The effect of interleukin-6 on the proliferation of prostate cancer cells in vitro and the modulation of this procedure.

The role of interleukin-6 (IL-6) in the growth of an androgen-independent prostate cancer cell line (PC-3 m) was defined and the effect of dexamethasone, which was previously shown to modulate IL-6/IL-6 receptor (IL-6R) on this procedure was investigated. By using a pretty sensitive and specific enzyme immunoassay (ELISA), it was found that PC-3 m produced certain IL-6, but there was no difference in IL-6 secretion between the group with or without dexamethasone treatment. It was also found that PC-3 m cells could not be stimulated to grow by exogenous IL-6 (P > 0.05), while it could be inhibited to grow by anti-IL-6 monoclonal antibody and dexamethasone with a dose-dependent fashion. Our observation indicated that IL-6 acted as an autocrine growth factor for PC-3 m, and dexamethasone could inhibit cell proliferation by a mechanism independent of its effect on IL-6 mRNA expression.