Stable luciferase transfected cells for studying steroid receptor biological activity.

In the course of steroid hormone research, firefly luciferase was used as a reporter gene to construct chimeric cellular models in which the firefly luciferase expression mimics natural hormonal response. Cells containing the endogenous receptor of interest were stably transfected with a reporter gene whose expression is controlled by this endogenous receptor. Based on the detection of luciferase activity in intact cells using a photon-counting camera, various stable transfected cell lines were established. We present potential experimental uses of these cellular models such as for screening new (anti)hormonal molecules. We also show that the hormonal responses can be modulated at any step, suggesting that these stable cell lines may be helpful in studying hormonal interactions. For example, we have detected the antiestrogen activity of molecules able to mediate their effect via a pathway other than the estrogen receptor. Lastly, we show that the detection of luciferase activity in intact living cells is particularly helpful in investigating the variation of the hormonal responses with time. Since chimeric response faithfully reflects hormone (or effector) actions in the cell, we conclude that stable transfected cells can be used in both pharmacological and fundamental studies to investigate different aspects of the endocrine research.