RESUMO
BACKGROUND: Prostate cancer is among the most common cancers in men with an increasing incidence rate. Radiation therapy (RT) is a therapeutic strategy for the management of prostate cancer after surgery; nonetheless, it has different side effects on neighboring healthy cells/tissues. Moreover, radioresistance has been an increasing phenomenon in the recent years. Therefore, there is an urgent need for the introduction of a safe and effective radiosensitizing agent. Accordingly, the recent trend in the development of novel drugs is accompanied by a push toward natural compounds. Our study evaluated the effects of betanin combined with RT as a potential radiosensitizing agent in the PC-3 cell line. METHODS AND RESULTS: MTT assay was utilized to determine the growth inhibitory impact of betanin. The possible synergistic effect was evaluated with CompuSyn software upon Trypan blue exclusion test. Apoptosis-related gene expression was evaluated via Real-time PCR and the protein expression of P21 was determined using western blotting. A synergistic anticancer effect with an optimal combination index of 0.61 was achieved by treating PC-3 cells with betanin and RT. The results pointed out that betanin synergistically triggered RT-mediated apoptosis and cell cycle arrest through modulating gene and protein expression in comparison with each of the monotherapies. CONCLUSION: These findings shed light on the synergistic antitumor effect of betanin and RT in prostate cancer, indicating the potential use of betanin as a radiosensitizer agent.