Validation of selected candidates from the lentiviral screen. (A) K562^S and K562^R cells were lentivirally infected with tetracycline-inducible constructs for expression of the top-scoring shRNA for each indicated gene. Expression of the candidate gene was measured by qRT-PCR 72 hours after addition of doxycycline to the culture medium (n = 3). (B) K562^S and K562^R cells stably expressing the doxycycline-inducible constructs were analyzed by MTS assay 72 hours after addition of doxycycline (n = 3). Error bars represent SEM; *P < .05.