Inhibition of proliferation and induction of apoptosis by JQ1 in B-ALL. (A) Dose-response of B-ALL cell line viability using a luminescent ATP detection assay with JQ1 treatment. Error bars represent SEM; n = 4. Inset: The chemical structure of JQ1. Table shows 50% growth inhibition values (GI₅₀) and maximum effected cells (E_max) with annotated characteristic translocations for each cell line. (B) MHH-CALL4 and MUTZ-5 cell numbers with 500nM JQ1 treatment, normalized to time = 0 levels. Error bars represent SEM; n = 4 counts. (C) Caspase-3 and -7 activity and cell viability with 500 nm JQ1 treatment; data shown relative to vehicle control values and normalized to baseline time = 0 levels. Error bars represent SEM; n = 3 measurements. (D) Cellular apoptosis after treatment with DMSO (Veh) or 500nM JQ1 for 48 hours by flow cytometry with PI and AV. (E) PARP immunoblotting with 500nM JQ1 treatment. *Cleaved PARP band; β-tubulin (TUB) shown as loading control. (F) Cell cycle analysis of total DNA content by PI staining with 500nM JQ1 treatment.