Human prostatic carcinoma cells produce an increase in the synthesis of interleukin‐6 by human osteoblasts

BACKGROUND The aim of this work was to evaluate the effect produced by conditioned medium from human prostatic carcinoma cell (PC-3) culture on human osteoblast (HOB) interleukin 6 (IL-6) synthesis. METHODS PC-3 cells were cultured in Ham's F12K medium with 10% fetal calf serum (FCS) up to confluence. Medium was changed by Dulbecco modified Eagle medium (DMEM)/F12K (1:1) with 0.1% bovine serum albumin. Cells were cultured for 24 hr, and medium (PC-3-CM) was collected. HOBs were cultured up to confluence, and after 48 hr without FCS, medium was removed and PC-3-CM was added to the wells. After 24 hr, supernatant was collected for the determination of IL-6. In another experiment, HOBs were cultured up to confluence in Petri dishes, and after 48 hr without FCS, PC-3-CM or DMEM/F12K (1:1) was added. After different periods of time, medium was removed, and total RNA was extracted. IL-6 mRNA was quantified using reverse transcription polymerase chain reaction. RESULTS PC-3-CM significantly enhanced IL-6 secretion into HOB culture supernatants (between 1,812% and 372%, depending on the osteoblastic line) with respect to HOBs cultured in DMEM/F12K. PC-3-CM also produced an increase in IL-6 mRNA levels in HOBs. CONCLUSIONS Prostate carcinoma cells (PC-3) produce a factor or factors that enhance the synthesis and release of IL-6, a known activator of bone resorption. Prostate 50: 241–246, 2002. © Wiley-Liss, Inc.