title: Genistein-induced neuronal differentiation is associated with activation of extracellular signal-regulated kinases and upregulation of p21 and N-cadherin.
abstract: Neuronal differentiation in the mammalian CNS is driven by multiple events. When treated with retinoic acid (RA), hNTera-2 (NT-2) cells undergo postmitotic neuronal differentiation. Here, we show that a prolonged exposure of NT-2 cells with non-cytotoxic doses of genistein, a protein tyrosine kinase (PTK) inhibitor, induced differentiation of NT-2 cells. Additionally, genistein enhanced RA-induced neuronal differentiation by increasing the activation of extracellular signal-related kinase 1/2 (ERK1/2) via phosphorylation at Thr183 and Tyr185 in 3-7 days. Meanwhile, genistein also upregulated N-cadherin and p21 (a Cdk inhibitor), but downregulated proliferating cell nuclear antigen protein (PCNA). MEK1/2 inhibitors, such as PD98059 and U0126, reduced RA-induced ERK1/2 activity, but could not block the genistein effects. Our observations indicate that genistein-induced neuronal differentiation is not dependent of the MEK-ERK signaling cascade. Instead, genistein-upregulated ERK activation is likely due to this chemical's direct effect on chromosome and gene transcription, rather than its inhibition on tyrosine kinases. Failure of inhibition of ERK1/2 activation by the MEK1/2 inhibitors PD98059 and U0126 suggests presence of an unknown activator for ERK1/2 in neuronal cells.
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan City 701, Taiwan.
authors.forename: S P
authors.initials: SP
authors.lastname: Hung
authors.forename: J R
authors.initials: JR
authors.lastname: Hsu
authors.forename: C P
authors.initials: CP
authors.lastname: Lo
authors.forename: H J
authors.initials: HJ
authors.lastname: Huang
authors.forename: J P
authors.initials: JP
authors.lastname: Wang
authors.forename: S T
authors.initials: ST
authors.lastname: Chen
mesh_terms: D002070:Butadienes / Q000494:pharmacology; D015820:Cadherins / Q000096:biosynthesis*; D002454:Cell Differentiation; D002460:Cell Line; D045744:Cell Line, Tumor; D002490:Central Nervous System / Q000378:metabolism; D051360:Cyclin-Dependent Kinase 5 / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology*; D006801:Humans; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D019000:Phosphotyrosine / Q000737:chemistry; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis*; D013912:Threonine / Q000378:metabolism; D013997:Time Factors; D014212:Tretinoin / Q000378:metabolism / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D002070:Butadienes; D015820:Cadherins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D009570:Nitriles; C113580:U 0126; D019000:Phosphotyrosine; D013912:Threonine; D014212:Tretinoin; D019833:Genistein; D051360:Cyclin-Dependent Kinase 5; D048049:Extracellular Signal-Regulated MAP Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D016283:Proto-Oncogene Proteins p21(ras); C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one