Ivermectin induces chloride influx and increases cell size in leukemia cells. (A) OCI-AML2 leukemia and DU145 prostate cancer cells were treated with increasing concentrations of ivermectin. After 24 hours of incubation, cell growth and viability were measured by MTS assay. Data represent the mean ± SD percent viable cells from representative experiments. (B) OCI-AML2 and (C) DU145 cells were treated with 10μM ivermectin for 1 hour, and levels of intracellular chloride were measured after staining cells with the fluorescent dye, SPQ, that is quenched by high chloride ion concentrations. Histograms from representative experiments are shown. (D) OCI-AML2 and (E) DU145 cells were treated with 6 and 10μM ivermectin for 1 hour. After treatment, cell size was measured by forward light scatter and flow cytometry. Data represent mean ± SD fold change in cell size compared with control from representative experiments performed in triplicate. **P < .01, by unpaired t test.