title: Phorbol ester 12-O-tetradecanoylphorbol-13-acetate down-regulates expression of the c-kit proto-oncogene product.
abstract: Modulation of expression of the c-kit proto-oncogene product, the receptor for the recently identified stem cell factor, was studied on 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated cultures of CD34+ normal bone marrow progenitor cells, blast cells from patients with primary acute myelogenous leukemia, cells from the leukemia cell lines HEL and MO7E, as well as cultured HMC-1 mast cells. Expression of c-kit was assessed on both RNA and protein level employing standard Northern blotting, reverse transcription, and polymerase chain reaction-based Southern blotting, as well as cell surface labeling with anti-c-kit mAb YB5.B8. Treatment of virtually all cell types with nontoxic concentrations of TPA (10(-9) M) for at least 48 h was associated with down-regulation of synthesis of c-kit transcripts and stem cell factor-receptor surface expression. Studies on the mechanism of action of TPA utilizing the HEL erythroleukemia line showed that TPA was primarily acting by accelerating the turnover of c-kit RNA most likely through induction of a destabilizing protein. The effect of TPA on c-kit expression levels was independent of TPA-mediated induction of differentiation since other compounds including IFN-gamma, vitamin D3, retinoic acid, arabinofuranosylcytosine, butyric acid, and camptothecin, which also effectively induced differentiation of HEL cells, failed to alter levels of c-kit expression.
authors.affiliation: Department of Internal Medicine I, University of Freiburg Medical Center, Germany.
authors.forename: Y
authors.initials: Y
authors.lastname: Asano
authors.forename: M A
authors.initials: MA
authors.lastname: Brach
authors.forename: A
authors.initials: A
authors.lastname: Ahlers
authors.forename: S
authors.initials: S
authors.lastname: de Vos
authors.forename: J H
authors.initials: JH
authors.lastname: Butterfield
authors.forename: L K
authors.initials: LK
authors.lastname: Ashman
authors.forename: P
authors.initials: P
authors.lastname: Valent
authors.forename: H J
authors.initials: HJ
authors.lastname: Gruss
authors.forename: F
authors.initials: F
authors.lastname: Herrmann
mesh_terms: D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation; D006801:Humans; D008969:Molecular Sequence Data; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics*; D019009:Proto-Oncogene Proteins c-kit; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D011505:Protein-Tyrosine Kinases; D019009:Proto-Oncogene Proteins c-kit; D013755:Tetradecanoylphorbol Acetate