Stimulation of prostate cancer growth by androgens and estrogens through the intermediacy of sex hormone-binding globulin

• Published in: Endocrinology (Philadelphia) 1996-10, Vol.137 (10), p.4126-4129
• Main Authors: Nakhla, A M, Rosner, W
• Format: Article
• Language: English
• Subjects: 17β-Estradiol; Androgens; Binding; Cell Division - drug effects; Cell membranes; Cyclic AMP; Cyclic AMP - analogs & derivatives; Cyclic AMP - metabolism; Cyclic AMP - pharmacology; Dephosphorylation; Dihydrotestosterone; Dihydrotestosterone - pharmacology; Estradiol - pharmacology; Estrogens; Globulins; Hormones; Humans; Intracellular; Male; Okadaic acid; Prostate cancer; Prostatic Neoplasms - metabolism; Prostatic Neoplasms - pathology; Protein phosphatase; Protein phosphatase inhibitors; Proteins; Serum-free medium; Sex Hormone-Binding Globulin - pharmacology; Sex hormones; Steroids; Thionucleotides - pharmacology; Tumor Cells, Cultured
• ISSN: 0013-7227; 1945-7170
• DOI: 10.1210/en.137.10.4126

Sex hormone-binding globulin (SHBG) not only regulates the free concentration of certain steroid sex hormones in plasma, but is involved in a nongenomic mechanism of steroid hormone action. It binds to a receptor on prostatic cell membranes and is activated by an appropriate steroid to initiate the generation of intracellular cAMP. Using the human prostate cancer cell line ALVA-41, we show that in serum-free medium, both dihydrotestosterone and estradiol increase growth in the presence, but not the absence, of SHBG. The increase in growth also follows the addition of cAMP to the cells and is enhanced by inhibiting protein dephosphorylation with the protein phosphatase inhibitor, okadaic acid. We conclude that cAMP causes increased growth in this prostate cancer cell line, and that both SHBG-dihydrotestosterone and SHBG-estradiol can regulate intracellular cAMP, and hence growth, in these cells.