title: Role of down-regulated neutral ceramidase during all-trans retinoic acid-induced neuronal differentiation in SH-SY5Y neuroblastoma cells.
abstract: Neutral ceramidase (NCDase) is considered to be a critical enzyme for controlling the turnover of ceramide, an important bioactive lipid, which determines cell's fate. All-trans retinoic acid (ATRA) has been reported to induce neuronal differentiation and cell-cycle arrest [Lopez-Carballo, Moreno, Masia, Perez, and Barettino (Activation of the phosphatidylinositol 3-kinase/Akt signalling pathway by retinoic acid is required for neural differentiation of SH-SY5Y human neuroblastoma cells. J Biol Chem 2002:277:25297-304.)]. In this study, we observed that ATRA-induced cellular ceramide accumulation, cell-growth arrest and differentiation accompanied with down-regulation of NCDase in SH-SY5Y cells, without a decrease in sphingosine or sphingosine 1-phosphate. We examined whether the down-regulation of NCDase was involved in the increase in ceramide and cell differentiation. ATRA was found to down-regulate mRNA, protein and the enzyme activity of NCDase. Interestingly, GATA-2 was also decreased with ATRA treatment, and experiments using its expression vector and siRNA and chromatin immunoprecipitation assay demonstrated GATA-2 acted as transcription-factor of NCDase gene expression. By establishing stable transfectants with decreased NCDase expression and activity, we clarified the significance of NCDase down-regulation for ATRA-induced neuronal differentiation. Those sub-clones showed both increased cellular ceramide and reduced cell growth as well as neuronal differentiation phenotypes. These results demonstrate that down-regulation of NCDase through ATRA-induced GATA-2 decrease plays an important role in induction of ceramide accumulation and neuronal differentiation in SH-SY5Y cells.
authors.affiliation: Department of Oncology, Graduate School of Pharmaceutical Science, Nagoya City University, Nagoya, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Keiko
authors.initials: K
authors.lastname: Tamiya-Koizumi
authors.forename: Kazumi
authors.initials: K
authors.lastname: Hagiwara
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ito
authors.forename: Akira
authors.initials: A
authors.lastname: Takagi
authors.forename: Tetsuhito
authors.initials: T
authors.lastname: Kojima
authors.forename: Motoshi
authors.initials: M
authors.lastname: Suzuki
authors.forename: Soichiro
authors.initials: S
authors.lastname: Iwaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujii
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakamura
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Banno
authors.forename: Reiji
authors.initials: R
authors.lastname: Kannagi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Tsurumi
authors.forename: Mamoru
authors.initials: M
authors.lastname: Kyogashima
authors.forename: Takashi
authors.initials: T
authors.lastname: Murate
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D009447:Neuroblastoma / Q000473:pathology*; D009474:Neurons / Q000187:drug effects* / Q000473:pathology; D055576:Neutral Ceramidase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D014212:Tretinoin; D055576:Neutral Ceramidase