Tamoxifen stimulates phospholipase D activity by an estrogen receptor-independent mechanism. 1994

Z Kiss
Hormel Institute, University of Minnesota, Austin 55912.

The effects of tamoxifen (TAM), a widely used agent in the treatment of breast cancer, were examined on phospholipase D (PLD)-mediated phospholipid hydrolysis. In drug-sensitive MCF-7 human breast carcinoma cells TAM, similar to several well-established activators of PLD, had no effect on phospholipid hydrolysis. In an estrogen receptor-deficient multidrug-resistant subline of MCF-7 cells, TAM preferentially stimulated the hydrolysis of phosphatidylethanolamine; two-fold stimulation required 2.5 or 5 microM TAM in the absence or presence of serum, respectively. In NIH 3T3 fibroblasts significant (4- to 4.8-fold) stimulation of phosphatidylethanolamine and phosphatidylcholine hydrolysis in the presence of serum required 10 microM TAM. These data establish that TAM can stimulate PLD activity by an estrogen receptor-independent mechanism.

UI MeSH Term Description Entries
D010713 Phosphatidylcholines Derivatives of PHOSPHATIDIC ACIDS in which the phosphoric acid is bound in ester linkage to a CHOLINE moiety. Choline Phosphoglycerides,Choline Glycerophospholipids,Phosphatidyl Choline,Phosphatidyl Cholines,Phosphatidylcholine,Choline, Phosphatidyl,Cholines, Phosphatidyl,Glycerophospholipids, Choline,Phosphoglycerides, Choline
D010714 Phosphatidylethanolamines Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids. Cephalin,Cephalins,Ethanolamine Phosphoglyceride,Ethanolamine Phosphoglycerides,Ethanolamineglycerophospholipids,Phosphoglyceride, Ethanolamine,Phosphoglycerides, Ethanolamine
D010739 Phospholipase D An enzyme found mostly in plant tissue. It hydrolyzes glycerophosphatidates with the formation of a phosphatidic acid and a nitrogenous base such as choline. This enzyme also catalyzes transphosphatidylation reactions. EC 3.1.4.4. Lecithinase D,Phosphatidylcholine Phosphohydrolase
D011960 Receptors, Estrogen Cytoplasmic proteins that bind estrogens and migrate to the nucleus where they regulate DNA transcription. Evaluation of the state of estrogen receptors in breast cancer patients has become clinically important. Estrogen Receptor,Estrogen Receptors,Estrogen Nuclear Receptor,Estrogen Receptor Type I,Estrogen Receptor Type II,Estrogen Receptors Type I,Estrogen Receptors Type II,Receptor, Estrogen Nuclear,Receptors, Estrogen, Type I,Receptors, Estrogen, Type II,Nuclear Receptor, Estrogen,Receptor, Estrogen
D001943 Breast Neoplasms Tumors or cancer of the human BREAST. Breast Cancer,Breast Tumors,Cancer of Breast,Breast Carcinoma,Cancer of the Breast,Human Mammary Carcinoma,Malignant Neoplasm of Breast,Malignant Tumor of Breast,Mammary Cancer,Mammary Carcinoma, Human,Mammary Neoplasm, Human,Mammary Neoplasms, Human,Neoplasms, Breast,Tumors, Breast,Breast Carcinomas,Breast Malignant Neoplasm,Breast Malignant Neoplasms,Breast Malignant Tumor,Breast Malignant Tumors,Breast Neoplasm,Breast Tumor,Cancer, Breast,Cancer, Mammary,Cancers, Mammary,Carcinoma, Breast,Carcinoma, Human Mammary,Carcinomas, Breast,Carcinomas, Human Mammary,Human Mammary Carcinomas,Human Mammary Neoplasm,Human Mammary Neoplasms,Mammary Cancers,Mammary Carcinomas, Human,Neoplasm, Breast,Neoplasm, Human Mammary,Neoplasms, Human Mammary,Tumor, Breast
D005260 Female Females
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006868 Hydrolysis The process of cleaving a chemical compound by the addition of a molecule of water.
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013629 Tamoxifen One of the SELECTIVE ESTROGEN RECEPTOR MODULATORS with tissue-specific activities. Tamoxifen acts as an anti-estrogen (inhibiting agent) in the mammary tissue, but as an estrogen (stimulating agent) in cholesterol metabolism, bone density, and cell proliferation in the ENDOMETRIUM. ICI-46,474,ICI-46474,ICI-47699,Nolvadex,Novaldex,Soltamox,Tamoxifen Citrate,Tomaxithen,Zitazonium,Citrate, Tamoxifen,ICI 46,474,ICI 46474,ICI 47699,ICI46,474,ICI46474,ICI47699

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