1. Characterization of a point mutation in the hormone binding domain of the estrogen receptor from an breast tumor.
- Author
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England GM, Bilimoria MM, Chen Z, Assikis VJ, Muenzner HD, and Jordan VC
- Subjects
- Animals, Binding Sites, Cell Division drug effects, DNA Primers, Estradiol analogs & derivatives, Female, Fulvestrant, Glycine, Humans, Luciferases biosynthesis, Mice, Mice, Nude, Ovariectomy, Polymerase Chain Reaction, Polymorphism, Single-Stranded Conformational, Receptors, Estrogen biosynthesis, Receptors, Estrogen chemistry, Tamoxifen analogs & derivatives, Tamoxifen pharmacology, Transfection, Transplantation, Heterologous, Tumor Cells, Cultured, Valine, Breast Neoplasms genetics, Breast Neoplasms pathology, Estradiol pharmacology, Estrogen Antagonists pharmacology, Point Mutation, Receptors, Estrogen genetics, Transcription, Genetic drug effects
- Abstract
It is clear that growth of the MCF-7 breast cancer cell line is stimulated by estrogen and when estrogen is removed, growth slows. We have observed a tumor derived from MCF-7 cells that grows in athymic mice in the absence of estrogen stimulation. We hypothesized that a mutation in the estrogen receptor (ER) could be responsible for this constitutive growth. Using single stranded conformational polymorphism (SSCP) and DNA sequencing analysis, we have identified an ER containing a point mutation at position 415 (gly to val) within the hormone binding domain. The functional activity of this mutant was assessed in vitro and in vivo. Using transient transfection into an ER negative breast cancer cell with an ERE luciferase reporter gene, we found that both the wild-type and mutant receptors have similar efficacy. Additionally, the estrogenic responses were blocked by antiestrogens in a concentration related manner. We also found that tumors with the mutant receptor show similar growth response in athymic mice as wild-type: stimulation with estradiol and inhibition with antiestrogens. We conclude that the point mutation at position 415 (gly to val) is not responsible for constitutive growth.
- Published
- 1998
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