Fig. 5

HSP90 inhibitors and ara-C exert a synergistic effect in killing AML cells. a, b Bar graphs illustrating the inhibition efficacy of ara-C and multiple HSP90 inhibitors (used as single agents or in combination) on a THP-1 cells and b Molm-13 cells following 72-hour exposure. Cell viability was assessed via MTT assay (n = 3). c Combination Index (CI) values for THP-1 and Molm-13 cells treated with ara-C plus IPI-504, PU-H71, or STA-9090. Drug interaction was evaluated using CompuSyn software via the Chou-Talalay method: CI < 1 denotes synergism, CI = 1 indicates an additive effect, and CI > 1 signifies antagonism. d, e Synergistic enhancement of cytotoxicity of other antimetabolites (fludarabine, and clofarabine), when combined with STA-9090, demonstrated in d Molm-13 (n = 3) and e THP-1 (n = 3). f, g Apoptosis analysis in THP-1 cells treated with STA-9090 and ara-C alone or in combination for 72 h. Apoptosis was assessed by flow cytometry after staining with 7-AAD and annexin V (n = 3). g Quantification of apoptosis rates from the experiment in (f). h Apoptosis rates of Molm-13 cells exposed to STA-9090 and ara-C as single agents or in combination for 72 h (n = 3). i Cytotoxicity analysis of shSAMHD1-transduced and control Molm-13 cells treated with ara-C and HSP90 inhibitors either alone or combined for 72 h (n = 3). j Cytotoxicity assay of Molm-13 transduced with exogenous SAMHD1 or empty control treated with ara-C and HSP90 inhibitors alone or in combination for 72 h. Cell viability was measured by MTT (n = 3). Data are shown as mean ± s.d. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001