Formononetin and Dihydroartemisinin Act Synergistically to Induce Apoptosis in Human Acute Myeloid Leukemia Cell Lines

Abstract

Objective: Enhanced cell survival and drug resistance in tumor cells have been linked to the overexpression of antiapoptotic members of the Bcl-2 family proteins, including Bcl-2 and Mcl-1. The aim of this study was to explore the impact of formononetin and dihydroartemisinin combination on the growth and apoptosis of acute myeloid leukemia (AML) cells. Materials and Methods: In this experimental study, the cell survival and cell proliferation were tested by MTT assay and trypan blue staining. The evaluation of cell apoptosis was conducted using Hoechst 33342 staining and a colorimetric assay to measure caspase-3 activity. To determine the mRNA levels of Mcl-1, Bcl-2, Bax, and Cyclin D1, a quantitative real-time polymerase chain reaction (qRT-PCR) was performed. Results: We showed that treatment with either formononetin or dihydroartemisinin alone, led to significant decrease in the cell survival and growth, and triggered apoptosis in U937 and KG-1 AML cell lines. Moreover, treatment with each of the compounds alone significantly decreased the mRNA levels of Mcl-1, Bcl-2 and Cyclin D1 mRNA, while, the expression level of Bax mRNA was enhanced. Combination of two compounds showed a synergistic anti-cancer effect. Conclusion: The anti-leukemic potential of formononetin and dihydroartemisinin is exerted through the effect on cell cycle progression and intrinsic pathway of apoptosis. Therefore, they can be considered as a potential anti-leukemic agent alone or along with existing chemotherapeutic drugs.