DNA fragmentation and apoptosis induced by safranal in human prostate cancer cell line

OBJECTIVES: Apoptosis, an important mechanism that contributes to cell growth reduction, is reported to be induced by Crocus sativus (Saffron) in different cancer types. However, limited effort has been made to correlate these effects to the active ingredients of saffron. The present study was designed to elucidate cytotoxic and apoptosis induction by safranal, the major coloring compound in saffron, in a human prostate cancer cell line (PC-3). MATERIALS AND METHODS: PC-3 and human fetal lung fibroblast (MRC-5) cells were cultured and exposed to safranal (5, 10, 15, and 20 μg/ml). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to assess cytotoxicity. DNA fragmentation was assessed by gel electrophoresis. Cells were incubated with different concentrations of safranal, and cell morphologic changes and apoptosis were determined by the normal inverted microscope, Annexin V, and propidium iodide, followed by flow cytometric analysis, respectively. RESULTS: MTT assay revealed a remarkable and concentration-dependent cytotoxic effect of safranal on PC-3 cells in comparison with non-malignant cell line. The morphologic alterations of the cells confirmed the MTT results. The IC(50) values against PC-3 cells were found to be 13.0 ΁ 0.07 and 6.4 ΁ 0.09 μg/ml at 48 and 72 h, respectively. Safranal induced an early and late apoptosis in the flow cytometry histogram of treated cells, indicating apoptosis is involved in this toxicity. DNA analysis revealed typical ladders as early as 48 and 72 h after treatment, indicative of apoptosis. CONCLUSIONS: Our preclinical study demonstrated a prostate cancer cell line to be highly sensitive to safranal-mediated growth inhibition and apoptotic cell death. Although the molecular mechanisms of safranal action are not clearly understood, it appears to have potential as a therapeutic agent.