A BTG1 transgene rescues GR expression and GC therapy response in REH pre-B ALL cells. (A) Western blot showing protein expression of HA-BTG1 and GR protein obtained after retroviral transduction of REH cells with the vectors indicated at the top. (B) Expression of GR mRNA analyzed by quantitative RT-PCR and normalized for TBP in REH control vector versus REH HA-BTG1–transduced cells, after exposure to prednisolone or mock treatment. (C) Determination of relative viability of REH control vector-transduced cells compared with REH cells transduced with HA-BTG1, GR, or HA-BTG1 and GR retroviral constructs using an MTS-based cytotoxicity assay after exposure to prednisolone for 3 days. (D) Quantitative RT-PCR of GR target genes TSC22D3/GILZ and ZFP36L2/TIS11D in REH cells after exposure to 1 mg/mL prednisolone or mock treatment for 8 hours. Error bars represent the SEM of triplicate experiments. (C) *Statistical significance (P < .05) was assessed with the Student t test compared with control vector-transduced cells that received the same treatment. (B,D) *Statistical significance (P < .05) was assessed with the Student t test compared with control vector-transduced cells that were mock treated.