Inhibition of protein kinase C by tamoxifen

O'Brian, C.A., Liskamp, R.M. , Solomon, D.H. and Weinstein, I.B. (1985) Inhibition of protein kinase C by tamoxifen. Cancer Research, 45(6), pp. 2462-2465.

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The antiestrogen drug tamoxifen inhibits rat brain protein kinase C in vitro, whether the enzyme is activated by Ca2+ and phospholipid (50% inhibitory dose, 100 microM), 12-O-tetradecanoylphorbol-13-acetate and phospholipid (50% inhibitory dose, 40 microM), or teleocidin and phospholipid. Tamoxifen does not inhibit the Ca2+- and phospholipid-independent phosphorylation of protamine sulfate by protein kinase C, indicating that the drug does not interact with the active site of the enzyme. The binding of [3H]phorbol dibutyrate to high-affinity membrane receptors of cultured mouse fibroblast cells is inhibited by tamoxifen (50% inhibitory dose, 5 microM). Our findings suggest that the growth-inhibitory and cytotoxic effects of tamoxifen, which have been observed at microM concentrations of the drug, may be in part due to its effects on protein kinase C.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Liskamp, Professor Robert
Authors: O'Brian, C.A., Liskamp, R.M., Solomon, D.H., and Weinstein, I.B.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Cancer Research
ISSN (Online):1538-7445

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