Trolox enhances As₂O₃-induced growth inhibition in NB4, AR2, and IM9 cells. NB4 (A), AsR2 (B), and IM9 cells (C) were treated with trolox, As₂O₃, or the combination. Cell viability was evaluated on days 1, 3, and 6 using trypan blue exclusion. Values are the mean of 3 independent experiments each performed in triplicate. Standard deviation bars are shown. ^*, ^**, and ^*** indicate a significant difference of P < .05, P < .01, and P < .001, respectively, from As₂O₃-treated cells.