Purpose: To investigate the effect of apatinib combined with cytarabine on acute myeloid leukemia (AML) HL60 cells and its relevant mechanisms.
Methods: HL60 cells were treated with control, apatinib alone, cytarabine alone and apatinib combined with cytarabine. Cell proliferation in each group was detected via methy thiazolyl tetrazolium (MTT) assay, changes in the cell cycle and mitochondrial transmembrane potential in each group after treatment were detected via flow cytometry, and apoptosis was detected via Annexin V-PI double labeling. Moreover, changes in cell cycle-related proteins and apoptosis-associated proteins in each group after treatment were detected via Western blotting.
Results: MTT assay revealed that the sub-lethal dose of apatinib combined with cytarabine had a higher inhibitory rate on tumor cells than cytarabine alone. Cell cycle assay showed that apatinib combined with cytarabine could effectively arrest HL60 cells in G0/G1 phase in the combination group. In combination group, the expression level of the positive regulator cyclin D1 was decreased, while the expression levels of the negative regulators p21 and p27 were significantly up-regulated compared with those in single application groups. Results of apoptosis assay manifested that in the combination group, the mitochondrial transmembrane potential of HL60 cells could be synergistically destroyed, and the proportion of apoptotic cells was also obviously increased. Results of Western blotting demonstrated that the levels of apoptosis-associated proteins cleaved caspase-9, cleaved caspase-3, cleaved PARP and Bax in the combination group after treatment were remarkably up-regulated, while the Bcl-2 protein level was significantly down-regulated.
Conclusion: Apatinib combined with cytarabine resists acute myeloid leukemia through synergistically regulating cell cycle and promoting apoptosis.