Nicotine-induced phosphorylation of Akt through epidermal growth factor receptor and Src in PC12h cells.
Nicotine treatment triggers calcium influx into neuronal cells, which promotes cell survival in a number of neuronal cells. Phosphoinositide (PI) 3-kinase and downstream PI3-kinase target Akt have been reported to be important in the calcium-mediated promotion of survival in a wide variety of cells. We investigated the mechanisms of nicotine-induced phosphorylation of Akt in PC12h cells, in comparison with nicotine-induced ERK phosphorylation. Nicotine induced Akt phosphorylation in a dose-dependent manner. A nicotinic acetylcholine receptor (nAChR) alpha7 subunit-selective inhibitor had no significant effect on nicotine-induced Akt phosphorylation, while a non-selective nAChR antagonist inhibited the phosphorylation. L-type voltage-sensitive calcium channel (VSCC) antagonists, calmodulin antagonist, and Ca2+/calmudulin-dependent protein kinase (CaM kinase) inhibitor prevented the nicotine-induced Akt phosphorylation. Three epidermal growth factor receptor (EGFR) inhibitors prevented the nicotine-induced phosphorylation of both extracellular signal-regulated protein kinase (p42/44 MAP kinase, ERK) and Akt. In contrast, an inhibitor of the Src family tyrosine kinase prevented the nicotine-induced Akt phosphorylation but not ERK phosphorylation. These results suggested that nicotine induces the activation of both PI3-kinase/Akt and ERK pathways via common pathways including non-alpha7-nAChRs, L-type VSCC, CaM kinase II and EGFR in PC12h cells, but Src family tyrosine kinases only participate in the pathway to activate Akt.
Nakayama
Hitoshi
H
Department of Pharmacology, Nara Medical University, Kashihara, Nara, Japan Division of Protein Biosynthesis, Institute for Protein Research, Osaka University, Suita, Osaka, Japan. hnakayam@naramed-u.ac.jp
Numakawa
Tadahiro
T
Ikeuchi
Toshihiko
T
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009538:Nicotine / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D016716:PC12 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D002121:Calcium Channel Blockers; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002147:Calmodulin; D004791:Enzyme Inhibitors; D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases; D009538:Nicotine; D018733:Nicotinic Antagonists; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D019061:src-Family Kinases; C494920:Akt1 protein, rat