HASPIN inhibitor CHR-6494 effectively targets AML and synergizes with BCL-2 inhibition. (A) Dose-response curves (left) and IC₅₀ comparison (right) of Kasumi-1 and healthy CD34⁺ hematopoietic progenitor cells treated with CHR-6494. IC₅₀ values determined by nonlinear regression. Data on curve are mean ± SD of technical triplicates. Representative curves of 3 independent experiments revealed. Data on bar plot are mean ± SD of 3 independent experiments. Significance determined by unpaired 2-tailed Student t test. ∗∗∗∗P < .0001. (B) Bar plots comparing CHR-6494 IC₅₀ values in leukemia cell lines. IC₅₀ values determined by dose-response curve with nonlinear regression for each cell line. Data are mean ± SD of 3 independent experiments. Dotted line indicates CHR-6494 IC₅₀ value of healthy CD34⁺ hematopoietic progenitor cells determined in panel A. (C) Bar plots depicting normalized HASPIN sgRNA counts in a genome-wide CRISPR screen in MOLM-13 cells treated with either DMSO or VEN for 8 or 16 days as performed by Chen et al.⁵⁰ Screen data were retrieved from BIOGRID ORCS. Counts were normalized to initial time point (d0). One data point was removed from DMSO (d16) as a significant outlier. Data are mean ± SD. Significance determined by 1-way ANOVA with Holm-Sidak multiple comparison correction. ∗P < .05; ∗∗P < .01. (D) Dose-response matrix (left) and corresponding zero interaction potency (ZIP) drug synergy contour plot (right) of Kasumi-1 cells treated with CHR-6494 and VEN combination for 48 hours. Each cell represents drug combined at indicated concentrations. Treatment response is percent inhibition; higher values indicate lower cell viability. Synergy scores represent ZIP synergy calculations of inhibition effects exceeding values expected between 2 noninteracting agents. Mean synergy scores and significance reported at top of respective contour plot. Representative plots of 3 independent experiments revealed. (E) Dose-response matrix (left) and corresponding ZIP drug synergy contour plot (right) of THP-1 cells treated with CHR-6494 and VEN combination for 48 hours. Each cell represents drug combined at indicated concentrations. Treatment response is percent inhibition; higher values indicate lower cell viability. Synergy scores represent ZIP synergy calculations of inhibition effects exceeding values expected between 2 noninteracting agents. Mean synergy scores and significance reported at top of respective contour plot. Representative plots of 3 independent experiments revealed. (F) Dose-response matrix (left) and corresponding ZIP drug synergy contour plot (right) of OCI-AML3 cells treated with CHR-6494 and VEN combination for 48 hours. Each cell represents drug combined at indicated concentrations. Treatment response is percent inhibition; higher values indicate lower cell viability. Synergy scores represent ZIP synergy calculations of inhibition effects exceeding values expected between 2 noninteracting agents. Mean synergy scores and significance reported at top of respective contour plot. Representative plots of 3 independent experiments revealed. DMSO, dimethyl sulfoxide.