Ivermectin synergizes with cytarabine and daunorubicin to induce cell death in leukemia cells. OCI-AML2 cells were treated with increasing concentrations of daunorubicin (A) and cytarabine (B) overnight. After treatment, ROS was measured by staining cells with Carboxy-H₂DCFDA (final concentration 10μM) and flow cytometric analysis. Data represent the mean ± SD fold change in ROS production compared with control. Representative experiments performed in triplicate are shown. The effects of different concentrations of ivermectin in combination with cytarabine and daunorubicin on the viability of OCI-AML2 and U937 cells were measured by MTS assay after 72 hours of incubation. Data were analyzed with CalcUSyn software as described in Methods. CI versus Fractional effect (Fa) plot showing the effect of the combination of ivermectin with cytarabine (C) and ivermectin with daunorubicin (D) in OCI AML2 and U937 are illustrated in the isobolograms. CI < 0.9 indicates synergism. Representative isobolograms of experiments performed in triplicate are shown. (E) Normal hematopoietic cells (PBSCs; n = 2) were treated with T increasing concentrations of ivermectin and cytarabine (0, 2.5, and 5μM). After 48 hours, cell viability was measured by annexin V–PI staining. Data represent the mean ± SD percent of viable cells from experiments performed in triplicate. (F) OCI-AML2 (i) and U937 (ii) cells were treated with ivermectin, cytarabine, or the combination of the 2 drugs at varying concentrations for 72 hours. Ivermectin→cytarabine denotes that ivermectin was added initially, and cytarabine was added for the last 48 hours of the 72-hour experiment. Cytarabine→ivermectin denotes that cytarabine was added initially, and ivermectin was added for the last 48 hours of the 72-hour experiment. OCI-AML2 (iiii) cells were treated with ivermectin, daunorubicin, or the combination of the 2 drugs at varying concentrations for 72 hours. Ivermectin→daunorubicin denotes that ivermectin was added initially, and the daunorubicin was added for the last 48 hours of the 72-hour experiment. Daunorubicin→ivermectin denotes that daunorubicin was added initially, and the ivermectin was added for the last 48 hours of the 72-hour experiment. After treatment, cell growth and viability was measured by the MTS assay. Representative experiments performed in triplicate are shown. Data represent mean ± SD fractional effect (cell death).