Prunetin Inhibits Nitric Oxide Activity, Proliferation and Induces Apoptosis in Urinary Bladder Cancer Cells (RT-4) Through the Enhancement of Apoptotic Pathway via CASP3 and TNF-α Genes That Are Involved

Urinary bladder cancer is considered one of the most prevalent malignant tumors worldwide. Complementary and integrative approaches for the treatment of bladder cancer, such as the intake of isoflavonoid phytoestrogens, are increasingly explored due to the risk of mortality and long-term morbidity associated with surgical procedures. The biological effects of prunetin, one of the less-studied phytoestrogens, have not yet been examined in this respect. Therefore, this study aimed to explore the efficacy of prunetin on urinary bladder cancer cells (RT-4). Cytotoxicity, nitric oxide synthase activity, apoptotic gene expression and cell cycle assays were performed to determine the biological effect of prunetin exposure on cellular toxicity, cell cycle progression and the expresions of selected apoptosis-related genes. The results suggested that prunetin has cytotoxic effects on RT-4 cells at 21.11 µg/mL. Flow cytometry analysis showed that prunetin induced apoptosis and cell cycle arrested in G0/G1 phase. Prunetin exposure was associated with increases in CASP3 and TNF-α gene expression in RT-4 cells at doses of 21.11 µg/mL and 42.22 µg/mL. Strong nitric oxide inhibition was determined with IC50 of 5.18 µg/mL under macrophage mediated inflammatory circumstances. Based on the experimental data, it is reasonable to conclude that prunetin possesses anti-cancer properties and may be a candidate compound for the prevention of urinary bladder cancer. This is the first study that evaluated prunetin for its in vitro antitumor activities, clarified its possible apoptotic molecular mechanism and provided novel insights into its anti-inflammatory nature and effects on the expression of related key genes.