siRNA suppression of KEAP1 levels enhance NRF2 nuclear translocation and tBHQ induced γ-globin mRNA expression. siRNA specific for KEAP1 was transfected into K562 cells. At 24 hours later, cells were treated with tBHQ at 25μM for 24 hours before protein and RNA isolation. Control siRNA and mock transfection (−) were used as controls. (A) Western blot analysis of total cellular KEAP1 protein and nuclear NRF2 protein levels. Bottom: Densitometric analysis of NRF2 nuclear protein relative to TATA binding protein (TBP) normalized to the untreated control. (B) Effect of KEAP1 siRNA on tBHQ induction of NQO1 and γ-globin mRNA levels. Results of real-time PCR are expressed as relative mRNA levels normalized to the untreated mock transfected control. Densitometric analysis was performed with Image J software. P values compare tBHQ treated control siRNA with tBHQ treated KEAP1 siRNA. *P < .05.