Human prostate cancer cells induce inflammatory cytokine secretion by peripheral blood mononuclear cells.

A substantial number of studies provide evidence that inflammation may play a significant role in the pathogenesis of prostate cancer via increased activity of inflammatory cytokines, particularly IL-6. We have previously shown that peripheral blood mononuclear cells (PBMC) are capable of carrying out an in vitro "immunomodulatory dialog" with colon cancer cells expressed by an increased production of pro-inflammatory cytokines by PBMC. The aim of the current study was to examine the model of cell-to-cell interaction between PBMC and prostate cancer cells from two lines - androgen resistant (PC-3) and androgen-dependent (LNCaP). For that purpose, cancer cells from both lines were incubated with PBMC, and cytokine secretion by PBMC was evaluated. The results showed a cell-concentration dependent increase in secretion of the pro-inflammatory cytokine IL-6 by PBMC induced by cells from both lines, whereas generation of IL-1β and the anti-inflammatory cytokine IL-10 were found to be increased after incubation with PC-3 cells only. The secretion of IL-10 was slightly lower following incubation of PBMC with supernatants derived from PC-3 cells. The results of the study support the possibility that prostate cancer cell-induced cytokine production by PBMC, and particularly IL-6, are involved in prostate cancer development. The discrepancy between the effect of the two prostate cancer cell lines on cytokine secretion by PBMC may be due to their different androgen dependency.