IL-8 secretion in primary cultures of prostate cells is associated with prostate cancer aggressiveness

Background: Chronic inflammation is believed to be a major factor in prostate cancer initiation and promotion and has been studied using prostate cancer cells and immortalized cell lines. However, little is known about the contribution of normal cells to the prostatic microenvironment and inflammation. We aim to study the contribution of normal prostate epithelial cells to prostate inflammation and to link the inflammatory status of normal cells to prostate cancer aggressiveness.

Materials and methods: Short-term primary cell cultures of normal epithelial prostate cells were derived from prostate biopsies from 25 men undergoing radical prostatectomy, cystoprostatectomy, or organ donation. Cells were treated with polyinosinic:polycytidylic acid, a mimic of double-stranded viral RNA and a potent inducer of the inflammatory response. Secretion of interleukin (IL)-8 in the cell culture medium by untreated and treated cells was measured and we determined the association between IL-8 levels in these primary cell cultures and prostate cancer characteristics. The Fligner-Policello test was used to compare the groups.

Results: Baseline and induced IL-8 secretion were highly variable between cultured cells from different patients. This variation was not related to drug use, past medical history, age, or preoperative prostate-specific antigen value. Nonetheless, an elevated secretion of IL-8 from normal cultured epithelial cells was associated with prostate cancer aggressiveness (P=0.0005).

Conclusion: The baseline secretion of IL-8 from normal prostate epithelial cells in culture is strongly correlated with cancer aggressiveness and may drive prostate cancer carcinogenesis. A better characterization of individual prostate microenvironment may provide a basis for personalized treatment and for monitoring the effects of strategies aimed at preventing aggressive prostate cancer.