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

Abstract

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 HL-60 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 down-regulated 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 mitogen-activated protein kinase pathway. In conclusion, the Aza–Hes combination is a potential antileukemia treatment.