Related Experiment Video
Updated: Jul 10, 2026

Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells
Published on: February 21, 2014
Estrogen receptor: current understanding of its activation and modulation
C K Osborne1, R Schiff, S A Fuqua
1Baylor College of Medicine, Breast Center, Houston, Texas 77030, USA. kosborne@breastcenter.tmc.edu
Abstract:
Breast cancer development and progression are directly related to the effects of the female hormone estrogen. The nuclear receptor for estrogen (ER) functions as a transcription factor controlling estrogen-regulated genes. Receptor conformation on ligand binding, its interaction with various coregulators, and response elements in the promoter region of target genes all contribute to the net estrogenic effects in a cell. ER is an important diagnostic and therapeutic target in breast cancer. Various polypeptide growth factors and their membrane receptors also contribute to breast cancer development and progression. Pathways mediating cell survival, cell proliferation, and response to stress not only generate signals through various protein kinase pathways to enhance cell survival and proliferation, but these pathways also interact with ERs. Kinases in the growth factor cascade can phosphorylate and activate ER, and ER in turn activates and augments signaling through the growth factor pathways. Signaling through the growth factor pathways may contribute to hormonal resistance states by ligand-independent activation of ER. Targeting growth factor pathways, in addition to ER, is a developing strategy that hypothetically may represent optimal therapy by preventing the development of resistance to endocrine therapy.
Related Concept Videos
Internal Receptors
Types of Receptors: Internal Receptors
Similar to membrane-bound receptors, the binding of a ligand to the intracellular receptor of causes a conformational change in the...
Signal Transduction: Overview
Typically, signal transduction involves three...
Transducer Mechanism: Nuclear Receptors
About 48 different soluble family members of nuclear receptors are identified that can be divided into two main classes:
The Two-State Receptor Model
The binding affinity of a drug determines its interaction with one...
Target Cell Response to Hormones
Notably, the cellular response can be regulated by altering the number of receptors expressed in the cell. For example, prolonged exposure to elevated hormone levels results in a gradual decline or down-regulation in the number of receptors for that specific hormone on the cell surface. Conversely, in response to low hormone levels, cells may use up-regulation, producing an...

