The effect of β-ionone on telomerase activity in the human leukemia cell line K562

Telomerase is highly activated in most human cancer cells, therefore, its inhibition has been proposed as a novel and promising strategy for cancer therapy. Many plant-derived anticancer agents act through inhibition of telomerase activity and induction of apoptosis. β-ionone, a carotenoid compound isolated from Roseaceae, has been reported to possess anticancer properties. The present study was undertaken to examine the mechanism of β- ionone-induced apoptosis in human leukemia cell line K562 with special emphasis on its role in telomerase inhibition. In this study the anti-proliferation effect of β-ionone on K562 cells was evaluated by MTT assay. Apoptosis rate was detected by Hoechst staining and flow cytometry analysis. Telomerase activity was measured by (TRAP) ELISA assay. Exposure of K562 cells to β-ionone caused a dose-dependent decrease in proliferation. Flow cytometry analysis and Hoechst staining showed that percentage of apoptotic cells markedly increased with an increase in β-ionone concentration. Compared to control cells, treatment of K562 cells with β- ionone resulted in a significant decrease of telomerase activity. Moreover, a positive correlation was detected between telomerase inhibition and apoptosis induction in the treated K562 cells. Based on these results, β-ionone is an appropriate candidate for inhibiting telomerase activity in K562 cells. Therefore, it may be utilized as a novel drug against some leukemia cell lines.