1Alpha,25-dihydroxyvitamin D3 and phorbol ester mediate the expression of alkaline phosphatase in NB4 acute promyelocytic leukemia cells.
Both 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] and phorbol 12-myristate 13-acetate [PMA] are cytodifferentiation agents regulating myeloid cell line differentiation along the monocyte/macrophage pathway. Alkaline phosphatase (ALP) activity has been reported to be absent or present at low levels in monocytes/macrophages. In the present study, the acute promyelocytic leukemia cell line (NB4) was found to undergo monocyte/macrophage differentiation and strongly express ALP activity after exposure to the combination of 1alpha,25(OH)2D3 and PMA treatment. The ALP stimulation was both dose- and time-dependent with the ED50 doses for 1alpha,25(OH)2D3 and PMA at 2 x 10(-10) M and 4 x 10(-11) M, respectively. Assessment of the cell morphology via cell adherence, phagocytosis and ALP staining confirmed that NB4 cells treated by 1alpha,25(OH)2D3 plus PMA showed macrophage characteristics, but were also strongly stained with ALP. The present study is the first report that NB4 cells express ALP activity as a consequence of combination treatment with 1alpha,25(OH)2D3 and PMA.
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Department of Biochemistry, University of California-Riverside, 92521, USA.
Norman
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D000469:Alkaline Phosphatase / Q000096:biosynthesis*; D002117:Calcitriol / Q000494:pharmacology*; D002273:Carcinogens / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000201:enzymology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D002273:Carcinogens; D000469:Alkaline Phosphatase; D002117:Calcitriol; D013755:Tetradecanoylphorbol Acetate