Androgen receptors and hormone sensitivity of a human prostatic cancer cell line (PC-3) are modulated by natural beta-interferon

Androgen recptors are expressed at a low level in the cell line PC-3, which does not respond to either androgens or antiandrogens. If these cells are exposed to natural beta-interferon (β-IFN) a reduction in cell growth and an increase in androgen receptors, evaluated by both biochemical and immunocytochemical techniques, occur. This increase seems not to be related to a selective block of PC-3 in any phase of the cell cycle. Pretreatment with β-IFN determines in PC-3 cells a partial responsiveness to the androgen dihydrotestosterone as reflected by the increase in cell number. Moreover, the antiandrogen hydroxyflutamide shows agonistic properties by increasing the cell number of PC-3 cells pre-exposed to β-IFN. When the antiandrogen is tested in combination with interferon, it produces a reduction in the β-IFN-induced inhibition of cell growth. It is not known whether these unexpected effects are due to the increase in androgen receptors or to other mechanisms.