Role of combination therapy in PI3k/Akt/mTOR pathway in AML cell lines

Introduction: Acute myeloid leukemia (AML) is a hematological malignancy that affects the differentiation and survival of myeloid precursors through arresting hematopoietic precursors in an early stage of development. Emerging evidence indicates that PI3K/Akt/mTOR signaling is frequently activated in AML patient blasts and has a pivotal role to many aspects of cell growth (including the self-renewal of stem-like cancer cells), survival, proliferation and chemoresistance and blockade of this pathway may facilitate cell death. The anticancer and cytotoxicity activities of arsenic trioxide (ATO) and sorafenib have been reported separately in different studies. Thus the aim of this study is to indicate combination effect of ATO and sorafenib in PI3k/Akt/mTOR pathway in AML cell lines.Method: In this study, we treated KG-1 and U937 cell lines with ATO and sorafenib and the effective concentration was evaluated by cell proliferation assay in both single and combination doses. After that the rate of apoptosis (annexin V FITC assay) and cell cycle arrest measured by flow cytometry. And finally we evaluated the level of gene expression by real-time PCR.Result: Our data indicated that the effective dose of ATO and sorafenib in KG-1 and U937 and their combination meaningfully enhanced apoptosis and decreased cell proliferation. This was further verified by Gene expression analysis of treated sensitive and resistant cell lines which indicated downregulation of PI3K/Akt/mTOR which was accompanied by activation of Caspase-3.Conclusion: taken together we showed that ATO, sorafenib and their combination represents an apoptosis-inducing and cell proliferation-inhibiting agents that its mechanisms may involve caspase-3 activations and PI3K/Akt/mTOR inhibition.Result: Evaluation of cell proliferation using MTT test: The cell proliferation rate of KG-1 and U937 which treated with different concentration of ATO (0.5μM - 5μM) and sorafenib (2μM - 12μM) were evaluated through MTT assay for 24h, 48h and 72h.