Induction of cyclooxygenase-1 in a human megakaryoblastic cell line (CMK) differentiated by phorbol ester

Human megakaryoblastic cells (CMK line) are known to differentiate to mature megakaryocyte-like cells by treatment with 12- O-tetradecanoylphorbol 13-acetate (TPA). There are two isozymes of prostaglandin-forming cyclooxygenase enzyme. Constitutive cyclooxygenase-1 and inducible cyclooxygenase-2 wer...

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Bibliographic Details
Published in:Biochimica et biophysica acta 1997-01, Vol.1344 (1), p.103-110
Main Authors: Ueda, Natsuo, Yamashita, Rieko, Yamamoto, Shozo, Ishimura, Kazunori
Format: Article
Language:English
Subjects:
Arachidonic Acid - metabolism
Blotting, Northern
Blotting, Western
Cell Differentiation - drug effects
CMK cell
Cyclooxygenase 1
Cyclooxygenase Inhibitors - pharmacology
Cyclooxygenase-2
Gene Expression Regulation, Developmental
Humans
Isoenzymes - metabolism
Megakaryocyte
Megakaryocytes - metabolism
Membrane Proteins
Microscopy, Immunoelectron
Nitrobenzenes - pharmacology
Precipitin Tests
Prostaglandin
Prostaglandin-Endoperoxide Synthases - metabolism
Prostaglandins - metabolism
RNA, Messenger - analysis
RNA, Messenger - metabolism
Sulfonamides - pharmacology
Tetradecanoylphorbol Acetate - pharmacology
Thromboxane
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Summary:Human megakaryoblastic cells (CMK line) are known to differentiate to mature megakaryocyte-like cells by treatment with 12- O-tetradecanoylphorbol 13-acetate (TPA). There are two isozymes of prostaglandin-forming cyclooxygenase enzyme. Constitutive cyclooxygenase-1 and inducible cyclooxygenase-2 were followed during differentiation of CMK cells. Treatment of the cells with 0.1 μM TPA for 4 days resulted in a 5–20-fold increase in cyclooxygenase activity. Northern and Western blot analyses revealed that cyclooxygenase-1 mRNA and protein increased in parallel with the enzyme activity. In contrast, cyclooxygenase-2 mRNA was detected only at 3 h. Furthermore, most of the increased cyclooxygenase activity was immunoprecipitated with anti-cyclooxygenase-1 antibody, and was not affected by a cyclooxygenase-2-specific inhibitor, NS-398. These results indicated that cyclooxygenase-1 rather than cyclooxygenase-2 was predominantly induced depending on TPA. The enzyme thus induced was localized by immunoelectron microscopy in nuclear envelope and endoplasmic reticulum of the CMK cells.
ISSN:0005-2760
0006-3002
1879-145X
DOI:10.1016/S0005-2760(96)00131-2