title: Ethanol induces cell cycle arrest and triggers apoptosis via Sp1-dependent p75NTR expression in human neuroblastoma cells.
abstract: Ethanol exposure has deleterious effects on the central nervous system. Although several mechanisms for ethanol-induced damage have been suggested, the precise mechanism underlying ethanol-induced neuronal cell death remains unclear. Recent studies indicate that the p75 neurotrophin receptor (p75NTR) has a critical role in the regulation of neuronal survival. This study was designed to examine the role of p75NTR in ethanol-induced apoptotic signaling in neuroblastoma cells. Ethanol caused highly increased level of p75NTR expression. The use of small interfering RNA to inhibit p75NTR expression markedly attenuated ethanol-induced cell cycle arrest and apoptosis. DNA binding activity of Sp1 was increased by ethanol, whereas inhibition of Sp1 activity by mithramycin, a Sp1 inhibitor, or short hairpin RNA suppressed ethanol-induced p75NTR expression. In addition, inhibitors of casein kinase 2 (CK2) and extracellular signal-regulated kinase (ERK) augmented ethanol-induced p75NTR expression. Our results also demonstrate that inhibition of ERK and CK2 caused a further increase in the activation of the p75NTR proximal promoter induced by ethanol. This increased activation was partially suppressed by the deletion of the Sp1 binding sites. These results suggest that Sp1-mediated p75NTR expression is regulated at least in part by ERK and CK2 pathways. The present study also showed that treatment with ethanol resulted in significant increases in the expression of p21, but not the levels of p53 and p53 target genes such as Bax, Puma, and Bcl-2. Furthermore, the inhibition of p75NTR expression or Sp1 activity suppressed ethanol-induced p21 expression, cell cycle arrest, and apoptosis. These data suggest that ethanol increases p75NTR expression, and CK2 and ERK signaling inversely regulate Sp1-mediated p75NTR expression in ethanol-treated neuroblastoma cells. Thus, our study provides more insight into the mechanisms underlying ethanol actions.
authors.affiliation: School of Medicine, Tan Tao University, Tan Duc ECity, Long An Province, Viet Nam.
authors.forename: Hang
authors.initials: H
authors.lastname: Do
authors.forename: Hey-Jin
authors.initials: HJ
authors.lastname: Park
authors.forename: Eun-Hwa
authors.initials: EH
authors.lastname: Sohn
authors.forename: Byung-Oh
authors.initials: BO
authors.lastname: Kim
authors.forename: Sung Hee
authors.initials: SH
authors.lastname: Um
authors.forename: Jong-Hwan
authors.initials: JH
authors.lastname: Kwak
authors.forename: Eun-Yi
authors.initials: EY
authors.lastname: Moon
authors.forename: Dong-Kwon
authors.initials: DK
authors.lastname: Rhee
authors.forename: Suhkneung
authors.initials: S
authors.lastname: Pyo
mesh_terms: D000437:Alcoholism / Q000473:pathology; D017209:Apoptosis / Q000187:drug effects*; D047390:Casein Kinase II / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000633:toxicity*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D000431:Ethanol / Q000633:toxicity*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009447:Neuroblastoma; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D017475:Receptors, Nerve Growth Factor / Q000235:genetics* / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000502:physiology*; D015533:Transcriptional Activation / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: C493956:CDKN1A protein, human; D002492:Central Nervous System Depressants; D050759:Cyclin-Dependent Kinase Inhibitor p21; C484065:NGFR protein, human; D009419:Nerve Tissue Proteins; D017475:Receptors, Nerve Growth Factor; D016329:Sp1 Transcription Factor; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D000431:Ethanol; D047390:Casein Kinase II; D048049:Extracellular Signal-Regulated MAP Kinases