Prunetin inhibits nitric oxide activity and induces apoptosis in urinary bladder cancer cells via CASP3 and TNF-α genes.

Background: Urinary bladder cancer (UBC) 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 of increasing interest 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 UBC cells (RT-4). METHODS AND RESULTS: The cytotoxicity and nitric oxide synthase activities of prunetin were determined in cell cultures. The expression of apoptosis-related genes was determined with RT-PCR. Cell cycle assays were performed using a flow cytometer and cellular apoptotic rate was measured. The results suggested that prunetin has cytotoxic effects at 21.11 µg/mL on RT-4 cells. Flow cytometry analysis showed that prunetin induced apoptosis and arrested th cell cycle in the G ₀ /G ₁ phase. Prunetin exposure was associated with increases in CASP3 and TNF-α gene expression in RT-4 cells at doses of 21.11 and 42.22 µg/mL, respectively. Strong nitric oxide inhibition was observed at IC ₅₀ of 5.18 µg/mL under macrophage mediated inflammatory circumstances.
Conclusions: Prunetin possesses anti-cancer properties and may be a candidate compound for the prevention of UBC. 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.
(© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)