Human prostate cancer regulates generation and maturation of monocyte-derived dendritic cells

Background The progression of prostate cancer is accompanied by a marked suppression of the immune system, including the apoptotic death of dendritic cells (DC) responsible for the induction of antitumor immunity. In this study, we evaluated whether prostate cancer might inhibit DC generation and maturation in vitro. Methods DC were generated from peripheral blood monocytes in the presence of the human prostate cell line LNCaP or nonmalignant cells, and characterized by light microscopy, FACScan analysis, and ability to stimulate T‐cell proliferation. Results Prostate cancer significantly inhibited the conversion of monocytes into DC, which was assessed by the expression of DC markers CD1a and CD83. These cells were weak stimulators of T‐cell proliferation, suggesting that DC generated in the prostate cancer microenvironment are functionally inhibited. Conclusions Prostate cancer not only kills mature DC, but also inhibits their generation and maturation, resulting in decreased production of antigen‐presenting cells and inhibition of their functional activity. Prostate 46:68–75, 2001. © 2001 Wiley‐Liss, Inc.