Borneol hinders the proliferation and induces apoptosis through the suppression of reactive oxygen species-mediated JAK1 and STAT-3 signaling in human prostate cancer cells.

The signal transducer and activator of transcription-3 (STAT-3) is a perilous transcription factor that regulates various proliferation and anti-apoptosis factors in prostate cancer cells. Therefore, inhibiting STAT-3 signaling is considered a potential therapeutic approach for treating prostate cancer. This study investigates the effects of borneol (BNL) on the proliferation and apoptosis of human prostate cancer cells by blocking Janus kinase (JAK) and STAT-3 expression. Human prostate cancer (PC-3) cells were treated with varying concentrations of BNL (10, 20, 30 μM) for 24 hours. Subsequent analyses included MTT based cytotoxicity, reactive oxygen species (ROS) production measured by 2,7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining, and apoptosis morphological examination was studied by acridine orange/ethidium bromide (AO/EtBR) staining. BNL treatment mediated protein expression of proliferation and apoptosis-related proteins associated with the JAK-STAT-3 pathways was investigated by Western blot. Results of this study indicates that BNL treatment with PC-3 cells induces cytotoxicity, increases ROS production, and causes apoptotic morphological changes in a concentration-dependent manner. BNL significantly reduced the expression of cell proliferation markers such as cyclin-D1, cyclin-D2 and cyclin-E1 (P<0.05) compared to untreated PC-3 control cells. BNL treatment enhanced apoptosis rates by observed overexpression of Bcl-2-associated X protein (Bax), caspase-3 and down regulation B-cell leukemia/lymphoma 2 (Bcl-2) (P<0.05) expression in PC-3 cells. Additionally, BNL reduced interleukin-6, JAK1, and STAT3 phosphorylation ((P<0.05) in PC-3 cells that obstructing the expression of proliferation and anti-apoptotic proteins in PC-3 cells. Thus, BNL may be a therapeutic agent against prostate cancer by blocking the STAT3 signaling axis.