylephrine rapidly activated PKCalpha in TFG2 cells, and the highly selective PKC inhibitor bisindolylmaleimide (GFX) completely abolished PMA-induced but not PE-induced scattering. PE rapidly activated p44/42 mitogen-activated protein kinase (MAPK), p38 MAPK, c-Jun N-terminal kinase (JNK), and AP1 (c-fos/c-jun). Selective blockade of p42/44 MAPK activity by PD98059 or by transfection of a MEK1 dominant negative adenovirus significantly inhibited the PE-induced scattering of TFG2 cells. Selective inhibition of p38 MAPK by SB203850 or SB202190 also blocked PE-induced scattering, whereas treatment of TFG2 cells with the PI3 kinase inhibitors LY294002 or wortmannin did not inhibit PE-induced scattering. Blocking JNK activation with a dominant negative mutant of JNK or blocking AP1 activation with a dominant negative mutant of c-jun (TAM67) significantly inhibited PE-induced cell scattering. These data indicate that PE-induced scattering of TFG2 cells is mediated by complex mechanisms, including activation of p42/44 MAPK, p38 MAPK, and JNK. Cell spreading has been reported to play important roles in wound repair, tumor invasion, and metastasis. Therefore, catecholamines acting via the (alpha1)AR may modulate these physiological and pathological processes.
Spector
M
M
Department of Pharmacology and Toxicology, Medical College of Virginia of Virginia Commonwealth University, Richmond 23298, USA.
Nguyen
V A
VA
Sheng
X
X
He
L
L
Woodward
J
J
Fan
S
S
Baumgarten
C M
CM
Kunos
G
G
Dent
P
P
Gao
B
B
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000730:Androstadienes / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002633:Chemotaxis / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D000077191:Wortmannin; D048051:p38 Mitogen-Activated Protein Kinases
C547716:ADRA1B protein, human; D000316:Adrenergic alpha-Agonists; D000730:Androstadienes; D002867:Chromones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D009025:Morpholines; D011725:Pyridines; D018340:Receptors, Adrenergic, alpha-1; D011994:Recombinant Proteins; D018808:Transcription Factor AP-1; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin