Reduced colony formation of AML cells after knockdown of Nrf2. (A) AML cells and control cells were transduced with Nrf2-targeted miRNA and control miRNA constructs and colony forming assays were performed to show the number of colonies in response to combined treatment with 0.5μM cytarabine and 0.2μM daunorubicin. In all panels values indicate the mean ± SD from 3 independent experiments. *Statistical significance of P < .05 between the different treatment groups when Student t test was used. (B) AML cells treated with 0.5μM cytarabine and 0.2μM daunorubicin from panel A expressed as number of colonies as a percentage of untreated AML colonies. *P < .05 and **P < .01 by 2-way ANOVA analysis. (C) Transmission light microscopic examination of colonies derived from AML cells and control cells infected with Nrf2-targeted or control miRNA construct.