Azacitidine-Hesperetin Combination Induces S-phase Cell Cycle Arrest and Apoptosis in Human Leukemia Cells

Background/Aim: Chemotherapy drugs for leukemia, such as 5-azacytidine (Aza), have often various adverse effects. Hesperetin (Hes), a naturally occurring compound, is a potential adjuvant agent for anticancer therapy. This study aimed to investigate the effect of an Aza- Hes combination on acute leukemia cell lines, which elucidates the role of combination treatment in leukemia progression. Materials and Methods: HL -60 and U937 cells were treated with Aza and Hes at various concentrations or their combination. Cell proliferation and apoptosis was evaluated using the Cell Counting Kit -8 assay and annexin V/propidium iodide staining, respectively. Cell cycle analysis was conducted using flow cytometry. The expression of apoptosis-related and cell cycle-related proteins in leukemia cells was analyzed through western blotting. The synergistic effect of the Aza and Hes agents was estimated using the Chou-Talalay method. Results: We observed that Aza or Hes monotherapy engendered a dose -dependent reduction in HL60 and U937 cell viability. However, treatment with the Aza- Hes combination for 24 h synergistically inhibited U937 cell proliferation by inducing both apoptosis and S -phase cell cycle arrest. Furthermore, the Aza-Hes combination downregulated p-ERK and p -c -Jun N -terminal kinase expression and up -regulated p -p38 expression. Conclusion: Overall, our findings indicate that the Aza-Hes combination induces apoptosis and S -phase cell -cycle arrest through the mitogenactivated protein kinase pathway. In conclusion, the Aza-Hes combination is a potential antileukemia treatment.