Calcium regulation of tissue plasminogen activator and prostaglandin biosynthesis in HeLa cells.
Phorbol 12-myristate 13-acetate, 1-20 nM, induced the synthesis in HeLa cells of a 65 200 Mr tissue-type plasminogen activator, and of prostaglandin E2. Omission of Ca2+ from the incubation medium inhibited the induction of plasminogen activator synthesis by 40-60% and abolished the induction of prostaglandin E2 synthesis. Maximal plasminogen activator synthesis could be maintained at extracellular Ca2+ concentrations of approx. 0.1 mM, while maximal prostaglandin synthesis required at least 0.45-0.9 mM Ca2+. The induction of each factor was inhibited by 10-100 microM 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), an inhibitor of intracellular C2+ mobilization. Prostaglandin synthesis, but not plasminogen activator synthesis, was also inhibited by 10-100 microM verapamil and nifedipine, which inhibit intracellular Ca2+ uptake via the so-called 'slow-channels' and by 0.5-10 microM trifluoperazine, an inhibitor of calmodulin. Neither plasminogen activator synthesis nor prostaglandin synthesis were stimulated by 5-50 microM 1-oleoyl-2-acetylglycerol or 1-250 microM 1,2-dioctanoylglycerol, alone and in combination with 50 nM-1 microM ionophore A23187. These results indicate that the synthesis of plasminogen activator and prostaglandins in HeLa cells is Ca2+-dependent, and that the Ca2+ requirements for each process are not identical. Thus, Ca2+ regulation of the production of tissue plasminogen activator and prostaglandin E2 occurs at multiple points in their biosynthetic pathways.
Crutchley
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D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D015232:Dinoprostone; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D010704:Phorbols / Q000494:pharmacology*; D011458:Prostaglandins E / Q000096:biosynthesis*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D010959:Tissue Plasminogen Activator / Q000096:biosynthesis* / Q000302:isolation & purification
D010704:Phorbols; D011458:Prostaglandins E; D000001:Calcimycin; D010959:Tissue Plasminogen Activator; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium