Combination therapy of acute myeloid leukemia by dual PI3K/mTOR inhibitor BEZ235 and TLR-7/8 agonist R848 in murine model.

Background: Due to the high relapse rate and toxicity of the common therapies in patients with acute myeloid leukemia (AML), modifications in the treatment strategies are required. The present study was conducted to determine the effects of combinational therapy with a dual PI3K/mTOR inhibitor, BEZ235, and TLR7/8 agonist, R848, on murine AML model.

Methods: BEZ235 and R848 were administered to AML leukemic mice in either a single or combination treatment. Frequency of T-CD4, T-CD8, MDSCs, NK, exhausted T cells and the degranulation levels was measured via flow cytometry. The cytotoxicity and proliferation levels were evaluated by MTT assay. Then, the expression of iNOS, arginase-1, PD-L1, Gal-9, PVR, IFN-γ, TNF-α, IL-4, IL-10, IL-12 and IL-17 was investigated by Real-Time PCR. Organomegaly, body weight and survival rate were also monitored.

Results: Following combinational therapy with BEZ235 and R848, increasing in the frequency of anti-tumor immune cells including T-CD4 cells and M1 macroghages, and decreasing in pro-tumor immune cells including MDSCs, exhausted T-CD4 and T-CD8 cells and also M2 macrophages were observed. The functional defects of immune cells in term of proliferation, cytotoxicity, degranulation, and cytokines expression were improved in leukemic mice after treatment with BEZ235 and R848. Finally, organomegaly, body weight and survival analysis showed significant improvements after treatment with BEZ235 and R848.

Conclusion: Taken together, we indicated that the combinational therapy with BEZ235 and R848 could be considered as a potential and powerful therapeutic option for AML patients. Further clinical studies are required to expand our current findings.