Inhibition of protein kinase C by tamoxifen.

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O'Brian CA, Liskamp RM, Solomon DH, Weinstein IB

Inhibition of protein kinase C by tamoxifen.

Cancer Res. 1985 Jun;45(6):2462-5.

PubMed ID

3157445 [ View in PubMed

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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.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Tamoxifen	Protein kinase C (Protein Group)	Protein group	Humans	Yes	Inhibitor	Details