Selenazoles (selenium compounds) facilitate survival of cultured rat pheochromocytoma PC12 cells after serum-deprivation and stimulate their neuronal differentiation via activation of Akt and mitogen-activated protein kinase, respectively.
The activation of extracellular receptor kinase (ERK) is one of the checkpoints to assess the activation of the classical Ras/mitogen-activated protein kinase (MAPK) cascade. Therefore, we tested more than 100 selenium-containing compounds for their ability to activate the MAPK signal pathway. Among them, we found that three selenazoles, 5-chloroacetyl-2-piperidino-1,3-selenazole (CS1), 5-chloroacetyl-2-morpholino-1,3-selenazole (CS2), and 5-chloroacetyl-2-dimethylamino-1,3-selenazole (CS3), induced the phosphorylation of ERK. These compounds also enhanced the phosphorylation of Akt, a signal transducing protein kinase for cell survival; and this phosphorylation was followed by suppression of cell death, thus suggesting that they had anti-apoptotic effects. Moreover, CSs 1-3 induced neurite outgrowth and facilitated the expression of neurofilament-M of PC12 cells, demonstrating that they induced neuronal differentiation of these cells. On the other hand, the CS-induced phosphorylation of MAPK was enhanced by buthionine sulfoximine (BSO), an activator of protein tyrosine phosphatases (PTPs), but inhibited by N-acetyl-l-cysteine (NAC), an inhibitor of receptor tyrosine kinase. These results imply that activation of some receptor tyrosine kinase(s) is involved in the mechanism of action of CSs 1-3. The activation of MAPK by CSs 1-3 was suppressed by U0126, a MEK inhibitor, but not by K252a, an inhibitor of TrkA; AG1478, an antagonist of epidermal growth factor receptor (EGFR); or by pertussis toxin. These results demonstrate that the CS-induced phosphorylation of Akt and MAP kinase (receptor tyrosine kinase(s)-MEK1/2-ERK1/2) cascades was responsible for suppression of apoptosis and facilitation of neuronal differentiation of PC12 cells, respectively. Our results suggest that CSs 1-3 are promising candidates as neuroprotective and/or neurotrophic agents for the treatment of various neurodegenerative neurological disorders.
Nishina
Atsuyoshi
A
Gunma Industrial Technology Center, 884-1 Kamesato, Maebashi, Gunma 379-2147, Japan. nishina@tec-lab.pref.gunma.jp
Sekiguchi
Akihiro
A
Fukumoto
Ryo-hei
RH
Koketsu
Mamoru
M
Furukawa
Shoei
S
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects*; D016895:Culture Media, Serum-Free; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D016716:PC12 Cells; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D018036:Selenium Compounds / Q000008:administration & dosage*
D016895:Culture Media, Serum-Free; D018036:Selenium Compounds; D051057:Proto-Oncogene Proteins c-akt; D020929:Mitogen-Activated Protein Kinase Kinases