JQ1 decreases c-Myc expression in CRLF2-rearranged B-ALL. (A) Quantitative PCR analysis of MYC transcript levels in MHH-CALL4 and MUTZ-5 B-ALL cells treated with 500nM JQ1. β-actin expression shown as control. Data for each time point are normalized to vehicle control and presented as the ratio of expression compared with baseline expression at time = 0. Error bars represent ± SEM. *P < .1 (paired t test). **P < .01 (paired t test). (B) Immunoblotting for c-Myc in whole cell lysates of cells treated with 500nM JQ1. (C) ChIP with a BRD4 antibody at 2 sites within the MYC promoter region in cells treated with 500nM JQ1 for 4 hours. Enrichment is shown as the percentage of total input DNA. The negative control region primers amplify within a gene desert ∼ 1 Mb upstream of MYC. (D) Heatmaps of MYC and c-Myc target gene expression in MHH-CALL4 and MUTZ-5 cells treated with 500nM JQ1 for 4 hours. Scale bars represent fold expression changes of each gene relative to the average gene expression across the 4 samples. HK indicates housekeeping controls. Data for 2 biologic replicates are shown.^1,2