The effect of co-treatments of chemotherapeutic drugs and curcumin on cytotoxicity and FLT3 protein expression in leukemic stem cells

Abstract This study aims to enhance efficacy and reduce toxicity of the combination treatment of a drug and curcumin (Cur) on leukemic stem cell and leukemic cell lines, including KG-1a and KG-1 (FLT3+ LSCs), EoL-1 (FLT3+ LCs), and U937 (FLT3− LCs). The cytotoxicity of co-treatments of Dox or Ida at concentrations of the IC10 – IC80 values and each concentration of Cur at the IC20, IC30, IC40, and IC50 values (conditions 1, 2, 3, and 4) was determined by MTT assays. Dox–Cur and Ida-Cur increased cytotoxicity in leukemic cells. Dox–Cur co-treatment showed additive effects in several conditions. The effect of this co-treatment on FLT3 expression in KG-1a, KG-1, and EoL-1 cells was examined by Western blotting. Dox–Cur decreased FLT3 protein levels and total cell numbers in all the cell lines. By contrast, the FLT3 protein levels and total cell number after Cur treatment did not show significant differences as a result of the co-treatments. Dox–Cur decreased FLT3 protein expression in a dose dependent manner. In summary, Cur was the effective compound in inhibiting FLT3 protein expression. Co-treatment with Dox–Cur could enhance the cytotoxicity of Dox by inhibiting the proliferation of AML leukemic stem cells.