A cell-specific and selective effect on transactivation by the androgen receptor

Area of Science:

• Molecular Biology
• Endocrinology
• Cell Biology

Background:

• Androgen receptor (AR) and glucocorticoid receptor (GR) are related transcriptional regulators.
• Despite binding the same DNA elements, they mediate distinct cellular responses.
• Cell-specific factors are hypothesized to explain these differential effects.

Purpose of the Study:

• To investigate cell-specific modulation of AR and GR transcriptional activity.
• To compare AR and GR function in prostate versus non-prostate cell lines.
• To identify the domains and factors involved in cell-specific steroid responses.

Main Methods:

• Utilized rat prostate epithelial cell lines and non-prostate cell lines.
• Compared AR and GR transcriptional enhancement of reporter genes with simple hormone response elements (HREs).
• Performed gel shift analyses to assess DNA binding affinity and examined cJun/cFos levels.

Main Results:

• Cell-specific effects on AR and GR activity were observed.
• The cell-specific modulation was independent of the AR hormone binding domain, residing in the N-terminal domain.
• AR DNA binding affinity was similar in prostate and non-prostate cell extracts.
• No significant cell-specific differences in cJun or cFos levels were found.

Conclusions:

• Cell-specific activities preferentially modulate transcriptional transactivation by the androgen receptor.
• These findings suggest a mechanism for differential steroid hormone action in specific cell types, particularly in prostate biology.
• The N-terminal domain of AR plays a crucial role in mediating these cell-specific responses.