Stimulation of osteopontin mRNA expression in HL-60 cells is independent of differentiation.
12-O-Tetradecanoylphorbol 13-acetate (TPA) induces HL-60 cells to differentiate along the monocyte/macrophage pathway and stimulates expression of the extracellular adhesion protein osteopontin (OPN). In this study, the mechanism of TPA-mediated OPN mRNA expression and its relationship to differentiation were investigated. The induction of OPN mRNA by TPA was dose dependently inhibited by staurosporine (0.4-10.0 nM) and chelerythrine (0.1-5.0 microM), indicating that OPN expression requires PKC activation. Furthermore, the mitogen-activated protein kinase kinase (MAPKK) inhibitor, PD 098059 (1.0-10.0 microM), inhibited the effect of TPA in a dose-dependent fashion. Cycloheximide (10 microg/ml) ablated the induction of OPN mRNA by TPA. To determine if OPN mRNA expression was associated with a particular differentiational pathway, HL-60 cells were treated with RA, 9-cis-RA, calcitriol, or sodium butyrate. None of these agents stimulated OPN mRNA. Treatment with TPA subsequent to a 120-h pretreatment with retinoic acid (RA), 9-cis-RA, or calcitriol resulted in a potentiation of the induction of OPN mRNA. These results support a role for protein kinase C (PKC) in promoting OPN expression because each of these agents increased PKC levels. An hOPN promoter/reporter construct was responsive to TPA, indicating that this effect is at the level of transcription. Thus, TPA-stimulated transcription of the OPN gene apparently occurs via a PKC/MAPK-dependent mechanism that is independent of that associated with differentiation and is not dependent on the maturational state of these cells.
Atkins
K B
KB
Department of Periodontics/Prevention/Geriatrics, School of Dentistry, University of Michigan, Ann Arbor 48109-1078, USA.
Simpson
R U
RU
Somerman
M J
MJ
D000470:Alkaloids; D053119:Benzophenanthridines; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002117:Calcitriol / Q000494:pharmacology; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000096:biosynthesis; D002454:Cell Differentiation / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D018922:HL-60 Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases; D053495:Osteopontin; D010617:Phenanthridines / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis; D012795:Sialoglycoproteins / Q000096:biosynthesis*; D019311:Staurosporine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology
D000470:Alkaloids; D053119:Benzophenanthridines; D002087:Butyrates; D015815:Cell Adhesion Molecules; D004791:Enzyme Inhibitors; D005419:Flavonoids; D010617:Phenanthridines; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D011994:Recombinant Proteins; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D053495:Osteopontin; D020148:Butyric Acid; D014212:Tretinoin; D003513:Cycloheximide; C016299:chelerythrine; D011493:Protein Kinase C; D020929:Mitogen-Activated Protein Kinase Kinases; D002117:Calcitriol; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one