The Proinflammatory Cytokine, IL-6, and its Interference with bFGF Signaling and PSMA in Prostate Cancer Cells

The aim of the present work was to study the expression of the proinflammatory cytokine, interleukin-6 (IL-6), mediated by bFGF signaling and its possible crosstalk with prostate-specific membrane antigen (PSMA) in LNCaP and PC3-PSMA prostate cancer cell lines. PC3 cells stably transfected with PSMA gene were used for restoring PSMA expression. LNCaP and PC3-PSMA cells were exposed to 10 ng/mL of basic fibroblast growth factor (bFGF). IL-6 production was measured by ELISA assay, and levels of PSMA expression were assessed by flow cytometry. AKT, ERK1/2, and p38 phosphorylation were detected by Western blot. bFGF enhances IL-6 production in LNCaP and PC3-PSMA prostate cancer cells. The effect of bFGF on stimulating IL-6 secretion was greater in LNCaP than in PC3-PSMA cells. In the presence of bFGF, PSMA expression was activated after 4 days of treatment in LNCaP and PC3-PSMA cells. This activation was not maintained after long term of treatment in both metastatic cell lines. Solely MAPKs pathways (ERK1/2 and p38) were activated after bFGF stimulation in both metastatic cell lines, whereas AKT did not show any activation. The interference of the proinflammatory cytokine, IL-6, with bFGF signaling and PSMA, should be of high clinical relevance in the treatment of metastatic prostate cancer. In developing novel therapeutic modalities targeting IL-6, significant attention should be given to PSMA and its inactivation to fight against prostate cancer.