title: Sphingosine kinase 1 is involved in dibutyryl cyclic AMP-induced granulocytic differentiation through the upregulation of extracellular signal-regulated kinase, but not p38 MAP kinase, in HL60 cells.
abstract: The role of sphingosine kinase (SPHK) in the dibutyryl cyclic AMP (dbcAMP)-induced granulocytic differentiation of HL60 cells was investigated. During differentiation, SPHK activity was increased, as were mRNA and protein levels of SPHK1, but not of SPHK2. Pretreatment of HL60 cells with N,N-dimethylsphingosine (DMS), a potent SPHK inhibitor, completely blocked dbcAMP-induced differentiation. The phosphorylation of mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 MAPK was also increased during dbcAMP-induced differentiation. Pretreatment of HL60 cells with the MEK inhibitor, U0126, but not the p38 MAPK inhibitor, SB203580, completely suppressed dbcAMP-induced ERK1/2 activation and granulocytic differentiation, but did not affect the increase in SPHK activity. DMS inhibited dbcAMP-induced ERK1/2 activation, but had little effect on p38 MAPK activation. DMS had no effect on the dbcAMP-induced membrane translocation of protein kinase C (PKC) isozymes, and PKC inhibitors had no significant effect on ERK activation. The overexpression of wild-type SPHK1, but not dominant negative SPHK1, resulted in high basal levels of ERK1/2 phosphorylation and stimulated granulocytic differentiation in HL60 cells. These data show that SPHK1 participates in the dbcAMP-induced differentiation of HL60 cells by activating the MEK/ERK pathway.
authors.affiliation: Department of Cell Signaling, Gifu University Graduate School of Medicine, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Koda
authors.forename: Takashi
authors.initials: T
authors.lastname: Murate
authors.forename: Shulin
authors.initials: S
authors.lastname: Wang
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohguchi
authors.forename: Sayaka
authors.initials: S
authors.lastname: Sobue
authors.forename: Mika
authors.initials: M
authors.lastname: Ikeda
authors.forename: Keiko
authors.initials: K
authors.lastname: Tamiya-Koizumi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nozawa
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Banno
mesh_terms: D000595:Amino Acid Sequence; D003994:Bucladesine / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D002454:Cell Differentiation; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006098:Granulocytes / Q000166:cytology; D018922:HL-60 Cells; D006801:Humans; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D008969:Molecular Sequence Data; D037342:Pertussis Toxin / Q000494:pharmacology; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D003994:Bucladesine; D004791:Enzyme Inhibitors; D048052:Mitogen-Activated Protein Kinase 3; D037342:Pertussis Toxin; D017853:Phosphotransferases (Alcohol Group Acceptor); D012333:RNA, Messenger; D048051:p38 Mitogen-Activated Protein Kinases; D000099157:Sphingosine Kinase