Figure 1

I-BET151 has activity in a broad range of AML (a) A panel of human AML cell lines encompassing a variety of oncogenic drivers were tested in cell proliferation assays using I-BET151. We have previously reported some of this data⁶ and report it again only to provide an overall appreciation of sensitivity of AML cell lines to I-BET151. (b) Clonogenic assays performed in cytokine-supplemented methylcellulose in the presence of vehicle (dimethyl sulfoxide (DMSO)) or I-BET151 show a marked reduction in colony numbers (enumerated in the bar graph) after treatment with I-BET151. (c) Primary murine hematopoietic progenitors were isolated from mouse bone marrow and retrovirally transformed with MOZ-TIF2 or NUP98-HOXA9. These cells were propagated in liquid culture as well as being used in clonogenic assays. Both proliferation and clonogenic assays (enumerated in the bar graph) demonstrate a marked sensitivity to I-BET151. (d) The degree of apoptosis in OCI-AML3 was assessed using the vital dye 7-amino-actinomycin D (7-AAD) and Annexin V in cells following 72 h incubation with DMSO or I-BET. These data demonstrate a marked induction of apoptosis. (e) Cell cycle progression in OCI-AML3 was assessed 24 h after incubation with DMSO or I-BET151. These data demonstrate a marked increase in G₀/G₁ fraction, which was accompanied by a concomitant decrease in the number of cells in S and G₂/M phases. (f) Clonogenic assays with primary human AML cells from five different patients (Supplementary Table S2). Cells were plated in cytokine-supplemented methylcellulose in the presence of vehicle (DMSO) or I-BET151. These show a marked reduction of colony formation in the presence of I-BET151. AML patient samples demonstrate apoptosis following treatment with I-BET. A representative sample is shown (g) and the results from five separate patients are enumerated in the bar graph (h).