Fig. 7. 753b is a more potent anti-leukemic agent than DT2216.

a Kasumi-1 AML cells are primarily dependent on BCL-xL/2 for survival. Viability of Kasumi-1 AML cells was measured after the cells were incubated with serially diluted ABT199 (a selective BCL-2 inhibitor), ABT263 (a dual BCL-xL/BCL-2 inhibitor), A1331872 (a selective BCL-xL inhibitor), or S63845 (a selective MCL-1 inhibitor), for 72 h. IC₅₀ values for ABT199, ABT263, A1331872, and S63845 are 866.9, 156.5, 3587.0, and 527.4 nM, respectively. b Potencies of 753b and DT2216 in degrading BCL-xL/2 by immunoblots in Kasumi-1 cells after 16 h treatment. Tubulin was used as an equal loading control. The normalized protein content in the immunoblots is presented as mean values (n = 2 biologically independent experiments) in the bar graph (right panel). c–h 753b is more potent against Kasumi-1 cells than DT2216. c Viability of Kasumi-1 cells was measured after the cells were incubated with serially diluted DT2216, 753b, ABT199, or ABT263 for 72 h. IC₅₀ values for DT2216, 753b, ABT199, and ABT263 are 1147.0, 59.64, 1130.0, and 130.9 nM, respectively. For the viability assays, the data are presented as mean ± s.d. from three replicate cell cultures in a representative experiment. Similar results were also observed in two additional independent experiments. d Representative immunoblot analyses of Kasumi-1 cells 16 h after treatment as indicated. Tubulin was used as an equal loading control. e Representative flow cytometry analyses of apoptosis using Annexin-V and DAPI staining in Kasumi-1 cells 24 h after treatment as indicated. f Representative flow cytometry analyses of apoptosis using Annexin-V and DAPI staining in Kasumi-1 cells after incubated with or without the pan-caspase inhibitor QVD (10 μM) for 2 h prior to being treated with DMSO (Veh) or 0.1 μM DT2216, 753b, ABT199, or ABT263 for 24 h. g, h Percentages of apoptotic cells in Kasium-1 cells analyzed by flow cytometry as shown in (e, f) are presented as mean ± s.d. from three replicate cell cultures in a representative experiment. Data are representative of two independent experiments. The dotted line represents the value from DMSO-treated cells. Source data are provided as a Source data file.