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Letters to the Editor
seq data, we wanted to determine which genes had alter- ations in BRD4 binding, leading to mRNA changes in the AML patient cells compared to normal CD34+ cells. For these analyses, the data obtained from RNA-seq counts, and ChIP-seq using BRD4, were merged by gene id. Our strategy to detect different patterns of changes in peak
scores and gene expression consisted in the conversion of the values into quartiles in way to define MLL-PTD spe- cific response to JQ1 treatment.
Furthermore, we also wanted to determine the alter- ations that were reversed by BRD4-inhibiton. First, we identified BRD4 binding sites that were close by to a
AB
CD
EF
Figure 1. Targeting BRD4/Brd4 using the inhibitor JQ1 has an effect on MLL-partial tandem duplication (MLL-PTD)/Mll-PTD acute myeloid leukemia cells. (A) WST-1 assay on EOL-1 and K562 cells treated with the indicated concentrations of JQ1 for 48 hours (h). (B) EOL-1 cells were treated for 24 h with the indicated concentration of JQ1. Cells were then assessed for apoptosis using Annexin V+ staining and flow cytometry at 24 h post treatment; *P<0.05, ***P<0.001. (C) Colony forming unit assays were performed on three CD34+ cord blood and three MLL-partial tandem duplication (MLL-PTD) acute myeloid leukemia (AML) patients’ samples, cells were plated in triplicates, normalized results are shown.13 Cells were treated with JQ1 at a concentration of 9 nM or 12.5 nM or with vehicle control (dimethyl sulfoxide [DMSO]); **P<0.01. (D) Primary murine MllPTD/WT Flt3ITD/WT blasts were treated for 24 h with the indicated concentration of JQ1. Cells were then assessed for apoptosis using Annexin V+ staining and flow cytometry at 24 h post treatment; *P<0.05, **P<0.01. (E) MllPTD/WT Flt3ITD/WT blasts were transplanted into sub-lethally irradiated BoyJ mice. Starting at 2 weeks post transplantation, mice were treated with 50 mg/kg body weight of JQ1 or vehicle control for 6 days each week for the entire duration of the study. Mice that died early without any signs of leukemia were excluded. The experiment was stopped after 120 days post treatment initiation. Treatment with JQ1 prolonged survival compared to controls (P=0.001) and (F) also led to a reduced weight of the spleen.
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haematologica | 2021; 106(9)