HHT and IPI504 synergistically induced apoptosis in AML cell lines harboring FLT3-ITD. (A and B) The FLT3-ITD mutant cell lines MV4-11 and MOLM-13 were exposed by HHT (8 nM or 4 nM) and/or IPI504 (0.8 μM or 0.4 μM) for 24 h and 48 h. Cells were harvested and co-stained with Annexin V and PI before apoptosis was analyzed by flow cytometry (mean ± SEM, n=3, *P < .05, **P < .01, ***P < .001). (C) After treated with HHT (8 nM) and/or IPI504 (0.8 μM) for 24 h, MV4-11, MOLM-13 and primary cell lysates were subjected to western blot analysis using the PARP, caspase3 and cleaved caspase3 antibodies, β-actin was displayed as a loading control.