Apoptosis And Cell Cycle Arrest In Acute Myeloid Leukemia (AML) Induced By Metformin Through Inhibition Of The PI3K/AKT/mTOR Pathway

Background:In order to find cost-effective drugs for synergistic therapy to improve the survival of acute myeloid leukemia(AML)patients.We explored the potential role and mechanism of metformin in AML.Methods:Human AML cell lines(HL-60,Kasumi-1,and KG-1)were treated with different concentrations of metformin from 0 to 40 m M.Cell viability was determined using MTT assay,and cell cycle was assessed by flow cytometry.Hoechst33258 and Annexin V-FITC/PI were used to evaluate apoptosis,and western blotting was used to determine the expression levels of proteins related to cell cycle arrest,apoptosis,and signaling pathways.The MTT assay was used to determine cell viability.Results:1.Metformin at different concentrations could inhibit the proliferation of AML cells and primary cells.MTT assays indicated dose-dependent growth inhibition of metformin treated AML cells.2.Hoechst33258 and Annexin V-FITC/PI double labeling showed that metformin induced apoptosis in AML cells.With increaseing metformin concentration,fragmention cells gradually increased.Compared with the medium control group,40 m M metformin induced apoptosis of HL-60(5.39±2.25% vs 47.4±4.49%,P < 0.05)and KG-1cell(3.02±1.46% vs 58.54±1.36%,P < 0.05).3.AML cells in G1 phase were significantly upregulated after metformin treatment.4.Western blot showed that metformin could activate Caspase3,Caspase9,PARP-1 and Bak,down-regulated the expression of Mcl-1,inhibited the expression of IGF-1R and PI3 K,and ultimately inhibited the phosphorylation of AKT and mTOR.Conclusion:This study verified that metformin inhibits AML cell proliferation,induces apoptosis and G0/G1 cell cycle arrest by inhibiting the PI3K/AKT/mTOR pathway.