by C.S. Chang, USA
Dr. C. S. Chang discussed the androgen receptor (AR) which is a member of the steroid receptor superfamily that plays an important role in the male sexual differentiation and prostate cell proliferation. He applied a yeast two hybrid system fused with the human AR peptide to isolate a ligand-dependent AR associated protein (ARA70) which functions as a coactivator of AR transcriptional activity. The transcriptional activity of AR can be enhanced by ARA70 in the presence of both dihydrotestosterone and estradiol but not diethylstilbestrol which is a more potent synthetic estrogen. These findings may allow us to reconsider the definition of so-called "androgenic" or "estrogenic" compounds and may provide an explanation as to why diethylstilbestrol, but not estradiol, has fewer side effects when used by clinicians to treat prostate cancer patients. The work of Dr. Chang may help our understanding of the molecular mechanism of sex hormones and their receptors and may lead to new hormonal therapy for prostatic cancer.
G.F. Menchini-Fabris, Italy