Quercetin induces type-II estrogen-binding sites in estrogen-receptor-negative (MDA-MB231) and estrogen-receptor-positive (MCF-7) human breast-cancer cell lines.

Abstract

We show that flavonoids positively regulate type-II estrogen-binding site (type-II EBS) levels both in MCF-7 (ER-positive) and in MDA-MB231 (ER-negative) breast-cancer cells. Type-II EBS were measured by a whole-cell assay at 4 degrees C for 2.5 hr using [3H]-estradiol as tracer. In both cell lines the effect of quercetin (Q) was dose-related and already evident after 12 hr of Q treatment. The increase of type-II EBS levels after Q exposure requires both RNA and protein synthesis, since actinomycin D and cycloheximide completely abolished the stimulatory effect. The ability of flavonoids in inducing type-II EBS is well correlated with their relative binding affinity for type-II EBS. The flavonoid-induced enhancement of type-II EBS levels is accompanied by increased sensitivity of cancer cells to the inhibitory effect of low Q concentrations. Our data suggest that type-II EBS are ligand-regulated receptors.

• Authors: G Scambia, F O Ranelletti, P B Panici, M Piantelli, R De Vincenzo, G Ferrandina, G Bonanno, A Capelli, S Mancuso
• Journal: International journal of cancer (Int J Cancer) Vol. 54 Issue 3 Pg. 462-6 (May 28 1993) ISSN: 0020-7136 [Print] United States
• PMID: 8509221 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Estrogens
• Flavonoids
• Receptors, Estrogen
• Quercetin

Topics

• Binding Sites
• Breast Neoplasms (metabolism, pathology, ultrastructure)
• Cell Division (drug effects)
• Estrogens (metabolism)
• Female
• Flavonoids (pharmacology)
• Humans
• Kinetics
• Neoplasms, Hormone-Dependent (metabolism, pathology, ultrastructure)
• Quercetin (pharmacology)
• Receptors, Estrogen (biosynthesis, drug effects, metabolism)
• Tumor Cells, Cultured (drug effects)