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.

Abstract

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
• Status: Published
• Refereed: Yes
• 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: 0008-5472
• ISSN (Online): 1538-7445