effects of thymoquinone on il-6 gene expression and some cellular signaling pathways in prostate cancer pc3 cells

background: thymoquinone (tq), a bioactive compound, has many pharmacological actions especially anticancer effects. prostate cancer (pc) is one of the most common malignancies among males in the world. objectives: the current study aimed at evaluating the effects of tq treatment on interleukin-6 (il-6) expression, il-6 secretion, cell viability, phosphorylated extracellular signal–regulated kinases (perk1/2), phosphorylated akt (pakt), and phosphorylated signal transducer and activator of transcription 3 (pstat3) signaling pathways in human prostate cancer pc3 cells. materials and methods: pc3 cells were cultured in different concentrations of tq for 48 hours. cell viability, expression, and secretion of il-6 were assessed by mtt assay, real-time quantitative polymerase chain reaction (rt-q pcr) analysis, and the enzyme-linked immunosorbent assay (elisa) technique, respectively. the changes of perk1/2, pakt, and pstat3 were determined using western blot procedure. results: treatment with tq caused the reduction of viability (inhibitory concentration [ic50 ] = 45 µm) and survival in pc3 cells. rt-q pcr had a significant reduction (p 0.05) in il-6 gene expression compared with the control cells (50%, 59%, 68%, and 70% at 30, 40, 45, and 50 µm of tq , respectively). tq treatment resulted in a significant decline (p 0.05) in the secretion of il-6 compared with the control cells (56.89%, 71.12%, 84.32%, and 85.89% at 30, 40, 45, and 50 µm of tq , respectively). western blot showed a reduction in the phosphorylated stat3, akt, and erk proteins. conclusions: the obtained results suggested that tq can effectively reduce il-6 signaling pathways (pstat3, pakt, and perk1/2). also, tq can decrease il-6 gene expression, which leads to the reduction of cell proliferation and viability. therefore, tq may be beneficial to treat prostate cancer.